The Adaptive Optics Revolution: A History

The Adaptive Optics Revolution A History

Science  |  History  |  Military

is the historian for the Air Force Research Laboratory’s Directed Energy and Space Vehicles directorates in Albuquerque. He is the author of Airborne Laser: Bullets of Light and Science and Technology: The Making of the Air Force Research Laboratory.

isbn 978-0-8263-4691-9

Author photo: courtesy of Air Force Research Laboratory. Jacket design: Kathleen Sparkes

University of New Mexico Press unmpress.com | 800-249-7737

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Robert W. Duffner

Jacket photo: Courtesy of Robert Q. Fugate. Exploration of the heavens and a fascination with the dynamics of light all started at an early age for Bob Fugate in his backyard in Dayton, Ohio, in 1954. At age 13 he purchased a defective telescope at a local flea market and took it home. There he tore the device apart, made the necessary adjustments, and reassembled it so it worked properly. It was a proud moment for the serious-minded boy scientist sitting in a rickety folding chair guarding his most prized possession. It was also a sign of things to come. Years later, Fugate became a leading scientific expert for the Department of Defense in the up-and-coming fields of laser guide stars and adaptive optics while serving as the Technical Director of Starfire Optical Range in a remote high desert telescope site at Kirtland Air Force Base, New Mexico.

Adaptive optics is the most revolutionary breakthrough in astronomy since Galileo pointed his telescope skyward four hundred years ago. It is critical technology that enables astronomers to answer challenging questions about the universe. Robert Duffner has written a unique history of the invention of laser guide stars and other contributions to adaptive optics made by the Department of Defense. He had access to a large collection of primary source material housed in the offices of government scientists and in the Air Force Research Laboratory’s archives at Kirtland Air Force Base, Albuquerque. Duffner also interviewed seventy-one prominent scientists who played key roles advancing adaptive optics research.

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ver the last four decades, a formidable and persistent team of scientists from the Air Force Research Laboratory, MIT/Lincoln Laboratory, and private contractors led the way in achieving groundbreaking advances in adaptive optics. They demonstrated laser guide star techniques and made adaptive optics practical on large telescopes. The military aggressively pursued the development of adaptive optics for two reasons—imaging of man-made space objects for space situational awareness and laser weapons. A significant part of this research occurred at the Starfire Optical Range in New Mexico and the Maui optical site in Hawaii. The program remained classified during the 1970s and 1980s, but the government declassified it in the early 1990s, enabling significant technology transfer to the astronomy community.

The Adaptive Optics Revolution

Robert W. Duffner

Robert W. Duffner

Foreword by Robert Q. Fugate

4/13/09 9:20:36 PM

The Adaptive Optics Revolution

The Adaptive Optics Revolution

A History

Robert W. Duffner

Foreword by Robert Q. Fugate

University of New Mexico Press  |  Albuquerque

© 2009 by the University of New Mexico Press All rights reserved. Published 2009 Printed in the United States of America 14 13 12 11 10 09    1 2 3 4 5 6 Library of Congress Cataloging-in-Publication Data Duffner, Robert W. The adaptive optics revolution : a history / Robert W. Duffner ; foreword by Robert Q. Fugate. p. cm. Includes bibliographical references and index. ISBN 978-0-8263-4691-9 (cloth : alk. paper) 1. Optics, Adaptive—History. 2. Optics, Adaptive—Research—United States—History. 3. Laser guide star adaptive optics. 4. Lasers—Military applications. 5. Space telescopes. I. Title. TA1522.D84  2009 621.36'9—dc22 2009005843

Book and jacket design and type composition by Kathleen Sparkes. The text in this book was composed with typeface Minion Pro ot 10.5/14, 26p. The display type is Helvetica Neue.

✩ For Rupert and Winifred

Contents Foreword by Robert Q. Fugate  |  ix Preface  |  xiii Introduction  |  xix List of Acronyms  |  xxv

Chapter 1: Sputnik, Reality, and Technology  |  1



Chapter 2: Early Days: The Romans  |  17



Chapter 3: Rome and Itek: First Adaptive Optics Systems  |  41



Chapter 4: Laser Guide Stars  |  65



Chapter 5: Fugate’s Rayleigh Guide Star Experiments  |  89



Chapter 6: Lincoln Laboratory  |  119



Chapter 7: Sharing the Gold: Astronomical Nuggets  |  145



Chapter 8: Strategic Defense Initiative  |  169



Chapter 9: Airborne Laser  |  203



Chapter 10: 3.5-Meter Military Telescope Complex:



Chapter 11: 3.67-Meter Military Telescope Complex:



Chapter 12: Sodium Guide Star Laser: The Future  |  313

Starfire Optical Range, New Mexico  |  237 Maui, Hawaii  |  277

Conclusion  |  339 List of Interviews  |  349 Notes  |  355 Index  |  439

Fore word

Adaptive optics: What is it? Why should I care? For nearly 400 years, astronomers have lived with blurry images of the planets, stars, galaxies, and indeed the universe when looking through their ground-based telescopes. Looking through the atmosphere with a highmagnification telescope is like looking through shower glass with your eye. You can see shapes on the other side of the glass, but you can’t make out any detail—you couldn’t, for example, see people’s faces clearly enough to positively identify them. Earth’s atmosphere acts like a shower glass for astronomers. They can make out shapes, but only with limited clarity. Large telescopes provide two critical ingredients for making new discoveries about the universe: they gather a lot of light, and they have the potential to provide detail and clarity (resolution). Eight-, 10-, and soon-to-be 30-meter class telescopes certainly gather a lot of light, but because of the atmosphere, they only provide the same image detail as an 8-inch telescope in your backyard. The most important science (for example, investigating whether there is carbonbased life on planets outside the solar system) is critically dependent on the fine details. Astronomers are losing out on that science because of the atmosphere. The science lost by observations from the ground was the main justification for building the Hubble Space Telescope—astronomers wanted to get on the other side of the “shower glass,” where a large telescope can

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gather lots of light and provide the resolution they are entitled to based on the laws of optics, not the limits imposed by the atmosphere. In 1953 Horace Babcock, an astronomer at Mount Wilson and Palomar observatories in California, had an idea that would enable astronomers to remove in real time the distortions created by the atmosphere. His idea was revolutionary, since it removed the distortions from the optical waves before they were focused on film in a science camera. Today we call his concept adaptive optics. There are other imaging techniques for getting beyond the limits imposed by the atmosphere. One, still in use today, was to make many very-short-exposure images and process them afterward. This approach is, however, limited to very bright objects. Long-exposure techniques were not effective, because if the telescope’s resolving power was not sufficient, details would not be recorded in the first place. Babcock’s idea was somewhat complicated, and the technology really didn’t exist at the time to support a practical implementation. However, by the mid-1970s, sensors and opto-mechanical devices had matured sufficiently that the first demonstrations of the concept could take place. In 1982, the Defense Advanced Research Projects Agency (DARPA) and the U.S. Air Force put into service the first practical adaptive optical system, called the Compensated Imaging System (CIS), on the 1.6-meter telescope on top of Haleakala on the island of Maui in Hawaii. This system provided the U.S. Defense Department images of bright earth-orbiting satellites at nearly the full resolving power of a 1.6-meter telescope. The goal was to get detailed images of new Soviet satellites on the first or second revolution after their launch. It was a significant step forward to space situational awareness in the Cold War era. Adaptive optics works by analyzing the rapidly changing shape of light waves passing from the subject being imaged through the atmosphere into the telescope. The optical wave distortions are corrected by reflecting the wave off a mirror (called a deformable mirror) whose shape is adjusted to be the opposite of the measured distortion. After reflection off the deformable mirror, the wave shape is restored to what it was before it entered the atmosphere. Adaptive optics thus effectively removes the atmosphere’s distortion. The most obvious source of light waves for analyzing the distortions (most often called the guide star) is sunlight reflected from the subject being

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imaged. However, a serious limitation arises for dim objects: they don’t provide enough light for the adaptive optics sensor (called the wavefront sensor) to make a measurement. It’s all a matter of timing. The wavefront sensor must measure the distortions on the optical wave much faster than the rate at which the distortions are changing. The distorted waves change to a new shape about 100 times per second. However, objects of high scientific interest to astronomers are just too faint to provide enough light to make the required measurements and subsequent corrections to the shape of the deformable mirror in one hundredth of a second. In fact, restricted to using natural stars bright enough for the wavefront sensor to operate adequately, adaptive optics is effective over only 1 percent of the sky—useful but not really adequate. This book tells the story of how a classified U.S. defense research program created a solution called laser guide stars that solves the problem of inadequate numbers of bright natural guide stars. The concept is to create an artificial guide star by pointing a laser beam in the direction of the target to be imaged and using the light backscattered by atoms and molecules in the atmosphere as the source of the light waves for the wavefront sensor. The idea was invented by members of the U.S. defense community during the Cold War era for correcting high-power laser beams directed against an adversary’s satellites. Laser guide star technology is now part of satellite imaging research conducted by the U.S. Air Force. The initial laser guide star experiments were done under a veil of secrecy in special-access programs sponsored by DARPA. The results were kept secret for over 10 years but eventually released to the public and subsequently embraced by the astronomy community. Robert Duffner, an Air Force historian, recognized an important story in the contributions made to adaptive optics by the Air Force and other Department of Defense (DoD) organizations. His detailed research and comprehensive account of the events, people, politics, and security of the DoD’s development of laser guide stars and adaptive optics for large telescopes is recorded in this book. Some astronomers feel that the development of adaptive optics is on a par with the invention of the telescope for producing new science about the universe, and ultimately about where humankind fits in the grand scheme. If you are a technical person interested in the historical events that led to scientific revolution, this book will fascinate you and provide details you Foreword

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can’t find elsewhere. If you are a tax-paying citizen, this book will reveal the positive side of a highly successful military research program and give insight into the dedicated people that made it possible—a view not available in the popular media. Adaptive optics has other civilian, industrial, and scientific applications: human vision research, laser eye surgery, ultra-highbandwidth laser communications between ground and space, and materials processing, to mention a few. These applications have benefited significantly from the accomplishment of the military programs in adaptive optics. This book is “the rest of the story”—a story that Robert Duffner has documented in great and fascinating detail. I highly recommend it to all. Robert Q. Fugate New Mexico Institute of Mining and Technology

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Preface

An important reason for undertaking this project was to assess the contribution of the Department of Defense (DoD) in the relatively new field of adaptive optics. The intent was to capture a history that serves as a bridge between a narrow group of highly specialized scientists and a wider general audience. In the past, the DoD has often been accused of wasteful spending on huge programs extending over decades that ended up going nowhere. That may have been true in many cases, but the question is: Did adaptive optics research represent the other side of the coin? Does it show that DoD did sponsor successful long-term research programs that proved to be revolutionary and produced large military dividends? The government kept this program classified during the 1970s and 1980s, but by the early 1990s much of the secrecy surrounding the new technology had been lifted. This presented an opportunity to write a history as documents became declassified. Moreover, many of these primary source documents were housed in the offices of government scientists and in the Air Force Research Laboratory’s archives in the Historical Information Office at Kirtland Air Force Base. As the historian for the Air Force Research Laboratory’s Directed Energy and Space Vehicles directorates, I had access to this unique collection. One of the essential tasks of a historian is selecting a credible topic to write about. At first glance, that might seem easier said than done. That process does not always lead to a clear-cut decision, taking into consideration

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that at the beginning of a writing project one usually does not have all the facts or knowledge to judge whether a particular topic is worth pursuing. However, after consulting with a number of scientists and others, I became convinced that the story of the development of adaptive optics deserved telling. Not only was there an abundance of primary source documents to examine, but scientists who had participated directly in research programs advancing adaptive optics were available for interviews. As it turned out, I interviewed 73 people (listed at the end of the book), all with different personalities but all sharing the belief that adaptive optics was a revolutionary change. They possessed a wealth of first-hand knowledge and truly were the pioneers of the adaptive optics movement. This account covers one slice of the historical pie, intentionally focusing on the interaction of various military organizations with heavy emphasis on the Air Force laboratory community. Although the relationship between military researchers and private-sector astronomers is addressed, a comprehensive treatment of astronomers’ contributions to adaptive optics—a legitimate subject—is beyond the scope of this book. This book started one hot Albuquerque afternoon with a chance encounter with Bob Fugate, who was about to cross the street in front of the Directed Energy headquarters building on Kirtland Air Force Base. As he stepped off the curb, I yelled, “Bob, do you have a minute?” He turned and squinted to make out who I was, and I could tell he was not anxious to stop and talk, especially about history. I had been leaving messages for him for several weeks to no avail, to try to get an appointment with him to discuss writing this history. Fugate had a strenuous schedule, and he was more interested in making scientific progress in the real world than in reminiscing about the history of his work over the past three decades. Eventually, I got a chance to sit down with Bob Fugate when he called me unexpectedly saying we could get together in his office at the Starfire Optical Range. As it turned out, he had a strong appreciation for the value of history, but his jam-packed schedule gave him little time to reflect on his and his colleagues’ life-long accomplishments relating to the integration of laser guide stars, adaptive optics, and large telescopes. By the time we finished, he supported the idea of a history of adaptive optics. Over the next several years, Fugate was a man of his word. He is recognized throughout the world as one of the leading authorities on adaptive

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optics, and I am grateful for his assistance. I feel fortunate to have worked with him. Once the research and writing got under way, he gave generously of his time and knowledge to make sure I had the right information to capture all parts of the story. I quickly learned he was a stickler for detail. He hunted down too many documents to mention and provided photographs and diagrams to illustrate important concepts and events. From the start he showed extreme patience making complex science and technology understandable. Moreover, he identified individuals I should interview to clarify all types of issues—the roles of different scientists and military and civilian leaders, hardware, budgets, accomplishments and failures, contributions of contractors, government facilities, Air Force missions, relationships with astronomers, and much more. I also thank him for his careful reading of all the chapters and his thoughtful comments. Another pillar of strength was Jim Mayo, an expert on large telescopes, who provided immeasurable insight and technical know-how to keep me focused on getting the facts straight on a complicated subject. He is a unique and very enthusiastic individual with an abiding interest in history. On too many occasions to count, Jim showed up at my office late in the day to check on how things were going and to offer encouragement. He was always willing to make the time to sit down and explain how things worked and to convey to me why and how large telescopes made a substantial difference in adaptive optics. I am grateful to Jim for reading the entire manuscript and offering his many helpful comments. Although Fugate and Mayo head the list of experts to whom I am indebted, many others also provided invaluable information and perspective on adaptive optics, lasers, and large telescopes. At the Directed Energy Directorate, R. Earl Good, L. Bruce Simpson, Gregory J. Vansuch, William E. Thompson, Craig A. Denman, Charles L. Matson, Charles B. Hogge, Edward A. Duff, John R. Kenemuth, Mark A. Kramer, and Lawrence D. Weaver were especially helpful in providing their viewpoints on many technical and people issues. I appreciate their wise counsel, which included pointing out discrepancies and how they could be fixed. A number of military officers and civilian scientists who worked at the Air Force Weapons Laboratory in the 1970s and 1980s, and at Phillips Laboratory in the 1990s, shared their experiences in the development of adaptive optics. Although there are too many to list here, I especially want to thank Preface

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Joseph F. Janni, Leonard John Otten III, John C. Rich, James L. McNally, John J. Russell, Brent L. Ellerbroek, David P. Dimiduk, and Robert F. Walter. To keep me straight on the workings and contributions of Rome Laboratory, I relied on Raymond P. Urtz, Donald W. Hanson, and Thomas W. Thompson. John W. Hardy, who led the early adaptive optics effort at Itek, was incredibly knowledgeable and very gracious, as was Jay Richard Vyce. Especially helpful in explaining the contributions of Lincoln Laboratory were Darryl P. Greenwood, Louis C. Marquet, Charles A. Primmerman, Charles Higgs, Daniel V. Murphy, and Thomas H. Jeys. I am grateful to J. Roger P. Angel, who gave me an eye-opening tour of his large telescope mirror manufacturing facility under the football stands at the University of Arizona, and equally thankful to William “Will” Happer at Princeton University for sharing his experiences as a Jason, as well as how he came up with the sodium laser concept. James C. Wyant, at the University of Arizona, took time to explain the contribution of his white shearing interferometer. At the national level, a number of key leaders who influenced the course of adaptive optics offered their candid comments on the pros and cons of the program. James A. Abrahamson, the former director of the Strategic Defense Initiative Organization (SDIO), made time to meet with me and underscored the importance of adaptive optics and its application to potential future laser weapon systems. Rettig Benedict Jr. and Thomas W. Meyer, two well-informed individuals who worked at SDIO and DARPA in the area of directed energy, clarified where adaptive optics fit into the big scheme of strategic and tactical planning. The following influential leaders also helped: Anthony “Tony” J. Tether, who served as the DARPA director; Paul D. Nielsen, commander of the Air Force Research Laboratory; Donald L. Lamberson and John R. Albertine, members of the Air Force Scientific Advisory Board; Ronald M. Sega, formerly assigned to the Office of the Director, Defense Research and Engineering; Lester L. Lyles, former commander of the Air Force Materiel Command; Ralph E. Eberhart, former commander of Air Force Space Command; and former Secretary of the Air Force James G. Roche. All concurred that adaptive optics was a revolutionary enabling technology destined to have a positive effect on Air Force missions of today and tomorrow. Also, G. Wayne Van Citters from the National Science

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Foundation put into perspective how military work on adaptive optics was relevant to astronomers. I would be remiss not to mention the major contractors that made enduring contributions over the years to the design, construction, and operation of a variety of telescopes and adaptive optics systems. I spent a rewarding afternoon in Massachusetts with Mark A. Ealey, president of Xinetics Inc., listening to his fascinating explanation of how deformable mirrors evolved. I spent an invigorating morning in California with David L. Fried, founder of the Optical Sciences Company, who amazed me with his memory—and his meticulous filing system, filled with records documenting the brightest individuals and most successful experiments advancing adaptive optics. I also spent several hours with Fried’s successor, Glenn A. Tyler, president of the Optical Sciences Company, who described the importance of adaptive optics to the Airborne Laser. Also, I am grateful to Kenneth W. Billman at Lockheed Martin, who shared his experiences and perspective on the Airborne Laser. Rene Abreu, formerly of Hughes Danbury Optical Systems and later with the Goodrich Corporation, provided information on the design, fabrication, and integration of the adaptive optics system with the 3.67-meter telescope on Maui. Rusty Hughes, of Trex Enterprises, the troubleshooter for the Maui adaptive optics system, enlightened me on the day-to-day operation of this sophisticated and sometimes temperamental piece of hardware. Three other participants who had a solid grasp of the twists and turns of the history of adaptive optics were Robert S. Cooper, of Titan Systems Corporation; Richard A. Hutchin, chief executive officer of the Optical Physics Company; and James E. Pearson, formerly of Hughes Research Laboratory and United Technologies Optical Systems. Several historians read the manuscript and offered helpful suggestions. I thank Donald R. Baucom for his knowledgeable and insightful perspectives about science and technology in the Department of Defense and the Air Force. Lawrence R. Benson presented solid commentary, especially on chapter 1. I am indebted to Daniel F. Harrington (Air Combat Command) for sharpening his editorial scalpel and applying it to every chapter in the manuscript. At the Air Force Research Laboratory’s (AFRL) Corporate Information Office at Kirtland, Michael D. Pietryga, Carlos A. Fernandez, and Stephen T. Martinick smoothed the way through the government chain of command to allow me to complete this work. They understood the value of this project Preface

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and offered their steady support. They gave me the time, freedom, and travel budget to interview key individuals throughout the country. I thank everyone in the AFRL Historical Information Office at Kirtland for their professionalism and support. They include Danielle E. Fraley, Kevin R. Ruybal, Stephen F. Watson, Barron K. Oder, Sylvia A. Pierce, and Rhonda O. Toba, who performed a variety of services that contributed to the final product. Also, I appreciated all the prompt responses from the staff of the AFRL Technical Library at Kirtland, especially those provided by Maryhelen Jones, Elizabeth Luebchow, Sandy Pacheco, and Maggie Cinnella. Danielle E. Fraley and Kevin R. Ruybal, two exceptionally hard-working University of New Mexico students, deserve special gratitude. In the early stages of this project, Danielle developed and organized over 220 subject files. And she built and tailored several databases to make it possible to quickly access the documents, articles, notes, photographs, schematics, fact sheets, and more contained in a comprehensive filing system. These files grew exponentially over the years and became the core source material for the book. In the latter stages of formatting the manuscript, Kevin proved to be a reliable and indispensable worker. He scanned all the photographs and schematics to provide high quality illustrations for the book and carefully checked 795 citations. When questions arose on historical details, Kevin conducted thorough searches and always found documents to corroborate or refute facts in question. Finally, I am grateful to the University of New Mexico Press, especially to its editor-in-chief, W. Clark Whitehorn, for his refreshing open-mindedness and steady support of this project. Adaptive optics is different from most topics the Press publishes, and I am thankful to Clark for seeing this as an opportunity to present an unusual subject with a strong connection to the history of science and technology in New Mexico. I appreciate the editorial improvements Maya Allen-Gallegos and her staff made in transforming the manuscript into a final product. Also, I have been extremely fortunate in the assistance I received from Amanda Morgan, the copyeditor, who made valuable suggestions throughout this book. Her superb editorial skills and meticulous attention to detail reduced unruly sentences to their essence and improved the quality of the storyline. A special thanks to Richard W. Schuetz for his constant support and interest.

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Introduction

Adaptive optics is the most revolutionary technological breakthrough in astronomy since Galileo pointed his telescope skyward to explore the heavens 400 years ago. The recent marriage of large ground-based telescopes capturing huge amounts of light with advanced adaptive optics technology has resulted in spectacular high-resolution images of objects in space that most scientists only a few decades ago would not have dreamed possible. Today, telescopes equipped with adaptive optics allow astronomers and other scientists to look deeper into the universe than ever before. The Department of Defense led the way in the development of adaptive optics by funding research programs carried out primarily at Air Force laboratories over the last 40 years. The military needed to collect sharp images of satellites, missiles, reentry vehicles, and space debris to support its space object identification mission. It also wanted to use adaptive optics to compensate laser beams propagating from the ground through the atmosphere to intercept satellites and missiles in space. Research on compensated laser beams was needed before any laser weapon system would be able to effectively engage satellites and missiles in space during a future conflict. Astronomers have relied on telescopes to survey the heavens for hundreds of years. Hans Lippershey (1570–1619) of Holland is credited with inventing the telescope in 1608. Almost immediately, Dutch officials at the highest level of government recognized the potential military application

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of Lippershey’s invention and asked him if he could build a binocular telescope; such a device would be a tremendous advantage on the battlefield. But the Italian Galileo Galilei (1564–1642), a mathematics professor at Padua, constructed his own telescope in 1609, which performed much better than Lippershey’s. One of the reasons for the success of Galileo’s telescopes was that he had learned how to grind and polish his own lenses using higher quality glass. At the time he was the finest lens maker in all of Europe. His first lenses, not quite 2 inches in diameter, worked well enough to allow Galileo to observe planets, craters on the moon, spots on the sun, the moons of Jupiter, stars of the Milky Way, and other celestial bodies. The images collected by Galileo’s first telescope appeared about nine times larger than those observed by the naked eye. Galileo attracted considerable attention because he was the first to describe the images he viewed through his telescope in writing, in a pamphlet called The Starry Messenger, published in 1610. His astronomical observations challenged the long-held belief that the Earth was the center of the universe, as espoused by the Greek philosopher Aristotle (384–322 BC), the Greek astronomer Ptolemy (AD 83–161), and others. Armed with empirical observations of the sun, planets, and stars provided by his new telescope, Galileo became an ardent supporter of the Polish astronomer Nicholas Copernicus’s (1473–1543) heliocentric theory that the sun was the center of the universe and the Earth moved around it. Although his scientific findings were correct, the Roman Catholic Church condemned Galileo and branded him a heretic for challenging the conventional teaching that the Earth was the center of the universe. Galileo fitted two lenses inside the lead tube of his simple refractive telescope. He positioned a small concave lens at the end closest to the observer’s eye and a larger convex lens at the opposite end. These lenses were small and of poor quality by today’s standards; the larger measured only 4.4 centimeters (1.7 inches) in diameter. The magnification power of his telescopes increased to 8, 20, and eventually 30. However, the clarity of fine detail (resolution) of objects viewed through Galileo’s telescope was limited by the inferior optical quality of his lenses. Telescopes slowly evolved from using small refracting lenses to larger reflecting mirrors to collect and focus light. In a refracting telescope like

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Galileo’s, light rays pass through a lens, which bends (refracts) and focuses the light rays to a point to form an image. How much the light is bent depends on the density of the medium (such as air, water, or glass) through which the light passes and on the wavelength of the light (shorter light waves bend more than longer waves). Reflecting telescopes, on the other hand, use curved or parabolic mirrors to focus light to form an image. The largest telescopes today are reflective.1 Galileo’s telescope was not big enough for atmospheric turbulence to be a problem in terms of distorting images. It was not until the Englishman Isaac Newton (1643–1727) built a reflecting telescope in 1668 that telescopes became large enough in diameter and high enough in quality to be vulnerable to turbulence. By 1730 the Scotsman James Short (1710–1768) had invented the parabolic reflecting telescope, and by 1789 Sir William Herschel (1738–1822) had constructed a reflecting telescope with a 4-foot diameter mirror. In spite of these advances, the problem of atmospheric turbulence remained because bigger telescopes encountered a larger viewing area of atmospheric turbulence and, therefore, collected more distorted light than smaller telescopes. In the last four decades, adaptive optics has emerged as the most advanced technology for generating images of space objects. Every major new telescope in the world today is equipped with adaptive optics, and many older reflecting telescopes—and some refracting telescopes—are being retrofitted with adaptive optics. Adaptive optics has revolutionized the telescope, transforming it into an extraordinarily precise optical instrument capable of generating extremely sharp images. That transformation has occurred thanks to the giant strides made by DoD research programs in the development of the basic components of an adaptive optics system—laser guide stars, wavefront sensors, high-speed computer processors, and deformable mirrors— that have made it possible for large ground-based telescopes to remove distortions from light waves and produce images with resolution at or near the limits set by the laws of physics. Today’s computer-controlled telescopes equipped with adaptive optics can view stars and galaxies 500 million times fainter and with 2,000 times more resolution than the unaided eye can see. Large telescopes cannot produce high-resolution images without the help of adaptive optics. A basic physics formula explains why large telescopes Introduction

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need adaptive optics to compensate light to produce high-resolution images and to compensate laser beams to make them of high quality and powerful enough to disable a target.

The Resolution Formula A telescope’s ability to detect fine detail in an object at a distance is defined as resolution or resolving power and is governed by the formula R=λ/D, where R is the angle in radians between two resolved objects, λ (lambda) is the wavelength in meters of the incoming light received by a telescope, and D is the diameter in meters of the telescope’s primary light-collecting mirror. Resolution can be thought of as the ability of an imaging system to make a clear distinction between close but separate objects. The formula shows that resolution is inversely proportional to the size of the telescope’s aperture or primary mirror. The bigger aperture results in a smaller resolution number, which translates to higher resolution or a sharper detailed image. A 13-centimeter (5-inch) telescope resolves detail as small as about 1 arc-second (1/3,600 of a degree) at visible wavelengths, which is very good resolution. One arc-second is approximately the angular size of a quarter viewed from 3 miles away, so at that distance, an observer with such a telescope could just barely distinguish two quarters placed an inch apart. In comparison, a 1.3-meter (4.3-foot) aperture theoretically has a higher resolution—about 0.1 arc-second at visible wavelength, which would allow one, for example, to easily distinguish heads from tails on the quarters at the same range. A telescope with a 10-meter (10.9-yard) aperture can resolve detail as fine as 0.013 arc-second, enough to read the letters on the quarter spelling out “IN GOD WE TRUST.”2 Bigger telescopes can also see fainter objects. The light-gathering ability of a telescope is determined by the area of its primary mirror, enabling bigger mirrors to see fainter objects. The starlight collected by a telescope decreases as the square of its distance from the star, but increases as the collecting area of the telescope’s primary mirror increases (proportional to the square of the mirror’s diameter). This means the maximum distance at which a telescope can detect a light source increases linearly with the telescope’s diameter. If a 1-meter telescope can detect a star of a certain

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brightness at distance X, then a 4-meter telescope would be able to detect a star of the same brightness at a distance of 4X. If a 1-meter telescope can detect a galaxy at a distance of one billion light years, a 10-meter telescope could detect a similar galaxy 10 billion light years away. Another way of conceptualizing this is that doubling the diameter of a telescope’s primary mirror results in being able to see an object in space that is only 25 percent as bright as observed by a mirror half as big. For example, at the same distance, a 2-meter telescope can see a star of a given brightness but a 4-meter telescope can see a star that is only one-fourth as bright. Doubling the diameter of a telescope’s primary mirror quadruples its area, which in turn quadruples the amount of light the telescope can receive from a celestial object. This is where atmospheric turbulence becomes a problem. Although bigger telescopes can collect more light and thus detect fainter objects, their ability to resolve fine detail is reduced dramatically by turbulence-induced distortion, which causes a 10- or 30-meter telescope to produce the same fuzzy image as a smaller backyard telescope. Turbulence affects larger telescopes more seriously than smaller ones. And this is where adaptive optics becomes important. The new technology makes it possible to compensate for those distortions and allow large telescopes to achieve the resolving power the formula says they can based on their diameter, namely λ/D. Adaptive optics allows the best of both worlds—maximum resolving power and maximum ability to detect faint objects. It helps cancel out the damaging effects of atmospheric turbulence by unscrambling distorted light received at a telescope to produce the best possible images allowed by the laws of physics. A bigger telescope’s adaptive optics system will produce higher-resolution images of objects viewed at the same range as a smaller telescope with a comparable adaptive optics system. NASA built the Hubble Space Telescope to operate in the vacuum of space to avoid the effects of the Earth’s atmosphere. Launched in 1990, Hubble eventually achieved the resolving power of its 2.4-meter aperture, approximately 12 times that of the same size telescope on the ground. NASA plans to deploy a follow-on to Hubble, the 8-meter James Webb Space Telescope, in 2013. The largest modern ground-based telescopes, equipped with adaptive Introduction

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optics, under the right conditions, are producing higher-resolution images than the Hubble Space Telescope. Space telescopes will continue to take advantage of other unique features offered only by space platforms, such as low background infrared, wider corrected fields of view, and ability to observe at wavelengths that are severely absorbed or not transmitted at all by the atmosphere. Future space-based and next-generation ground-based telescopes with adaptive optics are likely to complement each other in producing scientific discoveries in the years ahead. Although adaptive optics is a major breakthrough, it represents only the beginning of a scientific revolution. All signs indicate that over the next 20 years adaptive optics will surpass its current level of performance to generate the best images scientists have ever been able to capture.

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List of acronyms

AAS American Astronomical Society ABL Airborne Laser ABLE ACE Airborne Laser Extended Atmospheric Characterization Experiment ABLEX Airborne Laser Experiment ACE Atmospheric Compensation Experiment ACT Advanced Concepts Testbed ADONIS AMOS Daytime Optical Near-Infrared Imaging System AEOS Advanced Electro-Optical System AFRL Air Force Research Laboratory AFSC Air Force Systems Command AFSPC Air Force Space Command AFWL Air Force Weapons Laboratory ALL Airborne Laser Laboratory AMOS ARPA Maui Optical Site APRA Midcourse Optical Observatory Station ARPA Midcourse Observation Station Air Force Maui Optical Station Air Force Maui Optical Site Air Force Maui Optical and Supercomputing Site APAC astral point ahead compensation ARPA Advanced Research Projects Agency (see also DARPA)

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ARS active ranging system ARTO Advanced Radiation Technology Office BILL beacon illumination laser BMDO Ballistic Missile Defense Organization BUPRL Boston University Physical Research Laboratory CCD charge-coupled device CIA Central Intelligence Agency CIS Compensated Imaging System CLASP Closed-Loop Adaptive Single Parameter COIL chemical oxygen iodine laser DARPA Defense Advanced Research Projects Agency (see also ARPA) DDR&E Director, Defense Research & Engineering DE Directed Energy (AFRL Directorate) DEER Directed Energy Experimental Range DELTA Drone Experiment Laser Test and Assessment DoD Department of Defense FAA Federal Aviation Administration fasor frequency addition source of optical radiation FFRDC Federally Funded Research and Development Center FSSS Future Security Strategy Study FTT Field Test Telescope GBFELTIE Ground-Based Free Electron Laser Technology Integration Experiment GEN I Generation I Closed-Loop Experiment GEN II Generation II Closed-Loop Experiment GEODSS Ground-Based Electro-Optical Deep Space Surveillance HARP High Altitude Reconnaissance Platform HoPE Horizontal Path Experiment ICBM intercontinental ballistic missile IDA Institute for Defense Analyses IRST infrared search and track LAAT Large Aperture Acquisition Telescope LACE Low-Power Atmospheric Compensation Experiment laser light amplification by stimulated emission of radiation

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LDEF LFAT LITE maser

MDA MHPCC MIT MOMS MPM MSSC MSSS NASA Nd:YAG Nd:YLF NOAO NoDyCE NOP NRO NSF OCULAR PA&E PL PSSC PZT RADC RAND RME RPAC RTAC SAB SAGE SAM SDI SDIO

Long Duration Exposure Facility Large Field Acquisition Telescope Laser Integration Technology Program microwave amplification by stimulated emission of radiation Missile Defense Agency Maui High Performance Computing Center Massachusetts Institute of Technology mobile optical measurement system monolithic piezoelectric mirror Maui Space Surveillance Complex Maui Space Surveillance System National Aeronautics and Space Administration neodymium: yttrium aluminum garnet neodymium: yttrium lithium fluoride National Optical Astronomical Observatory Non-cooperative Dynamic Compensation Experiment North Oscura Peak National Reconnaissance Office National Science Foundation Optical Compensation of Uniphase Laser Radiation program analysis and evaluation Phillips Laboratory Physical Science Study Committee lead zirconate titanate Rome Air Development Center Research and Development Relay Mirror Experiment ray point-ahead compensation Real-Time Atmospheric Compensation Air Force Scientific Advisory Board Semiautomatic Ground Environment surface-to-air missile Strategic Defense Initiative Strategic Defense Initiative Organization

List of Acronyms

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SFG sum frequency generation SOML Steward Observatory Mirror Laboratory SOR Sandia Optical Range Starfire Optical Range SWAT Short-Wavelength Adaptive Techniques THAAD Theater High Altitude Area Defense TILL track illumination laser TRAPAF Target Return Adaptive Pointing and Focus USSPACECOM U.S. Space Command USSTRATCOM U.S. Strategic Command WDD Western Development Division WIYN Wisconsin, Indiana, Yale National Optical Astronomy Observatory XLD Experimental Laser Device Yb:YAG ytterbium: yttrium aluminum garnet

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Sputnik, Reality, and Technology

Military research on adaptive optics originated in a small Department of Defense research and development organization known as the Advanced Research Projects Agency or ARPA. That organization pursued cutting-edge research beginning in the 1970s that led to the development of sophisticated adaptive optics technology that supports a variety of military and astronomical systems today. Without ARPA’s financial backing and encouragement, it is unlikely that rapid progress in adaptive optics would have been possible. To understand why ARPA was set up in the first place to support defense research programs, one must return to the 1950s. At that time, volatile political circumstances threatened to disrupt the military balance of power between the United States and the Soviet Union. President Dwight D. Eisenhower’s decision to establish ARPA on 7 February 1958 (by way of DoD Directive 5105.15 and Public Law 85–325, dated 12 February 1958) was a direct response to the Soviet Union’s dramatic launch of the world’s first man-made satellite, Sputnik I, on 4 October 1957. A metallic ball weighing only 184 pounds and measuring about 23 inches in diameter, which circled the earth every 96 minutes at a speed of 18,000 miles per hour in an orbit 550 miles out in space, Sputnik marked the start of the modern space age. It shocked the world and, rightly or wrongly, convinced the U.S. government and the public that the Soviets were far ahead

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Photo 1. From the roof of Boston University’s Physical Research Laboratory

building, scientists tracked the first Sputnik across the night sky. In back, left to right: Bill Britton, Jim Chadderdon, Grant Ross, Joe Vravel, Bill Attaya, and Ray Babcock; Harold Alpaugh in the foreground.

of the Americans in the space race. America’s prestige reached a low point in 1957. Using Sputnik I as their Cold War ace card in the hole, the Soviets took full advantage of every opportunity to remind the world of the superior expertise of the gifted scientists who were responsible for this amazing technical feat.1 The Soviets were not simply engaged in idle talk. Barely 29 days had elapsed since Sputnik I began bleeping across the heavens when the Soviets staked another claim to technological supremacy in space. To add political insult to technological injury, the launch of Sputnik II on 3 November 1957 was even more spectacular, as its payload (1,121 pounds) weighed more than six times that of Sputnik I. Americans winced when they learned that the second Sputnik also carried a live dog, named Laika, suggesting the Soviets already had a program under way to put a man in space.2

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Photo 2. The first U.S. photograph of Sputnik I—the world’s first artificial

satellite, which ushered in the Space Age. The dotted line of light represents the satellite’s path. Photo taken by a team of Boston University scientists.

This was a brutal blow to the Americans in the opening round of an international prizefight that would ultimately decide who would reign in space. The triumphant launch of two consecutive Soviet satellites into orbit—followed by Sputnik III, a 2,914-pound geophysical satellite launched on 15 May 1958—sent a message that the Russians had outpaced the United States in developing the capability to build boosters with enough thrust and lift capacity to place heavy objects into orbit.3 Even prior to the launch of Sputnik I, on 26 August 1957, the Soviet Union had announced it had successfully test-fired the world’s first intercontinental ballistic missile (ICBM), dubbed the R-7. The Soviet Union was ahead of the United States in the missile race. What worried top Pentagon officials was the possibility that the Soviets might launch ICBMs into space loaded with nuclear weapons that could reach targets in the United States. Sputnik had ushered in the space race, but at the same time, in the eyes of American military leaders, it had accelerated a dangerous arms race.4 Sputnik, Reality, and Technology

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In reality, the U.S. space program did not lag appreciably far behind the Soviet Union’s. In fact, the American program was ahead of the Soviets in many core areas such as microelectronics, computers, guidance systems, sensors, solid fuels, nuclear warhead design, and survivability of systems. But Soviet development of reliable and powerful launch vehicles—specifically ICBMs—caused the United States to stumble momentarily, which gave the impression to the public that the country was in deep trouble. Top DoD officials were aware ahead of time that the Soviets were about to launch their first satellite. But that knowledge, shared by a relatively small group, did little to calm the fears and emotions of the majority of the people who believed that communism was on the verge of trumping the democratic way of life. As Walter A. McDougall wrote in his Pulitzer Prize-winning history of the space age, “As it happened, the public outcry after Sputnik was ear-splitting.” The press fueled these worries by reporting Sputnik as the Pearl Harbor of American science. The psychological effect of Sputnik on the American public was huge.5 Faced with this crisis, the United States realized it had to reform its educational system, perceived to be weak and complacent, by placing more emphasis on science and technology so that the universities could turn out a larger pool of disciplined scientists, mathematicians, and engineers. These talented individuals would manage multidimensional research and development activities in America’s modern aerospace companies and government laboratories. Everyone agreed that the United States had to reestablish the importance of math and science in the minds of all Americans if the nation was going to be able to deal with the rising Soviet threat.6 A renewed interest in building stronger math and science curricula reached down into high schools across the country. A year before the launch of Sputnik, a group of concerned university professors and high school teachers formed the Physical Science Study Committee (PSSC) at the Massachusetts Institute of Technology. The goal of PSSC was to develop a new high school physics course and textbook to get more young Americans interested in physics. Over time more money, provided primarily through the National Science Foundation, found its way to support PSSC’s mission. One student who participated in the newly designed PSSC high school physics course was Jim Mayo, a Memphis teenager who went on to spend over four decades of his career in the field of optics working for the Air

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Force and private industry. He later vividly remembered signing up as a youngster for one of only two PSSC high school physics courses offered in Tennessee. This positive educational experience persuaded Mayo to pursue a career in science. He recalled the new PSSC physics course “was driven almost entirely by Sputnik.”7 Once the cosmic dust of Sputnik had settled, cooler heads prevailed after taking time to analyze the long-term significance of this Soviet first. Many pointed out that the United States and the Soviet Union had planned to launch civilian satellites for scientific purposes as part of International Geophysical Year activities in 1957–1958. Looking back with the benefit of over 50 years of hindsight, the argument could now be made that the United States should have been more aggressive in placing its first satellite in orbit. But at the time, it seemed the government’s plan was on schedule to launch a research satellite as part of its Vanguard program for the International Geophysical Year.8 Dr. James R. Killian, president of the Massachusetts Institute of Technology, appointed a month after Sputnik I as special assistant to the president for science and technology, concluded America had not failed and was not as vulnerable as many people suspected. He was confident the United States would be able to put its first satellite up soon. As he was quick to remind people, “The Army Ballistic Missile Agency had demonstrated in a test firing of its Jupiter C [rocket] on 20 September 1956, that it could probably have put a satellite into orbit ‘on that day.’” The Jupiter-C had climbed to 682 miles, easily a high enough altitude to place a satellite into orbit.9 Killian’s words may have been correct, but they provided little comfort to the millions of Americans worried about the fact that the Soviets had beaten the United States into space. Many believed there was a huge “missile gap.” To counter the impression that America was falling behind, Eisenhower’s secretary of defense, Neil H. McElroy, directed the military services on 8 November 1957 to launch an American satellite as soon as possible. Scrambling to restore its preeminence in science, the United States attempted on 6 December 1957 to launch a Navy Vanguard rocket and place its first satellite into space. That effort ended in disaster as the Vanguard blew up on its launch pad while millions of anxious Americans watched on television. The scattered remains of the charred rocket showed that the United States had a long way to go to perfect the reliability of its launch vehicles.10 Sputnik, Reality, and Technology

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Failure to launch Vanguard prompted Secretary McElroy to resurrect Project Orbiter, an Army program headed by Major General John Bruce Medaris to develop intermediate-range ballistic missiles, which focused on advancing the Jupiter missile. Wernher von Braun headed a scientific team that worked on this project at the Army Ballistic Missile Agency, located at Redstone Arsenal in Huntsville, Alabama. In late 1956, Secretary of Defense Charles E. Wilson had made the decision to give the Air Force control over development of intermediate-range missiles, specifically the Thor missile. As part of this move, the Army was limited to working on missiles with a range of 200 miles or less. However, after the Vanguard catastrophe, McElroy was anxious to reconsider the Army’s missile program in the hope that von Braun’s team would quickly get a reliable missile ready to boost America’s first satellite into space.11 America’s space picture was not as bleak as many had envisioned. Four months after the launch of Sputnik I, on 31 January 1958, the Army’s fourstage Jupiter-C rocket—which used a modified Redstone missile as its first stage—lifted off an hour and twelve minutes before midnight from launch pad 5 at Complex 56 at Cape Canaveral and boosted the nation’s first satellite, Explorer I, into orbit. America’s first satellite had been built in just 84 days, in an effort led by William H. Pickering, director of the Jet Propulsion Laboratory at the California Institute of Technology in Pasadena. The weight of the Explorer I satellite instrumentation contained in the tip of the fourth-stage Sergeant empty rocket casing totaled 18 pounds. Explorer I was tiny in comparison with Sputnik I and II.12 The U.S. launch restored pride in America’s fledging space program and reassured critics that the United States was capable of meeting the Soviet challenge. However, the more enduring legacy of Explorer I was its discovery and initial measurement of the Van Allen belts of intense cosmic radiation circling the Earth (named after physicist James A. Van Allen from the University of Iowa). Not until almost a year later, on 18 December 1958, did the Air Force place its first satellite into orbit with an Atlas booster. Known as SCORE, for Signal Communications by Orbital Relay Equipment, it was the nation’s first communication satellite and beamed back to millions of Americans a tape recording of President Dwight D. Eisenhower’s Christmas message of peace and good will throughout the world. That was the first time a human voice had been heard from space.13

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Photo 3. Explorer I, America’s first satellite, launched on 31 January

1958. The photo shows the Sergeant fourth-stage rocket that made up the satellite. The forward half of the 6.6-foot long scaled-down version Sergeant rocket housed the satellite instrumentation (temperature sensors, two transmitters and a Geiger-Mueller counter to detect cosmic rays), which was attached to the lower half of the Sergeant rocket casing. The instrumentation section and lower rocket casing— the inert fourth stage that had expended all its fuel—combined to operate as a single satellite unit. To provide stability, the Sergeant rocket spun around its long axis at 750 revolutions per minute. The wispy tentacles protruding from the center of the rocket were antenna wires that made up part of the satellite’s communication system, which sent data to tracking stations on the ground. Explorer I continued to operate until its batteries died on 23 May 1958; it continued to orbit until 1970.

Sputnik, Reality, and Technology

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The success of Explorer I opened the door for the U.S. government and American scientific community to accelerate a plan to use satellites as reconnaissance vehicles to take pictures from space of Soviet missile sites, airfields, submarine and ship staging areas, rail yards, communication centers, and a variety of other targets. A year before Sputnik, the United States had relied on high-flying aircraft to carry out deep-penetration reconnaissance missions over Soviet territory. In late 1954 Eisenhower had authorized the controversial program using U-2 reconnaissance aircraft (U stood for utility) to gather aerial intelligence under the direction of the Central Intelligence Agency (CIA), a civilian organization. U-2 overflights of Soviet territory started on 4 July 1956. (Prior to the U-2s, American RB-47 aircraft conducted a limited number of reconnaissance overflights of Soviet territory to determine the size of the Soviet strategic bomber force.) Eisenhower chose the CIA over the Air Force because he believed having military pilots fly over the Soviet Union would be an act of war. Consequently, pilots who wanted to fly the U-2 had to resign from the Air Force and revert to civilian status temporarily while working for the CIA.14 The president soon found himself on the horns of a dilemma. On the one hand, the spy flights over Soviet airspace violated international law and ran the risk of starting a war. On the other hand, the U-2 provided valuable intelligence, including detailed photos of Soviet missile launch sites, such as the SS-6 ICBM site at Tyuratam. Flying at an altitude of over 70,000 feet— 20,000 feet out of range of Soviet surface-to-air missiles—with a 36-inch folded camera in its nose, the U-2 demonstrated the value of high-altitude reconnaissance. But the fear remained that the Soviets would eventually be able to advance their radar systems to detect and track it.15 After twenty-seven successful U-2 missions, this fear came true when a Soviet SA-2 surface-to-air missile brought down Gary Francis Powers’s U-2 aircraft on 1 May 1960 near the city of Sverdlovsk in western Russia. The Russian missile did not score a direct hit but exploded near the rear of the aircraft, causing it to spiral out of control and crash. Powers bailed out and was captured by a small group of Russian farmers. Soviet Premier Nikita Khrushchev gave a scorching denunciation of the United States at the summit meeting that began in Paris on 16 May and demanded an immediate apology from Eisenhower. The American president declined to

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issue a formal admission of guilt but announced there would be no more U-2 flights over the Soviet Union.16 The U-2 program had left an enduring legacy. One of its most compelling results was to verify that there was no “bomber gap”—the Russians did not have a lead over the United States in terms of the number of intercontinental bombers capable of delivering nuclear weapons. Eisenhower and his advisors were less certain of the progress the Soviets had made in missile development.17 Several years before Powers’s fateful flight, the Air Staff had decided to pursue development of a secret Air Force satellite reconnaissance program called weapon system WS-117L, officially the Advanced Reconnaissance System. General Operational Requirement No. 802, issued by the Air Force in late 1954, initiated preliminary studies. Originally, the Wright Air Development Center at Wright-Patterson Air Force Base in Dayton, Ohio, managed the program. But on 10 October 1955, Air Research and Development Command reassigned the program to Major General Bernard A. Schriever’s Western Development Division (WDD), which had been activated on 1 July 1954 in Inglewood, California, with responsibility for developing the nation’s first ICBM force. (In 1955, WWD moved to permanent quarters in El Segundo, and on 1 June 1957 it was renamed the Air Force Ballistic Missile Division.) The WS-117L transfer was a better fit with WDD because ICBM boosters eventually would be needed to launch reconnaissance satellites into orbit. With the transfer, WDD became responsible for developing the first military satellite system. From that point on, the development of satellites and missiles were linked together.18 To a large degree, the origins of WS-117L went back to a series of RAND studies starting in 1946 that looked at the feasibility of using satellites as reconnaissance platforms to collect intelligence on the Soviet Union’s military capability. Critics argued that a military satellite program would be far too costly and technically impossible. However, over a decade later, in January 1958, the president approved CORONA—this country’s first operational spy satellite program—to move forward as a joint CIA/Air Force program. To make this happen, the space photographic mission was separated from WS-117L and became the core of the covert CORONA program. Developing a more secure satellite reconnaissance system to replace the more vulnerable U-2 was one of the fundamental goals of CORONA.19 Sputnik, Reality, and Technology

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The CIA, with Eisenhower’s approval, took the lead in acquiring and developing imaging equipment and selecting targets to be photographed. Some friction and resentment existed between the CIA and Air Force as the CIA—responsible for the technical development of the imaging equipment for CORONA—emerged as the dominant player under this dual but unequal and informal management arrangement. However, in spite of their disagreements, the CIA and Air Force tried to work as a coordinated team to make the program a success. In reality, the struggle over control of CORONA continued as the Air Force felt it should play the leading role in directing the program. To end the squabbling, the National Reconnaissance Office (NRO) was established in September 1961 to manage all U.S. reconnaissance projects, including CORONA. Joseph Charyk, a former undersecretary of the Air Force and NRO’s first director, reported directly to the secretary of defense. CORONA lasted for 14 years and launched 145 satellites that produced 800,000 images before the program shut down in May 1972. Although CORONA ended, the U.S. satellite reconnaissance program did not. CORONA’s successors developed and deployed increasingly sophisticated space imaging systems that form an integral part of the U.S. national security structure today.20 Eisenhower chose Richard M. Bissell Jr., who was special assistant to the director for planning and development at the CIA, to manage the CORONA program. Brigadier General Osmond Ritland, who was General Bernard Schriever’s vice commander at the Air Force Ballistic Missile Division in Los Angeles, headed the Air Force portion of CORONA and worked closely with Bissell. Bissell was a logical choice because in 1954–55 he and Kelly Johnson, of the now famous Lockheed “Skunk Works” in California, were the catalysts for the successful development of the U-2, which went from concept to operation in a record 18 months. Lockheed also served as the prime contractor for CORONA.21 Two options seemed plausible for getting satellite reconnaissance images of ground targets back to Earth. One involved taking images using television cameras and then transmitting the video. A disadvantage was that the atmosphere could disrupt transmission of TV signals, resulting in poor images. The second method involved using cameras developed by Itek and Fairchild that recorded images on film designed by Eastman Kodak for use in space. At a predetermined point in orbit, the film would be ejected from the satellite

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in a container attached to a parachute. On its way down over the Pacific Ocean, the capsule carrying the film would be caught by an Air Force cargo aircraft—in the first years of CORONA a C-119 Flying Boxcar, later a C-130 Hercules. The air recovery crew used a trapeze-like frame extending from the rear of the aircraft to snag the capsule and winch it onboard. Then the film would be delivered back to base. CIA analysts would immediately examine the film to gain the most up-to-date intelligence on Soviet military facilities. Because electronic imaging technologies had not yet been fully developed, Eisenhower in January 1958 chose the film option, and it lasted until electronic imaging became more workable in the 1960s.22 The first attempts to snag the film capsules in midair, between February 1959 and July 1960, all ended in failure. Problems with four solid-propellant spin rockets caused the film capsules to veer off course, entering a different orbit and not reentering the atmosphere. Once engineers fixed that problem, Air Force Captain Harold F. Mitchell, piloting a C-119 on 19 August 1960, recovered the first space capsule in midair over the Pacific—the first object ever returned from a space orbit to earth. From then on, the Air Force was successful in retrieving the film capsules.23

Creation of the Advanced Research Projects Agency Despite the success of America’s first satellite in orbit, the nation’s military and political leaders still had to grapple with how to recapture U.S. dominance in science and technology after Sputnik. The immediate question was what could be done to expedite the discovery of new technologies that would enhance the nation’s war-fighting capabilities—specifically, how could the Defense Department develop radical technologies in order “to defeat existing and emerging national security threats.” The creation of the Advanced Research Projects Agency (ARPA) in January 1958 offered one long-range approach. At first, the small DoD agency reported directly to the secretary of defense. Today the agency—now called the Defense Advanced Research Projects Agency or DARPA—reports to the director of defense research and engineering in the Pentagon.24 Over the years ARPA underwent a number of name changes that reflected the shifting political climate. On 23 March 1972, ARPA’s name changed to Sputnik, Reality, and Technology

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DARPA to emphasize the fact that the new technologies the agency developed would eventually be transitioned into products and systems to support military operations. Understandably, Congress wanted a return on the money it spent on research and development; that meant getting new technologies into the field to sustain military missions. Nearly 20 years later, on 22 February 1993, DARPA briefly reverted to its original name, ARPA, as the notion of defense was deemphasized at the end of the Cold War. On 10 February 1996, as the threat of terrorism escalated and the need for defense increased, the agency was renamed DARPA.25 ARPA was initially headed by Roy Johnson, a former vice president of General Electric, and physicist Herbert York, from the University of California at Berkley, who served as ARPA’s first chief scientist. Its goals were not only to regain U.S. dominance in science and technology and to avoid technological surprises like Sputnik, but to be able to inflict technological surprises on an enemy, such as stealth aircraft, precision-guided weapons, and unmanned aerial vehicles.26 Originally, ARPA was responsible for both military and civilian satellite programs, partly to reduce competition and infighting among the three military services to gain control of space programs. However, Air Force leaders vehemently opposed this arrangement and argued the Air Force was the logical service to manage all military space programs. It took some time to sort out the nation’s space organization. In July 1958, Eisenhower signed into law the creation of the National Aeronautics and Space Administration (NASA) to manage the civilian space program free from military interference. In September 1959, Secretary McElroy announced the transfer of military space projects from ARPA to the three military services. Consequently, ARPA focused exclusively on military research and development, which included space and a wide range of other areas of scientific interest to the military.27 As a civilian-operated research and development agency, ARPA’s immediate goal was to recruit the best scientific and engineering minds in the country to conduct high-risk research that would lead quickly to the demonstration of extraordinary technical capabilities. ARPA’s intent was to rattle scientists out of their traditional comfort zone and force them to head off in different directions to come up with radical innovations to strengthen national security. The objective was to concentrate on technological breakthroughs of a “revolutionary nature,” as opposed to incremental

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improvements of existing systems using “old knowledge” that represented an evolutionary step-by-step approach for advancing research and technology. ARPA’s game plan was to fund DoD laboratories—working with private contractors and universities—to pursue nontraditional research projects. The resulting new knowledge would create new capabilities to be used in the development and deployment of radically innovative weapon, surveillance, and other military systems. The scope of these programs was limited only by the imagination of scientists.28 To attract such free thinkers, ARPA offered generous amounts of money and imposed the bare minimum of restrictions, empowering scientists to conduct independent research without interference. The focus was always on getting out of the way and encouraging scientists to do the impossible. ARPA officials knew that failures were likely, but if a 100-to-1 long shot came in, the payoffs would be incredibly high in terms of accomplishing military missions and saving lives.29 ARPA was the catalyst for the first stage or proof of concept, and in some cases, continued to support a project through the development of prototype systems. Then it usually dropped out of the process and it became the responsibility of one of the military services to pursue further development of the new technology. That meant the Air Force, Army, or Navy had to come up with its own money to fund and sustain research of the new technology to move forward with the development and engineering integration phases. ARPA functioned primarily as a funding agency that distributed work to government laboratories and private contractors. It conducted no laboratory research internally.30 ARPA concentrated on the future needs of the military services but did not have the authority to issue formal requirements to the military. The operating commands and Joint Chiefs of Staff made decisions on weapon requirements, with final approval from Congress. ARPA advocated and pursued the advancement of never-before-thought-of technologies and answers to strategic and tactical questions that the operating commands had yet to ask. Rettig Benedict, who worked for ARPA in the late 1970s and early 1980s in the area of directed energy, explained that ARPA’s job boiled down to alerting and pushing the operating commands to be receptive to new tools that could be integrated into their war fighting machine. As a recent DARPA report described it, “DARPA focuses on capabilities Sputnik, Reality, and Technology

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military commanders might want in the future, not what they know they want today.” That was often a difficult sell, because most career-minded commanders were more interested in perfecting current weapon systems to meet their immediate needs than in revolutionary weapons that most likely would not become operational for several decades.31 By investing in this course of action, the United States believed it would be in a stronger position to keep one step ahead of the Soviets. ARPA’s earliest funding went to support research and development in areas including lasers, solid-propellant chemistry, undersea and satellite surveillance, active illumination reconnaissance, and defense against ICBMs. By the mid-1960s and early 1970s, ARPA was taking the lead in the relatively unknown but rapidly growing field of adaptive optics, which many considered to be the most revolutionary advancement in astronomy and optics since Galileo built his first telescope in 1609.32 Military service chiefs, commanders at the operating command level, and scientific advisory boards had very little to do with getting adaptive optics work started in the Air Force. It was fundamentally a grass-roots movement spurred on by the intense interest of working scientists and the financial backing of ARPA. ARPA had the advantage of a mandate to support risky ventures without being penalized if the technology did not lead to a practical military application—a luxury that government laboratories did not enjoy.33 Why in the mid-sixties and early seventies was ARPA particularly interested in adaptive optics? At the height of the Cold War, the threat posed by the increase in the size of Soviet ground forces and Moscow’s ability to attack American cities with nuclear-tipped ICBMs—a danger that had lingered in the minds of many since the Cuban missile crisis of October 1962—was a grave concern to American military strategists. They knew that an effective reconnaissance and surveillance system was essential for keeping an eye on the Soviet Union. But they also realized the inability of conventional optics working with telescopes on the ground to produce quality images of Soviet systems such as satellites. Development of adaptive optics combined with larger telescopes might be the solution.34 Adaptive optics was a logical extension of the nation’s satellite surveillance program, unveiled in the 1950s. While the Eisenhower administration relied on satellite surveillance cameras in space to acquire images of

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objects on the ground, adaptive optics technology in the 1970s took just the opposite path—systems on the ground to acquire high-resolution images of space objects, primarily satellites and missiles. Many defense analysts believed a ground-based system would be less expensive to build, operate, and maintain than a space-based surveillance system. Adaptive optics offered the possibility of measuring and correcting for aberrations caused by atmospheric turbulence in reflected sunlight received from solar-illuminated satellites as a way of obtaining improved images of those satellites. The need was real, as the Soviets had launched 242 military reconnaissance satellites from 1965 through 1973. By collecting more accurate data on Soviet satellites, the United States would be in a much better position to evaluate the enemy threat. Moreover, in time of peace and war, adaptive optics would be an invaluable enabling technology for determining enemy satellite damage from natural causes or military action.35 Clear images produced with the help of adaptive optics would also be extremely useful in determining the health and operational status of friendly satellites. Radar could image satellites, but it lacked the higher resolution, which adaptive optics provides today, needed to capture the finer details of how a satellite was functioning. High-resolution images, for instance, could reveal if a satellite was positioned properly or if it was tumbling. With such data, adjustments could be made to correct satellite operating deficiencies, saving millions of dollars on satellites that might otherwise be damaged or lost. Finally, many argued that an adaptive optics system on the ground could be better protected and maintained, making it less vulnerable than space surveillance systems.36 At the time, two Air Force customers, Aerospace Defense Command (Cheyenne Mountain, Colorado) and the Space and Missile Systems Organi­ zation (Los Angeles), were especially concerned with identifying Soviet satellites and the functions they performed. Imaging enhanced by adaptive optics could potentially produce much better images than the conventional radar on which they then relied, which produced relatively poor images.37 Rettig Benedict recalled, “The radar community [at MIT’s Lincoln Laboratory in Massachusetts] was exploring a concept called range profiling—that is, the radar return was recorded as a function of time and interpreted as an ‘image’ in the range direction.” ARPA also funded projects at Lincoln Laboratory and elsewhere that produced “a two dimensional Sputnik, Reality, and Technology

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‘image’ by using the rotation of the object relative to the radar to measure a Doppler signal. When combined with the range data, a range-cross range image was obtained, quite different from an optical image.” This technology was useful but was not adequately developed until the early 1980s.38 Besides imaging space objects, ARPA was also looking at the possibility of using adaptive optics on space platforms for producing improved images of ground targets. As it turned out, adaptive optics was not needed for that purpose. Looking down from a space platform to obtain an image of an object on the ground is relatively easy to accomplish, because atmospheric turbulence is very close to the ground and thus does not blur the image. This has been proven over the years with the use of very high-resolution space cameras, which do not require adaptive optics. Project CORONA successfully used space cameras specially designed in the early 1960s by Itek Corporation in Lexington, Massachusetts. CORONA’s highly sophisticated cameras gained sufficient intelligence from photos of Soviet missile sites and military installations to make a realistic assessment of Soviet military capabilities. That information helped the United States maintain an advantage over the Soviets during the highly charged brinksmanship of the Cold War era. On the other hand, trying to acquire a clear image of a space object from the ground is very difficult because the most turbulent layer of the atmosphere is near the telescope. Some believed that adaptive optics was the solution to atmospheric turbulence and could enable a telescope to produce a sharp image of a space object.39 Another potential application of adaptive optics was to make laser weapons more accurate by cleaning up the effects of thermal blooming (dispersion of beams caused by atmospheric absorption). This could improve the quality of a high-power laser beam projected from the ground through the atmosphere to intercept and disable Soviet satellites and missiles. All these were legitimate and timely reasons for ARPA to explore adaptive optics. As it turned out, the Air Force laboratory system, funded by ARPA, would take the lead in adaptive optics. The origins of that work can be traced to the Rome Air Development Center, located at a secluded Air Force site in upstate New York.40

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Early Days The Romans

ARPA and the Air Force realized that before any serious work could be performed to design, develop, and build a working adaptive optics system to produce high-resolution images, scientists at several Air Force laboratories would have to better understand the main problem that adaptive optics needed to fix: turbulence caused by temperature fluctuations in the atmosphere. As one expert explained it, “Atmospheric turbulence is generated during the breakup of large-scale convective flows of the air into small spatial scales with the subsequent release of energy. The convective flows are driven by solar heating and radiative cooling of the earth’s surface and the resulting temperature gradients.”1 The atmosphere is constantly moving at different speeds, much like the surface water in the oceans. Some sections of the oceans can be perfectly calm with a mirror-like surface, while at the same time, other regions of the oceans experience violent churning surf and tidal wave conditions. In the atmosphere, similar conditions exist. Temperature changes at various altitudes in the atmosphere (60–90 kilometers or 37–56 miles in depth) equate to changes in the air density refractive index, which acts as a lens to cause one section of a

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light wavefront to bend differently and move faster ahead or lag behind other sections of the same wavefront. This produces the undesirable condition of an uneven wavefront. In other words, these random temperature fluctuations in different regions of the atmosphere conspire to produce a non-uniform and constantly swirling mixture of air, which in turn degrades the quality and intensity of a laser or light beam as it moves unpredictably through each sector of the atmosphere. Instead of all parts of the light wavefront traveling in a straight flat line in the same direction, atmospheric turbulence causes the light to follow an erratic path. The goal of adaptive optics is to get all sections of the wavefront to move in the same direction.2 Light travels as perfect plane waves from a point in space until at the end of its long journey it interacts with the natural thermal turbulence in the atmosphere. As a result, the turbulence impinges all across the light beam and distorts the quality of the beam. Atmospheric turbulence is most intense in the lower region of the atmosphere—from the Earth’s surface to about 4 miles up—where light beams, after having traveled millions of light years through space undisturbed, are very susceptible to distortions during the last fraction of a second of their long journey to Earth. (A light year is the distance light travels in a year, or about 6 trillion miles.) Distortions in the light occur because of the unevenness of the various layers of the atmosphere—each layer exhibits a different refractive index—which distorts or bends the light. Consequently, when this out-of-phase or “wrinkled” light filled with peaks and valleys (no longer a plane or flat wavefront) is collected and focused by a telescope, the resulting image is severely distorted and appears as a blur rather than a razor-sharp image. This optical effect is similar to the way distant objects appear to shimmer and blur when viewed through summer heat waves dancing above a hot asphalt road.3 Adaptive optics offered a way to correct this problem by restoring light to near its original, undisturbed condition before it enters the atmosphere. Putting it in lay terms, Robert K. Tyson, author of Principles of Adaptive Optics, defined it as “a method of automatically keeping the light focused when it gets out of focus.”4 The effects of air turbulence are more severe on shorter-wavelength light than on longer-wavelength light. If short-wavelength lasers used with large telescopes could be corrected for atmospheric distortion by using adaptive optics, then a laser could travel an extended range and still deliver

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Figure 1. The problem of atmospheric turbulence is that it causes a

blurred image. An adaptive optics system compensates or corrects for atmospheric turbulence to produce a sharp image of space objects.

sufficient energy on target. That would be a huge advantage for a groundbased laser weapon. Bigger telescopes collect more light, but are more vulnerable to atmospheric interference and thus need an adaptive optics system to produce high-resolution images or a tightly shaped laser beam. (Adaptive optics is only effective on telescopes with primary mirrors larger than about 20 centimeters or 7.9 inches.)5 Early Days

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But before any adaptive optics system could be designed, the first step was for scientists to better understand air turbulence and how it distorts light traveling through it. Then they would be able to design a ground-based adaptive optics system that would use an assortment of sensors, processors, and deformable mirrors to correct the distortion and produce quality images.6 In contrast, the $1.5 billion Hubble Space Telescope (deployed from the bay of the shuttle Discovery on 25 April 1990), with its 2.4-meter mirror, operates in the vacuum of space and produces high quality images of heavenly objects because it does not have to contend with atmospheric turbulence, which is absent in space; it does not require adaptive optics. However, it was very costly to build, launch, and maintain—and there is only one Hubble, with a long line of scientists waiting to use it. To build a fleet of Hubbles would be prohibitively expensive. But there is a realistic alternative: adaptive optics installed on telescopes on the ground that are available to a large number of users. For example, the 10-meter Keck I telescope in Hawaii cost $94.2 million, a fraction of Hubble’s price tag. Under the right conditions, over a narrow slice of sky (about 20 arc-seconds for visible light), ground-based telescopes can achieve images equivalent to those generated by the Hubble Space Telescope, although the Hubble can achieve those images over a larger field of view (28 arc-minutes in diameter).7 Some of the first military experiments to accurately define the effects of atmospheric turbulence on light and laser beams began in the mid-1960s at the Verona Test Facility at the Air Force’s Rome Air Development Center (RADC). RADC became involved in these experiments after the discovery of the laser. (A laser is a concentrated beam of light. The acronym stands for light amplification by stimulated emission of radiation). The laser breakthrough, on 16 May 1960 by Theodore H. Maiman at Hughes Aircraft Company’s Research Laboratory in Malibu, California, was unexpected. In 1958 two of the country’s most respected scientists, Charles H. Townes and Arthur L. Schawlow, had predicted the operation of an optical maser (microwave amplification by stimulated emission of radiation), considered to be the forerunner of the laser. In spite of the critics who showed little faith in his approach of using ruby as a lasing medium, Maiman stuck by his convictions and steadfastly continued to conduct his experiments. He bypassed everyone and used a flash lamp to excite a single rod made from ruby crystal to produce the first working laser.8

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Almost immediately, the laser caught the attention of the defense community, which was interested in its potential as a precision weapon. Scientists already knew that short-wavelength lasers shine brightly and can deposit maximum energy on target, but atmospheric turbulence interfered with the process. Because of this, RADC became involved in a number of studies and experiments in the mid-1960s directed at learning as much as possible about the degrading effects of air turbulence on laser beams. Another problem encountered was a phenomenon called thermal blooming, which is a nonlinear distortion that defocuses and spreads out a laser beam and can rob it of power.9 Conducting laboratory and field experiments would be a necessary first step to understanding exactly how the atmosphere influenced the behavior of a laser beam. With accurate measurements of atmospheric turbulence, RADC scientists would be better prepared to assess the feasibility of using lasers for surveillance radar, communications, imaging of space objects using ground-based telescopes, and other missions. Adaptive optics, developed with military sponsorship, would become one of the most important supporting technologies for these missions.10 The military was interested in adaptive optics’ potential utility for enhancing not only imaging but also for weapon systems. At the same time that work on adaptive optics moved forward in the late 1960s and early 1970s, the Air Force was investigating the merits of airborne lasers for air-to-air and theater missile defenses. If adaptive optics could solve the problem of air turbulence for laser beams, then the chances in the future for developing a ground-based laser antisatellite weapon would be greatly improved. Hence, adaptive optics was considered an essential enabling technology. Without it, it would take 100 to 1,000 times more laser power to deliver enough energy on target to disable or destroy the target. In sum, from the military’s viewpoint, adaptive optics could be applied to two different missions: compensating light to produce sharp images of space objects and compensating laser beams to propagate through the atmosphere with a minimum of disruption.11 The real-world application of these two missions, imaging and laserbeam propagation, were closely connected. For instance, before a compensated laser beam could engage a satellite, an adaptive optics system would need to locate the target by imaging it so the ground-based telescope could Early Days

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track it. Next, the adaptive optics system would have to sample the pointahead angle in relation to the satellite and the telescope on the ground, to collect sufficient air turbulence data in order to compensate the outgoing high-energy laser beam traveling along the path from the ground to the satellite. In other words, before you can shoot the satellite, you must find it and track it.12 RADC was a tenant organization located on Griffiss Air Force Base, a Strategic Air Command site in upstate New York near Syracuse responsible for operating a B-52 bomber wing. Verona, located about seven miles west of RADC, started out as a radar test facility in the 1950s, but later became an RADC optical test site. Raymond P. Urtz, a physicist who jointed RADC in 1961 after graduating from Manhattan College, became the leader of a series of pivotal atmospheric turbulence and laser beam propagation experiments conducted at Verona that were jointly funded by ARPA, RADC, and the Air Force Cambridge Research Laboratory, located at Hanscom Air Force Base, Massachusetts.13 Urtz was a competent scientist who liked to be in control. Even-tempered, self-assured, action-oriented, and all business, he was respected as someone who could get things done and deliver when the chips were down. He knew how to work the system. His approach resembled the turtle’s more than the hare’s, and he usually crossed the finish line first. Those who worked for him viewed him as a strong leader who led by example—they never had any doubt about who was in charge. He stood tall in his 5-foot-10 frame. His experience and New York street smarts combined to make him the type of manager who under-promised and over-delivered. Strong-minded with a hefty dose of tenacity—some might even describe him as stern—he took great pride in laboring long and hard in attacking difficult technical problems. Although demanding, he listened well and used the ideas of his scientific team to resolve the most perplexing technical issues. In addition, as a program manager, Urtz paid special attention to ensure prudent spending. He took his responsibility to protect the taxpayers’ money seriously.14 Urtz didn’t give up easily, no matter how tough the task. Accuracy in collecting and analyzing data was the cornerstone of his scientific work ethic. Once he had the information, he didn’t hesitate to make decisions. Steady determination and persistent resolve were his two strongest attributes, and they delivered quantitative and qualitative results. If he had weaknesses, he

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was reluctant to show them. It was the combination of all these sturdy character traits nurtured and refined over the years that added up to his consistently high level of performance that eventually elevated him to the top leadership position at Rome. In summer 1997, the new Air Force Research Laboratory (AFRL) commander, Major General Richard R. Paul, chose Urtz to become AFRL’s first Director of the Information Directorate at Rome. Urtz was extremely effective in managing people. He had a knack for matching the right person to a job. He and his team of “Romans” were truly scientific pioneers in the mid- and late 1960s. They were ahead of the pack— including researchers in university astronomy departments—conducting a variety of laboratory and real-time field experiments demonstrating the effects of atmospheric turbulence on laser beams propagated horizontally through the atmosphere a few feet above the ground. One of the prime reasons lasers were used as a light source in those experiments was because a laser displays a uniform or coherent wavefront, sometimes referred to as a flat wavefront or plane wave (like the smooth surface of a table) when undisturbed by atmospheric turbulence. That meant all of the photons (packets of light) along the laser wavefront are precisely “in step” or in perfect alignment—no photon ahead or behind its neighboring photons to its left and right. It is these in-step photons packed tightly in the wavefront that determine the quality and intensity of the beam.15 Unlike laser light, which is directed in one very specific direction, ordinary light waves, such as those given off by a light bulb, have many different frequencies and travel in all directions (360 degrees). Scientists knew exactly what an undisturbed coherent laser beam wavefront (consisting of only a single frequency) should look like—when focused ideally, the laser produced a near-diffraction-limited (almost theoretically perfect) image of a single point. By comparing a known uniform wavefront with a wavefront transmitted through the atmosphere, one could measure the degree of distortion the beam suffered as a result of atmospheric turbulence.16 At the broadest level, the purpose of the experiments at Verona was to better understand how random atmospheric turbulence affected laser propagation. That work involved propagating a laser through the atmosphere and collecting turbulence data to determine what degree the composition of the atmosphere—temperature, wind, and humidity—threw the uniform wavefront of a laser beam out of alignment. This phenomenon was known Early Days

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as phase shift and accounted for distortions (tip and tilt in X and Y directions) as well as higher-order aberrations (such as defocus, coma, and astigmatism errors) in the beam. It is the same phenomenon that causes starlight to twinkle and can produce a degraded or blurred image in a telescope. A variety of low-power lasers (5 microwatts to 25 watts) were used for these experiments, including helium neon, argon ion, and carbon dioxide.17 Urtz, who worked for the Space Surveillance and Instrumentation Branch of RADC’s Surveillance Division, led the Verona work efforts and served as the program manager. He and his colleagues explored numerous experimental approaches to collect and analyze data that would define atmospheric turbulence. A significant portion of the data collection consisted of remote probing of the atmosphere using micro sensors to determine micro fluctuations in temperature. Micro thermal probes mounted at various locations around the Verona test site measured temperature fluctuations in the atmosphere with thin-diameter wires to determine the magnitude of turbulence in different regions of the atmosphere. Balloon-borne radiosondes rising to altitudes of 100,000 feet collected data on temperature, wind speeds and directions, and humidity. A variety of other instruments were utilized, including acoustic sounders, turbulence profile sensors, and turbulence meters. Acoustic sounders were basically acoustic radars that emitted sound pulses that were reflected by temperature gradients in the air. By measuring and analyzing returned signals, Urtz and his team were able to determine the strength and height of turbulence levels. Turbulence meters were capable of measuring optical turbulence at ground levels.18 Urtz recalled using a series of mirrors (mounted on a concrete pier for stability) to direct a laser beam parallel to the ground and send it to a shearing interferometer located several hundred meters away in a laser propagation test facility (located in a tower) that provided a laboratory-quality environment in the field. There a Fourier plane shearing interferometer chopped the light wave on and off, creating bands that were used to determine the degree the light wavefront was out of phase. Phase errors were measured in micrometers. As Ray Urtz explained it, “the incoming wavefront is sheared and made to interfere with itself. Interference fringes [bright and dark bands] occur in the area of overlap. The fringe pattern is sensed by a series of small detectors and the wavefront deformation computed by measuring the fringe distortion.” By comparing the distorted wavefront

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to an ideal wavefront, one could calculate how much the wavefront was distorted from a plane wave. Another technique involved measuring the time-averaged modulation transfer function of an optical imaging system observing targets through the atmosphere. Equipment was devised to scan several points across the wavefront to measure distortion.19 Although most of the work at Verona concentrated on defining atmospheric turbulence and its effects on the quality of laser beams, some experiments looked at ways to improve imaging of space objects by methods other than adaptive optics. One of these techniques was called shadow imaging. “The whole idea,” as Urtz described it, “was to put a series of small telescopes in a line on the ground, and when the satellite passed through the path of a star, you could develop a silhouette for that satellite and it was a high-definition silhouette image.” That technique did not tell the viewer what was inside the satellite, but it did show what the outside of the satellite looked like, which would be useful for identification of foreign satellites as part of the Air Force’s space object identification program.20 Collecting the experimental measurements used to build a more accurate and comprehensive database on atmospheric turbulence took several years and used a number of different scientific approaches. Most experiments took place on the ground at the Verona test site, but on several occasions Rome researchers conducted airborne tests. For example, one series of tests from 1967–1968 consisted of flying a B-57 research aircraft belonging to RADC to measure the effects of upper-atmosphere (troposphere) turbulence on light. Attached to the underbelly of the plane was a 1,200-watt tungsten lamp. The atmospherically induced fluctuations in light amplitude were measured as the B-57 approached and passed over the Verona test site. The lamp could be seen 50 miles away.21 Flights took place at night and usually lasted for three or four hours with on average 35 to 40 flyovers of the test site, ranging from 15,000 to 45,000 feet in altitude, to sample turbulence at various levels of the atmosphere. A Nike radar tracked the B-57, with a telescope attached that collected light from the plane. The light was directed to a scintillometer that measured intensity fluctuations (changes in amplitude of the optical wavefront of the light) to determine how much the light beam had been distorted as it traveled from the aircraft to the telescope on the ground. This data helped to determine the intensity of atmospheric fluctuations and how they Early Days

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changed with the seasons, winds, and altitude. Urtz reported, “We’ve found that wind speed and fluctuations seem closely correlated.”22 Although the B-57 succeeded in collecting substantial scientific data, this particular series of experiments unexpectedly caused quite a stir in Rome and the surrounding area. The flyovers took place at night, and many unsuspecting residents found the eerie, bright-blinking lights, slowly moving across the darkened New York sky, unsettling and flat-out scary. A number of people called the Rome police department to report sightings of unidentified flying objects. One eyewitness, Mrs. Lloyd Bumpus, became frightened when driving and seeing a red light in the sky moving closer to her car. Bumpus’s passenger, Mrs. Henry Hilliker, was sure the object was not an airplane. Hilliker described the object as an oval shape that looked like it was rotating. “As it came through the air,” she said, “it was like a paper plate floating, except with a controlled action as if it actually was being steered.” Since the program was unclassified, RADC officials told the public what the Verona tests were all about, but a smiling Ray Urtz remembered later that many people simply did not believe that explanation. They seemed to long for a more mysterious explanation of the unfamiliar “bright-light” phenomenon.23

Laying the Groundwork—Partnering With Itek The work conducted at Verona gathering and analyzing atmospheric turbulence data from the mid-1960s through the early 1970s was an important first stage of research that had to be completed before anyone could start thinking about designing and building hardware for an adaptive optics system. Precise quantitative measurements of air turbulence formed the foundation. Building an adaptive optics system to make the required corrections to the beam and produce a high-quality image of the object being viewed was the critical next step. Rome played a big part in that step. One of the military’s first major efforts in adaptive optics was a joint research program funded by ARPA (now DARPA) and initiated in March 1973 by RADC and Itek Optical Systems, a private company headquartered in Lexington, Massachusetts, only a few minutes from Hanscom Air Force Base. The program was called

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the Real-Time Atmospheric Compensation system or RTAC, and it was the first Rome research effort dedicated to building a working adaptive optics system. Even before Rome came into the picture, Itek had invested its own money to initiate preliminary concepts on the design of RTAC—conducted by John W. Hardy—under the company’s independent research and development program.24 Formed in September 1957 as a venture capital investment with $600,000 supplied by Laurance Rockefeller, Itek (short for information technology) set out to develop products related to “information acquisition and utilization.” This involved, according to Itek’s first public notice, distributed in October 1957, “handling, storage, retrieval and presentation of information,” a cover phrase that translated to aerial and space reconnaissance in the classified world. Itek’s main business was to develop large surveillance cameras that would fly on reconnaissance satellites and take panoramic pictures of the Soviet Union. Richard Leghorn, who headed Eastman’s Kodak’s European Division, and Theodore “Teddy” Walkowicz, an advisor to Laurance Rockefeller, were the two driving forces responsible for the creation of Itek. Both men carried strong military credentials and had a special interest and ample experience in promoting aerial reconnaissance as a means to monitor the number and status of Soviet nuclear and conventional weapons before a war broke out.25 As an officer in the Army Air Forces in World War II, Leghorn had flown aerial reconnaissance missions taking photos of German defenses in preparation for the Normandy invasion. After the war he collected nuclear effects data by taking aerial photos of atmospheric tests at Bikini Atoll in the Pacific. In the late 1940s he became aware of, but did not yet avidly support, RAND studies advocating satellites as the preferred reconnaissance platforms of the future. He did not believe the technology was mature enough to justify spending large amounts of money for a satellite reconnaissance program. Instead, he thought balloons and high-flying aircraft undetected by Soviet radar were the most realistic and least vulnerable platforms for reconnaissance missions. However, after extended discussions with Merton E. Davies, RAND’s point man and advocate for getting the government to sponsor a satellite development program, Leghorn changed his mind. He became convinced that satellite reconnaissance was the best way to acquire intelligence on the Soviet military capabilities and accurate targeting prior to the start of hostilities. Early Days

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This new approach made sense since the closed society of the Soviet Union made it more difficult to collect human intelligence.26 Air Force Colonel Bernard A. Schriever also influenced Leghorn’s change of heart. Schriever, a staunch supporter of the idea that science and technology would transform military systems, went on to lead the country’s intercontinental ballistic missile program when he took charge of WDD in 1954. WDD’s sole mission was to develop the boosters that would launch American ICBMs (intercontinental ballistic missiles). But the Air Force had a strong secondary interest in WDD. It recognized that if powerful enough boosters could be built to lift ICBMs, then those boosters could also launch satellites into orbit. This dual interest in satellites and boosters was the main reason why the WL-117L satellite program shifted from Wright-Patterson Air Force Base to WWD in fall 1955. The move would take over a year to complete.27 Recalled to active duty in 1951, Leghorn served as an Air Force intelligence officer at the Pentagon. His job as an Air Force Reserve colonel was to assess the various reconnaissance options available to the United States. In 1953 he issued his findings as part of an Intelligence and Reconnaissance Development Planning Objective prepared for Colonel Schriever. Leghorn concluded that a combination of actions—high-altitude balloons, highaltitude reconnaissance aircraft, and eventually low-orbiting earth satellites—would all be needed to meet the nation’s surveillance needs. By the mid-1950s, and especially after the launch of Sputnik in 1957, Leghorn came to believe that less vulnerable satellites should replace the high-altitude (U-2) aerial-reconnaissance aircraft that were keeping an eye on Soviet Union. He believed satellites would provide invaluable intelligence on the extent of Soviet arsenals and serve as detection and monitoring platforms, thereby keeping nuclear arms control agreements honest. (The Soviet Union tested its first atomic bomb in August 1949 and a hydrogen bomb in August 1953.) In addition, in time of war, satellites out of harm’s way in space could provide early warning of an enemy attack, identify missile targets, and furnish timely post-strike bomb damage assessments to help plan future operations. Leghorn became Itek’s first president in 1957, and Walkowicz became one of the company’s first directors. Both men were instrumental in turning the concept of satellite reconnaissance into an operational reality by the end of the 1950s.28

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Two other men played critical supporting roles. Duncan E. MacDonald, who was dean of the Graduate School at Boston University and had overall responsibility for the University’s Physical Research Laboratory (BUPRL— formerly the Boston University Optical Research Laboratory, established in December 1946), helped Leghorn set up Itek, while Dow Smith was in charge of the day-to-day running of BUPRL. MacDonald helped to arrange the sale of BUPRL to Itek, as the Pentagon was having a difficult time justifying financing the laboratory and Boston University’s President Harold C. Casey was not overly enthusiastic about using it to support secret government programs. Consequently, Itek bought BUPRL from the university in January 1958 and hired most of its 100 scientists and engineers. McDonald also moved from Boston University to Itek to become one of its vice presidents.29 This highly qualified pool of workers formed the core of Itek’s expertise in optics and electronics. To supplement this initial workforce, Itek began recruiting individuals from private industry. By the end of 1958 the company employed 500 people. Very quickly it acquired a number of lucrative contracts with the CIA and other government agencies. After only one year in business, Itek sales reached $3.5 million, a large sum of money for those days. Within security circles, Itek would become known as the premier manufacturer of high-resolution reconnaissance cameras and other optical equipment supporting government defense projects. It was the scientific leader for the CIA’s (then highly classified) Project CORONA, America’s first photographic reconnaissance satellite program. The Air Force’s role in CORONA—carried out by the Ballistic Missile Division in Los Angeles (formerly the Western Development Division)—was to develop and use its Thor and Atlas missiles to boost the reconnaissance satellites into orbit. Controlling satellites in orbit, recovering payloads, and conducting their own experiments were other Air Force responsibilities. To deflect unwanted publicity and questions that might compromise the classified nature of CORONA, the Air Force referred to its satellite launches as being part of its Discoverer program to conduct an assortment of biomedical and other scientific experiments in space.30 CORONA got off to a shaky start. It took fourteen launches before the first successful midair recovery of a film capsule from a reconnaissance satellite—made by a JC-119 aircraft at 8,500 feet near Hawaii on 19 August Early Days

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1960. (Discoverer 1, launched in February 1959, was the first WS-117L satellite placed in orbit that was now part of the CORONA program.) But that first satellite spool of film ejected by Discoverer 14 was well worth the wait. The 3,000-foot, 20-pound spool produced more photos of the Soviet Union (covering over 1.5 million square miles of territory) than the twenty-four U-2 flights over the Soviet Union from 1956 to 1960 and provided a wealth of intelligence. One high official reported that the photos collected “literally bowled over the intelligence community.” The CIA reported that this first collection of space photographs identified “64 Soviet airfields and 26 new surface-to-air missile (SAM) sites.” Here was solid proof of the real value of satellites functioning as reconnaissance platforms. In the short run, this film from space filled the big intelligence void that had developed after Eisenhower shut down aerial reconnaissance flights over the Soviet Union in May 1960. But more importantly over the long run, it defined the start of this nation’s era of satellite reconnaissance.31 Part of the reason DARPA selected Rome to manage Itek’s work was the earlier series of successful atmospheric turbulence and low-power laser propagation experiments conducted by Rome scientists at the Verona site over the past several years. They had earned a solid reputation for doing excellent work. DARPA recognized they were the logical choice to develop a workable adaptive optics system.32 DARPA had been concerned all along about coming up with better techniques for obtaining high-resolution images of Soviet satellites and foreign reentry vehicles. Conventional image processing using groundbased telescopes and cameras was ineffective due to atmospheric turbulence. DARPA was looking for innovative technology that would reduce the effects of atmospheric turbulence and produce better images of Soviet satellites. The more detailed the image of a satellite, the better chance intelligence analysts had to deduce what was inside it and what its mission was. For example, a detailed image might reveal optical equipment such as sensors aboard a satellite, which would be a strong indicator that the satellite would be capable of surveillance.33 Richard Vyce, Itek’s director of marketing, was aware of this concern and saw it as an opportunity to attract new business and get a jump on industry competitors. Vyce met with DARPA officials in June 1972. Upon returning to Lexington, he sought out John W. Hardy, an extremely

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intelligent electrical engineer at Itek who over the years had earned a standing as a person who “could make things work.”34 Hardy, born in England, was a distinguished-looking gentleman with a neatly trimmed mustache. He had an aristocratic presence that might give the mistaken impression that he would fit in more comfortably running an English manor house than unraveling the mysteries of science in some outof-the-way laboratory in Massachusetts. But the laboratory was where John Hardy made his mark. Along the way he acquired many accolades and a reputation as a competent and methodical individual who was adept at breaking down complex science and engineering problems. He considered himself a practical person and liked to design instruments. Although there is no single person credited as the inventor of adaptive optics, Hardy made major contributions to its development, especially its imaging applications.35 As a child, Hardy had been fascinated by optical and electrical gadgets. Taking apart cameras to find out how they worked and building radio sets and amplifiers were his favorite youthful pastimes. Trained in electrical engineering and specializing in telecommunications, he graduated from London University in 1946. After a two-year stint with the Royal Corps of Signals, he began his professional career as a telecommunications engineer developing new equipment, first for Automatic Telephone and Electric Company and later for British Telecommunications Research. When American companies began recruiting for engineers in Europe, he told his wife, Ethel, “Let’s go to the States and see what it is like; if we don’t like it, we can always come back.” They never returned. Hardy took Westinghouse Electric Corporation’s job offer to work in Baltimore in 1956. He remained there until 1960, when he accepted an engineering position at Itek. He stayed with the company until he retired in 1990.36 After Vyce met with Hardy and explained what DARPA was looking for, Hardy conducted an extensive literature search on atmospheric turbulence. He also checked the methods used to correct for the effects of thermal blooming on a laser, but found those techniques just would not work. After several weeks of looking at various possibilities, he came up with the idea of using a white-light wavefront sensor to measure wavefront gradient across an incoherent light wave made up of many different frequencies. An analog computer would process the wavefront data nearly instantaneously to make corrections to a number of subapertures or sections using Early Days

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a deformable mirror, which would correct for the distortions in the light wave. As Hardy remembered it, “I finished off with the design of a system, which measured wavefront slope independently over a large number of subapertures, and this was processed analogically coupled into a deformable mirror.” He wrote up the details in a technical report titled “Space Object Imaging From The Earth’s Surface,” released in November 1972. Hardy and Vyce then briefed DARPA’s Strategic Technology Office on 3 November to sell the RTAC adaptive optics system. Hardy wrote an RTAC proposal that was formalized into his technical report, which was submitted by Itek to DARPA on 30 November 1972. This proposal recommended that Itek build and test an adaptive optics feasibility model.37 DARPA was impressed by Hardy and Vyce’s presentation. They were a formidable team—Hardy took care of the scientific and technical issues, while Vyce promoted Itek’s ability to get the DARPA job done expeditiously at a fair price. Hardy was confident he could design, build, and operate a compensated imaging system that would remove atmospheric distortions.38 Prior to Hardy’s proposal, DARPA, as well as universities and private industry, had been pursuing the idea of restoring blurred images by data processing techniques after a camera had already taken the picture and the image was recorded on film. That traditional post-detection method involved trying to restore the image by scanning and digital processing. That did not work very well, because the image was usually so degraded that no amount of scanning or digital processing with the equipment available at the time could significantly sharpen the image. Hardy argued that the way to improve images was to use an adaptive optics system that would be able to restore or sharpen the images of incoherent light before the image was recorded by a camera. This method consisted of sampling the incoming light to detect the distortions over the wavefront, and changing the settings on the deformable mirror, which in turn would make corrections to the follow-on flow of distorted light reflecting off the deformable mirror. This compensated light could then be sent to a camera to produce a sharp image. Again, the key point was that making corrections to the incoming light would take place before the camera took an image of the object.39 One of the long-term objectives of Itek’s initial contract with ARPA and RADC was to prove that an adaptive optics system could compensate incoherent white light made up of multiple frequencies and produce clear,

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sharp images of satellites. The job ahead would be extremely difficult, and Itek trusted Hardy to lead the RTAC technical effort.40 Although DARPA was receptive to Hardy’s proposal, the agency was aware of the enormity of the problem of atmospheric turbulence and its degrading effect on light transmitted through the air. As far back as 1703, Sir Isaac Newton had recognized that telescopes “cannot be so formed as to take away that confusion of the rays which arise from the tremors of the atmosphere. The only remedy is a most serene and quiet air, such as may perhaps be found on the tops of the highest mountains above the grosser clouds.”41 Two and a half centuries later, an astronomer named Horace W. Babcock, working at the Mount Wilson Observatory in the San Gabriel Mountains near Pasadena, California, wrestled with the same problem. Babcock, considered the first serious modern thinker to propose a solution to the problem using adaptive optics, said that only rarely did telescopes produce sharp images of space objects: “one may consider himself fortunate to experience one hour out of 1,000 of the finest seeing, even at the best locations.” However, when good seeing conditions are available—in the absence of atmospheric turbulence where most of the light converges in a diameter smaller than 1 arcsecond—uncompensated telescopes located on high mountains can produce images 10 times better than the same telescopes at sea level. Unfortunately, the very best seeing conditions occur infrequently even on the highest mountaintops, and the images produced still exhibit significant distortion from atmospheric turbulence.42 Besides Babcock, two distinguished Russian physicists, Andrei N. Kolmogorov in 1941 and V. I. Tatarskii in 1961, had made important early contributions, defining the properties and structure of atmospheric turbulence, which served as the mathematical foundation for others to build on. Building on Kolmogorov’s work, Tatarskii was the first to describe through mathematical modeling the wavefront structure function, which appeared in his book Wave Propagation in a Turbulent Medium, published in 1961. This groundbreaking work was considered the bible of theoretical atmospheric turbulence in the 1960s. Urtz recalled that he and his team geared much of the work at Verona to collect empirical data on atmospheric turbulence to test and refine Tatarskii’s theory.43 Most in the scientific community consider that the concept of adaptive Early Days

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optics started in 1953 when Babcock published his seminal paper on realtime sensing and correction. He proposed correcting light distortions by placing a thin layer of oil over a mirror’s reflective surface. By depositing an electric charge on the oil film, “through electrostatic forces the oil film is distorted according to the desired pattern. Through refraction this results in a controlled deviation of the light rays reflected by the mirror.” In other words, Babcock suggested that his procedure would be an effective technique for reducing the amount of distortion in a light wave and improving imaging of objects. Regrettably, the Carnegie Institute, which supported research at Mount Wilson, did not have the financial resources to turn Babcock’s theory into reality. Although Babcock never built a system, many consider him the father of adaptive optics because he came up with the first concept of adaptive optics. It would take another 20 years before Itek would successfully demonstrate the first real-time adaptive optics system.44 In spite of all the unresolved problems with distorted light, Hardy and Vyce’s compelling presentation to DARPA in November 1972 led to a contract award to Itek in spring 1973. Out of that contract emerged an Itek team led by Hardy that collaborated with a Rome team of scientists and engineers that set out to build a working adaptive optics system. Hardy went to Rome to meet with Urtz, who was responsible for administering the DARPA contract, and to coordinate the details of the entire project. This project was a major departure from the earlier Verona work, which had concentrated on defining and measuring atmospheric turbulence to determine its effects on beam quality. Hardy’s proposed adaptive optics system—for which he received a U.S. patent in December 1975—would be radically different because it would seek to compensate for atmospheric aberrations to produce a good quality image. As Hardy explained: Babcock deserves great credit for recognizing a general solution to the problem of turbulence compensation, but it was realized that the system he proposed was far too limited to be useful for military purposes. The new system had to be capable of correcting images of a rapidly moving satellite under all turbulence conditions—satellite passes only last a few minutes, so it is not possible to wait for better conditions. So Itek used a totally new approach to adaptive optics: the wavefront sensor was a shearing

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interferometer, based on work by James Wyant; the corrector was a deformable monolithic piezoelectric mirror (MPM), and the control system was a parallel processor. The MPM was a completely new concept developed by Julius Feinleib, Steven Lipson, and Peter Cone at Itek.45 James Wyant was one of the most impressive members of the Itek team that made these laboratory experiments work. He credited Ralph Berggren, his colleague at Itek, for the theoretical groundwork, but it was Wyant in 1972 who built the first practical white-light shearing interferometer. This device functioned as a sensor that calculated the shape of the wavefront— that is, how much the light was bent by atmospheric turbulence. That was accomplished by interfering two beams of light from which measurements of wavefront gradient or slope (optical aberrations in the beam) could be made. The slope data were then sent to an analog computer to be processed to determine the shape of the wavefront. Once the shape was determined, then the surface of the deformable mirror could be changed to remove the aberrations from the wavefront.46 The wavefront sensor had to detect and feed that new beam data in the form of electronic signals to the computer at a very high speed if it was to accurately reflect the most current conditions of the laboratory atmosphere. That meant the computer had to continually keep up and send in real time new information to the deformable mirror by way of computer-driven electronics to tell each section of the mirror (that matched its corresponding section of the distorted wavefront that needed to be corrected) exactly how much to change its shape to compensate for distortions in the beam. In essence, the computer converted wavefront sensor signals to compensated signals that changed the settings on the deformable mirror. Each cycle of sampling atmospheric turbulence, measuring distortions in the incoming light as it changed several hundred times a second, and adjusting the shape of the deformable mirror, occurred in milliseconds—thousandths of a second; this was known as a closed-loop system.47 Julius Feinleib at Itek was an independent and innovative thinker who headed a small team that devised the concept and design of the deformable monolithic piezoelectric mirror or MPM built by Itek. These were the first deformable mirrors made, a big step forward that made Itek the leader in Early Days

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Figure 2. Schematic of Itek’s first deformable mirror, used in the Real-Time

Atmospheric Compensation experiment.

the field. The small MPM (2 inches in diameter and 0.05 inches thick) was made of glass. Its actuators were made of a ceramic material called lead zirconate titanate, commonly known as PZT. Embedded in the solid block of piezoelectric material and positioned behind the mirror’s surface were 21 actuators (small pistons), each of which moved in a precise direction over a very short distance (a few micrometers) when stimulated by electrical voltage. The glass mirror was bonded to the block of piezoelectric material, as described in Figure 2.48 When the actuators were subjected to small jolts of electricity, the shape of the mirror surface changed to remove the distortions from the light beam. Hardy stated he wanted to use a sufficient number of actuators “to test the concept without the task’s becoming too complex. So we settled, rather arbitrarily, on 21 actuators.” Attached to the top of the piezoelectric block was a thin sheet of glass, which was optically polished and silvered to form a highly reflective surface. Once the wavefront sensor measured the distortions in the beam, that information was processed, converted to the appropriate electrical control signals, and sent to the mirror to place

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Figure 3. Adaptive optics works by measuring the distortion in a wavefront

(left) and placing the conjugate, or opposite, of that distortion on the surface of a deformable mirror (center), which in turn corrects the distortion, straightening out the wavefront on reflection (right).

the mathematical conjugate or opposite wavefront configuration of the distorted beam onto the mirror surface. Some referred to this technique as “distorting the distortion” or putting eyeglasses on a telescope so it could see better. In short, the deformable mirror transformed a distorted wavefront into a nondistorted wavefront (see figure 3).49 Electrical pulses sent from the reconstructor along a series of thin wires to the actuators allowed them to make precise corrections to the mirror’s surface. Each time a predetermined amount of electrical voltage reached one of the actuators and set up an electrical field, that actuator pushed or pulled against its assigned area of the glass (subaperture), causing it to move slightly (on the order of 10 microns or one hundredth of a millimeter, about oneeighth the diameter of a human hair—not visible to the naked eye). Each of the 21 actuators moved at a different rate and distance, so the glass surface was no longer flat or rigid; the shape changed several hundred times a second. Deformable mirrors were sometimes referred to as rubber mirrors. Once the beam reflected off the surface of the deformed mirror, a camera captured the compensated beam, producing a sharp rather than a blurred image.50 Early Days

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Although one major application of adaptive optics was improved imaging of space objects, scientists were also interested in a second important application, sending a compensated laser beam to intercept a target in the atmosphere or in space. In the latter case, the beam had to exit the telescope and travel through many layers of atmospheric turbulence before reaching its target. As Bob Fugate, the Air Force’s leading authority on adaptive optics, explained it, “When the laser beam leaves the telescope it will be distorted and tilted to exactly match the conjugate of the aberrations induced by the propagation medium [the atmosphere and/or space]. As the wavefront propagates through the aberrating medium, the preset distortion is undone and the beam arrives at the object with a near perfect wavefront.” In either scenario—imaging or laser beam projection—adaptive optics is a complex scientific process that demands a high degree of hardware and software precision to correct for atmospheric turbulence.51 During Itek’s glory days, the company’s main interest was developing adaptive optics systems for imaging, not for engaging space targets. Its monolithic piezoelectric mirrors were not built for high-power laser applications. Those uncooled mirrors could not deliver the stroke—the amplitude or the right amount of physical bending of the deformable mirror—to correct the wavefront of an outgoing laser beam. Nor could they absorb the heat deposited on their surfaces by an outgoing high-energy laser beam.52 Interest in adaptive optics extended beyond military applications into the medical community. Some optical scientists compared the imaging principles of an adaptive optics system to how the human visual system works. The biological makeup of a person’s eye gives it the capacity to adapt to various light conditions in order to obtain the best possible image of whatever it is looking at. Working together, the brain and eye focus on the object viewed. The brain—analogous to a wavefront sensor and high-speed processor—interprets light conditions and determines what corrections the eye should make to produce the best image. Those corrections are made “through biomechanical movement of the lens of the eye. This is both a closed-loop and phase-only correction.” The iris of the eye is critical because it “can open or close in response to light levels, which demonstrates adaptive optics in an intensity control mode. And the muscles around the eye can force a ‘squint’ that as an aperture stop is an effective spatial filter and phase-controlling mechanism.” While the human eye performs all these

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processes naturally and spontaneously, manufacturing an adaptive optics system from scratch was a difficult and challenging scientific endeavor.53 A wavefront sensor, a high-speed processor (reconstructor), and a deformable mirror were the three critical components of any adaptive optics system. All these parts had to work in harmony with one another in real time for the system to perform properly. As John Hardy pointed out, “The main problem in building adaptive optics is the design of the overall system, rather than individual components.” One report described the symbiotic relationship among these key components in more technical language: “The wavefront sensor is an optical instrument that measures the gradient of the distorted wavefront over small regions called subapertures, and the reconstructor is a computer that estimates the phase error at certain points in the aperture by mathematically manipulating the wavefront gradients measured by the wavefront sensor. The computed phase errors are the basis for corrective signals applied to the deformable mirror.” The process of integrating advanced optics and electronics to make all the components to work together as one integrated unit is referred to as electro-optics.54 The Department of Defense was more than willing to invest in adaptive optics research because it offered considerable potential strategic payoffs for the nation. The second half of the twentieth century was tumultuous. No one knew what unpredictable event might erupt and transform the Cold War into a “hot” war. Beginning in the late 1960s and into the 1970s, government adaptive optics research programs—conducted in secret—were in an enviable position for attracting money and qualified military and civilian scientists. That effort extended over the next three decades and led to the systematic advancement of the diverse technologies required to make an adaptive optics system work. The work was critical in the eyes of senior strategic decision-makers, who believed adaptive optics was a promising multidimensional technology that could assist laser beams to perform satellite and ballistic missile defense missions, as well as to obtain high-resolution images of space objects, both natural and manufactured. To turn that lofty strategic vision into reality, Rome Air Development Center and Itek Corporation joined forces as the early leaders in the development of the first adaptive optics systems.

Early Days

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Rome and Itek First Adaptive Optics Systems

As RTAC took off, Urtz went to his boss in 1973 and asked for more people to accommodate his increased workload. He understood the long-term significance of the RTAC work. The more competent people he could assign to this project, the more he believed he could build up Rome’s in-house expertise. Given the green light to hire, Urtz recruited electrical engineer Don Hanson. That came about because of one brainy lieutenant, named Darryl Greenwood, who worked for Urtz. Greenwood was the first to investigate the control servo requirements for an adaptive optical system. He analyzed an adaptive optical system in terms of the rate at which corrections needed to be made in order to stay up with changes in the atmosphere. This rate has become known as the Greenwood frequency. Later, he conducted groundbreaking adaptive optics work using sodium wavelength lasers (0.589 microns) at Lincoln Laboratory.1 Greenwood and Hanson met through their wives, who worked together. Hanson, who had been working on radar electronic counter-countermeasures at Rome since he entered the Air Force as a civil servant in 1968, said

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years later that he suspected Greenwood “whispered in Urtz’s ear” to hire him. Urtz took Greenwood’s advice and brought Hanson onboard, which turned out to be a savvy move. Besides Hanson, Urtz also hired Jim Cusack and Tom Pitts, two highly competent physicists who became indispensable members of Rome’s in-house compensated imaging team.2 Hanson eventually became Urtz’s right-hand man and over the next 10 years proved to be a key contributor to Rome’s tightly knit group of researchers. Working for Urtz gave Hanson invaluable on-the-job training. Along the way he earned his PhD in electrical engineering from Syracuse University.3 A committed and enthusiastic scientist, Hanson had a pleasant personality and quiet self-confidence that suited him well for working with others. He got along with people, but he was not averse to defending an unpopular point of view. He had that All-American manner about him that gave one the feeling he wanted the ball with the score tied and three seconds to go in the game. He was organized and methodical in how he approached day-to-day issues. He didn’t need Stephen Covey to remind him of the importance of setting priorities. He took pride in hitting the bull’s-eye and became impatient with those who continually nicked the outer fringes of the target.4 Hanson was thoughtful and precise in the way he presented answers to questions. He was technically smart and always interested in how things worked. He read widely, poring over technical reports to better understand and master complicated adaptive optics technologies. He achieved a large share of his scientific expertise through his firm work ethic and on-the-job experience that led to him making good decisions. From the start, he was a strong proponent of adaptive optics, and was extremely effective in coordinating projects between DARPA and contractors such as Itek. Like Urtz, Hanson over the years combined his scientific and management talents to build a solid reputation as an up-and-coming leader in the Air Force civilian research community. He rose steadily through the ranks and became the director of AFRL’s Sensors Directorate in August 2000, splitting his time between Wright-Patterson and Rome. In May 2005, Hanson replaced Ray Urtz, who after 44 years of civil service retired from his job as director of the Information Directorate at Rome.5 In March 1973 Rome awarded a contract to Itek to build the Real-Time Atmospheric Compensation system (RTAC)—not a fully operational system but a small-scale model with 21 actuators. Rome scientists worked with Itek

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Figure 4. In Real-Time Atmospheric Compensation, a telescope collects

distorted light that reflects off a deformable mirror to a wavefront sensor, which measures distortions in the beam. Corrections are calculated and sent by a data processor to actuators on the back of the deformable mirror, which reshape the mirror surface by placing the conjugate, or opposite, of the wavefront’s distortion. As follow-on incoming (distorted) light from the telescope strikes the reshaped deformable mirror, the distortion in the mirror cancels out the distortion in the light beam, and the corrected or “compensated” beam is reflected off a beam splitter, which sends the light to an image sensor or camera to produce a sharp image.

personnel to set up the RTAC equipment on a tabletop. It was then tested under laboratory conditions at Itek’s facility in Lexington. As part of the experimental procedures, scientists positioned a soldering device underneath the light path to create temperature and turbulence fluctuations similar to, but not exact duplicates of, those the beam might encounter in the operational world outside the laboratory. However, laboratory testing was a critical first step in the process to develop adaptive optics technologies.6 Rome and Itek

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Photo 4. RTAC testing at Itek. The deformable mirror is located in the black box (upper-right center of photo), and the analog computer is the vertical console at right.

After 9 months of intense work, Hardy’s three-person Itek team successfully demonstrated its laboratory RTAC system late at night a few days before Christmas 1973. They had proved that an adaptive optics system could correct for simulated wavefront distortions in a test laser beam. Hardy had worried that too much voltage to the 21 actuators during the experiment might generate large oscillations that could damage or destroy the mirror. This was a major concern, because the monolithic piezoelectric deformable mirror developed by the Itek team was the only one in existence and could not be easily replaced.7 Years later Hardy wrote, “It was with some trepidation that the 21 feedback loops were closed for the first time. We were elated to find that the compensation system was perfectly stable. When optical distortions were introduced into the beam, the RTAC produced well-corrected images.”

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Photo 5.

John Hardy making adjustments to the first RTAC breadboard at Itek in December 1973.

Characterizing the work as a major breakthrough, he added, “This was the first test of an adaptive optical system using a wavefront sensor, reconstructor, and deformable mirror, similar to those in standard use today.” With the success of RTAC, Hardy was optimistic about the future, believing that advanced adaptive optics systems using large telescopes eventually could obtain compensated images of satellites.8 Don Hanson, who served as the Rome project engineer for RTAC, reported that Itek had done an excellent job. He pointed out that the purpose of the RTAC experiments was not to image an object but to focus the corrected low-power test laser beam on a film to show that distortions had been taken out of the beam. To verify this, Hanson and his team observed Rome and Itek

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what was known as the Airy diffraction pattern, discovered by British astronomer George Biddell Airy (1801–1891): when light is sent through a telescope with a circular aperture and focused, a distortion-free beam will produce an Airy diffraction pattern consisting of a central bright spot of peak intensity (containing about 84 percent of the focused light) surrounded by several concentric dark rings. If there were no adaptive optics, the beam would randomly scatter or dance around rather than produce this sharp pattern.9 RTAC did not image an object (it imaged the focused test laser beam), but it did produce a good quality Airy pattern over an extended period of time, which meant the adaptive optics system was working. In other words, RTAC proved its wavefront sensor and deformable mirror were responding together quickly enough in real time to correct for simulated atmospheric turbulence under laboratory conditions. The excellent Airy pattern allowed one to deduce with a high degree of probability that with the RTAC system turned on, a good image of an object could be attained. However, imaging of objects would be reserved for future projects.10 Because the rate of change of atmospheric conditions in the real world was different from those simulated in the laboratory, the next step for the Rome/Itek team was to test the RTAC system outdoors at the Verona test site. Once transported to Verona and reassembled, RTAC had to undergo some minor changes so it could be integrated with the telescope system there. The marshy fields around the telescope tower at Verona made setup and operation of the precision test equipment more difficult, and the experiments did not start until late spring.11 Don Hanson was in charge of running the field tests. A low-power helium-neon laser was set up and fired at various ranges. Scientists collected atmospheric effects data by passing the beam through a 1-meter telescope mounted in a tower, processed and analyzed the data, made corrections to the deformable mirror, and focused the beam to determine if the Airy pattern revealed that the atmospheric distortions had been removed from the beam. These efforts showed steady progress.12 By the first week of June 1974, RTAC had proved it could compensate for the adverse effects of atmospheric turbulence on a helium neon laser beam transmitted along a horizontal path three feet off the ground over a distance of 300 meters. Hanson recorded the importance of this historic

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breakthrough when he wrote in his project notebook on 4 June 1974, “This is the first known successful predetection compensation [correcting the wavefront before it is recorded on film] of real atmospheric turbulence.” The test took place about 9:00 p.m. RTAC usually worked better at night, when atmospheric turbulence dropped off significantly. Between 6:30 and 10:00 p.m. was generally the optimum time, when solar heating is balanced by radiant cooling from the earth, providing a lull in the turbulence, sometimes called the evening neutral event. On 6 June, Hardy visited the Verona site and described his observations on the operation of RTAC with its laser beam traveling over a distance of more than three football fields. Around 3 p.m. the telescope was aligned with the laser, which was at the 1,000-foot range. The RTAC was set up to use an 11.4-inch diameter section of the 40-inch telescope. The RTAC locked on immediately when the loop was closed, and consistent operation was obtained for several hours. The improvement in resolution appeared very similar to that obtained in the laboratory with localized thermal turbulence. By monitoring the shearing interferometer outputs it was possible to determine the phase shift due to the turbulence which at this time was less than 2 waves peak to valley, which is the maximum capability of the phase corrector.13 More tests followed during the summer, confirming the reliability and credibility of the RTAC system. Rome and Itek scientists were elated. In July, Hardy presented the findings from the RTAC experiments to the Optical Society of America meeting in Boulder, Colorado. Twenty years later, writing in the 1994 special issue of the Journal of the Optical Society of America devoted to adaptive optics, Rett Benedict underscored the enduring legacy of RTAC when he pronounced, “The success of the experiments led to the acceptance of this technique of wave-front compensation, designated phase compensation, which is the one in use today.”14 The results of the RTAC laboratory and field tests marked a turning point for adaptive optics research—the first working prototype of a system to compensate for distortions in a laser beam caused by atmospheric turbulence. As Rome described it, RTAC “became the first practical approach Rome and Itek

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to atmospheric compensation that could be used to enhance astronomical seeing.” RTAC grabbed the attention of a small and determined group of pioneering researchers who sensed they were on the verge of unraveling a number of complicated problems and dramatically altering what they could do to improve beam quality and imaging.15 Two basic themes emerged from the RTAC research at Rome. First, the military—specifically, Rome Air Development Center (teamed with Itek) and DARPA—led the way in adaptive optics research. Rome and Itek far outdistanced other contractor and university groups investigating the problem. Without a doubt, as Hanson pointed out, the Itek team led by John Hardy deserved much of the credit for conceptualizing, designing, and building the wavefront sensor and deformable mirror for the RTAC system, as well as for integrating all the other critical components and making RTAC work.16 None of Rome and Itek’s achievements would have been possible without the support of the Department of Defense. The military mission to acquire a reliable ground-based system for imaging satellites drove adaptive optics research. Mathematician David L. Fried, an influential adaptive optics researcher, wrote, “almost all the work done to establish the field of adaptive optics was funded with military objectives in mind.” This longterm effort demanded a steady flow of money from DARPA and highly skilled personnel from RADC and Itek. The Department of Defense had deep financial pockets lined with taxpayer dollars year after year to fund government and contractor personnel—as well as very expensive hardware—through the Air Force laboratory system. Universities across the country were interested in solving the same problems, but they lacked the financial resources to sustain a program of this magnitude. They were unaware that the government was engaged in an aggressive adaptive optics program because, at that time, the program was classified.17 A second theme was that the Rome work reinforced DARPA’s confidence when its investment of less than $100,000 generated large technical dividends. Hardy described it as extraordinary that the Air Force had gotten such a big return on its investment. He was also amazed that such a major technical accomplishment as RTAC took place in only 9 months. “It was astonishing that thing [RTAC] came so quickly,” Hardy said. “It is one of these things where you think, oh yes, it is obvious, but before you’ve got

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it, it isn’t obvious at all. They did a great job in coming up with this device. It really did everything we wanted.”18 Hanson summed it up best when he remarked after the successful demonstration of RTAC, DARPA said, “this stuff might really work—let’s put some real money into this program.” Those at DARPA, including its director, Dr. Stephen J. Lukasik, were extremely pleased by the breakthrough. Rome had done exactly what DARPA’s charter expected in developing revolutionary technology quickly. For the future, it seemed plausible that adaptive optics could be used with larger telescopes. Overall, the RTAC test results convinced DARPA officials that they had a possible solution to their problem of imaging satellites. Consequently, DARPA embarked on an aggressive and high-risk plan to funnel even more dollars into adaptive optics research and development. Based on its enviable track record, it was no surprise that a large share of this money found its way to Rome to support even larger and more challenging programs over the next 15 years.19

Rome’s First Prototype Adaptive Optics: The Compensated Imaging System There was no shortage of contractors interested in competing and bidding for these challenging new DARPA programs, which represented the next phase of adaptive optics research. Rome, with the help of contractors, planned to build on the knowledge gained from RTAC to develop a more ambitious system that could be used with much bigger telescopes—for example, by greatly increasing the number of actuators on a deformable mirror. This project took shape in 1975 and was called the Compensated Imaging System or CIS.20 Captain Jim Justice, working as a program manager at DARPA, was extremely influential in endorsing the CIS program. He worked closely with Urtz at Rome to make sure DARPA dollars found their way to RADC. They intended that CIS would become an integral component of an operational telescope that could obtain near-diffraction-limited images of earth-orbiting satellites on a routine basis. (A diffraction-limited image is the best possible image the laws of physics will allow. It is not theoretically possible to produce a perfect image.) The plan called for the AMOS (ARPA Midcourse Optical Rome and Itek

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Observatory Station) 1.6-meter telescope on Maui to be equipped with CIS to produce improved images of space objects. This meant imaging satellites. But before this scaled-up system could be built, Rome insisted on preliminary engineering feasibility studies to determine the various scientific techniques and hardware that might be used to build it.21 In 1975 Rome issued separate contracts to a number of companies (Lockheed, Itek, the Optical Sciences Company, Hughes, Avco-Everett, Perkin-Elmer, and others) to obtain input on what approaches they would pursue to develop a more advanced adaptive optics system. One contractor, Hughes Research Laboratory in Malibu, California, thought there was no need to have a wavefront sensor if one tweaked the incoming beam and deformable mirror by using a multidither or trial-and-error technique, moving the mirror until a good image was produced. Another contractor proposed shining a laser beam through different types of crystals to remove wavefront distortions. The competition eventually came down to a horse race between Itek and Perkin-Elmer. On 18 June 1975, Rome awarded $1.125 million to each to develop their compensated imaging proposals. That was phase 1 of the CIS program.22 Itek and Perkin-Elmer presented similar systems, but there were fundamental differences in the types of devices to be used. Perkin-Elmer favored a Hartmann sensor to measure the wavefront. The company also pushed for using a thin-membrane mirror, similar to stretching plastic wrap tightly over the top of a bowl. By placing a metallic coating over the thin membrane and then applying electrical current, scientists could alter the surface area of the mirror to reduce distortions in the beam. One criticism of this approach was that the thin membrane might lack durability over time. Itek stuck with making improvements to the solid monolithic piezoelectric mirror (made of lead zirconate titanate, also referred to as PZT) it used in the RTAC experiments. In addition, Itek favored using Wyant’s white light shearing interferometer instead of a Hartmann wavefront sensor, because the latter had potential alignment problems when separating the beam into a large number of sections in order to measure the amount of distortions across the entire wavefront.23 Halfway through phase 1 of CIS, Itek’s Richard A. Hutchin made a significant contribution by introducing a new interferometer that, with one grating, was simpler to use and more efficient than Wyant’s device and less

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susceptible to misalignment. Hutchin’s invention was an improvement of Wyant’s shearing interferometer, which helped propel Itek ahead of PerkinElmer in the CIS competition. Hutchin had joined Itek in 1972 and earned a reputation as a very bright individual and an extremely capable physicist. Later, he rose to the position of chief scientist with Itek (1978–1979) before going out on his own as an independent consultant in 1980.24 Before making a final decision to award phase 2 of the CIS contract, Rome formed a group of compensated-imaging experts to review contractor proposals. One of the most influential members was mathematician David L. Fried, who was considered the leading theoretician on the compensation of atmospheric turbulence. Others who participated included Darryl Greenwood, who by this time had moved on to work at the Massachusetts Institute of Technology’s Lincoln Laboratory (a federally sponsored center for research and development with special emphasis on the application of technology to national defense), Marvin King from Riverside Research Institute (an independent nonprofit organization performing engineering research in the public interest), and a number of other scientists from within and outside the government. Urtz called and chaired many meetings, affording all the members an opportunity to exchange ideas and give their recommendations.25 Using input from the group along with its own assessment of the final two contractor proposals, Rome on 5 January 1976 announced its selection of Itek, based on its technical expertise, its previous experience in the development of RTAC, and its proposed hardware, as the winner of the CIS contract. The contract was funded out of DARPA Order 2646, with the approval of DARPA’s director, Dr. George H. Heilmeier (1975–1977). David Fried believed “the outstanding fundamental characteristics” of Hutchin’s interferometer “played a major part in making possible the successful completion of the [CIS] adaptive optical system.” DARPA was extremely supportive of this technical effort from the start and was committed to seeing the CIS program to a successful conclusion. Once again, RADC served as the technical and management agent to administer the contract on behalf of DARPA. Hanson served as the first CIS program manager until fall 1978, when he left RADC to work full-time on his PhD. John Vasselli, who had been working on the CIS team, served as the new CIS program director until late spring 1979. At that time, Hanson returned to RADC and reassumed Rome and Itek

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Photo 6. CIS team photo taken in July 1981 at Itek Optical Systems in

Lexington, Massachusetts. Back row, left to right: Paul Mailhot, Itek (CIS program manager); Darryl Greenwood, Lincoln Lab (scientist); Don Hanson, RADC (CIS program manager); John Doyle, Itek (department manager); David Fried (DARPA consultant, the Optical Sciences Company); John Vasselli, RADC (scientist); Earl Holbrooke, Itek (field engineer); Marvin King, Riverside Research Institute (DARPA consultant); Ben McGlamery, Scripps Oceanographic Institute (DARPA consultant); Bill Adamo, Itek (technician). Front row, left to right: Randy Moore, Itek (field engineer); Edward Wallner, Itek (systems engineer); Bill D’Agostino, Itek (engineer); John Hardy, Itek (CIS chief engineer); Rich Hutchin (formerly Hudgin), Itek (scientist); Steve Moody, Itek (technician); Sam Ronkin, Itek (technician).

his role as the CIS program manager, replacing Vasselli. The Itek contract underwent twenty amendments over the next several years. By the time the last amendment was put in place on 17 March 1981, the government had invested over $20 million in CIS.26 DARPA believed CIS would greatly enhance ground-based space surveillance. From 1976 through 1981 Rome and Itek labored to design, develop, test, and deploy the CIS hardware. John Hardy served as Itek’s chief engineer for CIS because of his expertise and experience with the RTAC project. He was responsible for the overall design of the CIS and depended on

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the expertise of two other highly regarded Itek scientists, Hutchin and Edward P. Wallner, who were key members of his design team. Hardy also called upon scientists from other organizations. David Fried and Marvin King, consultants to DARPA, as well as Ben McGlamery from the Scripps Oceanographic Institute in California and Darryl Greenwood of Lincoln Laboratory in Massachusetts offered valuable input. All were considered the top leaders in their fields.27 CIS was a much more complex and larger system with many more problems than RTAC. RTAC fit in a suitcase, but CIS was a huge system mounted on the side of a large telescope. The CIS deformable mirror measured 4 inches in diameter, roughly twice the diameter and four times the area of the RTAC deformable mirror. In addition, CIS had eight times as many actuators as RTAC. As Hardy described it: The CIS used the same basic technology as the RTAC, but expanded to a much larger aperture, with 168 actuators compared to 21 on the RTAC. It was also more than twice as efficient optically, using both transmitted and reflected light from the wavefront sensor gratings. The CIS employed four large end-on photomultiplier tubes, 608 detectors in all. These arrays had to be water-cooled to minimize the thermal noise in photocathodes.28 The logistical plan called for CIS—weighing several thousand pounds— to be installed on the 1.6-meter telescope atop the 10,023-foot summit of Haleakala at AMOS on Maui, Hawaii. Haleakala is a dormant volcano that last erupted in the late 1700s. The name means “house of the sun” in Hawaiian. The clean, dry air at the summit made it an ideal location for viewing space objects. This would allow CIS to demonstrate its space surveillance value in the real world by acquiring images of space targets—specifically, satellites in low-earth orbit. To accomplish this, the CIS would be working in tandem with a large astronomical telescope. Large telescopes were impressive in terms of the amount of light they collected, but they were not as effective in terms of producing high-resolution images by simply using a lens to focus light. As Urtz put it, “Optical phase distortion imposed by atmospheric turbulence causes a loss in resolution capability of from 10 to 30 times a system’s theoretical performance.” This meant the light entering a large telescope was Rome and Itek

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severely distorted. The missing link that would clean up this distorted light to produce clearer images was the development of Itek’s high-performance adaptive optical system, in this case, CIS.29 Another problem was that CIS was not a fixed system attached to a stable base. As Hanson explained, “We had to put this adaptive optical system [CIS] on the back of a telescope that swung around through space and so when you designed it, you had to design for changes in gravity—all that kind of stuff, which made it more complicated.” Also, there was limited space between the telescope and the walls and floor of the facility that housed it, so the CIS hardware could not be too large or it would interfere with the operation of the telescope. Plus, some worried that the CIS was too heavy to be mounted on the 1.6-meter telescope and that it would pose safety issues.30 Even after years of operation, experts still worried about the size, weight, and safety issues associated with the CIS. In 1990, an Air Force review team made up of David Fried, Paul Idell, and Jim Mayo inspected the 1.6-meter telescope. Mayo remarked that he “was amazed that the 1.6-meter telescope could even carry the load on the telescope’s inner gimbal, let alone work as well as it had over the years.” When a 3.67-meter telescope was built in the 1990s at the Maui facility (see chapter 11), to avoid the need for massive loads on the gimbal, a coudé facility—a laboratory room with optical equipment for analyzing light—was built underneath the floor of the telescope to house the unwieldy adaptive optics equipment.31 Originally, fabrication of the full-scale CIS at Itek’s Lexington facility was set for 1978, but technical problems turned out to be tougher than anticipated. For example, Itek had to design and build a 168-actuator monolithic piezoelectric mirror (the next generation of the RTAC mirror), which was more difficult and time-consuming than any deformable mirror it had manufactured up to that point. Delays also drove up the price of the final product from an estimated $7 million to $20 million by the time the CIS was originally scheduled for installation in 1980. However, in July 1981 RADC completed its final review of the CIS Acceptance Test and gave Itek approval to ship the CIS to Maui.32 Given authorization to ship the system, Itek and RADC began making preparations and taking extra care in packing up the CIS so that all its components would arrive safely. Once that was completed, the CIS was flown to Maui and trucked up a steep, winding mountain road to the top of Haleakala.33

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After the CIS arrived at Maui in the summer of 1981 and technicians began installing the system on the telescope, it became apparent that there would be more delays because of the many interface control issues that had to be resolved. For example, how would the camera that would be taking images with the corrective adaptive optics—which had been built by another contractor, Avco Everett—be integrated into the CIS built by Itek? Avco Everett Research Laboratory was the site contractor that operated and maintained all the telescopes at the Maui site and had some very definite ideas and opinions on how the new adaptive optics hardware components should be incorporated into the 1.6-meter telescope. Although there were a large number of complex interface control documents, Itek and Avco eventually came to agreement on all the disputed points so work could proceed.34 By December 1981, technicians had made significant progress installing and testing the CIS. In March 1982, the Rome scientists aimed the telescope at a star. The first image danced around and looked washed out and blurry. But when Don Hanson pushed the button to activate the adaptive optics on the telescope, “closing the loop,” a dramatic change occurred: the image became much brighter, clearer, and more detailed. This was the first time a stellar image was obtained using the CIS in conjunction with a telescope. “This major milestone,” RADC reported, “indicated that the basic design concepts of the CI system were correct.” Hardy concurred, stating, “The CIS gave us the real proof of how impressively adaptive optics can enhance the performance of ground-based telescopes.”35 On a scale of one to ten, with ten being the theoretically best possible image, Hanson rated the images eight, and Hutchin called them “massively better than what they had before.” Although not all of the air turbulence effects had been removed from the starlight, all agreed that this was an exciting achievement, proving for the first time that light traveling through the atmosphere could be corrected using adaptive optics technology. The CIS was also able in the summer of 1982 to take a single blurry image that represented two stars and turn it into two distinct images. In other words, CIS as the world’s first operational adaptive optics system mounted on a large telescope succeeded in producing clear binary images that previously had appeared as a single fuzzy image.36 Although the first CIS images represented a major milestone, that Rome and Itek

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Photo 7. Maui’s 1.6-meter telescope (upper right) with Compensated Imaging

System and its electronic wiring bundle attached underneath (center right).

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accomplishment was classified and could not be made public, even though the Rome/Itek team knew that astronomers in the private sector were pursuing similar approaches trying to produce better images of space objects. As Urtz described it, “We were far ahead of them” in advancing compensated imaging technology. Urtz gave ample credit to ARPA for “their willingness to invest in this broad area.”37 In June 1982, the CIS at Maui produced its first good quality satellite image. For imaging a satellite, the 1.6-meter telescope did not look at starlight to make wavefront corrections. Instead, CIS used sunlight reflected off the satellite. Its wavefront sensor (shearing interferometer) consumed most of that light to calculate the amount of distortion in the light wavefront, leaving only a fraction of light to image the satellite. Theoretically, in the absence of air turbulence, a 1.6-meter telescope should be able to resolve features on a 1-foot object at a distance of 500 miles. But if that same telescope had to collect light that had passed through the atmosphere and been degraded by air turbulence, it would have difficulty resolving 12-foot objects at that range. The purpose of the adaptive optics on the 1.6-meter telescope was to remove the distortions in the light to produce a near-diffraction limited image equivalent to one-foot resolution at a distance of 500 miles.38 The best window of opportunity for viewing a low-earth-orbit satellite passing over Maui was a couple of hours after dusk or before dawn, as sunlight reflected off the satellite as it appeared above the horizon. (This is known as the terminator phase, when a satellite is outside Earth’s shadow and the viewing telescope is still in the dark.) A smaller telescope with a wide field of view initially acquired and tracked the target satellite shortly after it appeared above the horizon. An operator positioned the satellite in the center of the console display to improve the accuracy of the satellite track. The satellite was then aligned in the center of the 1.6-meter telescope field of view for optimum viewing. The telescope collected the reflected sunlight from the satellite, and the CIS adaptive optics made the wavefront corrections to produce a high quality image of the satellite. This work represented another significant turning point; the Rome/Itek team had succeeded in gathering the first images of space objects observed by a phase-compensated telescope. The images proved to scientists that the theory of compensated imaging could be packaged into an electro-optical

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hardware system that, when combined with an operational telescope, could take the distortions out of light waves.39 Although imaging of the first satellite was a major step forward, the CIS was not flawless, and over the next 8 years Rome, Itek, and Avco scientists at Maui continually worked together to refine the system. One concern was to make the package lighter and more compact—for example, to develop an actuator that would require less voltage. The original version needed power supplies of up to 2,000 volts to make corrections to the deformable mirror’s surface. One of the daunting challenges was to develop an actuator that would require less than 2,000 volts to distort the surface of the deformable mirror. Another concern was that the CIS had only 168 subapertures and actuators. Although this was a giant leap forward from RTAC’s 21, a still higher number of subapertures and actuators would translate to finer spatial-scale corrections and produce better quality images. In addition, scientists were always looking at new ways to increase computer-processing speeds.40 One of the original CIS cameras, a short-exposure video system, failed to operate properly and had to be replaced with a new RCA camera. The shearing interferometer also needed to attain faster processing times, and there was discussion on whether to improve the original sensor or switch to a ShackHartmann wavefront sensor, a simpler and more light-efficient device. Part of the problem was that a wavefront sensor consumed most of the collected light, leaving only a small portion to create an image of the object. This made the CIS less effective for viewing dim objects. And less than one percent of the stars visible to the naked eye on a clear night were considered bright enough to serve as a natural guide star to furnish sufficient light to support an adaptive optics system. During the 1980s, the Air Force Weapons Laboratory and Lincoln Laboratory made significant headway in demonstrating Rayleigh and sodium guide stars as a way to obtain high quality images from dim objects in space, as described in chapters 5 and 6.41 Despite its early successes, the primary customers—first Aerospace Defense Command and later Space Command (established on 1 September 1982 and redesignated Air Force Space Command (AFSPC) on 15 November 1985)—were not totally sold on CIS. Strategic Air Command, the Foreign Technology Division at Wright-Patterson Air Force Base, and the Central Intelligence Agency, on the other hand, were impressed. There were some drawbacks. CIS viewing time was restricted to a few hours in any 24-hour

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period. Sometimes bad weather and clouds interfered with obtaining good images. Another problem was that images were captured on tapes that had to be shipped to the customer, creating a delay between the real-time capture of images of satellites and the time they were available for interpretation and analysis.42 On the more positive side, Air Force Systems Command committed to using CIS to test the Miniature Homing Vehicle as part of the nation’s space defense program. CIS also served non-DoD customers. For example, CIS provided NASA with satellite images that were useful for determining inorbit problems, such as satellite stability and damage incurred from space debris. Satellite images furnished useful surveillance and intelligence data to help NASA tell whether a satellite was functioning properly by observing such characteristics as the timely and proper deployment of its solar panels. CIS also provided quality images of the Hubble Space Telescope in 1992.43 Although CIS had both strengths and weaknesses, the DoD and the Air Force heaped high praise on it. In the eyes of the highest leaders in government, CIS represented “a significant advance in Department of Defense capabilities and an outstanding addition to the state of knowledge within the scientific community.” Hardy put it another way, stating that “CIS was huge compared with the RTAC. . . . The big proof concept came with CIS because that really was the groundbreaking thing as far as big telescopes are concerned.”44 The Harold Brown Award, given for significant achievement in research and development in support of the Air Force mission, thrust adaptive optics into the spotlight. Raymond Urtz received this prestigious award in 1982 for his technical competence and outstanding leadership “that produced a scientific breakthrough in the use of deformable [adaptive] optics to overcome the effects of atmospheric distortion on images of space objects.” This recognition was not restricted just to CIS, but extended back to cover Urtz’s work with adaptive optics from November 1973 through November 1981. The award was named for Harold Brown, a strong proponent of military research who served as secretary of the Air Force from 1 October 1965 through 14 February 1969 and secretary of defense from 21 January 1977 through 20 January 1981.45 Although the award recognized 8 years of superb work, including the atmospheric turbulence experiments conducted at Rome’s Advanced Rome and Itek

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Photo 8. Harold Brown (left) presents the Harold Brown Award medallion to

Ray Urtz on 27 October 1982 for his adaptive optics work.

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Optical Test Facility at Verona in the early 1970s and the RTAC program, it paid special attention to the contribution made by CIS. The CIS was important to the DoD for two reasons: First, the adaptive optics technologies developed and proven under the CIS program are critical to other high technology programs in existence throughout DoD. Secondly, the CIS itself will make available to the DoD operational community a source of satellite imagery never before available. The CIS sensor itself and future generation compensated imaging systems will be instrumental in fulfilling critical mission requirements in the area of satellite identification and assessment. The message was that adaptive optics technology had been progressing steadily over the previous 8 years, but that the future offered the promise of even more spectacular technology gains in the imaging of space objects.46 The Harold Brown Award was granted to individuals rather than teams, but Urtz was the first to point out that he was accepting it on behalf of all the people who were responsible for the advances in adaptive optics at Rome. That group included Air Force civil servants and military personnel as well as private contractors and the very small group of university scientists who had been cleared to participate in the program. In Urtz’s mind, there was plenty of credit to go around, and no single person anyone could point to as the discoverer of adaptive optics. Advancing the technology had moved forward relatively briskly thanks to the contributions of a number of people with different talents. However, Raymond Urtz was the principal person who brought this diverse team together, fostered a good work environment, and kept the program on track from the conceptual phase to the production of a quality CIS.47 CIS had performed exceptionally well, considering it was the first adaptive optics system mounted on an operational telescope. The original plan was for it to remain on the telescope for only a few years before being dismantled to make way for more advanced systems, but it continued to produce good images of space objects beyond its anticipated lifetime. During the 1980s it was the largest adaptive optics system in existence, and the telescope to which it was attached became one of the workhorses on Maui. Rome and Itek

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After 2 years, Hardy was still enthusiastic about its steady performance, noting that the system “had resulted in the collection of images of unprecedented quality and detail from a ground-based telescope, giving proof of the feasibility of image compensation on large telescopes.” CIS had gained a reputation as the elder statesman of adaptive optics telescopes by the time it was retired in the late 1990s. Moreover, its success led to the development of the 3.67-meter Advanced Electro-Optical System that went into operation with its adaptive optics in autumn 1998 atop Haleakala.48 In many ways, all current adaptive optics systems can be traced back to the work of the RTAC and CIS programs at Rome. The design of those systems provided great efficiency and flexibility, optimizing performance under varying conditions of atmospheric turbulence. Hardy earned acclaim as a scientific revolutionary because he was the first to apply theoretical principles to create a workable adaptive optics system. Hardy considered the basic design concept he came up with to build these two systems to be his “most important contribution to the development of adaptive optics.”49 In 1983 Urtz moved from the CIS program to work on command-andcontrol technology in the Senior Executive Service at RADC. Over the years Hanson deserved much credit for his technical management abilities in keeping the RTAC/CIS program moving forward. He left CIS in 1987 to become the associate director of the Photonics Laboratory at RADC. In spite of these two key personnel losses, the Rome/Itek team continued to move forward, making CIS a better performing system. In 1984 management and operation of the Maui site transitioned from DARPA to RADC.50 In December 1990, Air Force Systems Command—the organization responsible for funding and managing Air Force research and development programs—made an unpopular decision that many workers at Rome regarded as politically based. As a result of an Air Force laboratory reorganization, compensated imaging work and the management of the Maui site were transferred in May 1991 from Rome to the newly formed Phillips Laboratory at Kirtland Air Force Base in Albuquerque, New Mexico. The rationale for this change was that research and development activities at Maui aligned more logically with the directed-energy laser work and space research and development at Phillips (DoD defined directed energy as those technologies that relate to the production of a beam of concentrated electromagnetic energy or atomic or subatomic particles, i.e., lasers, microwaves, and

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particle beams.). Predictably, that decision was an emotional blow to Rome, given the work its scientists and engineers had done on compensated imaging since the 1960s. Many felt this was a morale buster to the electro-optical workforce at Rome, but in the end, the decision remained in force. Rome was no longer in the adaptive optics business, but the enduring legacy Rome left behind had paved the way in making revolutionary technological contributions to the development of adaptive optics.51 Even during the 1970s and 1980s, Rome was not the only Air Force research and development organization working on adaptive optics. Several hundred miles southwest of Rome, the Air Force Avionics Laboratory’s Reconnaissance Division made its home at Wright-Patterson Air Force Base in Ohio. The division conducted theoretical studies and experiments on the effects of the atmosphere on photo-optical and electro-optical reconnaissance systems. One of the goals of that work was to gain a better understanding of atmospheric turbulence and the effect it had on the large loss of resolution for film-based photographic reconnaissance systems, especially at high altitudes. Numerous aircraft and some balloon-borne experiments at Wright-Patterson measured atmospheric turbulence for different air masses, geographic locations, and atmospheric and meteorological conditions. A large part of that effort involved using RB-47s, RB-57s, and U-2s to collect turbulence data at various altitudes. This work proved that, except for the most severe atmospheric turbulence, the turbulence-induced wavefront error for down-looking imaging was not serious.52 To learn more about turbulence and its effects, the Reconnaissance Division operated the Cloudcroft Electro-Optical Observatory high in the mountains of southern New Mexico. The observatory was involved in active and passive imaging, tracking, and space object identification. In summer 1975 it was taken over by the 405B Laser Communication Program, managed by the Space and Missile Systems Organization in California. Air Force decisions to cut back on AFAL ground-based surveillance programs resulted in less and less work devoted to turbulence measurements. That left Rome as the principal agency for conducting the Air Force’s atmospheric compensation research.53 A number of organizations and individuals deserve credit for the success of adaptive optics; from the late 1960s through the 1980s, Rome and Itek were significant players. Itek, for the most part, did not design mirrors for use in directed-energy weapons, which would have to handle an intense Rome and Itek

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thermal flux load. Mark Ealey, the president of Xinetics Inc. (which manufactures mirrors for the commercial and military markets) and a former employee of Itek, observed that for mirrors used for compensated imaging, “Itek technology was the absolute flagship technology—just no doubt about it.” Demonstrating a “hardware capability” with deformable mirrors was a revolutionary contribution by Itek that had a tremendous influence on the future development of adaptive optics technology.54 During this same period and paralleling the Rome/Itek work, MIT’s Lincoln Laboratory assumed an increasing role in adaptive optics, working on improved laser beam propagation for future weapon systems. While Rome and Itek worked on producing high-resolution images of satellites, Lincoln focused on developing corrections for thermal blooming in high-energy laser beams as they moved through the atmosphere. Hughes Research Laboratory, Pratt & Whitney, and United Technologies Optical Systems were the dominant directed-energy leaders developing cooled mirrors that could accept high-power laser beams. During the 1980s and 1990s, Lincoln shifted more of its attention to testing systems to compensate for the effect of atmospheric turbulence on laser beams.55 Scientists and technologists at Rome Air Development Center and then Rome Laboratory laid the foundation in the late 1960s and the 1970s for the development of adaptive optics technologies, especially in the area of imaging. Rome continued to play a prominent role in the 1980s, but during that time the Air Force Weapons Laboratory won high praise for its work on laser guide stars—an important innovation in adaptive optics, which is the subject of the next chapter.

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Laser Guide Stars

At the same time that Rome researchers were making significant headway with programs such as RTAC and CIS, the Air Force Weapons Laboratory at Kirtland Air Force Base began assuming a more active role in the development of adaptive optics. Although Rome and Kirtland pursued similar programs, there was a fundamental difference in how the command leadership and senior scientists at each site looked at the application of adaptive optics to specific Air Force missions. At Rome, the focus was primarily on imaging objects in space, essentially a surveillance mission to identify friendly or enemy satellites, and to learn more about satellite configuration and specific applications. In contrast, Kirtland sought to use adaptive optics for weapons applications as part of the Air Force’s and the Strategic Defense Initiative Organization’s antisatellite and antiballistic-missile defense missions. That was a tall order, as AFWL first had to perfect a number of technologies using low-power lasers and sophisticated optics at AFWL’s Starfire Optical Range (SOR), located in a remote, off-limits section of Kirtland.1 SOR was a critical part of the military’s adaptive optics work. There, AFWL scientists developed building-block technologies that eventually

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would result in high-power ground-based lasers able to engage and disable enemy satellites and missiles. Weapon applications were not restricted to high-power lasers. For instance, part of an antisatellite mission might use low-power lasers to disrupt a satellite’s sensors or electronic components rather than destroy it.2 Although one of the Air Force’s long-range goals was to be prepared to develop laser weapons to intercept satellites, missiles, and other potential targets, the more immediate job of SOR was to explore and better understand the technology issues associated with finding, tracking, and projecting focused lasers on satellites or other targets. Obtaining clearer images of space objects was a big part of this process. SOR was not in the business of trying to build a laser weapon, but instead concentrated on conducting experiments to improve and perfect those adaptive optics technologies essential for the success of future military imaging and laser weapon systems.3 Part of the reason SOR became involved in compensated laser research was that in the mid-1980s the F-15 Miniature Homing Vehicle program was canceled. The goal of that politically sensitive program had been to have an F-15 fly to an altitude of 60,000 feet and then launch a small missile that would intercept and destroy a satellite overhead. The problem was that success—impacting the satellite—would create a large amount of space debris that could interfere with operation of our own space systems. When the program shut down, it left a technological vacuum in terms of what would be available to replace it. One of the most promising options at the time was the use of laser guide stars, telescopes, and adaptive optics working together to deliver a compensated ground-based laser beam to a satellite target. The Department of Defense authorized SOR to pursue research in this area. Hence, 1987 marked the origin of a ground-based laser technology antisatellite program at SOR funded by the Air Force with the aim of demonstrating the performance and feasibility of those technologies that offered the most promise of a future ground-based laser system.4 The man who would lead the adaptive optics technology effort at SOR was an able physicist and experimentalist named Robert Q. Fugate (the Q stands for Quentin, in honor of Quentin Kelly, an Army buddy of his father). Fugate became one of the undisputed leaders in the nation in the field of adaptive optics. He, more than any other individual, transformed SOR into a world-class adaptive optics research site.5

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Fugate—The Man Bob Fugate’s rise to the top of the adaptive optics world came as no surprise in light of his life growing up in the Midwest. Born in Jenkins, Kentucky, in 1943, he moved with his family to Dayton, Ohio, after the Second World War. He admired and was greatly influenced by his father, Arthur, a high school math teacher who served as a pilot in the Army Air Forces during the war. In Dayton, both his parents worked in the business anchor of the town, the National Cash Register Company, his father on the assembly line and his mother in the payroll department. What Fugate remembered most was that his family was middle class and hard working, but there was no record of a scientific pedigree from previous Fugate generations. He proudly described his parents as “commoners” who instilled a strong sense of self-worth and a powerful work ethic in their only child. Above all, he brought away from his childhood experiences the fundamental principles he applied throughout his entire life—commitment, hard work, persistence, focus, and unwillingness to consider the possibility of failure.6 At an early age Fugate began showing signs of unusual talent that would point him down the scientific road he would travel for the rest of his life. When only 8 years old he developed an interest in amateur radio. With the encouragement of his father, the younger Fugate took and passed the Federal Communication Commission’s novice test to obtain his ham radio license, decoding five words of Morse code per minute. At the age of 13 he purchased an old Unitron telescope at a flea market. When he found it didn’t work, he took the defective telescope apart, cleaned and refurbished the parts, put it back together, and pointed it to the heavens, beginning his fascination with light and images in an unheard of neighborhood in Dayton in the 1950s.7 Throughout his high school years, his interest in science continued to grow. He freely admitted that he and his closest friends were the “nerds and geeks” of their class. That didn’t matter, especially when he was engaged in scientific adventures, including concocting rocket fuel in his mother’s electric skillet for the launch of unpredictable model rockets from an abandoned lot near his home. “It was a scene right out of the movie October Sky,” he recalled, laughing. His curiosity and willingness to try new things led to solid scientific accomplishments that set Bob Fugate apart from his peers. For example, while a high school senior he built from scratch some Laser Guide Stars

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rather elaborate electroluminescence panels. That project won him the Westinghouse Science Talent Search prize and earned him a ride in a Navy plane to Florida, where he spent an unforgettable week on a minesweeper.8 By the time he finished at Belmont High in Dayton, there was no doubt in Fugate’s mind that he would pursue a career in science. Although National Cash Register awarded him a 4-year scholarship to the University of Cincinnati in engineering with the promise of a good job awaiting him after graduation, he turned it down. He wanted to be a physicist, and his heart was set on attending Case Institute of Technology in Cleveland. That decision placed an extra financial burden on his parents, but they supported him completely. While at Case he spent a great deal of his time using the student telescope at the Warner and Swasey Observatory 25 miles east of Cleveland. Across the hall in his dormitory lived Jim Wyant, who later developed a white-light shearing interferometer, a critical component of the CIS program at Rome discussed earlier. Fugate graduated from Case in 1965 with high honors and an undergraduate degree in experimental physics.9 Fugate’s senior thesis at Case, under the direction of Professor Don Schele, focused on measuring sodium chloride at 77 degrees Kelvin. The thesis was turned into an article and published in The Journal of Physics and Chemistry of Solids in 1966. Fugate also won the Dayton C. Miller Prize for the best senior thesis. Those accolades, with a strong recommendation from Schele, earned Fugate a NASA fellowship at Iowa State University working under Professor Clayton Swenson. Swenson, it turned out, had a profound effect on how Fugate tackled difficult physics problems, especially his insistence that his students would build—rather than buy—their experimental equipment.10 Fugate has a definitive presence. His most revealing physical feature is a sense of balance and proportion, the very character traits that govern his thinking. If he were a car, Fugate would be a Ford Taurus, even though today he has chosen an Infiniti G-35 sports coupe the manufacturer describes as “laser red” to power him through what he openly describes as his mid-life crisis. He appears to be in better shape than most men his age and takes pride in not looking like the stereotypical disheveled scientist. He is his own man. He would rather wear jeans to work than to suit up in a coat and tie. Clearly, there is an order and well-thought-out structure to his life both in terms of how he presents himself and how he attacks difficult mental

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Photo 9.

Dr. Robert Q. Fugate played the lead role advancing the Air Force’s adaptive optics program.

problems. Getting organized and sticking to the game plan to get something done are important to him. Fugate’s intense focus applies also to his life outside the scientific community. His wife, Marilyn, will readily attest that when her husband goes into a store he heads straight for the item on the shelf he wants and then leaves. He doesn’t roam the aisles. Even if it is just picking up groceries, Fugate is committed to completing the task at hand in the most efficient way. From his photograph, Robert Fugate looks more like the dean of an Ivy League college in New England than like a front-line scientist getting his hands dirty tinkering with temperamental lasers and optics in the high desert of New Mexico. Few would suspect he is one of the world’s leading authorities working on complex telescopes that are literally changing our image of the universe. And that’s the way he likes it. Fugate gives the appearance of a man who is at complete peace with Laser Guide Stars

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himself, one who exudes quiet confidence and intellectual ability. Initially, he seems friendly and somewhat remote at the same time. It’s almost as though he doesn’t want to waste too much time getting to know you unless he sizes you up as an individual who is serious about accomplishing some worthwhile project that will improve the status quo. Nor is he likely to make you feel overly at ease at first. Rather, as is the case with many prominent scientists deeply immersed in their research, he is more analytical than emotional in his dealings with those outside the circle of his closest and most trusted associates. In short, it takes a little time to get to know Bob Fugate. Unassuming, Fugate does not seek the spotlight. Slick Air Force slogans designed to inspire have little or no effect on his overall persona. Primarily self-motivated, he takes a hands-on approach and invests extraordinarily long hours—often 16 or more at a stretch—pursuing a variety of activities to obtain the best scientific results possible. Delegating more work to others goes against his nature. His inclination is to be totally involved in all aspects of a work effort, to approach it as a perfectionist, and to set the bar high for himself and for others. During the early days his work schedule was so hectic that, when he was able to break away and participate in family activities with his wife, his son, Jeff, and his daughter, Elizabeth, he almost seemed like a mystery guest.11 Fugate has managed to effectively organize and direct a diverse team of scientists and technicians, which started out as a team of three and grew to a 100-person operation involving government civilians and military and contractor personnel. One of his professional strengths has been his consistent ability to attract competent scientists and engineers, get them focused on a project, and keep them there. Besides working well with people, he is articulate. “He knows how to take technology,” as one former associate put it, “and turn it into prose that decision makers can understand and put into context of what is important for the Air Force and is one of the reasons he is so successful. He can translate science into language for a non-scientist. This is incredibly important.”12 In a group of highly qualified people engaged in leading-edge research, egos tend to soar. Fugate has succeeded in keeping those egos in check by establishing and nurturing a strong team. The combination of Fugate’s scientific know-how and his serene but strong and capable leadership style has played a large part in accounting for the advancement and success of the

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Air Force’s complicated and technically challenging adaptive optics program over the last two decades.13 Fugate is also the type of person who can do more with less. If he didn’t receive enough money for a project, rather than complaining about the situation, he would get his staff together to build the equipment he needed, an approach he has practiced since his college days. Colonel Tom Meyer, who ran the directed-energy section of the Strategic Defense Initiative in the late 1980s and early 1990s, observed that Fugate “could do with far less [money] and still produce excellent results.” No matter what the financial obstacles, Fugate had a knack for getting things done.14 In all fields of endeavor, people weigh their contributions differently. Some measure their sense of self-worth by the amount of money they have accumulated. Others seek constant praise and recognition for their performance. But another category of individuals values the long journey of plain hard work to reach scientific accomplishments of lasting importance. Fugate belongs to the last group. And at the start of his journey working for the government there was some rough going. One of the major turning points in his life was his decision to move from Dayton, Ohio, to Albuquerque, New Mexico.

DARPA Explores Options Fugate arrived at the Air Force Weapons Laboratory at Kirtland in a rather roundabout way. Early in his career in the 1970s he had worked at the Avionics Laboratory at Wright-Patterson Air Force Base in Dayton, Ohio. There one of his responsibilities was to investigate Rayleigh scattering of high-energy lasers related to intelligence collection missions. In Rayleigh scattering, focused laser light is reflected in all directions by molecules (nitrogen, oxygen, and aerosols) high in the atmosphere. A portion of that light travels back down to a telescope (backscatter) where it can be separated and analyzed. The phenomenon is named after Lord Rayleigh (1842–1919), born John William Strutt, a British physicist and mathematician who won the Nobel Prize for physics in 1904. Rayleigh’s pioneering work in advancing the theory of backscattered light provided the foundation for developing the laser guide star as an effective technique for measuring atmospheric turbulence by Fugate and others in Laser Guide Stars

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the 1980s. At Wright-Patterson, Fugate essentially did laser detection work to improve threat-warning techniques so pilots would know if a laser was aimed at their eyes or their aircraft. That and other work had given Fugate a strong background in experimental research. While at the Avionics Laboratory, he had collaborated with Captain Ron Grotbeck on several beam control experiments making aerosol measurements on high-energy laser beams.15 In summer 1978, Fugate, still assigned to the Avionics Laboratory, spent several months on temporary duty at Kirtland making off-axis backscatter measurements from a 10.6-micron carbon dioxide laser beam used on the Air Force’s first Airborne Laser Laboratory (ALL) aircraft. He conducted this work behind the ALL hangar at the east end of the Albuquerque International Airport runway, where a high-power beam was propagated downrange to a target 1 kilometer (0.6 miles) away. Part of his research looked at using Rayleigh scattering (viewed from the side of the beam) as a way to remotely sense if an adversary was propagating a high-energy laser through the atmosphere to threaten an aircraft.16 By fall 1978 Fugate was back at Wright-Patterson. Grotbeck, by then a major, had been reassigned from the Avionics Laboratory to the Weapons Laboratory, where he headed the laboratory’s Pulsed Laser Systems Branch, responsible for conducting a series of beam control experiments to support the planned second-generation airborne laser program, or ALL-II. Grotbeck lobbied to get Fugate assigned to help him with the pulsed CO and CO2 beam control test efforts. Meanwhile, Fugate’s job at WrightPatterson had become increasingly consumed with contract management work that entailed more travel and temporary duty assignments. That did not appeal to Fugate the physicist, so in November 1978 he agreed to transfer to Kirtland. It took a year to overcome bureaucratic obstacles in the civilian personnel office before he officially reported to Grotbeck and began working at AFWL on 1 October 1979.17 Grotbeck assigned Fugate to SOR to investigate a number of beam control problems. SOR had performed hundreds of ground tests in the 1970s to validate the performance of the carbon dioxide laser and the associated beam control system that would eventually be installed in the ALL. But once those tests were done and attention turned to flight-testing the ALL, SOR had turned into a virtual ghost town. It was from this inauspicious beginning that Bob Fugate took the first step of a 25-year journey that would transform SOR

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into a first-rate adaptive optics research facility equipped with some of the best telescopes and optical diagnostic equipment in the world.18 For the next 3 years, Fugate spent most of his time upgrading the site and working on pulsed beam control research. The work included a series of experiments propagating a very high repetitive rate copper vapor laser (100 watts) to a downrange rotating target (rotoplane) at a 1-mile target site. One of the main goals was to measure the effects of air turbulence on a visible pulsed short-wavelength copper vapor laser (called the Tag laser) as it traveled in a horizontal path from the SOR to the target. This laser had a shorter wavelength than a potential infrared weapon laser. (Shorter wavelengths have more power but are more affected by the atmosphere.) By 1983, Fugate was heavily engaged in running the Advanced Tag Team Phase I Experiment, which focused on improving data processing equipment and software to convert the turbulence measurements so that they could describe the amount of wavefront distortion in the laser beam. The experimental data helped to better define the fundamental physics of local air turbulence caused by temperature and wind gradients. These atmospheric distortion measurements also provided a knowledge baseline needed to design any future ground-based, short-wavelength laser weapon system.19 Precision and care in the collection of atmospheric measurements in near real time was one of the most challenging parts of this Advanced Tag Team Experiment. Once collected, the data were compared to effects of air turbulence on an infrared laser propagated along the same path as the copper vapor laser, to determine how air turbulence affected performance of different wavelength lasers. Results vastly improved understanding the effects of atmospheric turbulence on laser propagation.20 From 1981 on it became evident that the expertise Fugate gained from his experimental work at SOR would play an important role in supporting new adaptive optics concepts emerging from DARPA-sponsored research. The beam control experiments Fugate oversaw at the revitalized SOR facility would eventually lead to the startup of AFWL’s adaptive optics program. DARPA was the agency that first funded research in 1982 at SOR into the feasibility of using what would be known as a laser guide star to correct for the degrading effects of atmospheric turbulence on light.21 A guide star is a man-made reference source of light (as opposed to a natural star or solar-illuminated satellite) that passes through a path in Laser Guide Stars

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the atmosphere and becomes distorted because of atmospheric turbulence. Those distortions can be measured to provide the data needed to define the distorted shape of the light beam. That information is then used to adjust a deformable mirror to compensate for the distortions. (A control algorithm converts wavefront sensor measurements into deformable mirror actuator commands.) The laser guide star is also referred to as a laser beacon, synthetic beacon, artificial star, and artificial beacon.22 Until the early 1980s, adaptive optics used hardware systems, such as CIS, that relied on passive illumination—collecting light emitted exclusively from the object being imaged. This system was adequate as long as the object was bright enough to provide the luminosity needed to acquire and process the wavefront distortion data with enough light left over to produce a high-resolution image of the object. But the vast majority of heavenly objects viewed by ground telescopes appear as very dimly lit objects. With only a small amount of light available to start with, and most of it consumed by a wavefront sensor, there was insufficient light remaining that could be sent to a camera to produce a sharp image of the object.23 Because of this limitation, DARPA and others began searching for ways to maximize the use of available natural light. From 1978 through 1980, DARPA provided seed money so that Richard Hutchin at Itek and Robert Hunter at Western Research Corporation (later ThermoTrex Corporation) in San Diego could search for a controlled light source independent of the light emitted from the object being viewed. Hutchin had pursued one possibility in 1977, called the ray point-ahead compensation (RPAC) method, which studied the possibility of projecting a single pulsed laser beam into the atmosphere to be focused at some high altitude, resulting in the illumination of a fairly large area. This was one of the first guide star concepts. By observing the return backscatter from the side of the beam, Hutchin hoped to build an atmospheric turbulence profile. Hutchin and Don Hanson conducted RPAC experiments in 1980 at Rome to test this theory, but the tests were unsuccessful because the experimental design turned out to be much more complicated than originally envisioned.24 Much of Hutchin’s and Hunter’s work focused on developing a number of backscatter theories built on mathematical analysis and modeling. At the time, neither of them was able to prove any of their concepts experimentally. Yet both were pioneers who contributed to introducing and conducting the

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preliminary theoretical work on backscattering techniques that would be applied to adaptive optics systems. Their preliminary theoretical work and research efforts led to an artificial Rayleigh guide star system, which would be critical to the development of superior adaptive optics systems.25 Julius Feinleib, Itek’s chief scientist, left in 1978 to form his own company, Adaptive Optics Associates, in Cambridge, Massachusetts. He kept abreast of Hutchin’s preliminary theoretical work on the use of independent light sources. One summer night in 1981 Feinleib was observing a laser beam transmitted through the atmosphere as part of a detection and ranging experiment using one of the telescopes at the Air Force’s Maui Optical Station on Haleakala. As he stared at the laser beam penetrating the dark sky, it occurred to him that it might be possible to use the beam to sample air turbulence in the lower section of the atmosphere—the area closest to the telescope, where the air was most dense and turbulence did the greatest damage to the quality of the beam. Using the backscattered light from a man-made reference star, created by a laser focused to a small point in the sky (active illumination), it might be possible to measure air turbulence levels without having to rely exclusively on the limited amount of natural light available from the star being imaged (passive illumination)—because the light from both sources would degrade at the same rate.26 Feinleib’s approach, known as the “A” or astral point ahead compensation (APAC) method, was different from the approach Hutchin conceived in 1980, then known as the “S” or shearing point ahead compensation (SPAC) method. Feinleib chose to view the laser backscatter directly below where the laser was focused in the sky, while Hutchin’s approach was to propagate a single laser that separated into two beams as it moved through the atmosphere and observe the return backscatter from a side-angle view. As Hutchin described it, the SPAC could be thought of as “a shearing interferometer in the sky” because the beam interfered with itself and split up.27 In fall 1981, Feinleib submitted a proposal for a single pulsed-laser guide star to Rett Benedict at DARPA. Feinleib’s concept favored using a Hartmann wave-front sensor to measure the backscatter instead of a shearing interferometer as proposed earlier by Hutchin. Benedict was very receptive to Feinleib’s proposition because most people did not believe it was possible to compensate for the effects of turbulence in order for a ground-based laser to perform an antisatellite or space object identification mission.28 Laser Guide Stars

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Feinleib was a “bulldog,” according to one observer. He pushed hard to sell his idea to DARPA. Benedict and others at DARPA recognized the artificial laser guide star concept as just the type of outside-the-box thinking that DARPA had always promoted. Benedict later recalled that when Feinleib “came up with the idea, we clamped the lid down on everything and went classified.” The research program was named LODESTAR. It was routine practice to keep a promising technology program classified until a better understanding of its potential, limitations, and military application could be determined. Most importantly, the government wanted to keep breakthrough technology out of the hands of any adversary and not to reveal the direction the U.S. research effort was taking.29 Feinleib’s artificial laser guide star relied on Rayleigh scattering: some of the light from a laser beam, scattered in the atmosphere, would return to the Earth’s surface as backscatter and be captured by a telescope. The returning light would serve as an artificial star, hence the name. If the outgoing laser was pointed in the direction of the viewed object in the sky, the theory went, the Rayleigh-reflected laser light would follow the same path in the atmosphere to the ground as the natural light from a faint distant object in space. (The light going up to create the guide star and the return light traveled the same path but did not interfere with one another because all the light was of the same wavelength. This is known as the principle of optical reciprocity.) By using only the backscattered laser light to measure atmospheric turbulence and compensate for its distortions, researchers could use all of the small amount of natural light given off by the object, sent directly to a deformable mirror and then to a camera, to create the image. If the laser guide star concept worked, then the Air Force would be in a position to acquire better images of space objects and possibly to generate a ground-based compensated laser beam for antimissile and antisatellite missions in the future.30 Before Benedict would authorize DARPA funding for Feinleib’s proposal, he called a meeting of adaptive optics experts, including David Fried, considered one of the top adaptive optics mathematical theoreticians in the country, who at the time was president of the Optical Sciences Company in Placentia, California. Fried, Benedict, Feinleib, Hanson, Fugate, and a few others met in Boston in fall 1981 to discuss the validity of Feinleib’s approach. Opinions were far from unanimous. Fugate later recalled that

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Photo 10.

John William Strutt, 3rd Baron Rayleigh, laid the theoretical groundwork later used to advance the laser guide star concept. Photo courtesy of the American Institute of Physics Emilio Segre Visual Archives.

Fried stood up at the start of the meeting and blurted out in a feverish pitch, “this will never work because you are not measuring enough of the turbulence.”31 Fried was pessimistic for two reasons. First, he questioned how effective the Rayleigh scattering technique would be since the laser guide star only sampled a small portion of the atmosphere at altitudes between 10 and 20 kilometers from the Earth’s surface. What about all the air turbulence, Fried asked, that existed above the guide star spot in the sky and extended all the way up to the object being viewed? Although the air was less dense and air turbulence was not as intense at higher altitudes, the distortion to the light in this upper region could not be ignored.32 The second reason Fried was not convinced that a laser guide star Laser Guide Stars

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Photo 11. David L. Fried, a mathematical theoretician, founder of the Optical

Sciences Company, and long-time technical consultant to the Air Force, contributed immensely to the success of the laser guide star concept.

would work was a phenomenon known as focal anisoplanatism, which creates a difference in measurement between light from the star or other object to be imaged and light from the laser guide star. The problem was that light from an astronomical object travels to a telescope in a different way than light from the closer guide star. Light from the astronomical object travels in parallel fashion—as if a transparent pipeline, with the same diameter as the telescope’s primary mirror, hundreds of miles long, connected the space object to the telescope— and the light is exposed to turbulence all along the path.33 The artificial guide star, on the other hand, has to be created at an altitude of between 10 and 20 kilometers. At higher altitudes, the air is not dense enough to create sufficient Rayleigh backscatter without much more powerful lasers. (It would take about 16 times more laser power to create a

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guide star at 20 kilometers than to create one of the same magnitude at 10 kilometers.) The backscattered light reflects off the guide star, not in the shape of a pipeline but in a cone-shaped pattern with the tip at the guide star and the base at the telescope’s primary mirror.34 With the “cone” of light from the laser guide star fitting inside the “pipeline” of light from the real star (they both have the same base: the telescope mirror), it is clear that the guide star’s light would not sample atmospheric turbulence in all the areas a star would (between the cone and walls of the pipeline and in the area above the focused Rayleigh laser guide star). This is the focal anisoplanatism area, inside which distortion of the light could not be measured or corrected (see Figure 5). Neither, of course, can turbulence be measured in the area between the guide star and the more distant object to be imaged. (Light emitted by another form of guide star—the sodium guide star, discussed later in this chapter and in chapter 12—travels a longer path that encounters more atmospheric turbulence and thus reduces the problem of focal anisoplanatism, but this method is still far from perfect.) This was a major concern to scientists who were trying to take the most precise measurements possible.35 Although Fried was pessimistic, he kept an open mind. He stayed up most of the night after the meeting trying to figure out exactly what effect anisoplanatism would have on the laser guide star’s usefulness for measuring atmospheric turbulence—but he knew he needed more time to conduct a more thorough mathematical analysis. He was willing to accept the possibility that the numbers might just prove him wrong as to its feasibility.36 Fried and mathematician John Belsher, who worked for Fried’s company, spent several months building mathematical equations and models to determine the effects of the nonsampled area outside the Rayleigh conical beam in order to predict theoretically how well a laser guide star would work. By spring of 1982, Fried had changed his mind. He “showed that useful performance could be achieved even with the wave-front-distortion error caused by focal anisoplanatism” and predicted the guide star would work well enough to sample a sufficient amount of the atmospheric turbulence to produce a higher-resolution image.37 In summer 1982, an independent Defense Department advisory group called Jason asked that briefings on the laser guide star concept be presented at a meeting in La Jolla, California, part of Jason’s DARPA-funded summer Laser Guide Stars

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Figure 5.

Light from a distant star follows a cylindrical or parallel path to the telescope, while reflected light from a much closer Rayleigh laser beacon follows a conical path. In the space between the cone and the cylinder, the star’s light encounters atmospheric turbulence but the laser beacon’s light does not. Scientists debated how much the effect of this difference in sampled space, referred to as focal anisoplanatism, would affect the accuracy of the laser beacon. Schematic is not to scale.

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study program. The purpose of the meeting was to discuss the merits and liabilities of proposed laser guide star technologies, which by this time had become a hot topic.38 Jason (organized in 1958 in response to Sputnik) was an elite group of scientists, predominantly from the university world, who advised the military on a wide range of national security matters, including evaluating new and promising technologies. DARPA had funded the Jasons to conduct a 6-week summer study in 1982 to assess the future course of adaptive optics and to offer ideas on new technologies to advance its application to military systems. Since the Jasons held their meetings primarily in the summer and autumn, many thought the name was an acronym for “July, August, September, October, November.”39 But in reality, the name emerged from a discussion between Princeton physicist (later Caltech president) Marvin L. Goldberger and his wife, Mildred. Goldberger was one of the founding members of Jason and was instrumental in getting the Institute of Defense Analyses to agree to administer Jason’s activities.40 When Goldberger showed his wife the letter confirming that IDA would manage the group, she noticed the IDA logo, which consisted of three pillars and reminded her of a Greek temple. She proclaimed, “I guess you are going to be the Jasons!” She associated Jason, the mythical Greek explorer and his band of followers who sailed on the ship Argo to the land of Colchis in search of the Golden Fleece, with her husband and his fellow scientists, who were about to set off on their own high adventure in search of new scientific knowledge that would be as valuable to the DoD as the Golden Fleece was to Jason.41 At the La Jolla meeting, the Jasons—who had a hard-nosed reputation for evaluating the validity of new scientific proposals—reviewed and discussed the Rayleigh guide star approach briefed by Fried. In addition, Fried presented his findings on focal anisoplanatism that showed a low-altitude guide star would work better with a small-aperture telescope because the larger the aperture, the larger the problem of anisoplanatism. Hutchin then briefed the group on the shearing interferometer (SPAC) approach. The Jasons favored the Rayleigh method. Fugate then described the first proposed Rayleigh guide star experiment, which would focus a laser beam low in the atmosphere and pointed at a star. The goal was to collect and analyze Laser Guide Stars

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the guide star’s backscattered light and compare that measurement with light from the star, in order to more accurately determine the validity of Fried’s prediction of errors in measurements from a laser guide star versus a natural star. In the end, the Jasons supported the notion of a DARPAsponsored project to experimentally test the validity of the Rayleigh theory—using Feinleib’s approach and Fried’s mathematical calculations confirming that the focal anisoplanatism was not as big a problem as originally thought.42 The second outcome of the La Jolla meeting was a contribution by Princeton physicist Will Happer, who would play a pivotal role in laser guide star research over the next two decades. Upbeat, affable, and well respected in scientific circles, Happer was an extremely bright and levelheaded person who was not reluctant to speak out on controversial issues that crossed the lines of science and politics. President George H. W. Bush appointed Happer in 1991 as the director of energy research at the Department of Energy in Washington, DC.43 In that position, Happer challenged claims by Al Gore and others about the severity of ozone layer depletion, and argued that the more critical problem was determining precisely how damaging the ultraviolet sunlight passing through the ozone layer was for animal and plant life. To Happer, there was no compelling proof that low levels of ultraviolet light were detrimental to plants and animals. Although Happer was willing to take an unpopular political stand in the interest of sound science, he was rewarded for his efforts by being dismissed from his job five months after the Clinton administration came into office.44 At the Jason meeting in summer 1982, Happer proposed creating a laser beacon in the mesosphere at an altitude of 90–100 kilometers (56–62 miles). In that region of the upper atmosphere existed a layer of atomic sodium that could be probed by a sodium wavelength laser. Happer proposed causing sodium atoms to fluoresce or glow by raising their electrons to an excited state with a laser precisely tuned to the required wavelength (0.589 microns). As the excited atoms relaxed back to their ground state, they would emit photons of the same orange-yellow color emitted by a sodium street light. Because the atoms emit photons in all directions—but predominantly in the direction the laser beam is traveling (forward scatter) and the direction it came from (backscatter), many of the re-emitted photons would return through

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Photo 12. Princeton University physicist Will Happer came up with the sodium guide star concept.

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the atmosphere to the ground-based telescope just as though they had come from a star. This would produce an artificial star at a very high altitude, orders of magnitude stronger than a Rayleigh guide star. Fugate and others at the meeting were shocked but elated by Happer’s proposal because they simply hadn’t heard about the layer of sodium atoms in the mesosphere!45 Happer keyed on the sodium concept once he understood the benefit of getting the laser beacon to a higher altitude. He speculated that a sodium beacon would significantly reduce the focal anisoplanatism error because of its greater distance from the telescope. As Benedict explained it, “focal anisoplanatism error decreases as the altitude of the laser star increases.” That meant a sodium guide star could provide more comprehensive atmospheric turbulence measurements than a Rayleigh guide star, which encountered a higher degree of anisoplanatism. Thus, an adaptive optics system could do a better job compensating distorted light from a sodium guide star than compensating distorted light from a Rayleigh guide star. Sodium scattering would also be resonant rather than reflective, and would thus produce much brighter light than Rayleigh scattering. If equally powerful lasers produced a Rayleigh guide star and a sodium guide star at the same distance from the telescope, the sodium guide star would be 10,000 times brighter. Hence, a sodium beacon is the only practical way to create a guide star at altitudes required for large-aperture telescopes (greater than 3 meters in diameter). The drawback was that it was very difficult to generate a surgically precise laser beam at the sodium wavelength. More than 20 years after the concept was proposed, sodium wavelength lasers for guide stars are still a very active area of research (see chapter 12). On the other hand, any laser wavelength worked for Rayleigh scattering experiments.46 Happer had gained much of his knowledge about sodium and the mesosphere through his own research efforts at Columbia University in New York City. When pressed to explain how he came up with the sodium laser guide star recommendation at the Jason meeting, Happer explained, “It was a combination of things. In my professional work, I worked a lot with alkali atoms and optically pumped alkali atoms where you shine lasers on atoms. I had spent nearly 10 years studying alkali atoms with light.” So Happer’s research experience played a big part in developing the sodium guide star concept, but so did his association with several very talented and

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Figure 6. The sodium laser guide star, while still much closer to Earth than

a natural star, samples more atmospheric turbulence than the lower altitude Rayleigh laser guide star. Schematic is not to scale. Laser Guide Stars

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influential colleagues who enthusiastically shared their knowledge about sodium in the mesosphere.47 One important such individual was Gordon McDonald, a capable and energetic geophysicist who had studied the upper atmosphere extensively. Happer described McDonald as “knowing a lot about the atmosphere, the oceans, and the interior of the Earth.” McDonald encouraged Happer to attend the laser guide star session at the 1982 Jason meeting, which fundamentally changed the way military researchers looked at laser guide stars.48 Another key Happer acquaintance was Fred Roessler, a smart and respected astronomer from the University of Wisconsin who also had spent a great deal of time studying the sodium layer. Happer got to know Roessler during a sabbatical to Munich, Germany, in 1977. Over coffee, Happer recalled, Roessler “would tell me about the sodium layer and how useful it was to astronomy, and learning about the upper atmosphere, and learning about stars, and how hard it was to observe because they really didn’t have lasers in those days.”49 Happer also furthered his education on the sodium layer through the works of Alfred Kastler, who in 1966 won the Nobel Prize in physics for advancing optical pumping techniques for studying resonances in atoms. The sodium layer was discovered in 1929, and Kastler conducted extensive studies in the late 1930s observing the “glow” of the sodium layer caused by the sun shining on it just after sundown. Using a spectrometer, Kastler confirmed that light came down from this region of the atmosphere in a bright yellow line, the sodium line. He also verified there were large numbers of sodium atoms, released by micrometeorites burning up at an altitude of about 100 kilometers and releasing sodium atoms. That was how the sodium layer was formed. It grows or shrinks each year depending on how many micrometeorites burn up in the upper atmosphere as they head toward Earth.50 Happer’s own research and the knowledge he acquired from his peers positioned him at the right time and place to recommend the sodium laser guide star concept to the Jasons in June 1982. Over the next five weeks, he prepared a report on the sodium laser guide star technique: how many photons one would expect to get back from the sodium layer, how long it took for the sodium layer to absorb and re-emit light, and how a sodium laser guide star would work. That report, completed in August, convinced

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some people who had been lukewarm to the recommendation to agree that the sodium laser guide star approach could work. Happer put Gordon McDonald’s name on the report as a coauthor because, as Happer put it, “I wouldn’t have written the report without Gordon recruiting me to the meeting because I wouldn’t have even joined that study.”51 The seminal discussion about the theory and merits of Rayleigh and sodium guide stars at the 1982 Jason summer meeting resulted in a much higher level of optimism about the future of adaptive optics. Logically, the next step was to demonstrate experimentally that Rayleigh and sodium guide star techniques could accurately measure atmospheric turbulence in the real world. As it turned out, Rett Benedict and DARPA would again play the leading role to ensure these projects were sufficiently funded and staffed.

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Fugate’s Rayleigh Guide Star Experiments

The Jasons’ 1982 summer meeting represented a major turning point in the development of adaptive optics. Rett Benedict became convinced that DARPA should fund parallel programs to investigate two different techniques for creating laser guide stars to measure wavefront distortion—the Rayleigh backscattering method and the sodium-layer guide star. Each would cost an initial $100,000, with several million dollars to follow over the next few years.1 The Rayleigh effort was led by Bob Fugate at Sandia Optical Range at Kirtland Air Force Base. At the same time, Charles A. Primmermann and Ronald A. Humphreys from Lincoln Laboratory headed the sodium guide star investigation at White Sands Missile Range in southern New Mexico. Lincoln used a dye laser built by Avco for its experiments. Although both programs began by looking at stationary space objects, their efforts to measure atmospheric turbulence would in the long run be applied to the Air Force’s antisatellite mission.2 Once it had received the Jasons’ recommendations, DARPA, through Rett Benedict, approached Petras Avizonis in July 1982 at the Air Force Weapons Laboratory to get the first Rayleigh backscatter experiment under way. Avizonis, a no-nonsense sort of guy, was the technical advisor to the lab’s advanced radiation technology office and turned out to be very

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supportive of the experiment. He believed the ideal place to carry out this experiment was at the Lab’s Sandia Optical Range and selected Bob Fugate to be in charge.3 The objective of Fugate’s first proof-of-concept experiment at SOR was to test whether the Rayleigh artificial guide star would work in the real world. As discussed earlier, only a tiny percentage of stars are bright enough that a telescope can use their light to measure atmospheric distortion and still have enough light left to record an image—thus the need for artificial guide stars. Researchers knew that at lower altitudes—where the air is denser and most atmospheric turbulence occurs—the backscatter return is stronger than at higher altitudes. They also knew that shorter-wavelength lasers produced more backscattered photons than longer-wavelength lasers.4 The question became, could the Rayleigh backscatter from a laser beam focused at an altitude of 5 kilometers (about 3 miles) be used to accurately measure the extent of distortion (phase errors) induced on the laser wavefront? To confirm that the measurements were of the highest quality, Fugate’s team needed to compare the data from the guide star with an independent reference—light from a real star. (The difference between the wavefronts of the star’s light and the laser’s backscatter, as discussed in chapter 4, is the focal anisoplanatism error—and the theory, which needed to be verified, was that this error would be small enough that the measurements would still be valid.) The narrow laser beam was directed within a few microradians of Polaris, the North Star. The starlight and the laser backscatter light would travel through nearly identical paths from the atmosphere to a telescope. Polaris was chosen because it does not move in the sky more than one degree in a 24-hour cycle, which allowed the experiment to be conducted without a gimbaled telescope. For most tests, Fugate explained, “the beam was focused at a range of 5 kilometers and the sensor was range-gated to accept backscattered light from 4.5 to 5.5 kilometers.” The gating mechanism allowed scientists to pick the exact altitude of the Rayleigh backscatter they wanted to view.5 Fugate and his small team of military, civilian, and contractor personnel began designing and building equipment in fall 1982 and started testing in late spring 1983. Members of the team included lieutenants Bruce R. Boeke and Richard A. Cleis, Raymond E. Ruane and Lawrence M. Wopat from the Weapons Laboratory, and contractors David L. Fried, George A. Ameer,

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Figure 7. Sketch of the laser guide star concept from Bob Fugate’s lab notebook.

Steven L. Browne, Phillip H. Roberts, and Glenn A. Tyler from the Optical Sciences Company. David Fried worked closely with Fugate to design the experiment. It did not involve a highly sophisticated telescope and optical system sitting high on a mountaintop. Instead, Fugate configured the hardware components of the experiment in a garage-like facility on the east side of the hill at SOR. This facility was originally known as the FTT building, the old home of the field test telescope used to support the Airborne Laser Laboratory program in the early 1970s.6 On the floor of the SOR facility were a laser device and a large table where the optical equipment was mounted. The walls in the corner section of the high bay of the building were hinged, allowing them to fold back, exposing the laboratory to the open air and providing a limited view of the sky. Positioned just outside the large doors was a 60-centimeter (23.6-inch) tracking mirror that served as a beam director. This flat mirror projected a laser beam (10 centimeters or about 4 inches in diameter) into the sky, Fugate’s Rayleigh Guide Star Experiments

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focused the beam on a small spot at an altitude of about 5 kilometers to create an artificial guide star, and collected the light it returned to Earth. To create the Rayleigh guide star—1,000 times brighter than Polaris— Fugate used a commercially available pulsed frequency-double Nd:YAG (neodymium-yttrium aluminum garnet) short-wavelength (0.532 microns) visible green laser that exhibited the desirable optical and thermal qualities and produced a beam of good quality. Another advantage of using a short-wavelength laser was that it produced more photon backscatter than longer-wavelength lasers. Rett Benedict described Fugate’s experimental configuration as “simple and straightforward” and said it was assembled “on an impressively small budget, cobbled together with very few people.”7 When the pulsed laser was turned on, scientists collected backscattered measurements. When the laser was turned off, they collected natural starlight measurements. The experiment did not use a traditional tracking telescope. Instead, the tracking mirror collected the backscattered light from the laser guide star and the natural starlight. From there, an 18 subaperture Hartmann-type arrangement (Risley prism plate) split the light into 18 separate images, which then reflected off the 40-centimeter (15.7-inch) primary mirror to a secondary mirror installed on the optical table. Fugate explained that, as part of the beam analysis, “two distinct sets of 18 such images were formed, one set being images of the laser guide star and the other being the images of the star [Polaris].” Using a series of prisms, the light was further processed to determine the wavefront tilt in each subaperture. This complicated process involved using one side of a camera to look at the 18 subapertures from the starlight while the other side of the camera simultaneously imaged the 18 subapertures from the laser guide star light. These images appeared as 18 spots on each side of the camera. “So we would grab a frame of images,” as Fugate described it, “and we had 18 spots on each side of the camera and then we measured how those spots moved frame to frame. And that’s what told us what the distortion was.” By comparing all these data, the difference between the distortions in the laser backscattered light and the starlight could be determined.8 Setting up and maintaining the optical components for the experiment was a tedious process. The equipment required constant attention and adjustments in order to obtain the precision measurements desired. Time was a critical issue, because there was a series of experiments that took place

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Photo 13. The first Rayleigh laser guide star experiment, conducted in

summer 1983 at Sandia Optical Range on Kirtland Air Force Base, New Mexico. The laser and optical components were housed inside the facility (lower left), with the exception of the 60-centimeter tracking mirror (lower center), which projected the laser beam in the direction of the star Polaris. Because of the classified nature of laser guide star work in the 1980s, this was the only photo taken during the experiment.

over several months to sample a wide range of atmospheric conditions. The more data were collected over a long period, the more reliable the measurements would be. The goal was to develop a comprehensive database that would demonstrate the similarities in the degree of distortions in starlight and laser light traveling along the same path through the atmosphere.9 Testing at SOR was interrupted many times because rain or clouds interfered with the way the laser propagated through the atmosphere. Even when the skies were clear enough to project a beam, the temperature was sometimes so low that when the doors of the test facility opened, Fugate and his team had to work wearing coats and gloves.10 Fugate’s Rayleigh Guide Star Experiments

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By the end of the summer and into October 1983, Fugate’s team was consistently measuring wavefront phase errors from the Rayleigh scattered light. But the best measurements were obtained in December. Findings showed that distortions of light from the natural star and the guide star closely matched. “These results demonstrate qualitatively,” Fugate proudly pronounced, “that laser guide-star beacons are effective in measuring atmospheric-turbulenceinduced wavefront distortion.” Fugate’s experiment proved for the first time that an artificial laser guide star could work. Moreover, Fried’s prediction about the difference in distortion measurements between starlight and laser backscatter was correct, which contributed to a better understanding of the physics associated with focal anisoplanatism. Fried’s theory on the effects of focal anisoplanatism was expressed in scientific language thus: the “meansquare wavefront error created by using an artificial guide-star at a finite distance rather than a real (infinity distant) star is proportional to the fivethirds power of the telescope aperture.” All of this represented a major turning point, as scientists now could point their telescope in any direction in the sky and establish a laser beacon that would accurately measure atmospheric turbulence. As one scientist described it, the guide star experiment was like taking a picture or X-ray of the atmosphere.11 Although the Rayleigh experiment at SOR was successful in proving the theoretical physics of using a laser guide star to detect and measure atmospheric turbulence—an open-loop experiment—it did not demonstrate the ability to correct for that turbulence. Not until 1989—after acquiring SOR’s 1.5-meter telescope—would Fugate and his Air Force Weapons Laboratory associates successfully demonstrate a closed-loop adaptive optics system that included a wavefront sensor, a high-speed computer processor, and a deformable mirror working together to correct for the wavefront distortions caused by the atmosphere.12 The Rayleigh experiment greatly improved the chances of developing a ground-based laser that could intercept a satellite. During this era, there was keen interest in delivering intense laser beams to targets in space, a concept that followed naturally from laser beam weapons being considered by the Strategic Defense Initiative (SDI) for ballistic missile defense. To make this happen required the development of large-aperture (3- to 4-meter) telescopes working in conjunction with high-performance adaptive optics.13 Precompensating an outgoing laser beam for a weapon is the opposite

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of compensating incoming light for an image. In essence, the adaptive optics system would purposely distort the outgoing laser beam wavefront. As it traveled through the atmosphere, distortions it encountered there would cancel out the distortions induced by the system, thus producing an undistorted beam focused on the satellite. The target satellite itself did not reflect enough light to serve as a beacon to measure distortions induced by atmospheric turbulence. However, a laser guide star could serve as an artificial beacon to make adjustments to the deformable mirror to precompensate a laser beam. A laser guide star would also help solve the point-ahead problem when trying to hit a satellite with a laser beam. Although the speed of light is extraordinarily fast (186,000 miles per second), the operator of a ground-based laser system would still need to lead the satellite slightly, much like a duck hunter must aim in front of a duck so that buckshot arrives at the moving target at precisely the right time. For the laser to be successful, a telescope would first have to acquire and track the satellite.14 The telescope would then point the laser slightly ahead of the satellite (approximately 50 microradians) so the laser could hit the satellite. A satellite orbiting at a range of 1,000 kilometers would travel about 50 meters (just over half a football field) from the time reflected sunlight traveled from the satellite to the telescope and the laser beam made the return trip to the satellite. To hit the target, it was essential to be able to measure the air turbulence along the point-ahead path from the laser device on the ground to the target satellite. The tracking and laser paths were different and encountered different degrees of air turbulence. After using a laser guide star to collect air turbulence data along the point-ahead path, an adaptive optics system on the ground would correct for the turbulence and send a compensated outgoing laser beam to hit the satellite as it moved across the sky.15 After the Fugate team produced accurate Rayleigh measurements at SOR in 1983, the Lincoln Lab experiment run by Ronald A. Humphreys at White Sands Missile Range succeeded, in early 1985, in projecting its large dye laser (tuned to the sodium wavelength) into the mesospheric sodium layer (see chapter 6). This was the first experiment of a sodium beacon that returned light to the ground in which two apertures less than a meter apart measured wavefront slopes from a star and from the sodium layer. As predicted by Fried’s theory, the higher-altitude sodium beacon was affected significantly less by focal anisoplanatism than the lower-altitude Rayleigh beacon.16 Fugate’s Rayleigh Guide Star Experiments

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Although the sodium beacon offered a more complete picture of air turbulence than the Rayleigh beacon, there were definite tradeoffs. One was that it was difficult to create a laser suitable for exciting mesospheric sodium atoms. As Humphreys explained, “The laser requirements for a sodium beacon are . . . more demanding than for a Rayleigh beacon. For efficient utilization of the sodium atoms, the laser must have a narrow linewidth and be accurately tuned to the resonant wavelength.”17 It was much easier to produce a Rayleigh beacon. Although it did not sample as much atmosphere as the sodium beacon, a Rayleigh beacon could collect enough data on air turbulence where its effects on light were the most damaging. Predictions made using Fried’s theory indicated a Rayleigh beacon would perform well on a 1.5-meter telescope, but that a sodium beacon would be needed for a telescope in the 3- to 4-meter class. In any case, there was no disputing that Fugate’s and Humphreys’s experiments at different locations in New Mexico—using two different techniques for collecting atmospheric turbulence data—made a fundamental contribution to the advancement of adaptive optics.18 In recognition of his 1983 work on laser guide stars, the Air Force Weapons Laboratory awarded Fugate its Giller Award, the highest honor a scientist could receive for scientific contributions to the laboratory. His work, the award citation read, “thrust the Air Force Weapons Laboratory into the forefront of atmospheric physics understanding” and “contributed immeasurably to the technological achievements of the High Energy Laser Program.” The Strategic Defense Initiative Organization also recognized this work as a major technical breakthrough that was essential for the development of high-energy short-wavelength lasers capable of performing future ground-based laser missions.19

Acquiring the 1.5-Meter Telescope Developing a real-time adaptive optics system at SOR was the next step after confirming that a Rayleigh guide star could measure atmospheric turbulence. The computers available in 1983 took several days to process atmospheric turbulence data, but to be effective, an adaptive optics system would need to process data in near real-time. A millisecond or so after measuring

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wavefront distortion, the system had to be able to convert the measurement to electrical signals that would change the surface of the deformable mirror and compensate for the distortion.20 To build a real-time closed-loop system, Fugate first had to acquire a telescope for SOR, which had not used one in the 1983 experiments. Ideally the aperture should be 2 meters (6.6 feet) in diameter. At the time, that was considered large, and Fugate and his team needed to understand how a telescope that size would perform in terms of air turbulence and wavefront distortions. A large-aperture telescope theoretically offered the advantage of collecting enough light to be useful for military applications such as antisatellite missions. For that type of mission, most experts believed a 4-meter (13.1-foot) telescope would be required. With plenty of light to provide the measurements to compensate for wavefront distortions, a larger telescope could place more laser power on target than a smaller telescope could, if beam compensation technologies could be sufficiently advanced. The only problem was that there was no telescope at SOR to conduct experiments.21 Fugate knew he needed a large-aperture telescope capable of tracking low-earth-orbit satellites to complete the next stage of his research. But it would take him 3 years of tough campaigning before a 1.5-meter telescope would become operational at SOR. Initially, Fugate took his case to the influential Pete Avizonis, the number-two person in the Advanced Radiation Technology Office of the Weapons Laboratory. Fugate proposed purchasing a 1.5-meter telescope mounted on a gimbal that could slew and observe any portion of sky. This would be a tremendous improvement over the existing equipment: a 24-inch flat mirror combined with a 16-inch offaxis parabolic mirror (used for the first Rayleigh experiments) that could move only one degree to track the star Polaris with a laser. Fugate got nowhere with the intractable Avizonis, who guarded the Lab’s money with an iron fist. Avizonis understood the scientific merit of a new telescope but said that the Weapons Lab simply did not have the money to pay for a piece of hardware that carried an estimated price tag of $800,000.22 But Fugate did not give up; the telescope was essential. He explored every potential backer. His next plan of attack was a visit in 1985 to the newly created Strategic Defense Initiative Organization (SDIO) in Washington, DC. (The organization had been formed after President Ronald Reagan’s Fugate’s Rayleigh Guide Star Experiments

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speech on the Strategic Defense Initiative on 23 March 1983.) There, Fugate impressed upon Colonel Tom Meyer, who headed SDIO’s directed-energy programs, the urgency of funding a 1.5-meter telescope at SOR. He assured Meyer the telescope would not only be critical for current adaptive optics research but, looking farther into the future, would also be essential for enabling laser beams to efficiently intercept and disable Soviet satellites.23 Fugate found SDIO very receptive to his proposal, but he also learned that Lincoln Laboratory, which also had been lobbying SDIO to fund a new telescope, was a strong competitor. Lincoln argued that it had been performing research in adaptive optics longer than SOR and was more entitled to a new telescope.24 In the end, Lou Marquet at SDIO decided to fund part of the cost of the proposed 1.5-meter telescope at SOR. Fugate suspected that what swayed SDIO’s decision was the Air Force’s commitment to pay for half of the $1 million cost. That was not the only reason that Marquet, who had worked at Lincoln Lab himself for 18 years and retained a close connection with his former employer, chose SOR over Lincoln. As a federal employee, Marquet felt honor bound to support the strongest proposal, and in this case he found Fugate’s application more convincing. SDIO agreed to pay for half of the 1.5-meter telescope’s cost—the other half of the bill was to be paid by the Air Force. Acquisition of the 1.5-meter telescope depended to a large degree on timing and President Reagan’s announced shift in national policy. SDIO gave a big boost to space technology research, and adaptive optics benefited enormously from it. Without SDIO, it was unlikely that the financial resources would have been available to support construction of SOR’s 1.5-meter telescope. Funding the telescope was a hefty obligation for SDIO and the Air Force, but it turned out to be a wise decision.25 Even though Lincoln lost out on its bid to SDIO for a new telescope, SOR and Lincoln Lab ended up working in parallel on a number of different projects involving laser beacons over the next few years. As an example, Lincoln conducted a series of experiments at Maui called Short-Wave Adaptive Optics Techniques, or SWAT, from May 1988 to April 1991. The purpose of these experiments, funded by SDIO, was to use adaptive optics to image stars and to propagate a low-power laser beam to a low-orbiting satellite. SWAT was the follow-on program to Lincoln Lab’s Atmospheric Compensation Experiment or ACE, conducted in the mid-1980s and also

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funded by SDIO. Scientists had attached beacons to aircraft and sounding rockets that served as a light source to provide air turbulence measurements in order to transmit a compensated laser beam to the aircraft and sounding rockets. Fugate noted that SOR and Lincoln scientists built a very productive relationship, usually meeting twice a year to share adaptive optics theory and experiments.26 Although SDIO funded half the cost of the 1.5-meter telescope destined for SOR, Fugate was responsible for determining exactly what size the telescope should be. He and a couple of colleagues from SOR traveled to Pittsburgh in 1985 to meet representatives of the Contraves Corp., which had a reputation for manufacturing optically superior telescopes. At the start, Fugate had set his sights on having a telescope built relatively quickly with a primary mirror about 1/2 meter in diameter. Once the discussions started with the Contraves engineers, Fugate asked whether they could scale up the telescope to 1 meter. After huddling to discuss the question, the engineers came back and replied that they could easily build a 1-meter telescope.27 Sensing he was on a roll, Fugate then asked, “What about a meter and a half?” More Contraves engineers joined the conversation, and they deliberated longer, but their answer was the same: they could do it. Pushing his luck, Fugate next inquired somewhat sheepishly, “How about 2 meters?” But the Contraves engineers immediately balked; they could not go that big. And that is how the size of the 1.5-meter telescope came about. Contraves used a MOMS (Mobile Optical Measurement System) telescope built for NASA as a baseline. The diameter of the MOMS aperture was only 0.75 meter. They would have to double that to reach 1.5 meters.28 By today’s standards, the meeting between Fugate’s small contingent and the Contraves representatives was remarkable considering all of the business and decision-making that occurred in the span of one afternoon. Part of the reason for this was that Contraves was a highly customer-oriented company that did not fit the mold created by larger aerospace companies that put high price tags on the products they sold to Department of Defense. As Fugate put it, he was very comfortable with Contraves’s business practices and was confident the Pittsburgh company would give SOR the most bang for the buck. He never regretted that decision. Contraves worked closely with Fugate and his team at every stage of the manufacturing process to ensure that specifications were met and the customer was completely satisfied.29 Fugate’s Rayleigh Guide Star Experiments

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Photo 14. A large crane gently lifts the 1.5-meter telescope off a flatbed truck

and prepares to lower it through the roof of the dome on the side of the hill at Starfire Optical Range at Kirtland Air Force Base, New Mexico.

It took Contraves 2 years to design and build the 1.5-meter telescope. Using a standard Cassegrain design, the new telescope came equipped with a parabolic primary mirror and a hyperbolic secondary mirror. Once it was completed, Contraves crated up the assembled telescope and its base, loaded it on a truck, gingerly transported it cross-country, and delivered it to an eagerly awaiting crew at SOR in May 1987. Driving the telescope from Pittsburgh to New Mexico was an event in itself: if the primary mirror had cracked or broken during shipment, it would have been a major setback. But the telescope arrived in perfect condition. It only took 3 days using a crane and lots of nervous manpower to position the telescope on its reinforced concrete base, which was isolated from the dome enclosure in which it was housed. Any unwanted vibrations on the dome’s floor would be isolated and not affect the telescope. Ash-Dome of Plainfield, Illinois, provided the steel dome that surrounded the telescope.30

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Photo 15. Contraves built the 1.5-meter telescope installed at

Starfire Optical Range.

Fugate and his crew rolled up their sleeves and participated in the construction work, using a large crane and scaffolding to put together the interlocking segments of the telescope dome. The building used for the 1983 Rayleigh experiments was modified by pouring a new concrete pier at one corner of the building to accept the 1.5-meter telescope and dome. A second floor was added to the original high-bay Rayleigh building to house the electronics and adaptive optics system to support the new 1.5-meter telescope. Fugate’s Rayleigh Guide Star Experiments

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When finished, the telescope looked through a narrow slit in the dome (an up-and-over style shutter) that shielded it from the wind. Rotating at an azimuthal (horizontal) rate of 10 degrees per second (fast for an astronomical telescope), the telescope and dome revolved in unison so the telescope could view any section of sky. By November, Fugate’s group had installed, aligned, and integrated all components of the telescope and started to test it.31 Fugate’s persistence showed that individual commitment to a cause could make a huge difference. At the time, Lieutenant Colonel Jim Mayo headed the newly formed Optics and Beam Control Division at the Weapons Lab that oversaw Fugate’s Propagation Phenomenology Branch. Like the SDIO’s Tom Meyer and others, Mayo attested to Fugate’s ability to get things done with a minimum of funding and staff. He had first convinced Mayo of the need to acquire a larger telescope, before presenting his case to a wary Avizonis. Not only did he succeed in winning the Lab’s endorsement, but he was able to acquire outside funding from SDIO to support his new venture. The Lab, perhaps not fully recognizing the potential consequences at the time, was about to embark on a whole new level of atmospheric compensation research, beginning with a series of defining experiments at Starfire Optical Range.32

That Magic Moment: Generation I and II Experiments Fugate and his team were relatively sure that the new 1.5-meter telescope would produce good images of astronomical objects. However, Fugate did not want to leave anything to chance and realized that neither he nor his team had hands-on experience operating such a large telescope. As a precautionary measure and to gain a better understanding of the new telescope, he asked Jim Mayo—who had retired from active duty and was working in the civilian world as head of the Optical Engineering group for Logicon RDA in Albuquerque—to conduct an independent evaluation of the 1.5-meter telescope’s optical performance.33 Mayo conducted his assessment in fall 1987 and reported to Fugate in December that as far as he could determine, the optical performance of the telescope was excellent. For all practical purposes, it seemed to be limited only by normal atmospheric turbulence, the thermal environment around

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Photo 16. The 1.5-meter telescope up and running at Starfire Optical Range

with the Manzano Mountains in the background. Air Force scientists used this telescope, equipped with adaptive optics, to conduct the Gen I and Gen II experiments.

the primary mirror, and to some extent, thermal conditioning in the coudé room beneath the telescope. These limitations were to be expected, and Mayo predicted the telescope would operate as advertised.34 With this reassurance in hand, Fugate and his team charged ahead with their experimental plans. SOR’s first successful series of closed-loop adaptive optics experiments were known as Generation I (Gen I) and Generation II (Gen II). Gen I lasted nearly a year, from June 1989 to May 1990. Gen II took place between February and May 1992. Both demonstrated that the SOR adaptive optics system was able to correct continuously for atmospheric turbulence using the laser guide star technique. During Gen I, the Air Force Weapons Laboratory operated SOR. When the Air Force inactivated the Weapons Lab in 1990, Phillips Laboratory took over operation of SOR. While the name of the organization changed, the mission, the people conducting the work, and the research facilities at SOR remained the same.35 Fugate’s Rayleigh Guide Star Experiments

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Although the official start date of Gen I was June 1989, Fugate’s team had already performed a number of preliminary experiments using the 1.5-meter telescope, to help integrate the telescope and the adaptive optics equipment and to get all the equipment calibrated and performing up to operational standards.36 Part of the reason for carrying out the pre–Gen I experiments was to confirm that Fugate’s team actually could close the loop and correct for atmospheric turbulence in the real-world environment. (Closing the loop for the first time was similar to the approach Alexander Graham Bell used to make his first telephone call to a person in the next room.) In late 1988 the team was able to prove that the adaptive optics system would work without using a laser guide star, a series of more extensive experiments followed to perfect the hardware, prove the theoretical concepts, and establish the reliability of the adaptive optics system using a laser guide star.37 After years of work, the confidence level was high in early 1989 among the SOR scientists, engineers, and technicians who had designed, assembled, and demonstrated the first closed-loop adaptive optics system. Fugate described those days as one of the high points of his career. He recalled, “We were so confident that this was going to work that it was almost a matter of course. It just happened to be that that was the particular time. It was a historical event!”38 Fugate drew a bold rectangular border around the 13 February 1989 entry in his SOR lab notebook to mark an important milestone: at 1 o’clock on that cold, dark morning, he and his team succeeded for the first time in closing the loop using the 1.5-meter SOR telescope in conjunction with an adaptive optics system and continuously correcting for distortions, in real time, using the Rayleigh laser guide star technique. The telescope and its optical hardware were configured just as they would be later for the Gen I experiments.39 One of the main reasons for the Fugate team’s confidence was that they had already proven the concept of the laser guide star technique in 1983 without using a telescope. With the 1.5-meter telescope, Fugate believed, closing the loop would be much easier. Still, a great deal of time and energy went into the preparation for this first round of experiments using the 1.5-meter telescope.40 Fugate’s team used the 1.5-meter telescope situated on a two-story concrete pier at the corner of the same building where the 1983 laser guide star

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experiments had taken place for the Gen I and II experiments. All the beam diagnostic equipment and adaptive optics components were mounted on an optical bench that had been built at SOR and was located in a coudé room on the ground floor directly underneath the telescope. All this equipment was housed in a temperature-controlled environment to avoid heat buildup, which could be damaging to the optics.41 For Gen I, the outgoing laser (built by Oxford Lasers Ltd., an English company) was a 75-watt copper vapor laser operating at 5,000 pulses per second that was passed through the telescope and focused at an altitude of 10 kilometers to form a laser guide star. The higher the pulse rate of the laser, the more samples of atmospheric turbulence could be made per second and the better the equipment could keep up with the changing conditions of the atmosphere. The telescope’s 1.5-meter parabolic primary mirror, covered with aluminum and a protective overcoat of silicon monoxide, collected the backscattered light from the guide star and then used the telescope’s secondary mirror and reimaging optics to focus the light to a beam 10 centimeters in diameter, which could then be diagnosed to measure the amount of wavefront distortion in the beam.42 A Shack-Hartmann wave-front sensor built by Adaptive Optics Asso­ ciates, Cambridge, Massachusetts, measured wave-front distortions in light waves from two bright sources—a natural star named Betelgeuse (Alpha Orionis, a giant red star near the shoulder of Orion) and the laser guide star. The wavefront sensor, using a fast charge-coupled device (similar to what is used in video cameras), measured hundreds of times per second exactly how much distortion or tilt was present in each of the 124 small light samples making up the beam that were distributed over 124 corresponding areas (subapertures) that comprised the surface area of the 1.5-meter telescope’s primary mirror. The wavefront sensor used a series of tiny lenses to focus the light reflected off all the subapertures of the primary mirror. It did that by assigning each sample of light across the wavefront to a single lens (124 lenses to 124 samples of light) whose job it was to focus its portion of light in the center of its assigned section of a “lenslet” detector array consisting of 124 subapertures. If there was no distortion in the light, that is a flat wavefront, each light sample would end up focused directly in the center of its assigned subaperture in the detector array. That was rarely the case as each portion of light was displaced from the center of its target because of distortions caused Fugate’s Rayleigh Guide Star Experiments

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Figure 8. Schematic of Shack-Hartman wavefront sensor concept. The inset

shows one magnified subaperture in the CCD array with the focused spot just left of center. If (as was rarely the case) there was no distortion in the light, the light sample would have been focused exactly in the center.

by atmospheric turbulence. (In the upper left quadrant [b] of the CCD array at the top right in Figure 8, the focused spot—a black dot—is just left of center.) However, the Shack-Hartman wavefront sensor could measure the amount of displacement in each of the 124 light samples plus combine all that information by mathematically calculating (matrix multiplying) how much the total light wavefront was displaced or out-of-phase from its ideal focus.43 To bring the distorted beam wavefront back into phase, a high-speed processor took the distortion measurements, computed the opposite displacement or conjugate for each of the 124 light samples (called subapertures), and sent an electrical signal to each of the corresponding actuators on the back of the deformable mirror, which in turn applied the conjugate on the mirror’s thin glass facesheet. Each of the 124 sections of the wavefront was thus corrected individually. As Fugate put it, “We’re measuring

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Figure 9. An electrical signal applied to each actuator determines the degree

of change to each section of the deformable mirror’s surface.

how much the wavefront is tilted over each little part of the aperture of the telescope. We don’t want these rays to be tilted—we want them all to be perpendicular to the telescope and so we make them perpendicular by moving the actuators on the deformable mirror and that’s what fixes them.” All this took place within milliseconds, and then the process started over.44 Using two separate light sources, a natural star and an artificial guide star, allowed almost simultaneous comparison to see if the distortions in the two light sources closely matched. With data revealing similar distortion measurements from the two, Fugate and his team were confident they could accurately change the surface of the 6-inch (15-centimeter) diameter deformable mirror to compensate.45 Computers had to process the data in near-real time to keep up with the constantly shifting pattern of air turbulence and calculate precisely the right voltage to apply to each of the 149 actuators that changed the shape of the mirror—833 times per second. This was one of the biggest challenges for Gen I. The number 833 was based on 1980s computer processing capabilities. Because of advances in high-speed processors over the years, today’s systems can make changes to a deformable mirror 8,000 times per second.46 “What we wanted to do,” Fugate explained, “was to make measurements at a high enough rate that we could then close a control loop on the deformable mirror and stay up with the changes in the atmosphere so we would have a high enough control bandwidth to correct for turbulence on a continuous basis.” That was accomplished, making Gen I a major milestone in the advancement of laser guide star adaptive optics.47 Fugate’s Rayleigh Guide Star Experiments

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Proof that the SOR adaptive optics system worked as predicted were two sets of clear images Gen I made—one using only the light from Betelgeuse to measure the wavefront distortions and to produce an image, and the other using the laser guide star light to measure distortions and the light from Betelgeuse to produce an image. The scientific yardstick for measuring the performance of the adaptive optics system was known as the Strehl ratio, after Karl Strehl, a professor at the University of Mittweida in Germany, who came up with the idea in 1902. The Strehl ratio measures image resolution by comparing the peak intensity spike of a compensated image to a perfect image. It results in a value between 0 and 1; 1 means there are no distortions in the wavefront. As Fugate explained it, “Strehl ratio is kind of like how bright is the brightest part of the image compared to what it would be if there were no distortions.”48 A Strehl ratio of 0.5 is considered very good when viewing objects through atmospheric turbulence. For the Gen I experiments, on average, the Strehl ratio of the images compensated by the laser guide star was 0.202. For images created using only the natural light from the star Betelgeuse, the number was 0.275. That number was higher because a higher percentage of the atmosphere was sampled along the full path of the natural starlight (from the star to the telescope) than along the shorter guide star corridor in the sky. As more atmospheric turbulence samples were taken, more comprehensive data could be collected to make more precise corrections. The natural starlight and laser guide star light produced satisfactory images and compared well with predictions based on the design of Gen I. Furthermore, the brightest parts of the images were 30 times brighter than images collected when the Gen I adaptive optics was not operating. Those uncompensated images appeared as foggy blurs, with Strehl ratios in the 0.03–0.05 range. But Fugate wanted to achieve higher Strehl ratios.49 The Gen I experiments helped pave the way not only for producing clearer images of distant space bodies, but also for ground-based laser beam propagation. The ability to correct for atmospheric turbulence acquired from the Gen I experiments put weapon designers one step closer to an operational ground-based laser weapon for antisatellite/ballistic missile defense.50 After Gen I reached completion, Fugate and his team turned their attention to Gen II, a second-generation adaptive optics system using more advanced hardware components and a much more proficient optical design.

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Among the critical components that resulted in higher quality images was a more sensitive and accurate Shack-Hartman wavefront sensor that used two separate detector arrays—one for the natural starlight and the other for the guide star light. Another was a new and larger deformable mirror, manufactured by Itek for Rome Air Development Center nearly 7 years earlier, which had 241 actuators compared with Gen I’s 149. The mirror consisted of a thin layer of ultra-low-expansion glass provided by Corning Glass in New York. A new processor and a more powerful copper-vapor laser also boosted performance. The new laser had 5,000 pulses per second and an average power of 180 watts, which generated more backscatter light than the 70-watt laser used in Gen I. With more light provided by the laser guide star, more accurate readings of atmospheric turbulence could be acquired, resulting in a higher level of mathematical precision for changing the surface of the deformable mirror. Gen II also used a high-resolution chargecoupled device (CCD) camera—better than the Gen I CCD—to capture images. CCDs made up of a silicon chip with thousands of light-sensitive pixels have replaced film and offer an instantaneous electronic readout of the image.51 On 18 February 1992, the Gen II adaptive optics system at SOR closed the loop for the first time and acquired a sharp image of Betelgeuse. The Strehl ratio of this first image was 0.55, which surpassed the quality of any image created during Gen I. Gen II provided clear images of a number of other heavenly objects including the star Arcturus and the binary stars Capella and Zeta Orionis. To produce these images, the Gen II system made changes to its deformable mirror 1,664 times per second, twice as fast as Gen I. Improved processing speeds and the use of a more powerful laser made possible extremely fast changes to the deformable mirror, removing distortions in the light wavefront. Brent Ellerbroek, a mathematician on Fugate’s team, played a key role by developing the algorithms needed to make the Gen II system work.52 Image resolution improvement from Gen I to Gen II was enormous. For example, prior to Gen II, images of the two parts of the binary star Zeta Orionis were fuzzy. This changed dramatically with Gen II, which produced images at a reduced size, improving the resolution by a factor of nearly 200. The images captured by Fugate’s team rivaled those of the Hubble Space Telescope, and the adaptive optics system used with the 1.5-meter telescope Fugate’s Rayleigh Guide Star Experiments

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was considered the most advanced system anywhere in the world, surpassing the system Lincoln Lab used in its SWAT experiments on Maui.53 The data produced by Gen II were of much higher quality than those from Gen I. On average, Gen II images revealed a Strehl ratio of 0.513 for a natural star and 0.321 for a laser guide star. The best Strehl reading obtained from a single Gen II experiment was 0.64 using light from a star. For a laser guide star, the top Strehl measurement was 0.48. Gen II, when using a laser guide star, was able to capture images at a resolution nearly a factor of 30 better than those taken by an uncompensated telescope. When the openloop images were compared to the closed-loop images, Fugate wrote, “there is an incredible difference in intensity, the open-loop images being barely visible.” At the time it operated, Gen II was the world’s most technically advanced adaptive optics system. It served to establish a solid technical foundation for the Air Force adaptive optics program and reinforced the notion that adaptive optics was a realistic and reliable technology.54 Gen I and Gen II received generous praise from the upper echelons of the Air Force. On 19 June 1992, Major General Robert R. Rankine Jr., deputy chief of staff for technology at Air Force Systems Command at Andrews Air Force Base in Washington, DC, announced that the Air Force Scientific Advisory Board had selected the Fugate team’s work from over 40 nominations as one of the two top science and technology activities in the Air Force.55 Rankine stated he had been following SOR’s work since the early 1980s and was greatly impressed by the progress made, which he described as world-class research that set the example for the entire Air Force laboratory community. Moreover, Fugate’s advances in adaptive optics had attracted national and international attention, which greatly enhanced the scientific reputation of Phillips Laboratory. “As you know,” the general wrote, “the potential payoff of their work is phenomenal. It is the enabling technology for any ground-based laser application, from high-energy weapons to lowenergy communications and imaging.”56 One of the main benefits derived from Fugate’s program was that it helped promote the scientific reputation of the Air Force. SOR had established an enviable track record as the most advanced military adaptive optics research site in the country. In the process, Fugate emerged as a world leader in adaptive optics.57 Gen I and Gen II work laid the groundwork for compensated imaging

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Photo 17. Starfire Optical Range’s 1.5-meter telescope imaged Saturn and its

moon Titan. Above is an image produced without adaptive optics. Below is a much higher-resolution image, produced with adaptive optics, with Titan clearly visible on the right. Fugate’s Rayleigh Guide Star Experiments

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experiments extending into the 1990s. The 1.5-meter telescope became the workhorse of the SOR site and continued to produce high-resolution images of space objects. As an example, in January 1994 the 1.5-meter telescope delivered excellent images of the Orion nebula, a gaseous region 1,500 light years from Earth in the sword of the constellation Orion. These ionized gases surrounding stars are comet-like in appearance and similar in mass to our sun. The Hubble Space Telescope had captured similar images a year earlier, but the SOR images were taken closer to the star that created the Orion nebula.58 SOR’s 1.5-meter telescope also played a key role in the mid-1990s in experiments that advanced techniques for acquiring, tracking, and imaging low-earth-orbiting satellites. As part of that process, SOR’s 1.0-meter coelostat or beam director projected a low-power laser beam to illuminate a satellite passing overhead. The 1.5-meter telescope received the reflected laser light from the satellite and used it as a reference point to track the spacecraft. Since this was active tracking—as opposed to passive tracking, which relied on sunlight reflected off a satellite and was limited to viewing times just before sunrise and after dusk—a satellite could be tracked 24 hours a day, including when it was in the Earth’s shadow and when daytime background light levels were too high for conventional tracking. The reflected light could also be captured and processed by the 1.5-meter telescope’s adaptive optics system to produce high-resolution images of the satellite that would be useful for surveillance and for determining the satellite’s health. Those images were about 25 times better than uncompensated imagery and near the diffraction limit of the 1.5 meter telescope.59 Over the years the steady performance of the 1.5-meter telescope led to a number of collaborative research opportunities in adaptive optics. One such project, sponsored by the Air Force Office of Scientific Research in spring 1994, involved five astrophysicists—four from the Arcetri Astrophysical Observatory in Florence, Italy, and one from the Max Planck Institute for Astronomy in Heidelberg, Germany—who teamed up with Fugate’s group at SOR to conduct experiments using the 1.5-meter telescope and its adaptive optics system. Dr. Domenico Bonaccini, who headed the Italian contingent, was in charge of designing an adaptive optics system for Italy’s new 3.5-meter Galileo National Telescope, scheduled to be operational in the Canary Islands in 1995, and wanted to learn as much as he could about the system at SOR. Fugate and his associates

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were interested in Italian research that looked at the feasibility of transferring the atmospheric compensation functions normally carried out by the deformable mirror to a telescope’s secondary mirror.60 Although beset with poor weather at SOR during most of their 3-week visit, the Italians managed to take advantage of several good nights of seeing conditions. They were able to use their cryogenically cooled nearinfrared camera, working first without the 1.5-meter telescope’s adaptive optics system and then with it, to produce high-quality images of several star groupings. The compensated images acquired using adaptive optics were a marked improvement over the images obtained without it. In addition, the images of a multiple star system taken with the Italian camera were “the first in these wavelength regions [1.25, 1.62, and 2.2 micron bands] made with the SOR adaptive optics system, and will help us [the Air Force] understand system performance in this part of the spectrum.” Part of that understanding was learning more about how well the adaptive optics system performed when viewing two separated stars over a large field of view as opposed to a single, narrow view. Those experimental data helped to determine how closely theoretical predictions of image quality, based on computer modeling, compared with results obtained experimentally.61 SOR made it a policy to take advantage of every opportunity to participate in cooperative research, including work with the 10-meter Keck telescope at Mauna Kea in Hawaii, the largest telescope in the world, and with the Mount Wilson Observatory in California. Moreover, in a move to promote the sharing of knowledge between the military and civilian astronomers—referred to in Air Force parlance as technology transfer— the National Science Foundation (NSF) established funding for astronomers affiliated with universities to spend several weeks using SOR’s 1.5-meter telescope, supporting civilian astronomical research at military facilities. In 1995, for example, the NSF awarded $400,000 to university astronomers to conduct research at SOR on potential applications of adaptive optics to astronomy. The visiting astronomers came from the University of Texas, the University of Chicago, Columbia University, the University of Arizona, Ohio State University, Georgia State University, and the Rochester Institute of Technology. These cooperative agreements went a long way to establish strong research ties between the Air Force and academic astronomers.62 Fugate’s Rayleigh Guide Star Experiments

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Sandia Optical Range: Anchor of Adaptive Optics Research Sandia Optical Range is a 190-foot topographical bump in the relatively flat landscape adjacent to the foothills of the Manzano Mountains, a few miles south of Albuquerque, New Mexico. Located in an isolated and offlimits area in the southeast corner of Kirtland Air Force Base, SOR consists of a hill formed from a natural outcropping of granite that rises 6,240 feet above sea level. The solid granite provides an ideal foundation for stabilizing the telescopes and other sensitive optical equipment used at the site. The Manzanos to the east serve as a natural backstop to absorb stray laser beams fired from the range. SOR is bordered by the Isleta Indian Reservation to the south; land to its north and west belongs to Kirtland Air Force Base. SOR’s total area, including the hill and surrounding downrange sites, is about 3 square miles.63 SOR has been the Air Force’s premier experimental laser and beam propagation test range since the early 1970s. Construction began in February 1970. It became fully operational in March 1971, making it the first high-power longrange laser propagation and test range in the country. It was originally built to support the Airborne Laser Laboratory (ALL), which sought to develop and install a high-energy laser aboard a modified NKC-135 aircraft in order to determine the feasibility of a laser weapon that could engage tactical air missiles. SOR was the most important facility supporting experiments that proved the physics of high-energy lasers as potential weapons. The result of that work eventually led to the engineering integration of a high-energy laser (Air Force Laser I, which was part of the DoD Tri-Service Laser program) with a first-generation field test telescope (FTT) built by Hughes. The job of the FTT pointing and tracking system was to focus and direct a groundbased laser beam to intercept an aerial target. That work was a critical part of Project DELTA, or Drone Experiment Laser Test and Assessment.64 Project DELTA was one of the first field technology tests conducted at SOR. An Air Force Weapons Laboratory team used a CO2 laser in November 1973 to shoot down a radio-controlled aerial target (drone) as it flew a racetrack pattern between SOR and the nearby Manzano Mountains. This was the first time that a high-energy, ground-based laser had disabled an aerial target; it took place when lasers had only been on the scene for 13 years. It served as a political rallying point to sustain laser research in

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general and helped persuade those unfamiliar with the still-new technology of the urgency to move forward with the airborne laser program.65 DELTA could be seen as the first in a long line of technological advances that led to the ALL shooting down five AIM-9B “Sidewinder” air-to-air missiles over China Lake, California, in May 1983. By 1979, for all practical purposes, the ALL had completed its work at SOR and progressed to flight testing. It was at that point that SOR started to shift from an airborne laser facility to an adaptive optics research site. Fugate was responsible for getting adaptive optics research underway at SOR and shepherding it through its difficult early days. Much like the Airborne Laser Laboratory activities at SOR, adaptive optics advanced in small incremental steps but culminated in major technological breakthroughs, such as the laser guide star proofof-concept in 1983, followed by the closed-loop successes of the Gen I and II experiments from 1988 through 1992.66 SOR had several advantages for adaptive optics work. First was its proximity to the laboratory—first known as the Air Force Weapons Laboratory, then as Phillips Laboratory, and then as the Air Force Research Laboratory—which made working there more cost-effective than moving to an operational site such as Maui. At SOR, scientists had complete control over budget, personnel, administrative issues, hardware, real property, and so on, without having to deal with the distractions of an operational organization. Second, from previous programs, SOR already had in place experienced staff and facilities suited for generating laser beams. Third, and probably most important, SOR did not have the luxury of pristine viewing conditions as did the Maui site, sitting at the top of a high mountain in the middle of the ocean—but that was actually an advantage, because the technologies the team aimed to develop would have to perform effectively in the harsh environments that operating commands would face.67 SOR was one of the main reasons that Fugate and other adaptive optics scientists continued working for the Air Force. Not only was the work extremely challenging, but those employed there believed they were making important contributions to the national defense. “We have a unique set of capabilities and equipment,” Fugate pointed out, “that just doesn’t exist at other places, and opportunities to look into what kind of problems exist and how we can help solve those problems.” In addition, funding for SOR research efforts remained steady. Long-term investment and strong commitment to Fugate’s Rayleigh Guide Star Experiments

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SOR were necessary to support SOR’s one-of-a-kind telescopes, optical diagnostic equipment, laser devices, and highly qualified workforce.68 SOR stood in stark contrast to most university operations, which did not have the budgets to compete with this expensive military operation with its cutting-edge facilities and state-of-the-art equipment. This led to some professional rivalries and jealousies. Universities could not compete at that financial level, but the military scientists could certainly compete with academia in terms of advancing the theory and application of adaptive optics. The intellectual capacity of the Air Force military and civilian workforce took good advantage of the first-rate facilities at its disposal by achieving breakthrough technologies in physics and optics before their counterparts in academia.69 While universities were hampered by budget limitations, private industry, motivated almost exclusively by profit, was also at a disadvantage because it was not always willing to maintain a fixed flow of funding for adaptive optics research. Companies made money on a time cycle dependent on when the Air Force awarded contracts, which could be unpredictable because of political and economic factors as well as changes in the military’s mission. Issuance of government contracts could be a tricky and risky business depending on how much the military needed outside help from year to year. A private company had no guarantee of a new or renewed contract from the government. But scientists working on adaptive optics for the Air Force could be more confident of continued funding. Although the Air Force adaptive optics program itself was on stable footing, the name of SOR went through changes. When SOR first opened in 1971, the acronym stood for Sandia Optical Range. On 1 November 1984, it was renamed the Directed Energy Experimental Range or DEER by the commander of the Air Force Weapons Laboratory, Colonel James M. Walton. His rationale was to make the site available for laser research and other promising directed-energy technologies such as microwaves and particle beams. The newly created Strategic Defense Initiative Organization had charged Air Force laboratories with accelerating their research efforts to explore not just lasers but all technologies with potential for helping to achieve the nation’s ballistic missile defense mission.70 The name DEER never caught on, as employees and visitors continued to refer to the site as SOR. Shortly after Colonel John Otten became the

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commander of the Weapons Laboratory in August 1988, he phoned Fugate and told him that he wanted to reinstate the acronym SOR—but that it could not stand for Sandia Optical Range, because too many people associated that with Sandia National Laboratory (also located on Kirtland Air Force Base, but having nothing to do with SOR). Otten directed Fugate to call him back by the end of the day with a new name that would match the initials SOR.71 Otten was the type of commander who wanted to charge ahead and accomplish the mission at hand without delay. Waiting was not his strong suit. That’s why he turned to Fugate for help. He knew Fugate was the most knowledgeable person about SOR and would come up with the right answer. Fugate didn’t disappoint the Weapons Laboratory commander. He proposed the name Starfire Optical Range, based on a photo taken at SOR showing a green laser beam propagating through the dark sky in the direction of a bright natural star far off in the heavens. The image of the “star” combined with the laser’s heat or “fire” seemed a fitting combination. “So I called Otten back,” Fugate remembered, “and suggested that we call it Starfire Optical Range—he loved it and that’s the way it happened.” On 7 December 1988, Otten signed a letter making the name change official.72 The name change was successful, and the research program flourished, but a new problem arose: the Federal Aviation Administration (FAA) became increasingly concerned about the potential health hazards of SOR lasers penetrating the night sky so close to Albuquerque International Airport. The FAA was particularly concerned about the possibility of commercial pilots being exposed to laser light that exceeded eye safety standards and might affect a pilot’s ability to fly or land an aircraft. In general, the FAA considered laser beams “hazardous to aircraft and all persons on board.” The FAA requested that SOR stop firing any lasers where the beam might stray into commercial airspace and direct laser beams only into restricted airspace. But officials said the agency would withdraw its objection if there were adequate safety measures in place.73 On 1 September 1989, FAA and Air Force Weapons Laboratory representatives met at SOR to settle the issue. Much of the meeting focused on the operation of the laser and the aircraft detection radar at SOR. The laboratory’s Major John Anderson led much of the discussion to dispel the perception that all lasers instantly vaporize anyone in their path. He explained that SOR was not using a high-power laser that could blow an airplane out Fugate’s Rayleigh Guide Star Experiments

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of the sky but rather a low-power copper vapor laser beam with only about 30 watts of output—not enough to cause damage unless it was focused directly onto the eye. On average, SOR fired the laser only about five nights per month. Each firing lasted no more than 15 minutes. In short, the laser was harmless and seldom used.74 SOR set up two safety precautions to prevent any laser beam from inadvertently intercepting an aircraft. First, SOR installed a Bendix aircraft detection radar system on the end of the laser telescope. Wherever the beam went, the radar followed along the same path. If the radar malfunctioned, then the laser shut down automatically. During any laser test, the radar would always be able to detect any aircraft within 3 miles of the beam. If that occurred, the test would immediately terminate.75 A second safety procedure involved a human spotter to back up the electronic radar system. The spotter, positioned on the roof of the telescope facility, was to constantly scan the sky before and during a laser test to make sure no aircraft was nearby. As explained to the FAA, “The roof spotter has an auto shutoff switch in his hands. If an aircraft is observed by the spotter before the aircraft enters the radar coverage, the spotter can also shut down the laser beam in one-tenth of a second.”76 As the FAA representatives became more familiar with SOR, they became convinced that the laser testing there was not a threat to aircraft flying near the airport. They agreed that the radar and human spotter system were adequate precautions. However, if SOR used higher-power lasers in future testing, the FAA wanted to study the matter and approve all safety procedures before those tests took place in unrestricted airspace.77 Safety had been a priority at SOR since the beginning. SOR as a firstclass research facility—often referred to as an Air Force center of excellence—was an invaluable national resource that helped Fugate and his team to achieve significant technical milestones. This work was strictly classified. But that changed in 1991 when the Air Force decided to declassify the program and share its revolutionary technology with the astronomical community. Up to that point, astronomers had been unaware of—literally in the dark about—the tremendous progress made by military scientists in the field of adaptive optics.

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Lincoln Laboratory

At the same time that Bob Fugate’s team of Air Force scientists were conducting the Rayleigh guide star experiments, Charles Primmerman was leading a Lincoln Laboratory team at White Sands Missile Range in southern New Mexico that would be the first to experimentally verify the sodium guide star concept. Located in Lexington, Massachusetts, on Hanscom Air Force Base, Lincoln Laboratory had established a reputation as one of the premier research and development institutions in the country. For over 50 years Lincoln has performed theoretical studies and experiments in areas including air and space defense, earlywarning systems, space and tactical battlefield surveillance, computers and signal processing, and advanced electronics. Lincoln’s origins go back to the early days of the Cold War. Because of the growing threat that the Soviet Union had the capability of using longrange aircraft to drop atomic bombs on American cities, Air Force Chief of Staff General Hoyt S. Vandenberg approached James R. Killian, president of the Massachusetts Institute of Technology (MIT), about creating a special laboratory dedicated to developing the technologies needed to defend

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the United States against a nuclear attack. Formed in 1951, MIT/Lincoln Laboratory’s original mission was to assist the Air Force in developing an air defense system made up of dispersed systems of radars that could find and intercept enemy aircraft carrying nuclear weapons. Lincoln Laboratory came into existence as a self-governing research agency under the operational control of MIT. The government funded MIT, which in turn administered the laboratory and paid the salaries of the approximately 200 technical staff who initially worked there. That number grew to over 600 by the early 1980s.1 Lincoln Laboratory fit into a special category known as Federally Funded Research and Development Centers or FFRDCs. Under that arrangement, the laboratory served as a civilian partner to the military but conducted its day-to-day research outside normal military channels of command. Lincoln Lab scientists had a level of technical expertise that was not readily available within the government’s civil service system. Design of a computer-driven air defense system against enemy bombers, known as the Semiautomatic Ground Environment or SAGE, was the first tangible result of Lincoln’s research efforts.2 The Defense Department sponsors several other FFRDCs including the following: the Aerospace Federally Funded Research and Development Center, operated by The Aerospace Corporation, El Segundo, California; Arroyo Center, National Defense Research Institute, and Project Air Force, all run by the RAND Corporation, Santa Monica, California; C3I Federally Funded Research and Development Center, administered by the MITRE Corporation, Bedford, Massachusetts, and McLean, Virginia; the Software Engineering Institute at Carnegie Mellon University, Pittsburgh; the Institute for Defense Analyses Studies and Analyses, operated by the Institute for Defense Analyses, Alexandria, Virginia; and the Center for Naval Analyses in Alexandria, Virginia.3 Over its first five decades, Lincoln Laboratory expanded beyond its original air defense mission to include satellite communications, ballistic missile defense, and space surveillance. By the 1970s and 1980s, Lincoln had become more active in studying the transmission of high-energy laser beams through the atmosphere and the effects of thermal blooming on beam quality—and in investigating adaptive optics. DARPA, the Strategic Defense Initiative Organization, the Air Force, the Navy, and the Army funded a large share of the laboratory’s work.

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White Sands: The Sodium Guide Star Experiment One of Lincoln’s most important contributions to adaptive optics was the sodium guide star experiment that had evolved from discussions at the Jasons’ 1982 summer study. Like the Rayleigh guide star at Kirtland, Lincoln’s sodium guide star was intended for use as a reference light source to replace light from a natural star, but it was located at a higher altitude and returned light to Earth in a somewhat different way. Both were funded by DARPA.4 The goal of the first sodium experiment was to determine how much distortion was present in the laser light returned from the mesospheric sodium layer. This layer is about 10 to 15 kilometers thick and 90 kilometers in altitude. A laser must be tuned precisely to the wavelength of the selected sodium line, usually the D2 line at 589 nanometers, for resonant backscatter to occur from the sodium layer. At that wavelength, a portion of the laser light shined into the sodium layer is absorbed by the sodium atoms and then reemitted. The reemitted light travels to the ground and serves as the sodium beacon. In comparison, light from a Rayleigh guide star is not absorbed and reemitted but rather reflected off molecules in the lower atmosphere.5 For the sodium beacon experiment, Lincoln scientists simultaneously measured distortion of light from a natural star and light from a sodium beacon aligned in the same direction. Measurements from the natural star and the guide showed a good match. At this stage, Lincoln purposely did not attempt to compensate for the distortions in the light, but simply to detect the degree of atmospheric turbulence and distortion. In September 1984, a Lincoln Laboratory team demonstrated for the first time that “phase distortion could be measured with a synthetic beacon in the mesospheric sodium layer.”6 DARPA’s motivation for funding Lincoln was to find out if a sodium beacon could provide the necessary atmospheric turbulence data to accurately propagate a short-wavelength laser beam to an uncooperative target (one with no beacon or light source on it) such as a satellite or missile. To accomplish this required measuring turbulence along the beam’s path and compensating for it with adaptive optics. Because of the satellite’s distance and speed, the synthetic beacon had to be pointed ahead of it (much, as discussed in the previous chapter, as a hunter leads a duck). In the process Lincoln Laboratory

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of solving this problem, scientists had to sample and measure turbulence along the same atmospheric point-ahead path that a laser beam from the ground would follow in order to intercept the satellite.7 This point-ahead angle was determined by the direction of the satellite and the direction of the laser beam trying to intercept it. The formula used to calculate the angle was 2v/c, where v is the target velocity and c is the speed of light. For low earth-orbiting satellites, the point-ahead angle is about 50 microradians. The sodium wavelength laser was aimed in the point-ahead direction, 50 microradians ahead of the satellite. Turbulence measurements from the sodium beacon, which served as a light source from the projected target intercept point, was then used to purposely distort or conjugate the wavefront of the outgoing laser beam in such a way that atmospheric turbulence would cancel out the distortion and put the beam on target.8 Lincoln Lab’s Darryl Greenwood was responsible for the overall sodium experiment at White Sands. Chuck Primmerman, who worked for Greenwood, served as group leader and provided guidance for the sodium beacon test, which was identified as the first Short-Wavelength Adaptive Techniques or SWAT experiment. Primmerman, who had started working for Lincoln Lab in 1975, revealed a deliberate and calm demeanor in his dealings with science and people. One could almost see the wheels turning in his head as he came up with solutions for tough technical problems. He was smart and well organized and earned a solid reputation as one of Lincoln Lab’s leaders in the field of adaptive optics.9 The sodium guide star’s success was the product of work by a number of Lincoln Lab technical staff under the direction of Ron Humphreys, who worked in Primmerman’s group. Humphreys came from the United Kingdom, worked for Lincoln, and then returned to his native land upon retirement. He relied heavily on the engineering talents of Robert Knowlton. Lincoln scientists had two objectives for the experiment: to demonstrate the feasibility of the sodium beacon and to show that it sampled a larger proportion of the atmosphere than a Rayleigh beacon, which would validate the concept that focal anisoplanatism decreases as the beacon’s altitude increases. On both counts, the experiment proved successful. Data showed that sodium beacons provided more complete information on atmospheric turbulence than Rayleigh beacons, and Lincoln Lab scientists

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concluded that an adaptive optics system using a sodium beacon would perform better.10 Humphreys used a 1-meter aperture auxiliary beam director, built by Contraves, that projected a pulsed dye laser from the ground to the sodium layer. The beam director, consisting of two flat mirrors, had no optical power to focus a beam but simply pointed it into the sky. Dye lasers can be tuned to almost any frequency, including sodium. Most of the laser firings occurred in the late evening, when there was less turbulence. The return wavefront from the sodium layer traveled to two receiver systems, subapertures of a Hartmann wavefront sensor located in the beam director—two telescopes positioned on an optical table 76 centimeters (30 inches) apart. Tilt measurements of the wavefront were then compared between the two subapertures. In comparison, SOR used 18 subapertures for the Rayleigh beacon experiment in 1983. Lincoln chose to limit the experiment to two subapertures for simplicity’s sake. Theory suggested that if these measurements were accurate, then it would not be unreasonable to believe that, in time, measurements could be made over four subapertures, then six, and so forth.11 Lincoln Laboratory had trouble from the start with its flashlamppumped pulsed dye laser, built and operated by Avco Everett Research Laboratory. That was one of the main reasons why the sodium beacon experiment did not produce positive empirical results until late 1984. The Avco laser was not a sodium laser per se, but a laser that worked at the sodium wavelength by using a dye—Rhodamine 590 6G chloride, one of the most highly fluorescing materials known—tuned to the desired wavelength. The medium for a dye laser is liquid dye (similar to organic dyes used to color fabric) flowed in a solvent to create lasing action. Perfecting the laser to operate at the desired wavelength required patience and precision. Results frequently fell short of Lincoln Lab’s operating expectations.12 Even under the most favorable conditions, only about one photon in sixteen interacts with the few sodium atoms that exist in the sodium layer. The energy level of the Avco laser was lower than predicted, and it failed at this task. A more potent laser would have produced more photons and increased the probability of photon interaction with the limited number of sodium atoms, which in turn would result in a greater sampling of the desired portion of the atmosphere for turbulence. The laser was also big, complicated, and unpredictable. The circulation pumps and the large tanks Lincoln Laboratory

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Photo 18. Research facilities at White Sands Missile Range, New

Mexico, used for Lincoln Laboratory’s sodium beacon experiment. At right is the dome housing the 1-meter auxiliary beam director that aimed a low-power laser beam to the sodium layer at an altitude of 90 kilometers. This 1-meter beam director originally was set up at Rome Air Development Center’s Verona Test Facility and was later moved to White Sands and used for Lincoln Lab’s sodium beacon experiment. After completion of the sodium work, this same 1-meter beam director was moved to Kirtland Air Force where today it resides on top of the hill at Starfire Optical Range and is used for a variety of optical experiments.

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that stored the chemicals required frequent monitoring and maintenance for the dye laser to work.13 It took nearly 2 years to work out all these problems and reach the point where the sodium beacon experiment was producing a steady flow of data, which occurred between September 1984 and early 1985. In spite of the difficulties, the experiments proved for the first time that a sodium beacon could measure phase distortions in a beam caused by atmospheric turbulence, information needed to make corrections to an outgoing laser beam.14 Lincoln Laboratory was not the first to create an artificial guide star— that honor went to Starfire Optical Range in 1983. But SOR was able to use almost any kind of laser (it chose a visible green frequency doubled Nd:YAG laser), while Lincoln was restricted to using a dye laser tuned to the sodium line of 589 nm, which was a daunting challenge. The Rayleigh beacon was also focused relatively low in the atmosphere, which meant anisoplanatism was a bigger problem, but the return signal was also stronger. The higheraltitude sodium beacon, on the other hand, sampled a greater portion of the atmosphere and had less of a problem with focal anisoplanatism. The two projects complemented each other and made a major contribution to the advancement of adaptive optics.15 Often it takes time before the significance of an experiment and the contributions of the people who worked on it become recognized. Nine years after the sodium beacon experiment, Primmerman received the Technical Achievement Award from the International Society of Optical Engineering for his contribution to laser guide star technology, which the society described as revolutionizing ground-based astronomy. Primmerman was careful to point out that this was a team contribution and that the other key team members—Humphreys, Knowlton, Lee Bradley, Jan Herrmann, and others—were the scientific wizards who made the sodium beacon work.16 To underscore the success of the collaborative approach, Primmerman shared his 1993 award with three contributors from other organizations: David Fried of the Optical Sciences Company; Robert Fugate of the Air Force Phillips Laboratory, and Richard Hutchin of Optical Physics Consulting.17 Lincoln Laboratory’s work on artificial beacons had solved only half of the problem. The team’s next big challenge was to develop a closed-loop adaptive optics system that could assimilate the data on atmospheric turbulence and use it to compensate for distortions in light beams. Lincoln Laboratory

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Maui: The First Closed-Loop Synthetic Beacon Following the success of the sodium beacon experiments at White Sands, Lincoln Laboratory shifted its attention to a series of adaptive optics experiments at the Air Force Maui Optical Site (AMOS) atop Haleakala mountain on the Hawaiian island of Maui. These August 1988 experiments made up the second part of the SWAT program. In February 1988, Lincoln shipped its adaptive optics system to Maui, where it was installed on the 60-centimeter (23.6-inch) beam director. Primmerman remained overall group leader for the work at Maui, but Lincoln Lab’s Byron Zollars, the lead engineer, designed and ran the experiments.18 The SWAT adaptive optics system used a Hartmann wavefront sensor and wavefront reconstructor built by Lincoln Lab and a deformable mirror with 241 actuators built by Itek. The system’s design allowed it to compensate for atmospheric turbulence both in images of space objects and in outgoing laser beams. The purpose of the Lincoln Lab SWAT experiments was to demonstrate that atmospheric compensation could be accomplished using a synthetic beacon. If the adaptive optics system worked, it would produce high-resolution images of stars viewed coaxially with the beacon lasers. Although Lincoln’s pioneering work had been with the sodium beacon, the team decided to use a Rayleigh beacon at Maui instead because of the difficulty in fabricating a sodium beacon.19 Lincoln used a flashlamp to excite a mixture of Coumarin dye, acetic acid amide, and water to generate a low-repetition-rate dye laser for its Maui experiment. Proving the SWAT adaptive optics system could operate in a closed loop meant first sensing the atmospheric distortions in the return beacon laser beam and then compensating for them. The light backscattered from the Rayleigh beacon was collected by the beam director and directed to a wavefront sensor that measured distortions in the light. Based on those measurements, electrical signals were sent to change the shape of the deformable mirror to correct for the distortions. The dye laser’s repetition rate (about 10 pulses per second), as Primmerman reported, meant that the system could not perform as a conventional closed-loop system—it was too slow. Instead, it employed a go-to technique that closed the loop on a pulse-by-pulse basis. This technique is considered a more difficult type of free-running closed-loop system, so that if it worked, a conventional closedloop system was likely to work as well.20

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Photo 19. This deformable mirror was a critical component of the

SWAT adaptive optics system.

In any opto-mechanical control system, there is a lag time between measurement and correction of turbulence that affects how well the system corrects the distortion. The operating sequence in the go-to system entailed firing at five pulses per second and then applying a correction measurement to the deformable mirror in the open-loop position. That setting would be held on the mirror, and a very short exposure of the star (much shorter than the time between laser pulses) would be taken. The mirror’s shape would remain fixed Lincoln Laboratory

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until the next laser pulse, after which the mirror would be reset and another picture of the star would be taken. This process would be repeated over and over again, but each time a mirror correction was made there was no continuous feedback verifying that the mirror was at the right setting. There were intermittent corrections, but not continuous correction.21 The problem with this approach was that the interval between laser pulses (each laser firing) was sufficiently long that the adaptive optics system was always trying to “catch up” to make the next correct setting to the deformable mirror in order to keep up with changing atmospheric conditions. The intervals between laser pulses were measured in milliseconds, but that was long enough for turbulence conditions to change and the mirror settings’ accuracy to deteriorate. The key point was that the time delay between the firing of successive laser pulses made the initial measurement setting on the deformable mirror outdated because during that interval turbulence in the atmosphere changed, which required a new setting on the mirror. The system was always slightly behind real-world conditions. But as one observer put it, that did not detract from the accomplishment of Lincoln’s SWAT experiment at Maui, because any closed-loop system has a time lag.22 Lincoln Lab’s laser fired five pulses per second. In comparison, the laser at Starfire Optical Range ran at 5,000 pulses a second, which made it possible to change the surface of the mirror an incredible 2,500 times per second, responding almost immediately to changes in the atmosphere. The Maui system resembled individual snapshots, while the SOR system resembled a continuous movie. The SOR images were also of higher resolution.23 Lincoln Lab, however, completed its closed-loop synthetic beacon adaptive optics system first—in summer 1988, 5 months before SOR. On 25 August 1988, Zollars and his team recorded “the first stellar image ever compensated for atmospheric turbulence with a synthetic beacon.” This was a major breakthrough, even though the “degree of compensation was relatively poor.” As Zollars explained, “Subsequent to the first experiments, improved equipment and accumulated experience allowed substantial improvements in the quality of the compensated images.” Eventually, the Lincoln team generated images with a Strehl ratio of 0.46, which was considered very good.24 Part of the reason Lincoln could obtain better images in later experiments was that the second phase of the original plan called for switching from a single Rayleigh laser beacon to using four beacons focused very

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Photo 20. This photo shows the complexities of the electro-optical hardware in Lincoln Laboratory’s SWAT adaptive optics system.

close to one another in the same area of sky. This method, called beacon stitching, produced more backscatter, which sampled a wider path of atmosphere. This was a distinct advantage over a single beacon. “Measuring the atmospheric distortion with an array of synthetic beacons,” Zollars wrote, “reduces the wavefront error due to focal anisoplanatism because of the more accurate sampling of turbulence close to the edges of the aperture.”25 Primmerman’s team at White Sands and Maui and Fugate’s team at Kirtland shared a feeling of friendly competition and camaraderie. The goal of both groups was to advance the science of laser guide stars and help the Air Force perform its mission through the use of adaptive optics. So it was not surprising that by the mid-1980s, as Fugate later recalled, scientists from both labs met annually to exchange information on the progress of their research. As Lincoln’s Darryl Greenwood put it, Rayleigh and sodium guide star experiments were complementary and “we all learned from each other in those days.” There was no doubt that Air Force officials appreciated the value of the Rayleigh and sodium beacon accomplishments. However, Lincoln Laboratory

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Photo 21. Air Force Maui Optical Site (AMOS) atop Haleakala on

the island of Maui, Hawaii, where Lincoln Lab conducted the second phase of its SWAT experiments.

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Photo 22. Pioneering adaptive optics scientists in a photo taken circa 1982.

Left to right, Rett Benedict, DARPA; Bob Fugate, Air Force Weapons Laboratory; Dino Lorenzini, DARPA; Darryl Greenwood, Lincoln Laboratory; Don Hanson, Rome Air Development Center; Chuck Primmerman, Lincoln Laboratory; David Fried, the Optical Sciences Company; and Barry Hogge, Air Force Weapons Laboratory.

they also knew that these were expensive and complex experiments riddled with hardware problems and finicky instrumentation.26 Chances were slim that any of these breakthroughs would have taken place without the government’s commitment and willingness to invest heavily over many years. The need for government support for military research and development had been debated at least since 1945, when General Hap Arnold and the distinguished aerodynamicist Dr. Theodore von Kármán led a movement to promote the importance of research and development in the military services. In 1945 they published Toward New Horizons, a military blueprint for the future, arguing that science and technology were crucial to the nation’s defense.27 Lincoln Laboratory

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Adaptive optics research exemplified the spirit of the Arnold/von Kármán legacy. The stakes were high, but so were the potential payoffs. University researchers were at a distinct disadvantage. They lacked the resources to build the large telescopes and conduct the elaborate experiments adaptive optics required. For the most part, universities also lacked the infrastructure to orchestrate large research programs spanning a wide range of organizations—like the government laboratories, the military services, DARPA, private contractors, and federally funded research agencies such as Lincoln Laboratory were able to do. The Air Force laboratory system and Lincoln Lab were in the best position in the 1980s to make advances in adaptive optics research.28 Although early guide star research was classified, that would change dramatically in the early 1990s, when the Air Force decided to share its adaptive optics findings with the rest of the astronomy community. This is discussed in detail in chapter 7.

High-Energy Lasers and Thermal Blooming Lincoln Laboratory—through Greenwood, Primmerman, and others— had established itself as a leader in laser guide star research in the 1980s using low-power lasers. The focus of that work was on improved imaging of objects in space, but that was only one side of the lab’s adaptive optics research. Lincoln had also been involved since the 1960s in experiments using low-power and high-energy lasers to intercept space targets. In the late 1960s and early 1970s Lincoln Laboratory started a major research effort involving high-energy lasers that lasted into the 1990s and continues today at a reduced scale. Initial work focused on theoretical studies and laboratory experiments to better understand laser characteristics and beam quality issues. At that time, DoD was interested in improving beam quality in high-power lasers—first with CO2 gas dynamic lasers and later with chemical lasers—and adaptive optics was one possible solution. The long-term objective was to develop adaptive optics techniques that would reduce the effects of thermal blooming—a high-energy laser beam’s tendency to lose power as it heats up the air through which it passes. This work was primarily funded by DARPA and the Navy with an eye toward

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using high-energy laser weapons for tactical ballistic missile defense, antiship missile defense, air defense, and antisatellite missions.29 The Navy was looking at lasers in the 3.5 micron wavelength range. At that wavelength, a laser operating at ground level was more susceptible to the effects of thermal blooming than to atmospheric turbulence. The Air Force, on the other hand, was interested in placing lasers in planes flying at high enough altitudes that thermal blooming was less of a problem, and thus was more concerned about atmosphere turbulence than thermal blooming.30 Thermal blooming was one of the most daunting obstacles to developing a ground-based, high-energy laser weapon. The problem was that as a laser beam travels through the atmosphere it heats up the air along the way; that spreads out the beam and reduces its intensity at the target. The atmosphere absorbs a small portion of the beam’s energy, and the heated air expands and becomes less dense than the surrounding cooler air. This changes the index of refraction; the burned-through air functions as a lens that bends the laser light outward, defocusing the beam and causing it to “bloom.” Both thermal blooming and atmospheric turbulence distort the laser beam. One of the worst conditions for thermal blooming is when there is no wind, because motionless air absorbs more heat, hence more blooming.31 A low-power laser beam does not heat up the atmosphere as much as a high-power laser does. Consequently, the higher the power of the laser, the greater the thermal blooming and the greater the distortions in the beam wavefront. It can also be more difficult for an adaptive optics system to compensate for thermal blooming than for atmospheric turbulence, depending on the wavelength of the laser and the geometry of the engagement scenario.32 Thermal blooming was thus a serious problem that had to be solved if the military expected to field an effective ground-based laser weapon. Not only does thermal blooming reduce beam quality, but it also limits a weapon’s operating range. Lou Marquet, who had earned a PhD in physics from the University of California, Berkeley, eventually worked his way into jobs aimed at finding solutions to thermal blooming. Marquet was confident but not cocky, willing to take calculated risks and go where the work was most demanding and satisfying. Career management experts did not easily sway him. Rather he opted to follow his own instincts, choosing to move into more risky territory to take the most challenging and scientifically rewarding jobs. He started his career conventionally enough. After 2 years of active Lincoln Laboratory

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duty in the Army Signal Corps, he became an assistant professor of physics and astronomy at the University of Arizona in the early 1960s.33 Though he spent several years teaching, Marquet did not find university life all that appealing. Years later, looking back, he confessed he was just plain bored and unmotivated by university research. He was yearning for something else but didn’t know quite what it was until he met an old friend from Berkeley at a physics conference in New York City in 1966. His friend urged him to interview at Lincoln Laboratory, because there were all kinds of innovative and futuristic research programs going on there. Although knowing little about the Massachusetts laboratory, Marquet followed his friend’s advice and landed a job in 1967 in the lab’s optics group working on ballistic missile defense. The main thrust of this work was to find ways to discriminate, based on infrared measurements, between a real reentry vehicle and a decoy. Marquet recognized that the issue was one of the military’s toughest challenges. He quickly found his niche and ended up staying at Lincoln for the next 18 years. Darryl Greenwood and Chuck Primmerman, two of the recognized leaders in adaptive optics at Lincoln Lab since the mid-1970s, later praised Marquet for initiating and directing the adaptive optics program at Lincoln with enthusiasm and strong leadership.34 Lincoln Laboratory worked for the military, and Marquet was part of a growing corps of military scientists working on specialized and often classified research projects for the government. He found military research more exciting than academic research. Universities often make discoveries, Marquet noted, but in many cases what they discover is not applied to the real world. Does it really matter from a practical standpoint, he pondered, what kind of soil there is on Mars? Academics are content with finding the truth for the sake of truth. On the other hand, military scientists can find the truth, which an adversary can then negate by coming up with a new truth or countermeasure. This “fighting back” aspect, as Marquet put it, forced the military scientist to constantly keep his eye on the practical application of his research and to always be ready to anticipate the research step that will counter an opponent’s latest countermeasure. It was this aspect that made the work more interesting and intellectually satisfying to Marquet.35 In addition, Marquet believed the stakes were higher in military

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research because the outcome often had life-or-death consequences for individuals as well as for the security of the entire country. This was another factor that attracted Marquet to government service.36 Early in his career with the optics group at Lincoln Lab, Marquet found himself heavily involved with high-energy laser beam diagnostic work at Pratt & Whitney’s jet engine test facility in West Palm Beach, Florida. Since the discovery of the laser in 1960, DARPA had been interested in determining the feasibility of laser weapons—specifically, a high-power ground-based laser system for antisatellite and ballistic defense missions. That was DARPA’s motivation for funding Pratt & Whitney’s work on one of the earliest high-power laser devices, called the XLD or Experimental Laser Device. The XLD was a megawatt-class CO2 gas dynamic laser, with a wavelength of 10.6 microns, that worked similar to a rocket engine. Pratt & Whitney had a strong national reputation for design and fabrication of jet engines, which partially explained why the XLD ended up at the company’s Florida test site.37 The XLD operated by combusting a mixture of gases and then flowing the mixture at supersonic speeds through an array of nozzles. This caused a population inversion of excited molecules in the high-speed flow, generating a CO2 laser beam. Although the beam was robust and potentially powerful, it lacked focus and stability. Instead of a pencil-thin beam packing all of the laser’s energy, the XLD beam resembled a big flashlight that shone in all directions (Marquet described the beam as “ugly”) and could not disable or destroy a target at long range. DARPA sought a practical way to harness the energy of the XLD laser into a more coherent beam. Atmospheric turbulence and thermal blooming were the two main hurdles to overcome, and there were no clear solutions at this early stage in laser research.38 As a first step, DARPA asked Lincoln Laboratory to go to West Palm Beach in 1968 and determine exactly what was happening to the quality of the XLD high-energy laser beam. Pratt & Whitney employees knew how to operate and maintain the XLD, but they were not experts in the physics of beam characteristics. DARPA turned to Lincoln Lab for help developing techniques for measuring the behavior of the beam from the time it exited the laser device until it reached the target. Lincoln sent a team of scientists led by Lou Marquet to attack the problem. Gaining a better understanding of beam quality was the first goal. The second step would be to figure out a Lincoln Laboratory

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way to use adaptive optics to compensate for the poor quality of the beam and the additional degradation of thermal blooming.39 From the late 1960s through the mid-1970s, Marquet and his team engaged in theoretical studies and experiments at West Palm Beach to acquire a better understanding of how thermal blooming and atmospheric turbulence affected the behavior of a high-power laser beam. The ultimate objective was to improve propagation of a high-energy laser from the ground to a target in the atmosphere or space. But before that could happen, one of the first problems Lincoln Lab scientists had to solve was how to define the characteristics of a high-energy laser beam. That was not easy. Trying to diagnose the beam profile for a focused high-energy laser beam was impractical, because the beam’s spot would be so small, and the power so high, that the beam would melt any kind of diagnostic device. To solve this problem, Marquet came up with a creative diagnostic method called the transmissive hole diffraction grating technique, which used a copper plate mirror with holes drilled in it. The tiny holes were arranged in a regular pattern that covered an area approximating the diameter of the beam. As the XLD high-power beam struck the copper plate, more than 99 percent of the beam reflected off the plate and was harmlessly dumped into a calorimeter. The remainder—less than 1 percent of the beam—passed through the holes in the copper plate. This attenuated beam was much easier and safer to deal with, as it had only about 100 watts of power as opposed to tens of kilowatts.40 After passing through the holes in the copper plate, the weakened beam reflected off a concave mirror and was focused to a far-field diffraction pattern. The focused beam reflected off another mirror, and a special infrared scanning camera (made by AGA, a Swedish company that built cameras for medical purposes) took an image of diffuse scatter from the beam. This provided vital information on the beam’s characteristics, including shape, size, intensity, jitter, wavelength, phasefront, near- and far-field irradiance, and power fluctuations. Based on these data, overall beam quality could be calculated. Marquet’s technique facilitated the direct measurement of a highpower beam by diagnosing a small but representative portion of it, which served as a true sample of what the high-power beam would look like focused in the near field and the far field on the target. It furnished, for the first time, direct diagnostic measurements of beam quality on a high-power laser.41

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While Marquet and his group were conducting experiments to better define beam quality, two other scientists at Lincoln Lab, Lee Bradley and Jan Herrmann, were developing the first wave optics propagation code that incorporated the effects of thermal blooming. Running the code predicted mathematically how a beam would perform as it propagated through the atmosphere and encountered thermal blooming. It also predicted what would happen to the beam when it was focused on target. The idea was to compare the code predictions—a computer simulation of a laser beam propagating through an absorbing medium—with experimental results to see how closely they matched.42 In 1975 Chuck Primmerman and Dan Fouche conducted the first laboratory experiment to compensate for thermal blooming in a laser beam. This work, conducted at Lincoln Laboratory, validated the accuracy of the Bradley and Herrmann codes. Primmerman and Fouche, under tightly controlled laboratory conditions, transmitted a low-power argon laser beam through an absorption cell that simulated a real world thermal-blooming environment. Using the computer code predictions, they then applied phase corrections to a 57-actuator deformable mirror built by Itek. This was an open-loop adaptive optics system that relied on the experimenters to manually adjust the setting on the deformable mirror at the appropriate time.43 Each time a new setting was placed on the deformable mirror, Primmerman and Fouche measured the intensity of the beam at its focal point to see if the change on the deformable mirror increased or decreased the intensity of the beam at the target. An increase in intensity meant that compensation of the beam was occurring. Experimental results were encouraging: “We see that the peak intensity has increased by almost a factor of 3,” Primmerman and Fouche wrote, “and that the shape of the beam has been greatly improved.” The experiment did not demonstrate perfect compensation in the beam. But even partial correction under controlled laboratory conditions constituted an important first step.44 In the next phase of research, Marquet and his group used a mirror that could accept a high-power laser beam. Pratt & Whitney Aircraft, a subsidiary of United Technologies Research Center, constructed and tested the first high-power, water-cooled mirror at United Technologies Research Center’s facility in East Hartford, Connecticut.45 Everything did not go exactly as planned during the early stages of Lincoln Laboratory

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the mirror’s development. At one point, a technician torqued the mirror too much, producing a big dimple in the middle. One person on the scene reported, “We were all hysterical for awhile. We felt we were in a disaster, but it turned out in those days companies were very responsive. Pratt & Whitney had in parallel built another mirror. They had another mirror actually built and substituted it for the dimpled mirror. They just showed us, they knew it was risky, so they built two mirrors simultaneously and used the second one for the experiments at West Palm Beach.”46 Pratt & Whitney’s water-cooled mirror was a critical component used in conjunction with the XLD laser during the West Palm Beach experiments. Measuring 21 centimeters (8.3 inches) in diameter, the surface of the mirror was made of a thin sheet of molybdenum. Attached to the backside of the mirror were 52 actuators that moved to reshape the front to compensate for distortions in the high-power beam. The contractor shipped the completed mirror in fall 1975 to Pratt & Whitney’s high-energy laser beam test range at West Palm Beach, located on a remote section of Florida wetlands. An unusual feature of this site was the occasional intrusion by the area’s resident alligators.47 Facilities at one end of the range housed the laser device, optics room, offices, and a fuel storage site that provided the fuels to be combusted to produce the laser. Two kilometers (1.2 miles) downrange was a target board mounted on a railroad flatcar, designed and built by Lincoln Laboratory along with 670 meters (0.4 miles) of track perpendicular to the path of the laser beam. The car was remotely controlled and powered by an auxiliary power unit of the type used to start jet aircraft engines. The unit supplied power to a hydraulic pump that powered hydraulic motors on each of the four wheels. When the system started up, the noise was extremely loud and sounded like a jet aircraft engine. While some on-site wanted to name the railroad car The Diffraction Limited—a reference to a perfect beam—Lincoln Lab settled on the name Everglaser. Since the work involved lasers in the Everglades, the nickname seemed to make the most sense.48 The XLD experiments were conducted from 1975 through 1977. Some of the work measured beam characteristics with the beam focused in the near field before being sent downrange. The first compensation tests on the XLD using the 52-actuator deformable mirror looked at techniques for correcting for phase aberrations in the beam as it exited the laser device and moved downstream through the optical train in the optics room. For this particular

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scenario, the beam was not sent downrange. Later tests expanded the beam to 1.2 meters (3.9 feet) and transmitted it downrange to instrumented targets.49 Exiting the laser device, the 7.5 centimeter (3 inch) diameter beam traveled through a pipe into the optics room, where beam diagnostics took place. There the beam was reflected off a series of mirrors in the optical train, and at various stations measurements of beam characteristics—such as phase distortions—were made. Eventually the beam reached a telescope that expanded it to 1.2 meters (3.9 feet). It then left the optics room through a large window and traveled downrange 400 meters (a quarter mile) to a stationary target consisting of a concrete pad. Farther downrange, at 2 kilometers (1.2 miles)— the longest distance the beam traveled—was the mobile railroad car.50 As the beam moved from the laser device through the pipe and into the optics room, the humidity it encountered resulted in thermal blooming. To minimize this, Marquet and his colleagues devised a system that injected fresh air into the laser pipeline. They also set up a series of large floor fans, purchased from the local Sears store, to circulate cool air across and around the beam’s path through the optics room. The makeshift system worked. Fresh air blown across the beam’s path removed much of the stagnant air heated by the laser beam and reduced thermal blooming.51 Marquet’s improvised beam path conditioning system was a simple solution and very successful. He reported that the XLD beam in the pipe went from 16 times diffraction limited to 4 times diffraction limited, meaning the beam suffered less degradation from thermal blooming. Marquet believed this was an important step forward, thanks in large part to Lincoln Lab, in understanding the effects of thermal blooming on a laser moving through the atmosphere—and in scientists’ ability to compensate for it.52 After the high-power deformable mirror was installed, Lincoln ran a series of low-power tests before moving on to using the high-power XLD. One part of those experiments involved reflecting a 30-watt CO2 laser off the deformable mirror. Because of its low power, the laser did not experience thermal blooming. The mirror was adjusted to provide the best focus of the beam in the near and far field. Low-power testing showed what a beam looked like without the effects of thermal blooming. Later, testing of the high-power beam would reveal how badly it was affected by thermal blooming. Also important, the preliminary low-power tests showed that Lincoln Laboratory

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Photo 23. In the XLD’s optics room, floor fans (lower right) purchased

from the local Sears store cooled the high-energy laser beam path to reduce the effects of thermal blooming.

the laser and mirror operated successfully together without causing any damage to the mirror’s surface.53 Firing the high-power XLD laser and assessing how it reacted with the water-cooled deformable mirror was the next phase, which took place from November 1975 to April 1976. A total of 181 tests were conducted, including thirty-one XLD beam diagnosis tests and 140 firings to downrange targets. Fifty-eight experiments propagated the beam to the stationary target at 400 meters. Eighty-two other experiments tested thermal-blooming compensation, sending the beam 2 km downrange to the mobile railroad car. The main goal of these tests was to evaluate the performance of the deformable mirror and determine if it could compensate a high-power laser exposed to thermal blooming and atmospheric turbulence in a real-world environment.54 Efforts to propagate a high-energy beam (of several hundred kilowatts) to the outermost target at the 2-kilometer site were the most realistic experiments to date in terms of simulating what an actual laser weapon system might encounter in the atmosphere. As the 16,000-pound railroad car traveled down the track at under 20 mph, Marquet and his team slewed the

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laser to follow it. (Slewing simulated how an operator on a ship or plane would direct the beam to its target.) Because of the slewing, the beam was constantly moving into a new and fresh path of air, thereby reducing the degree of thermal blooming. The exception to this, and the most problematic for thermal blooming, was the area nearest to where the beam exited the aperture. Test results showed that slewing did not significantly reduce the effects of thermal blooming in that narrow region.55 An unpolished aluminum plate mounted on the railroad car served as the farthest downrange target on which the XLD beam was focused. Prior to sending the laser beam to the target, settings on the deformable mirror were made based on computer code predictions of the intensity of the beam on target. Two infrared cameras took a picture of the beam reflecting off the target, and five detector arrays measured the irradiance on target. That information was transmitted back up range to the optics room and used to adjust the settings on the deformable mirror to compensate for the distortions that had been measured in the beam. Those distortions were constantly changing, resulting in new diagnostic data being transmitted to the optics room and new signals to the mirror. This cycle allowed, “for the first time, continuous monitoring of the far-field beam during thermal-blooming tests with slewing.”56 Marquet reported that the West Palm Beach experiments were the first successful adaptive optics tests using a high-energy laser beam and a deformable mirror to compensate for thermal blooming in the real atmosphere. In summing up the accomplishments of the XLD experiments, Marquet wrote: “In shot after shot during the thermal-blooming compensation tests, the farfield irradiance distribution was significantly improved (factors of up to 2.5 reduction in bloomed area) by using the deformable mirror to add predictive phase compensation to the beam.” However, the system was not yet refined enough to generate the near-diffraction-limited beam needed for a ballistic missile defense or antisatellite weapon system.57 More work did occur in 1977 with a Closed-Loop Adaptive Single Parameter (CLASP) low-power experiment conducted at Lincoln Laboratory by Primmerman, F. Bruce Johnson, and Irving Wigdor. Previous to this, all the XLD experiments were open-loop. Primmerman described CLASP as a proof-of-concept laboratory experiment for a closed-loop system that “compensates for thermal blooming by optimizing only one parameter—the amplitude of the phase correction.”58 Lincoln Laboratory

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Photo 24. Lincoln Laboratory’s mobile railroad car target, dubbed the Everglaser, was positioned 2 kilometers downrange. A high-energy laser beam reflected off the shining rectangular surface near the center of the car.

This first CLASP experiment used a low-power argon-ion laser that reflected off a 57-actuator deformable mirror, which focused the laser beam in the far field. A cell filled with ethyl alcohol and iodine absorbed about half of the low-power beam’s radiated energy, thereby simulating thermal-blooming conditions for a beam slewing through the atmosphere. “The shape of the deformable-mirror correction was fixed,” Primmerman reported, “but the amplitude [of the signal going to each actuator] was adjusted automatically to maximize the far-field intensity.” This approach worked well; the far-field intensity of the beam on target did increase, demonstrating that this closedloop adaptive optics system performed as expected. Primmerman and his colleagues concluded the CLASP system “has shown itself to be a viable concept for thermal-blooming correction.” The next step after this laboratory experiment was to conduct a field test to show that the CLASP system would work with the high-energy XLD laser.59 The CLASP test in the field at West Palm Beach was also a stunning success. As in the laboratory experiment, it collected beam intensity data at the target spot and relayed it to the optics room so changes could be made

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to the 52-actuator, water-cooled deformable mirror. There was no wavefront sensor to measure beam phase aberrations. Instead, CLASP relied on a single-dither approach that made changes to the mirror according to the continuous feedback of data on far-field beam intensity. Lincoln Lab and DARPA, which funded the work, were pleased by the results, which confirmed “the first closed-loop thermal-blooming compensation of a highenergy laser.” Once again, the adaptive optics system did not compensate completely for the high-energy laser beam, but it did prove it could provide limited compensation for thermal blooming in the atmosphere. Time was required to move the scientific process forward.60 Two other important experiments took place at West Palm Beach. One was called OCULAR, which stood for Optical Compensation of Uniphase Laser Radiation. The other was called Target Return Adaptive Pointing and Focus or TRAPAF, the last phase of Lincoln’s experimental program in Florida. Both experiments were designed by Lincoln Lab to look at ways to improve the quality of a high-energy laser beam propagating through the atmosphere.61 Under the direction of Lincoln’s Dave Kocher, planning and design of the OCULAR experiments began in 1975, followed by field testing in June and July 1977. While Pratt & Whitney provided the laser and the 52-actuator deformable mirror, Itek supplied the sensor optics, dither mirror assembly, and driver electronics. The XLD did not exit the laser device as a perfect beam. Rather, a number of forces impinged upon the beam to degrade its quality. Noise signals and vibrations generated by the hardware and gas flow to produce and direct the beam corrupted it as it traveled from the resonator, through the optical train to the deformable mirror, and finally to a telescope that focused it downrange. Moreover, when the beam reflected off a mirror in the optical train, the surface of the mirror absorbed a portion of its heat, which created additional distortions. OCULAR was an adaptive optics system mainly concerned with cleaning up the beam as it exited the laser device and moved through the optical train to the telescope. Corrections made to the beam in this region were referred to as local loop corrections.62 Lincoln Lab scientists used an alignment laser beam in conjunction with a multidither technique (rapidly changing the position of the deformable mirror by trial and error with a “hill climbing” servo loop) to correct for the distorted wavefront of the XLD beam. This concept had originally Lincoln Laboratory

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been developed by Tom O’Meara at Hughes Research Laboratories. The OCULAR experiments were complex because each of the 52 actuators on the deformable mirror had to be individually controlled. Overall, OCULAR “worked as planned with the alignment laser source, even in the XLD acoustic and vibration environment.” As Primmerman pointed out, the OCULAR experiments “demonstrated the first ever compensation for device aberrations in a high-power laser.”63 The TRAPAF experiments, led by Darryl Greenwood, differed from the OCULAR experiments in that they did not use the 52-actuator deformable mirror. TRAPAF’s mirror was of a simpler design, with only four actuators, and could compensate only for tilt and focus. In addition, TRAPAF experiments corrected the beam beyond the local-loop region—that is, compensation took place as the beam made its way downrange to the target on the railroad car. However, results showed that only a small degree of correction occurred because of the higher level of noise associated with the XLD laser.64 Much of Lincoln Laboratory’s experimental work in Florida confirmed theoretical concepts involving the complicated interaction of high-energy lasers with thermal blooming. Not every test worked precisely as planned, and the Lincoln scientists never completely solved the problem of thermal blooming. But they made significant headway toward improving the quality of a high-power beam affected by thermal blooming. At the time, they were the only U.S. experiments applying adaptive optics to the problem of thermal blooming.65 The late 1960s through the mid-1970s were the early days of lasers, and scientists were just beginning to understand thermal blooming. They were familiar with how atmospheric turbulence degraded beam quality, but turbulence was not much of a problem for the XLD 10.6-micron CO2 laser because of its long wavelength. On the other hand, the longer-wavelength beam was more vulnerable to thermal blooming, which was the more difficult scientific nut to crack. If they could have turned back the clock, most Lincoln Lab scientists would have opted to attack the problem of atmospheric turbulence first, rather than the more complex issue of thermal blooming.66

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seven

Sharing the Gold Astronomical Nuggets

Bob Fugate’s team at Kirtland and Chuck Primmerman’s team at Lincoln made pioneering contributions to laser guide star technology in the 1980s that had a lasting effect not only on the United States Air Force, but also on academic astronomy. The military, through DARPA, RADC (later Rome Laboratory), the Air Force Weapons Laboratory (later Phillips and now the Air Force Research Laboratory), and the Strategic Defense Initiative Organization, played a lead role in sponsoring and funding laser guide star research from the 1970s through the early 1990s. Moreover, the Air Force was extremely careful to ensure that all work on laser guide star experiments were kept under tight wraps. With few exceptions, civilian astronomers were unaware that the Air Force had been conducting research involving laser guide stars.1 Since DARPA funded the laser guide star program, it logically became responsible for the program’s security. Laser guide star research remained classified because the Department of Defense considered it breakthrough technology with potential weapons applications. The Air Force did not want to reveal the interest, thrust, and status of its research, because that might convince an adversary to turn its attention to adaptive optics. As a

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first step, DARPA designated the laser guide star research a special-access program, identified as LODESTAR, allowing only a very limited group of people with a “need to know” to obtain or use information about the program. LODESTAR had much tighter restrictions on access than the normal classified government programs.2 DARPA, besides determining who would have access to LODESTAR, also established the security classification guides that spelled out in detail exactly what information could and could not be released about the program. Laser guide star technology was placed on the Military Critical Technologies List, making it subject to rigorous export controls. These restrictions were intended mainly to keep the guide star technology from the Soviets. They remained in place until 1984, when sponsorship of the laser guide star work, along with responsibility for security, shifted from DARPA to the Strategic Defense Initiative Organization. SDIO substantially expanded its investment in LODESTAR technology to support its ground-based antiballistic missile program. In 1991, SDIO scaled back directed-energy research in favor of space-based kinetic interceptors. The space-based chemical laser effort continued, but at substantially reduced funding. LODESTAR research funded by SDIO, and later the Ballistic Missile Defense Organization, was eventually phased out as funding, along with the Soviet threat, decreased.3 At the same time, the Air Force continued down a slightly different road, focusing on the potential of laser guide star research to improve space control applications such as ground-based laser antisatellite weapons. For those types of operations, technology would be needed to sense atmospheric turbulence in the point-ahead direction (the path the laser beam would travel to intercept a satellite), where no natural beacon existed. There were no plans to build an antisatellite system in the short run. Rather, the Air Force engaged in research to demonstrate the feasibility of adaptive optics technology in order to be in the position to build such a system if it was needed in the future. Astronomers, on the other hand, were not interested in perfecting antisatellite weapons. Their main goal was to acquire sharper images of celestial objects—a goal the military shared, but not exclusively.4 Many government leaders strongly believed that SDIO had played a major role in ending the Cold War. By the late 1980s and early 1990s, many also believed that, with the threat of a massive Soviet attack virtually

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eliminated, SDIO had served its original purpose and was no longer needed in its current configuration. The new perception of threat that emerged emphasized third-world nations that might acquire enough technical expertise to launch a missile attack on the United States. Consequently, theater ballistic missile defense became a national defense priority in the post–Cold War period. To prepare for this challenge, Secretary of Defense Les Aspin announced in May 1993 that SDIO had been reconfigured and renamed the Ballistic Missile Defense Organization (BMDO). In January 2002, BMDO’s name changed to the Missile Defense Agency or MDA.5 Two years before SDIO became BMDO, the leadership at SDIO and the Weapons Lab at Kirtland (which had merged with several other organizations to become the Phillips Laboratory in December 1990) jointly made the decision to declassify a large portion of the military’s work on laser guide stars. Several other defense advisory groups—including the airborne laser Independent Review Team, headed by Dr. Bob Cooper—also recommended the move. Parts of the program remained classified, so a new classification guide was needed. That job fell to a small group of people at Phillips Lab headed by Bill Thompson. Thompson, who had a keen eye for detail and who had started working for the Air Force Weapons Laboratory in the 1960s, had the right temperament and a reputation for thoroughness in successfully guiding the most difficult projects through the laboratory’s bureaucratic maze. Because a substantial part of the government laser guide star work had taken place at the Air Force Weapons Lab and Lincoln Laboratory, and because the former was a government entity while the latter functioned as a private contractor, it made sense that the Weapons Lab would be responsible for security.6 To put the new security program on solid footing, SDIO terminated LODESTAR in 1988 and replaced it with a program called HAVE REACH. Now the Air Force was in complete control of security for the laser guide star program. Government code names usually have two words. HAVE was the arbitrary term to denote work performed by Air Force Systems Command, the research and development arm of the Air Force at the time. Thompson came up with the second word, REACH, which conveyed a mental picture of a laser propagating through the atmosphere and reaching for the stars. Later, HAVE REACH came under Air Force Materiel Command (established on 1 July 1992, the result of the merger of Air Force Systems Command Sharing the Gold

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with Air Force Logistics Command). Phillips Lab, which had absorbed the Air Force Weapons Laboratory (AFWL) in 1990, was in turn consolidated with other research and development organizations in 1997 and became the Phillips Research Site of the Air Force Research Laboratory. Today, HAVE REACH is still the responsibility of the scientific security team of AFRL’s Directed Energy Directorate at SOR.7

The Decision SDIO and AFWL worked together to declassify a good portion of the laser guide star work. Initially, Tom Meyer, who was responsible for managing the laser guide star program at SDIO, approached Bill Thompson at AFWL about taking the step to declassify the laser guide star work. Thompson contacted Bob Fugate, who became a strong advocate for this idea. He and others firmly believed that astronomers in the academic community were on the verge of duplicating guide star experiments that military scientists and contractors had already demonstrated in the 1980s. While many others would eventually endorse the move to declassify, Meyer, Thompson, and Fugate led the charge.8 In 1990, while commander of the Weapons Laboratory, Colonel John Otten convened a number of preliminary discussions with Thompson, Fugate, Colonel John J. Russell (director of the lab’s Advanced Radiation Technology Office), and a few others to address the pros and cons of declassifying at least portions of the program. A number of events over the previous 7 years prompted these discussions. For a long time astronomers outside the defense community had been searching for ways to use adaptive optics to produce clearer images of objects in space and documenting their progress.9 Two French scientists, Renaud Foy and Antoine Labeyrie, in 1985 published an influential article contending that it was feasible to use Rayleigh scattering from molecules in the atmosphere and resonance scattering from sodium atoms as laser guide star techniques for adaptive optics systems. Edward Kibblewhite from the University of Chicago and Laird Thompson from the University of Illinois were among a growing number of American astronomers also conducting and publishing research on laser guide stars. Foy and Labeyrie, as well as their American counterparts, were following

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avenues of research that the Air Force and Lincoln Laboratory had already successfully completed.10 Publication of the Foy and Labeyrie paper stirred speculation that someone may have leaked information about the principles of Rayleigh and sodium guide stars. It seemed an odd coincidence that the French paper covered so much of the same information discussed at the 1982 and 1983 Jason summer sessions. Timing seemed also to have played a role. The findings of the Jason summer sessions appeared in two classified reports issued by the MITRE Corporation in McLean, Virginia—the first in 1982 and the second in 1984. Only a year after the second MITRE report, the Foy and Labeyrie article appeared in the open literature. Although no concrete evidence ever surfaced that a Jason member had leaked information, circumstantial evidence caused suspicions to linger in the minds of some through the end of the 1980s. Others such as Chuck Primmerman and Darryl Greenwood put no credence in the leak theory. Greenwood said he asked Foy directly how he came up with the Rayleigh guide star principles he discussed in his 1985 article. Foy’s answer was, “without any help from the United States.”11 Because astronomers (with the possible exception of Foy and Labeyrie) knew nothing about the classified government programs on adaptive optics, they unknowingly expended an enormous amount of time, money, and resources investigating concepts already tried and proven. The duplicated research included detailed measurements of atmospheric turbulence, simulation of laser guide star techniques based on complicated modeling methodologies and computer codes, and experiments that supported or rejected specific compensation techniques. As one government official described it, civilian astronomers were “adopting approaches to solve the atmospheric compensation problem which were in many ways identical to DoD-sponsored work, although the DoD programs were significantly more mature in terms of sophistication of technology and results achieved.”12 This posed a dilemma for the Air Force. If the Air Force kept its own research under wraps, astronomers would waste their time and taxpayers’ money conducting duplicate research. Yet to release the information might benefit the nation’s enemies. The basic question for the Air Force in 1990 became, was it still necessary to keep the laser guide star work classified?13 The answer to that question was no, and the Air Force and SDIO leadership worked closely first with the Weapons Laboratory and then with Phillips Sharing the Gold

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Laboratory to declassify much of its laser guide star findings. Colonel Otten helped ensure that bureaucratic obstacles were overcome to allow the declassification process to proceed. (On 13 December 1990, with the inactivation of AFWL and the formation of Phillips Laboratory at Kirtland AFB, Otten relinquished his duties as AFWL commander and was reassigned to head up the Lasers and Imaging Directorate at Phillips Laboratory.)14 Thompson played a big role in the decision to release the information to the public. He strongly believed that declassification of most of the laser guide star material would benefit both the Air Force and the astronomy community, give Air Force scientists (military and civilian) the credit and recognition they deserved for their contributions to adaptive optics, and enhance the Air Force’s reputation to the worldwide scientific community, to university astronomy departments, and to the public. As long as their work was classified, Air Force scientists were prohibited from publishing their findings in scientific journals.15 Extensive study and analysis took place before the final decision was made to declassify. (The discussion focused on laser guide star work by SOR and Lincoln Laboratory, not the more general topic of adaptive optics. Techniques to correct for distortions in light waves by using wavefront sensors, high-speed processors, and deformable mirrors went back to the 1970s and were not classified.) Because the commanders of the Weapons Laboratory and Phillips Laboratory had authority to declassify material, Thompson and his group did not need outside permission. But they prudently consulted with higher authorities and a number of government agencies before making a decision.16 As a first step, Thompson drafted a letter that was signed by Russell and sent to sixteen organizations that had access to the Air Force adaptive optics program—including the National Science Foundation, Air Force Systems Command, Air Force Space Command, the Secretary of the Air Force Office for Acquisition, DARPA, the Air Force’s Foreign Technology Division, the Jasons, the Defense Intelligence Agency, and SDIO—asking for their comments on declassification. Thompson had previously been in contact with and had briefed some of these organizations beforehand.17 With the letter, Russell attached a paper summarizing the benefits and costs of declassification. The attachment pointed out that astronomers had been duplicating work done by the HAVE REACH program and were

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Photo 25. Colonel John Russell spearheaded the effort to

get input from other government agencies on the decision to declassify adaptive optics research.

publishing their findings in scientific journals for all, including our adversaries, to see, and pointed out the potential benefits to both civilian and military scientists as well as the risks of releasing information from which the country’s adversaries might benefit.18 Most of the concern about declassification focused on the drawbacks of giving an adversary information that could support development of ground-based laser systems for either ballistic missile defense or antisatellite weapons. However, some did not believe the threat was that great, arguing that the knowledge would be useless without complex and Sharing the Gold

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expensive equipment—such as high-speed processors, integrated circuits, and deformable mirrors—which was not readily available in the Soviet Union and elsewhere. The Foreign Technology Division—which kept a close eye on the level of military technology in countries around the world— wrote to Colonel Russell that AFWL’s planned declassification would not likely result “in a significant Soviet gain of military capability.” Moreover, the demise of the Soviet Union and Russia’s subsequent economic struggles left the country with fewer financial resources to devote to the military. In the eyes of many American officials, the threat from that quarter had greatly diminished.19 Other potential consumers of the declassified information were easier to assess. Astronomers were interested in laser guide star technology only for the purpose of obtaining better images of dim space objects, and their work did not threaten the American military establishment. Guide star technology for astronomy did not cross over into the more sensitive areas of satellites, point-ahead problems, and high-power lasers associated with ground-based laser antisatellite research.20 Although there was some risk involved in releasing laser guide star information, Russell, Thompson, Otten, Fugate and others believed sharing information with civilian astronomers would benefit the Air Force in the long run. It would make more brainpower and private research dollars available to pursue a wide range of alternative solutions that would improve laser guide star techniques and adaptive optics in general. As Russell put it, “Because of funding limitations, the astronomy community is likely to be innovative in developing approaches to atmospheric compensation which are less expensive and time-consuming to implement; these approaches may have a direct pay-off to DoD programs.”21 The response Russell received to his letters was positive. Input from Dr. Wayne Van Citters of the National Science Foundation (NSF)—the lead agency for the support of ground-based astronomical research in the United States—represented the general feeling among the organizations polled: declassification would be an exceptional opportunity that would benefit the astronomical community and the government. Van Citters was one of the few astronomers outside the military with a security clearance. He had acquired it in 1979 while a consultant to a number of defense contractors and later while working for SDIO developing detector concepts for

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large telescopes. It was through SDIO that he was given access to the Air Force adaptive optics program.22 Van Citters explained that the NSF was convinced that the next generation of ground-based telescopes would deploy mirrors 2.5 meters in diameter and larger. Adaptive optics would be an absolute necessity for these larger telescopes to produce near-diffraction-limited images. Van Citters’s enthusiasm ran high over the possibility that the Air Force might be willing to share its technical accomplishments with the civilian world. He felt the military’s support was essential for improving the performance of groundbased telescopes. Van Citters made an exceptionally strong appeal in favor of declassification when he wrote back to Colonel Russell: Without assistance [declassification] the astronomical community would have to rediscover much of the basic knowledge that has already been obtained with the Department of Defense support. The availability of the technology and knowledge base from HAVE REACH research would be a tremendous boost to this effort [adaptive optics] in the United States. The value of such a contribution is difficult to quantify, but a conservative estimate would be a savings of at least five years of research and development effort and many millions of dollars. That savings translated to “valuable and scarce astronomy dollars” that would not have to be expended for “a re-invention of the wheel.”23 Van Citters mentioned other tangible benefits that he was confident would be derived from declassification. First, the exchange of information among civilian and military scientists would almost certainly help astronomers as well as benefit “the future defense related programs as the astronomical community pursues developments stressing a different set of performance parameters and applications.” In other words, astronomers might come up with their own breakthroughs in adaptive optics that could be applied to Air Force operational systems. The Jasons sent a similar response, predicting that once astronomers were given access to the military’s guide star program, chances were good that their research would help the DoD programs. The Jasons also pointed out that, if the Air Force did not declassify its guide star work, it was only a matter of time before civilian Sharing the Gold

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astronomers would develop the technology on their own. Claire Max, a respected astronomer (currently director of the Center for Adaptive Optics at the University of California at Santa Cruz) and the first woman to serve on the Jasons, was a strong advocate for the Jasons’ position that the time was right to declassify the government’s adaptive optics research.24 Second, Van Citters pointed out that European astronomers’ publications had captured a large share of the spotlight shining on adaptive optics and argued that it was time that American scientists be given full credit for their research achievements. “They deserve the recognition of their colleagues in the astronomical community,” wrote Van Citters, “and the satisfaction of seeing their efforts under Department of Defense sponsorship help to establish a solid leadership role for the U.S. in this highly visible and popular scientific field.” Van Citters’s assessment of this issue closely matched the position of Phillips Lab and the Air Force.25 The NSF was eager to obtain the most up-to-date information on the military’s progress with adaptive optics, but also viewed declassification as an opportunity for civilian astronomers to acquire expensive stateof-the-art hardware from the government. Following up on that idea, Frederick M. Bernthal, the acting director of the NSF, wrote to the director of the Strategic Defense Initiative Organization, Henry F. Cooper, asking if SDIO might be willing to transfer to the NSF some of the adaptive optics equipment left over from a Lincoln Laboratory experiment conducted at the Air Force’s Maui Optical Site in Hawaii. “Such transfer,” Bernthal argued, “would provide an enormous boost in this effort [research by astronomers] and would be an extremely valuable and visible spin-off from the Strategic Defense research program.” Although the Air Force did not transfer the hardware to the NSF, the government did make arrangements later in the 1990s for civilian astronomers to have access to a variety of governmentowned adaptive optics equipment and to conduct experiments at Starfire Optical Range and Maui. On the other hand, Lincoln Lab did transfer its Atmospheric Compensation Experiment adaptive optics system, used in Strategic Defense Initiative research in the 1980s, to the 60-inch telescope at Mount Wilson in southern California, where it became the first adaptive optics system used in civilian astronomy to image a star after correcting for the effects of atmospheric turbulence.26 There was another important reason Van Citters believed the time was

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right to release the Air Force guide star information. Publication of Foy and Labeyrie’s article in 1985 had stimulated civilian astronomers’ interest in the potential of laser guide stars. As a result, scientists at American universities began submitting grant proposals to the NSF for guide star research, which put Van Citters in an awkward position. Based strictly on scientific merit, he should logically disapprove a proposal on laser guide stars, because he knew that a classified program had already accomplished the research. It did not seem reasonable that tax money should pay for the same research twice. But he could not give this classified explanation to a prospective researcher who did not hold a clearance.27 Van Citters asked for advice from Bob Fugate and Darryl Greenwood. Since there were only a few such proposals, they suggested that it might be wise to grant them NSF funding. One reason was that the number of astronomers interested in adaptive optics was much larger in the civilian world than in DoD. So it would not be a bad idea to approve a few NSF research grants to university researchers who could form a small cadre of civilian experts in laser guide star technology. Another reason was to prevent American researchers falling too far behind the French. With NSF support, American researchers would be in a better position to come up with ideas that could advance adaptive optics beyond what the military had already accomplished. For example, their work might result in improved wavefront sensors and deformable mirrors that could lead to development of an industrial base capable of manufacturing adaptive optics equipment from which the military could benefit. That was a compelling argument.28 Although the NSF did award academic scientists a limited number of grants in the late 1980s, they were only a small minority of American astronomers, and they were conducting research without the benefit of guide star knowledge that the Air Force possessed but could not disclose. To devise a way to share more information with civilian astronomers, Thompson moved forward from informal discussions on declassification to a formal review. The goal was “to provide the information needed to make a rational choice among various options for classification and public release policies for adaptive optics and artificial beam technologies in the compensation for atmospheric turbulence.”29 Thompson realized from the start that he and others would have to do their homework if they expected to convince the Phillips Lab commander, Sharing the Gold

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Colonel Peter J. Marchiando, that it would be in the best interest of the Air Force to declassify the laser guide star information. Marchiando, as commander, had the power of original classification authority, which meant he could declassify any research program work that took place under the organization he commanded. Realistically, however, the commander would be acting on behalf of the entire Air Force on a very sensitive issue if he decided to declassify the laser guide star work. Therefore, it came as no surprise to anyone that he expected Thompson and his group to conduct a thorough and objective assessment before deciding for or against declassification.30 Based partially on responses to the letters Colonel Russell had sent out earlier, Thompson began his formal assessment by developing a benefits and cost analysis for each possible option. Those options ranged from keeping the program classified to five varying degrees of declassification.31 Thompson’s team recommended first to Colonel Otten that the DoD declassify information related to artificial beacons—concepts, theories, and experimental results that pertained to laser guide stars. Fugate was the strongest supporter for declassification, believing that the benefits of sharing information with astronomers outweighed the cost of disclosing technology to our adversaries.32 The main benefit of sharing information, Thompson argued, was that it would create stronger ties between astronomers and the Air Force. That new relationship would bring academic astronomers up to the same level of technical maturity as the Air Force scientists who had participated in classified programs. They would then be able to function as a “second team” and come up with new adaptive optics techniques that could benefit the Air Force.33 Otten agreed with Thompson’s endorsement for declassifying the laser guide star work, but he wanted to make sure not to act prematurely. He sent a letter in March 1991 to the same organizations that Colonel Russell had contacted in June 1990. Otten attached Thompson’s report, plus a description of how the declassified information would be released.34 Otten asked each recipient to review and comment on the Phillips Lab’s assessment process. The response was uniformly supportive. Darryl Greenwood from Lincoln Laboratory’s Optics Division wrote: “I want to applaud your efforts in revising classification policy regarding adaptive

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optics using artificial beacon technologies.” He was encouraged that the Air Force was on the verge of making “a wealth of technology and knowhow” available to astronomers. Knowing that the key to make the declassification decision stick was the issuance of a new classification guide, his final comment to Otten was, “I urge you therefore to move expeditiously on the revisions to the classification guide.”35 As expected, Wayne Van Citters strongly endorsed the proposal. “This action,” he wrote, “would provide information and technology of enormous value to the astronomical community.” He offered his support for a joint DoD/NSF conference as outlined in Otten’s implementation plan. This event would bring together Air Force and academic scientists to share information for the advancement of adaptive optics. In particular, it would give Air Force scientists an opportunity to make presentations covering the technical details of their newly declassified work to all interested astronomers. The conference was tentatively planned to take place in Albuquerque in December 1991.36 A second part of the implementation strategy involved arranging for a special issue of the Journal of the Optical Society of America devoted exclusively to adaptive optics and artificial beacon technology, with a separate editor and a good cross-section of papers representing scientists from government, academia, and private industry. Publication was planned for 1992.37 Once Otten received feedback, he acted quickly. He met Thompson and his group in mid-April; the group was unanimous in favor of declassification. Otten and Thompson next brought their case for declassification to Marchiando. The Phillips Lab commander was impressed by the thoroughness of the assessment process. He also took into account the rationales offered by outside organizations in support of declassification. Marchiando made the final decision in late April 1991 to approve the declassification of laser guide star technologies. Declassification would not become official, however, until the revised classification guide was complete. Thompson had already been working on that for months and was able to distribute it on 15 May 1991. The new guide, signed by Colonel Marchiando, became effective immediately. Even though HAVE REACH information was declassified, each request for information still had to be reviewed by the appropriate government public affairs office before the information could be released to the public.38 Sharing the Gold

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The Announcement Publication of the revised HAVE REACH classification guide, arrangements for the special edition of the Journal of the Optical Society of America, and the planned laser guide star adaptive optics workshop were all critical elements of Phillips Laboratory’s plan to release material on laser guide stars. But of more immediate concern was the need for a dramatic announcement of the Air Force’s successful laser guide star experiments. Bob Fugate would make the announcement. The 178th meeting of the American Astronomical Society (AAS) in Seattle in May 1991 provided the ideal setting for Fugate to announce that his laser guide star work was an unqualified success and that information about it could now be released to the public. A large crowd was expected to attend. Fugate’s proclamation at such a prestigious gathering would represent a huge step by the Air Force in terms of technology transfer by the military to astronomers. But it almost did not happen, because Fugate’s paper was not cleared for public release until the last moment.39 Three months before the AAS conference, Charles H. Townes, who shared the 1964 Nobel Prize for physics, had placed Fugate and Primmerman on the AAS program with identical titles for their presentations. Townes had a security clearance and a strong interest in adaptive optics. He had followed the research at Starfire Optical Range and made two site visits. With Townes’s influence, Fugate and Primmerman would participate in the AAS session listed on the agenda under “Atmospheric Fluctuations: Their Nature and Techniques for Compensation.” Both talks were entitled simply “Adaptive Optics Experiments” and had to be sent up the chain of command for review, first at various Air Force levels and then at the DoD, which would make a final ruling as to whether or not the papers would be cleared for public release. This took time.40 On 1 March, DoD notified Fugate that the title and a one-paragraph abstract of his paper had been cleared, with a reminder that “Clearance of abstract does not satisfy requirement for clearance of entire paper.” DoD wanted time to scrutinize the entire paper before clearing it. However, Fugate was able to submit the cleared title of his paper, which now read “Experimental Discussion of Real Time Atmospheric Compensation with Adaptive Optics Employing Laser Guide Stars,” for inclusion on the AAS Bulletin’s list of papers that would be presented at the Seattle meeting. Fugate, very much

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aware of others’ contributions to the first laser guide star work, listed 16 coauthors: C. H. Higgins, J. L. Wynia, W. J. Lange, A. C. Slavin, W. J. Wild, M. P. Jelonek, M. T. Donovan, S. J. Cusumano, and J. M. Anderson, all from Phillips Laboratory’s Starfire Optical Range; J. M. Spinhirne, B. R. Boeke, and R. E. Ruane, from Rockwell Power Systems in Albuquerque; J. A. Moroney, K. S. Nickerson, and D. W. Swindle, from Adaptive Optics Associates, United Technologies Optical Systems, in Cambridge, Massachusetts; and R. A. Cleis from the Optical Sciences Company in Placentia, California.41 Once the AAS Bulletin was sent out, some people became curious about, and even suspicious of, what Fugate and Primmerman were going to talk about. A number of people called Fugate to ask for details about his presentation. Fugate explained that he could not pass on any information because his paper had not yet been cleared by DoD.42 Two months passed and then another two weeks, but the DoD still had not cleared Fugate’s and Primmerman’s papers. With the AAS meeting date fast approaching, Fugate suspected that Townes used his influence to get the DoD to expedite clearance for the two papers. Although he had nothing in writing, Fugate deduced from the rumor mill that in all probability either Secretary of Defense Dick Cheney or President George Bush made the final declassification decision. On 21 May, only a week before the Seattle meeting, Fugate and Primmerman received notification that their papers had been cleared.43 When Fugate walked up to the podium at one o’clock on 27 May to deliver his paper, he was a little nervous as he gazed out across the audience in the jam-packed room. Nearly 400 people had showed up, some standing two to three deep in the back and along the side walls. Fugate was overwhelmed with the scene; he had never talked to more than thirty people at a time on the topic because of its classified nature. He sensed anticipation in the air; rumors had circulated at the conference that his and Primmerman’s papers would reveal some technological breakthrough in adaptive optics and the use of laser guide stars.44 Fugate did not disappoint the audience; he got to the heart of the matter right away. The first words out of his mouth were delivered in a confident and deliberate manner: “Ladies and gentlemen, I am here to tell you that laser guide star adaptive optics works!” To provide historical substance and scientific credibility to his opening statement, Fugate had projected two Sharing the Gold

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Photo 26. Bob Fugate showed this image during his presentation at the American Astronomical Society Meeting in Seattle on 27 May 1991 to demonstrate the success of Rayleigh laser guide star adaptive optics.

images of the binary star 53 Ursa Major on a large screen behind him. The uncompensated image shown on the left appeared as essentially a blank in the heavens. But the image on the right, compensated with laser guide star adaptive optics, was dramatically clear, an improvement greater than a factor of 25 over conventional astronomical imaging. Fugate explained that the photo “was taken while the deformable mirror was continuously correcting atmospheric wavefront distortions.” For a brief moment there was silence as the audience tried to grasp the significance of Fugate’s startling announcement. Within seconds, the silence was replaced by noisy chatter as the astronomers turned to one another and began muttering about the amazing image that they had just seen.45 Fugate explained that the 53 Ursa Major image was made on 16 March 1990, more than a year after the SOR team had closed a laser guide star loop

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for the first time as part of the Gen I experiment. He told the AAS audience that the Air Force had sponsored laser guide star adaptive optics research since 1982—a shocking revelation to the academic astronomers in the audience—and described his first laser guide star experiment, conducted in fall 1983. Because of the time restraints on his presentation, it was impossible to cover the full history of nearly a decade of Air Force laser guide star work. Instead, he showed the hardware used at SOR, along with a series of other compensated images—as he told the gathering, “just to convince you that we didn’t get one lucky picture.” Although he skipped over most of the technical details—theory, design, and performance of the hardware—Fugate promised that information would be shared at future joint workshops between military and academic astronomers and through publication of scholarly and technical articles.46 Primmerman followed Fugate’s talk with a short presentation on Lincoln Laboratory’s successful sodium laser guide star experiments at White Sands and Maui. Fugate described the scene when the floor was opened for questions as “a forest of hands that went up!” Thompson, sitting in the audience that day, recalled it was “quite a day” as the astronomers were simply flabbergasted by the release of previously classified information. “A lot of people in the audience,” Thompson observed, “were stunned by the amount of work that had already been done by DoD when that was presented at the meeting.” Wayne Van Citters remembered that the people witnessing Fugate’s and Primmerman’s presentations slowly leaned back in their chairs, mentally regrouped, and reacted with one telling word—“Wow!”47 One of the more humorous aspects of the meeting took place when the Fugate/Primmerman portion of the session ended. Laird Thompson, an astronomy professor from the University of Illinois at Urbana-Champaign, was scheduled to speak next on his research on adaptive optics. He was in the unenviable position of following the Fugate/Primmerman talks. As a sheepish Thompson approached the podium and turned to face his audience, he hesitated for a moment and then good-naturally blurted out, “I’ve never felt so scooped in my entire life!” Those in the still buzzing crowd grinned and grimaced at the same time in empathy. Thompson took only a few minutes to summarize his paper and then conceded the remainder of his time to allow the highly charged audience to ask more questions of Fugate and Primmerman.48 Sharing the Gold

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Photo 27. The day after his formal presentation to the American Astronomical Society, Bob Fugate briefed the press on his revolutionary laser guide star findings, while Charles H. Townes (center) and Chuck Primmerman (next to Townes) looked on.

After Thompson sat down, Fugate was bombarded with more questions from the energized astronomers in the audience. How do you do this? What kind of hardware and instrumentation is required? Does it really work outside the laboratory? Where can I get one of these? What are the downsides of the technology? How much does it cost? Can it go on any telescope? How can we get more information? Fugate fielded the questions as best he could, but only covered the tip of the iceberg in his responses because of time restrictions. However, the next day at a news conference at the AAS meeting, Fugate reached out to a larger audience by explaining to reporters the significance of the guide star research and the effect it would have on the military and on astronomers.49 There would be more time available later to share the nearly 10 years of DoD-sponsored research with astronomers. In addition to one-to-one talks at the meeting and Fugate’s news conference, there were two more

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formal public forums for the newly released information. One was a workshop arranged by Fugate and Primmerman and held in March 1992 in Albuquerque. The second was the publication in January 1994 of a special edition of the Journal of the Optical Society of America devoted to adaptive optics. The workshop and the journal were the key parts of Phillips Lab’s plan to release as much of the newly declassified information as possible.50 Fugate and Primmerman took the lead in arranging the Albuquerque workshop, as they were the ones who had made the revolutionary announcements at the Seattle meeting. But neither had a good feel for how many people would show up. Primmerman did not think many people would attend, so Fugate reserved a Phillips Lab conference room that could accommodate 50 or 60 attendees. Within three or four days after the workshop was announced, Fugate was inundated with calls. Over 200 people said they planned to attend. After some last-minute maneuvering, Fugate was able to secure Kirtland’s West Officers Club as the new site of the workshop. The extra space was needed: 205 people showed up to fill the room, including astronomers from Germany, Canada, France, Japan, and Great Britain.51 To add a sense of historical perspective to the workshop, Horace W. Babcock, who had first proposed the concept of adaptive optics back in the 1950s, was invited to make the keynote address. When he got up to speak, the audience waited with great anticipation as to what the venerable dean of adaptive optics would say. Babcock, who now worked at the Carnegie Institution in Washington, looked the audience squarely in the eye, made sure he had their attention, and said in a clear voice, “What took you guys so long?” When the laughter subsided, he went on to deliver his talk on the tremendous strides that had been made in astronomy from the 1890s to the present.52 Fifty-eight presentations followed Babcock’s talk. The papers were divided among four topics: basic principles and experiments, theory, astronomy programs, and applications and components. Fugate presented his experimental findings on Gen I and Gen II, the latter having taken place after the Seattle meeting. Primmerman explained results from Lincoln Laboratory’s SWAT experiment. With Fugate as editor, the papers were published in two volumes, creating a valuable reference source for both the DoD and civilian astronomers.53 A long list of top achievers—a virtual Who’s Who in adaptive optics— made presentations. Francois Roddier, from the Institute of Astronomy at Sharing the Gold

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the University of Hawaii, and Edward Kibblewhite, from the University of Chicago, talked about laser beacons. Government and contractor personnel who had participated in the classified adaptive optics programs in the 1980s presented many of the papers. For example, David Fried, the respected mathematician from the Optical Sciences Company, discussed the complexities of focal anisoplanatism and its effect on laser guide stars. Mark Ealey from Litton/Itek Optical Systems spoke on low-voltage requirements of deformable mirrors. Brent Ellerbroek spent his allotted time on adaptive optics performance predictions under good seeing conditions at Starfire Optical Range.54 The impressive speakers accounted in large measure for the success of the workshop. The astronomers in the audience having access for the first time to the technical details of the previously classified information were simply blown away. Perhaps even more beneficial and rewarding than the formal presentations were the private conversations that took place in the hallways during the breaks. At the end of the workshop, Otten commented, “I don’t think there is anybody in the professional community who should doubt that atmospheric compensation has been demonstrated.”55 One of the highlights of the workshop was a tour, three nights in a row, of Starfire Optical Range, where Fugate showed off the 1.5-meter-telescope and demonstrated the laser beacon. He also showed workshop attendees the site under construction at SOR that would eventually house the 3.5-meter telescope. Needless to say, the academic astronomers were especially taken with the scope and up-to-date hardware of the SOR operation. It was obvious to them that the military had invested heavily in adaptive optics, creating a firstrate research enterprise that had to be the envy of any university astronomy department. There was no denying that adaptive optics was an expensive long-term venture that had been bankrolled to a large degree by the massive financial resources of the DoD. This reinforced the notion that most university astronomy departments could not afford the expensive telescopes and adaptive optics systems needed to compete in this field of research.56 Clearly, workshop participants gained a great deal of knowledge and the tours of SOR were a great success. The downside was that arranging tours created an extra workload for Phillips Laboratory and SOR staff. Fugate and his team were inundated with requests to tour the site over the next couple of years. As he described it: “We had forty tours a month. It was just everyone you could imagine. I mean huge amounts of people.” It took

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an incredible amount of work to conduct tours during the day and night at SOR. Not only did the tours themselves take time, but so did the logistical arrangements beforehand. Since SOR was in a remote and off-limits location, a myriad of security requirements had to be met for each visitor, and transportation had to be arranged from Kirtland to SOR and back in the evening and early morning hours. Although all this was labor intensive, the payoff was substantial, as the tours promoted the Air Force’s scientific reputation as the leader in adaptive optics research.57 The workshop presentations and the tours certainly put Phillips Lab’s adaptive optics contributions on the scientific map. The word spread quickly, but apparently did not reach everyone. A few months after the Kirtland workshop, Otten attended the Optical Society of America’s meeting in Maui, designed to establish long-term communication and collaboration among researchers in adaptive optics, and found some astronomers still expressing surprise over the clarity of images produced using adaptive optics. When one of the speakers showed an image of a star taken in the early 1980s using an Air Force closed-loop adaptive optics system at Maui, two academic astronomers sitting in the row in front of Otten were amazed. One astronomer leaned over to the other and in a troubled voice said, “He [the speaker] certainly must have meant this year, not ten years ago!” Otten recalled, “They just couldn’t believe it. They felt, how could this go on and they not knowing it? This was a group who thought they were well ahead and thought they were going to invent all of this and make their mark on science. It was very gratifying to hear all these professors and astronomer instrument developers who thought this was going to be theirs and in fact the Air Force had accomplished this some years before.” This was only one incident, but it revealed that a few astronomers had a hard time accepting that Air Force scientists had been far out in front of the university community for over a decade in the advancement of adaptive optics.58 Undoubtedly, face-to-face interactions at workshops and meetings served to strengthen cooperation among the various groups involved in adaptive optics—military, contractors, academia, and private institutions. Another means for disseminating information on adaptive optics was the written word: publication of a special edition of the Journal of the Optical Society of America in 1994. Rettig Benedict (W. J. Schafer Associates, Albuquerque), James B. Breckinridge (Jet Propulsion Laboratory, Pasadena, California), and Sharing the Gold

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David L. Fried (the Optical Sciences Company, Anaheim, California) served as editors; 29 articles on atmospheric compensation appeared in two consecutive issues—January and February 1994—of the journal.59 The purpose of the double special issue, as explained by Benedict, was “to present the results of the most recent experimental and theoretical advances in the compensation for atmospheric turbulence.” He pointed out that since the release of formerly classified material in May 1991, “a significant expansion in turbulence-compensation program activities has occurred.” Some of those advances were included in the journal articles, along with research that had taken place in the 1980s.60 The first four papers in the two-volume special edition provided a historical overview of adaptive optics research starting in the early 1980s. Will Happer’s paper appeared first. Originally a classified account written for the Jasons, Happer’s revised article discussed the early concept of creating artificial beacons for atmospheric-turbulence compensation using resonant backscattering from the sodium layer in the upper atmosphere. David Fried’s article followed and addressed the limitations of artificial guide stars caused by the effects of focal anisoplanatism. Ronald Parenti’s paper looked at how Lincoln Laboratory approached the use of laser guide stars for astronomical applications, while the fourth paper, authored by Fugate, covered laser guide star experimental work at SOR in the late 1980s and early 1990s.61 The remaining twenty-five journal articles covered a variety of topics on adaptive optics. Most focused on different aspects of laser guide star theory and field results obtained from Rayleigh and sodium backscattering experiments. Several considered the effects of thermal blooming on laser guide stars. Two articles discussed atmospheric compensation system designs for large-aperture telescopes. Collection and publication of these articles provided a comprehensive foundation and valuable reference guide—based on previously classified research—for astronomers from a diversity of institutions to use to further advance adaptive optics.62 The overwhelming response to the journal’s two-issue special edition was favorable. Not only did the articles open up a valuable source of information, but their publication recognized the military’s civilian scientists for their groundbreaking work over the last 10 years. Rett Benedict, who served as one of the editors, pointed out that the vast majority of astronomers were delighted with the progress that had been accomplished on

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adaptive optics by the military, because they knew these advances could be applied to future telescopes and help astronomers produce high-resolution images of heavenly bodies.63 Benedict recalled only one negative incident related to the special issue. He received a letter from a professor who had been conducting research in adaptive optics. Although his reasons were not completely clear, the professor wrote that he did not believe that people involved in classified work should get any credit for advances in research conducted “behind closed doors.” Benedict’s response to the professor was that military and civilian scientists had to be just as creative as their counterparts in making new scientific discoveries. Just because other people, including university professors, did not know about the classified research, did not change the fact that military and government scientists deserved credit for their findings.64 Fugate attested to the massive outpouring of respect and credit from astronomers in recognizing the military’s leading role in adaptive optics laser guide star work. For the most part, there exists a high level of mutual admiration between DoD scientists and university astronomers. Fugate put it best when he said, “I have never seen such support for government workers as I get from astronomers. Their respect and appreciation is truly amazing—even today.”65 Phillips Laboratory’s decision to declassify more than a decade of research proved beneficial for everyone. Astronomers now had access to a gold mine of information. As Fugate remarked, “One of the things declassifying this technology has done is give people the insight to know they are going in the right directions.” At the same time, the declassification allowed Air Force and contractor scientists to receive the recognition they deserved for their scientific and technical achievements in adaptive optics.66 The scientific reputation of the Air Force and Lincoln Laboratory soared with Fugate’s and Primmerman’s presentations in Seattle in May 1991. In addition, publication of the special edition of the Journal of the Optical Society of America offered strong testimony to the importance of the military’s groundbreaking contributions to adaptive optics. The Air Force’s next challenge would be to apply the technological advances it had discovered to the building of adaptive optics systems that could be mated with new large-aperture telescopes and operational systems under development such as the airborne laser. Sharing the Gold

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Strategic Defense Initiative

By early 1978, the Lincoln Laboratory work at West Palm Beach had wound down and come to a halt because Lincoln scientists believed they had accomplished what they had set out to do. Interest within the Air Force had also moved to shorter-wavelength lasers—such as the chemical oxygen-iodine laser or COIL, first developed at AFWL in 1977, and the Navy’s deuterium fluoride mid-infrared advanced chemical laser or MIRACL. Lincoln had shown at West Palm Beach that adaptive optics could improve but not completely correct for thermal blooming in high-energy lasers. Another reason for not proceeding with more work on thermal blooming was that at the highest levels in the Department of Defense there was a shift of emphasis away from tactical to strategic applications of lasers. First Air Force and DARPA leaders, and later officials at the Strategic Defense Initiative Organization (SDIO), wanted to investigate the potential use of short-wavelength lasers fired from the ground into space, which in general were less susceptible to thermal blooming than longer wavelength lasers. In the 1980s, Lincoln Lab scientists first conducted work on guide stars and then an assortment of other laser/adaptive optics experiments through the early 1990s.1 In January 1983, Marquet left Lincoln Laboratory to join DARPA. His new workplace was on Wilson Boulevard in Arlington, Virginia, just across the Potomac River from the nation’s capital. Bob Cooper, DARPA’s director, asked Marquet to head the organization’s Directed Energy Office. His

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previous experience made Marquet a good fit at DARPA. As one coworker described it, Marquet brought with him “lots of ideas, lots of balls in the air” and was “very energetic and enthusiastic” when he arrived. Many of the projects he was responsible for explored the feasibility of projecting lasers into space to kill targets, specifically missiles and satellites. However, DARPA also looked at other possible applications of lasers. That included using lasers to power future space stations, to communicate with submarines, and for other communication functions, such as bouncing them off space mirrors to ground receivers in place of transmission wires.2 DARPA was not the only organization interested in potential future technologies. In spring 1982, George Keyworth, science advisor to President Reagan, brought together a group of prominent scientists to study new technology options and make recommendations to the president as part of his modernization program for the military. The group was made up of Saul Buchsbaum, David Packard, Edward Teller, and Edward Frieman, who chaired the panel. This was part of a huge military buildup that represented a fundamental shift from the Carter administration’s policy, which had reduced the amount of money spent on national defense. The panel’s job was to take a broad look at the military, across all services, and to identify innovative technologies that could make a difference to military capabilities. Ballistic missile defense was only one part of the program. The panel delivered its final report to the White House Science Council in January 1983, two months before the president gave his landmark Strategic Defense Initiative (SDI) speech.3 The highly classified report was pessimistic about the feasibility of using directed-energy technologies—lasers, microwaves, and particle beams— for developing weapon systems, because they simply had not shown sufficient scientific progress and maturity. Teller, a passionate proponent of lasers in space, vigorously disagreed with the report’s conclusions, saying, as Edward Frieman later remembered, that “the report should be trashed and never see the light of day.”4 There was one notable exception to the panel’s overall negative conclusions. The report singled out adaptive optics as the most promising technology for compensating for atmospheric turbulence in light beams. Panel members arrived at that conclusion based on the successful research at Rome, Kirtland, and Maui. Frieman noted that adaptive optics was a “clever” technology that was appealing because it was understood in terms

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of its theoretical concept and basic science. Moreover, the Air Force had demonstrated that an adaptive optics system could work effectively on its 1.6-meter telescope at Maui (the CIS or compensated imaging system described in chapter 3).5 Keyworth believed that adaptive optics would strengthen the nation’s strategic defense system for several reasons. At the time the report came out, one of the leading proposals advocated by Edward Teller was a space-based X-ray laser system called Excalibur. It would rely on a nuclear explosion in space to generate laser beams that would destroy intercontinental ballistic missiles launched at the United States. Many scientists were skeptical of this plan, because even if the system worked, it would be extremely vulnerable to enemy countermeasures and far too expensive to maintain. Keyworth and others believed that adaptive optics offered a more realistic alternative. If adaptive optics could remove distortions in a laser beam caused by atmospheric turbulence, then a beam transmitted from the ground would have a good chance to intercept an enemy missile. And a laser system installed on the ground could be maintained and defended more easily and at less cost than a space-based system.6 Keyworth believed that adaptive optics was not the end-all solution but a key element to modernizing the existing strategic force structure, the triad of strategic bombers, ICBMs, and submarine-launched missiles. As an enabling technology for an antimissile defense system, adaptive optics could complement and enhance the land-based ICBM leg of the triad by making it more survivable. Also, under this scenario, because success would be less certain, the Soviets would be less tempted to launch a first strike against American land-based ICBMs. Advice to combine adaptive optics with lasers was the type of input that influenced President Reagan’s decision to pursue a revolutionary strategic defense system under his SDIO program.7 Recognition of adaptive optics at the highest level of government encouraged military scientists to invest more money and resources in it. With the establishment of SDI, the Air Force laboratory system, DARPA, and Lincoln Laboratory renewed their commitment to adaptive optics; the consensus was that this technology would work. Over the next two decades, adaptive optics made astonishing progress. Today, nearly every new largeaperture telescope in the world is equipped with adaptive optics. In addition, adaptive optics is an enabling technology for the airborne laser (see Strategic Defense Initiative

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chapter 9), currently under development and designated to serve as the nation’s first high-energy laser weapon system. Marquet’s stay at DARPA was relatively short; President Reagan’s 10-minute “Star Wars” speech to the nation on 23 March 1983 changed everything about strategic thinking. Reagan’s unexpected pronouncement made clear that the nation would focus its resources on the development of strategic space-based weapons to defeat the Soviet ballistic missile threat. The president wanted to make nuclear weapons “impotent and obsolete”; the way to do that was for the United States to move forward with a “comprehensive and intensive effort to define a long-term research and development program, to achieve our ultimate goal of eliminating the threat posed by strategic nuclear missiles.” The press dubbed the president’s presentation his “Star Wars” speech. Reagan objected to this name because it gave a science-fiction aura to a serious goal: moving away from a strategic balance of terror, known as mutual assured destruction, which counted on the fear of annihilation to prevent either side from launching a first strike and had resulted in 30 years of dangerous brinksmanship between the two superpowers.8 The president argued strongly for replacing that approach with a ballistic missile defense. Such a system would intercept missiles during various phases of flight—boost, mid-course, and terminal—toward their targets. This intercept capability would in theory deter the Soviets from launching a nuclear attack, knowing that all their missiles would not get through the U.S. defensive shield. But to some, including the Soviets, the name Star Wars gave an offensively aggressive tone to the new proposal. It seemed plausible to antinuclear and peace groups that SDI weapons could be used not only for defense but also to attack enemy satellites. In addition, a country immune from retaliation might feel free to launch its own nuclear attack. The Kremlin certainly viewed SDI in this way. However, the president responded to his critics by repeating the question he used in his 23 March speech: “Wouldn’t it be better to protect the American people rather than avenge them?” That simple message was intended to convince the public that a shift to a strategy based on defense was the most effective and realistic way to respond to the enormous buildup of Soviet conventional and nuclear forces over the last 20 years.9 Why did Reagan, who was not by any stretch a deep scientific thinker, decide to make his SDI speech, especially in light of the scientific evidence

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he had at his disposal from the Frieman panel and other sources? Frieman speculated, “I think he honestly believed that if a bunch of smart people worked on this problem [ballistic missile defense] they could solve it and then he could protect the country. Simple as that.”10 Although Reagan’s decision may not have been difficult to make, implementation of the new policy was complex and challenging. Two days after his speech, Reagan issued a broad policy statement in National Security Decision Directive Number 85 to begin implementing an SDI program. He tasked his national security advisor, William P. Clark, to formulate detailed instructions for a study “to assess the roles that ballistic missile defense could play in future security of United States and our allies.” Reagan also directed a second study be conducted “to define a long-term research and development program” that would lead to the defeat of any enemy-launched missile attack against the United States.11 Reagan appointed James C. Fletcher from the University of Pittsburgh (a former chief administrator of NASA from 1971 to 1977) to lead a study to assess technologies for defeating a ballistic missile attack. Richard D. DeLaurer, undersecretary of defense for research and engineering, oversaw the work of Fletcher’s Defensive Technologies Study Team, also called the Fletcher Commission. The group worked from 1 June to 1 October 1983, an extremely short time to evaluate such a large and complex topic. Directedenergy weapons emerged from the study as one of five technical areas that SDIO should vigorously pursue. The other four areas involved technologies for (1) surveillance, acquisition, and tracking, (2) kinetic-energy weapons, (3) systems analyses and battle management, and (4) survivability, lethality, and key technologies.12 The main goal of directed-energy research was to develop weapons that could intercept ballistic missiles when they were most vulnerable: in their boost phase (immediately after launch, when the missile is slowly gaining altitude) or post-boost (when the missile has reached full velocity, but before decoys can be deployed). The Fletcher team envisioned using powerful ground- and space-based lasers with sophisticated adaptive optics systems to clean up the beam and accurately direct it to its target, whether the target was in space, in the air, or on the ground.13 The Fletcher study, along with a separate study—the Future Security Strategy Study (FSSS), directed by Fred C. Ikle, undersecretary of defense Strategic Defense Initiative

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for policy, which assessed the political and military implications of the new ballistic missile defense system—convinced Reagan in September 1983 that he was right to go ahead with SDI. Two teams, an interagency team headed by Franklin C. Miller, director of the Pentagon’s Office of Strategic Forces Policy, and a team of consultants led by Fred S. Hoffman, contributed to the final FSSS. The Hoffman report endorsed the president’s strategy to place increased reliance on defensive systems. The defense consultants arrived at a similar conclusion: “U.S. national security requires vigorous development of technical opportunities for advanced ballistic missile defense systems.” It seemed clear that the “vigorous development” would be carried out in large part by SDIO. Findings of the Fletcher study (seven volumes of closely guarded technology assessments along with a 5-year research and development plan) and the two FSSS panels were basically identical in urging the president to pursue the missile defense program.14 Nearly a year after his speech advocating a defensive shield against ballistic missiles, Reagan issued National Security Decision Directive 119 on 6 January 1984 to formally establish the Strategic Defense Initiative Organization. Secretary of Defense Caspar W. Weinberger formally set up SDIO on 27 March 1984 with the mission to establish a ballistic missile defense system. In a memo to all secretaries of military departments and directors of defense agencies, Weinberger attached “the highest priority to the Strategic Defense Initiative” and said that it required support from all DoD employees, both military and civilian. Weinberger also announced the president’s choice of Air Force Lieutenant General James A. Abrahamson as SDIO’s first director.15 Abrahamson was not the first choice for the SDI job, as the secretary of defense had been looking for a civilian with experience in running large military research and development programs. Weinberger’s initial preference was the highly respected John S. “Johnny” Foster, who had served from October 1965 to June 1973 as director of the defense research and engineering office in the Pentagon. However, Foster had been retired for years and was not interested in coming back to take on such a heavy responsibility.16 At a White House meeting attended by Weinberger and General Lawrence A. Skantze, commander of the Air Force Systems Command, the president asked his secretary of defense, “Where is my program director, and why aren’t we getting going on this?” Weinberger replied that there

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was an intensive search under way, but so far they hadn’t been able to find a civilian with the right mix of qualifications.17 At that point General Skantze said, “I know exactly the right person for the job, General Abrahamson. By the way, Mr. President, you know him. You pinned on his third star when you went out for the shuttle landing on the 4th of July at Edwards [Air Force Base]. He may be a general, but he thinks he is a civilian!” A few days later a surprised Abrahamson was standing in front of the secretary interviewing for the job of director of SDIO. Weinberger was impressed with the general’s résumé and his views on strategic defense, which coincided with the president’s. Abrahamson’s experience in successfully leading large defense programs as the director of the F-16 Multinational Air Combat Fighter Program (1976 to 1980) and as the associate administrator for the Space Transportation System at NASA headquarters in Washington, DC, helped to convince Weinberger that he had found the right man for the job. Abrahamson had the right personality and was highly credible in representing the merits of SDI to Congress. He remained as SDIO director for nearly 5 years, leaving in January 1989.18 Reagan was able to persuade Congress to inject billions of dollars— not millions—into SDIO’s elaborate research program. SDIO’s directedenergy work built on foundations created by technology programs from the 1970s and early 1980s sponsored by DARPA and the Air Force, Army, and Navy. DARPA had funded about 75 percent of these efforts, while the Air Force had established its position as the leader in the field of lasers. For example, by the time SDIO had gotten under way, the Air Force had already developed and tested a much-publicized high-power CO2 gas dynamic laser aboard a specially modified NKC-135 aircraft known as the Airborne Laser Laboratory (ALL) under the leadership of Colonel Don Lamberson. (Lamberson went on to become a major general and a leading spokesman for the development of directed energy.) In May 1983, the ALL shot down five AIM-9B Sidewinder missiles over the China Lake Test Range in California—proving for the first time that an airborne laser could intercept and destroy air-to-air missiles.19 The arrival of SDIO had a significant influence on Marquet’s directedenergy group at DARPA. Joseph A. Mangano and Robert Sepucha from Marquet’s team worked on the directed-energy portion of the Fletcher study, which was chaired by Gerold Yonas of Sandia National Laboratory. Strategic Defense Initiative

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Photo 28. A year after his appointment as director of the Strategic Defense

Initiative Organization, Lieutenant General James A. Abrahamson appeared on the cover of Newsweek. Photo courtesy of Newsweek.

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Between 1983 and 1984, when SDIO was officially established, an informal relationship had evolved between DARPA and SDIO. “I was working both for DARPA and SDIO in my DARPA job,” Marquet recalled, “which involved all the different programs in directed energy.” As he explained it, “I was still head of the Directed Energy Office at DARPA, and at the same time I was head of the now forming Directed Energy Office of SDIO.” Eventually, Marquet’s office moved completely out of DARPA and reemerged as a permanent office in SDIO.20 Tom Meyer, an extremely knowledgeable Air Force officer (and a firstrate tennis player) who worked for Marquet, claimed that DARPA’s director, Bob Cooper, was not a huge fan of developing directed-energy technologies for ballistic missile defense. At the same time, General Abrahamson, the director of SDIO, was trying to lure Marquet and his staff to SDIO, which was in the process of shaping its initial management structure. Subsequently, General “Abe” called a meeting with everyone in Marquet’s group to explain the benefits of working for SDIO. Meyer attended the session and remembered: “He [Abrahamson] said, ‘What’s your budget now?’ At the time there was about $300 million a year and there were six or seven of us. . . . He said, ‘What do you think if each of you had $300 million apiece?’ The office [SDIO] was a billion-dollar office, so it was a great sales pitch!” By the time the general finished his presentation, everyone in Marquet’s group was eager to move over to SDIO. “We figured we were getting that big budget,” Meyer recalled, “and we did. The budget went up substantially [from DARPA]!”21 Although Meyer’s account of General Abrahamson’s meeting was accurate, the decision to move Marquet’s directed-energy group to SDIO had already been made. Part of the reason was that Cooper’s boss at the Pentagon, Richard “Dick” D. DeLaurer, undersecretary of defense for research and engineering (DDR&E), knew that President Reagan wanted the SDI program to start big. Cooper was holding two jobs at the time, assistant secretary of defense for research and technology at DDR&E and director of DARPA. Secretary Weinberger appointed Cooper, along with Major General Donald L. Lamberson and Brigadier General Robert R. Rankine (both of whom served as assistants for directed-energy weapons under Deputy Secretary of Defense Paul Thayer) to build the Strategic Defense Initiative Organization “from scratch.” Cooper suggested that it would Strategic Defense Initiative

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make sense to move the entire DARPA laser group into SDIO. That would accomplish two things. First, moving the DARPA group—and other relevant technology programs from the three military services—would help to create a large centralized SDIO organization consistent with the president’s guidance to consolidate all the key technologies under one roof. Second, since Marquet’s laser group was eating up so much of Cooper’s DARPA’s budget—roughly 300 to 400 million dollars annually—Cooper suggested that, to gain some financial relief, “we take the whole laser group and put them into SDIO.”22 The secretary of defense aimed from the beginning to move the missile defense technology programs out of DARPA and into SDIO. The president wanted a centrally controlled SDI program that would administer research in many different technologies. Most of the directed-energy, surveillance technology, and ballistic missile defense programs that transferred to SDIO had already been under way at DARPA for years, primarily in DARPA’s Directed Energy and Strategic Technology offices. Moving the programs entailed a major shift of resources. Of DARPA’s nearly $800 million annual budget, between $300 and $400 million transferred to SDIO. As Cooper pointed out, “When SDIO was formed, we just took those offices and literally formed SDIO out of DARPA.” The move meant that, for all practical purposes, DARPA was now out of the adaptive optics business.23 By spring 1984, everyone in Marquet’s group had moved into the Matomic building in downtown Washington to work full-time for SDIO. Abrahamson and his staff had reservations about the building, because they were convinced there was a group of Russian spies in an apartment directly across the street. That wasn’t the only concern. Marquet recalled that one day he came to work to find the building swarming with pickets demonstrating outside. His initial dismay in believing that Star Wars detractors had discovered the nerve center of SDIO soon vanished when he realized the crowd was protesting the Nuclear Regulatory Commission, which shared the building with SDIO. Nevertheless, everyone felt SDIO offices should be in a more protected area.24 Two years later, SDIO relocated to a secure vault in the basement of the Pentagon, occupying what had formerly been bus tunnels, now closed for security reasons. After a major scrub-down, the area was remodeled into office space. It was not prime real estate in the Pentagon, and it certainly

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was off the beaten path. Abrahamson liked to direct visitors to SDIO by telling them his office was directly under the bakery on the main corridor of the Pentagon. Shortly after the move to the Pentagon, Marquet was promoted and became Abrahamson’s deputy for technology. From the start, Abrahamson realized he needed a technical expert who could advise him on tough scientific questions. As he put it, “Lou was the right guy. . . . he was broadly based and had such an incredible scientific education along with the right instincts.” Marquet remained as SDIO’s deputy for technology until he retired in 1988. For his services, he was awarded the Strategic Defense Achievement Medal by the National Defense Industrial Association.25 To address the missile defense and antisatellite missions, SDIO and DARPA funded numerous scientific projects. One of those projects was an outgrowth of a DARPA program in the late 1970s that put Lincoln Laboratory to work on submarine laser communications. Darryl Greenwood had headed this project, which took place at Lincoln Laboratory and on Maui. The goal was to bounce a blue-green laser off a space mirror and then direct the beam to a submarine under water. Getting a good quality beam from the ground to the mirror—the uplink portion of the experiment—required a reliable adaptive optics system. If the research proved successful, then the Navy could use lasers to communicate with its submarines anywhere in the world.26 The motivation for working on blue-green lasers was partly political. In the late 1970s and early 1980s, many in the military advocated developing laser systems capable of shooting down missiles and satellites. But at the time, research in this area was extremely sensitive. Deploying such a system would violate the 1972 Anti-Ballistic Missile Treaty, signed by the Soviet Union and the United States. Moreover, some felt developing new technologies to intercept and disable missiles and satellites would destabilize the delicate balance of power between the two countries, adding more risks rather than making the United States safer. One way to get around this was to pursue development of lasers for non-hostile purposes such as communication. The resulting technologies could then be applied—at some time in the future if the military situation demanded it—to direct a high-power compensated laser beam against a missile or satellite.27 Until the early 1980s, the Navy showed little interest in using lasers and space mirrors to enhance submarine communications. There were several reasons for this. First, the Navy did not want anyone to know the location Strategic Defense Initiative

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Figure 10. Concept for submarine laser communications.

of its submarines, and feared that a laser beam illuminating the surface of the ocean might give it away. Second, the Navy did not believe the technology was mature enough to improve communications in the immediate future. Third, Navy officials were concerned about the reliability of a system that had to bounce a laser beam off mirrors in space. Some argued that the scheme was unrealistic because it would take an extensive and costly constellation of relay mirrors to cover the globe 24 hours a day.28 Others were more enthusiastic about the technology, including Duncan Hunter, a long-time conservative Republican who represented California’s 52nd Congressional District and served on the House Armed Services Committee. Hunter believed there was merit in the potential application of lasers to submarine communications, and he worked to secure a congressional mandate for the Navy laser research to move forward using DARPA funds until the program ended in the mid-1980s.29 The DARPA project did move forward under the able leadership of a former Navy officer named Bill Wright, who now worked in DARPA’s Directed Energy Office. Based on Wright’s urging, DARPA funded a

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Lincoln Lab team that conducted some very successful experiments. The Navy Ocean Systems Center in San Diego made progress in propagating a laser beam from an aircraft down through the water to a submarine. These initial tests suggested it would be feasible to use lasers to communicate with submarines, but DARPA did not fund the next stage of experiments, which called for reflecting a beam off a space mirror. The Navy remained lukewarm about the project, convinced that the best and most reliable solution was to continue to use its extremely low-frequency 50 Hertz low-bandwidth system, which had operated out of transmission sites in northern Wisconsin and the upper peninsula of Michigan for many years. Although the Navy’s interest in the DARPA-sponsored project faded, DARPA remained committed to the concept of using lasers and mirrors in space—and turned its attention in the opposite direction: away from the oceans and into space.30 The man who would lead the DARPA-sponsored effort to propagate lasers into space and figure out a way to compensate for atmospheric turbulence was Darryl Greenwood at Lincoln Lab. Greenwood had a knack for putting together the right people and managing complicated experimental programs. A tall and imposing figure, Greenwood revealed a down-home and friendly demeanor. Listening carefully, one could detect a slight Texas drawl as he explained esoteric scientific principles. One of the things he was best known for in the scientific community was his discovery of the “Greenwood frequency,” a key principle of adaptive optics. Greenwood left Rome Air Development Center in 1975 after completing his military obligation in the Air Force, hoping for a career with the federal government. As a distinguished graduate of Air Force ROTC at the University of Texas and a PhD in electrical engineering, he had all the right credentials. His thesis focused on laser scattering in atmospheric turbulence, which turned out to be a good match for his work first with the Air Force and later with Lincoln Laboratory. In the early 1970s he gained valuable work experience while at Rome honing his theoretical and experimental know-how in the areas of atmospheric turbulence, laser propagation, and compensated imaging. When rumors circulated that Rome might close, Greenwood decided to apply for a job at AFWL in Albuquerque. The Oklahoma civil service personnel office responsible for processing his application lost his paperwork for several months. While Greenwood waited to hear from AFWL, Lou Marquet recognized his outstanding scientific Strategic Defense Initiative

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Photo 29. Darryl P. Greenwood was a prominent member of the Lincoln

Laboratory team that led a number of adaptive optics programs, including the Atmospheric Compensation Experiment or ACE. A model of the ACE sounding rocket is on top of cabinet.

talents and hired him on the spot in 1975 to work at Lincoln Laboratory. The federal government’s loss was Lincoln Laboratory’s gain.31 Greenwood fit in well at Lincoln Lab, and he distinguished himself early on in his career. By 1981 he had become the leader of the High-Energy Laser Propagation and Beam Control Group, which performed work that led to the SWAT experiments described earlier. The group was responsible for the success of the Atmospheric Compensation Experiment or ACE, a series of laser experiments that ran from 1981 through 1985. ACE involved engaging cooperative targets outfitted with beacons that provided samples of distorted light so researchers could generate compensated laser beams propagating from the ground into space. Greenwood’s expertise with ACE, and his authorship of several influential papers in the late 1970s and early 1980s, elevated him into exclusive scientific company when he became an

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elected fellow of the Optical Society of America in May 1991 for his “contributions to the fundamental understanding and early development of adaptive optics.”32 The purpose of ACE was to demonstrate that a laser beam propagated from the ground through atmospheric turbulence and into space could be compensated using an adaptive optics system, and thus could deposit sufficient energy on a target to disable it. Greenwood and his team divided the ACE research into phases. First a laser would be fired horizontally to a ground target, next to an airplane in flight, and finally to high-altitude sounding rockets. DARPA, and later SDIO, invested heavily in this research. Their long-range goal was to advance new technologies that could be applied to both ballistic missile defense (hard targets) and ground-based antisatellite (soft targets) missions. However, by the late 1980s, SDIO’s interest in ground-based antisatellite research had diminished. The agency turned to space-based lasers as an option for its primary mission of ballistic missile defense. A few years later, in the early 1990s, SDIO decided to reduce its attention on lasers and concentrate on kinetic-kill systems as its main missile defense weapon.33 The ACE adaptive optics systems evolved from the Real-Time Atmospheric Compensation (RTAC) and Compensated Imaging System (CIS) programs of the 1970s, discussed in chapter 3. Itek was the contractor responsible for building components for a new adaptive optics system— based on CIS adaptive optics technology—to be used in ACE. This nextgeneration experimental system consisted of a 69-actuator deformable mirror and a shearing interferometer that defined the distorted wavefront of a laser beam. CIS, as an operational system mounted on the side of a telescope, needed 168 actuators in order to obtain high-resolution images of space objects. ACE, on the other hand, consisted of a smaller, 60-centimeter (23.6-inch) telescope and a breadboard configuration mounted on an optical bench that required fewer actuators because of the smaller aperture—69 actuators were sufficient.34 One of the defining characteristics of the ACE adaptive optics system was that Lincoln scientists used it exclusively to correct an outgoing lowpower laser, not to improve images. ACE was designed to demonstrate theoretical compensation concepts, the first step of which could be accomplished using low-power lasers. Therefore, there was no need for Lincoln Strategic Defense Initiative

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Lab to use high-power lasers for any of the ACE experiments. In addition, all ACE testing used targets that were “cooperative”—they carried a reflector that made it easy for a beam to travel from the ground station to the target and back, carrying the information about atmospheric distortion that the system needed to adjust the outgoing laser beam for maximum impact on the target.35 In 1981 Itek completed fabrication of the ACE wavefront sensor. Lincoln scientists designed and integrated the system on an optical bench and tested it in a laboratory in Lexington. Experimenters introduced simulated atmospheric turbulence conditions into the laboratory environment and fired a laser through that artificial medium. Once laboratory testing demonstrated that the system operated up to specifications, Lincoln shipped the system to the Air Force Maui Optical Site in Hawaii in 1982 and installed it on the 60-centimeter beam director. Lincoln Lab scientists then began their threephase ACE field test program.36 The first phase of ACE involved propagating a laser beam along a horizontal path from a beam director, which remained in a fixed position and did not move, for 150 meters (164 yards) to an instrument trailer on top of Haleakala. A laser at the trailer served as a beacon and traveled from the trailer to the beam director, where the adaptive optics system was located. The adaptive optics system’s shearing interferometer detected and calculated the amount of atmospheric distortion in the beacon’s laser light. Those data drove the changes that had to be made to the surface of the deformable mirror to compensate for the effects of atmospheric turbulence on the outgoing beam traveling from the beam director to the trailer. Because the beam was low power, and absorption of the green light was very low, experimenters did not have to contend with the difficult issue of thermal blooming. The big question for this first phase was to determine if the beam passing through atmospheric turbulence could be tightly focused on the trailer target.37 The ACE phase one experiments conclusively showed that this was possible; the adaptive optics performed well. The relatively short range the laser beam had to travel simplified the compensation process somewhat. But even though the range was short, the turbulence the beam encountered was similar to what it would encounter on a path from the Maui mountaintop to space. Only a small portion of the atmosphere, 150 meters, had to be

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diagnosed, which was easier to do than measuring turbulence and correcting for a beam extending from the ground to space, where the beam would have to traverse long distances through multiple atmospheric turbulence layers that were constantly changing.38 The ACE adaptive optics operated as a closed-loop system that could continuously change the settings on the deformable mirror on a real-time basis. Measurements of beam intensity at the trailer target served as the yardstick to tell if the adaptive optics system was working properly. A solidstate camera at the target spot inside the trailer imaged the beam transmitted from the beam director. Low beam-intensity measurements at the target spot meant turbulence had weakened and degraded the quality of the beam. High beam-intensity measurements on target meant the adaptive optics had canceled out a good portion of atmospheric turbulence. After adjustments were made to the ACE adaptive optics system early in the testing, the phase one ACE field experiments concluded in 1982 and confirmed that a tightly focused ground-to-ground compensated beam propagating from the beam director could be placed on the trailer target.39 While ACE phase one succeeded in sending a compensated laser beam to a stationary target, phase two attempted to transmit a low-power laser over vertical paths from the beam director on the ground to a small Cessna 441 Conquest aircraft flying 10,000 feet above the Maui site. The phase two experiments, led by Jacob “Jack” Lifsitz, took place during 1983 and 1984. Installed on the left side of the Cessna’s fuselage, aft of the wing, was a customized door with a window. As the plane flew in a slow racetrack pattern, it emitted light from an onboard beacon back to the ground.40 Wavefront measurements of the beacon’s distorted light allowed Lifsitz’s team to adjust the deformable mirror settings so that atmospheric turbulence would not degrade the outgoing laser beam. The outgoing lowpower beam from the ground was aimed through the window on the left side of the aircraft. Once the laser beam entered the aircraft, scientists used diagnostic cameras to measure its intensity and determine how well the adaptive optics system on the ground had compensated the beam.41 Results from the ACE phase two experiments were encouraging. This was the first time that an adaptive optics system was able to compensate a laser beam transmitted from the ground to a moving airborne target. Greenwood reported that the beam quality during most of the tests was Strategic Defense Initiative

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Photo 30. Diagnostic aircraft used by Lincoln Laboratory for ACE experiments at Maui.

very good. Beam quality also matched closely to theoretical predictions. Completion of ACE phase two set the stage for an even more demanding sequence of experiments that involved sending a laser beam into space. But before phase three began, attention was temporarily diverted to a more pressing SDI experiment.42 The SDIO High Precision Tracking Test involved firing a laser into space. The first test firing, from the Maui ground station to the space shuttle Discovery on 21 June 1985, was well publicized. General Abrahamson needed to show some dramatic progress with lasers in space, and the shuttle experiment seemed to be the best and quickest way to give SDIO credibility in the eyes of the public. From the start, Abrahamson had viewed the shuttle as an ideal platform for conducting space experiments.43 Some suggested that the president had been pressuring the general to act quickly. But Abrahamson refuted that claim, stating, “Reagan was aggressive. He wanted to see progress, but he didn’t try to direct or try to say do this or do that.” Setting up the SDIO test aboard the shuttle was a slow and arduous process at first. It usually took years of planning before any experiment got a place on the shuttle, and NASA engineers and program managers were reluctant to give preferential treatment to SDIO.44 Abrahamson personally intervened. Before taking over SDIO, he had

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served as the associate administrator for the Space Transportation System at NASA, where he had been responsible for the space shuttle program. After moving to SDIO, he maintained powerful connections at NASA. Chuck Primmerman, on loan from Lincoln Lab to SDIO to work on the High Precision Tracking Test, recalled that the shuttle experiment would never have happened if it were not for General Abe. “He twisted arms at NASA and was able in the shortest time—a record few months—to get the experiment onboard Discovery,” Primmerman said. Others close to the program agreed.45 The only adaptive optics component required aboard the shuttle was an 8-inch (20.3-centimeter) retroreflector—a precision mirror that reflected a laser to the ground. The mirror cost $30,000 and weighed 20 pounds (9.1 kilograms). Even this relatively small item took up precious space. But as Greenwood related, “The astronauts were happy to do the experiment, and we were told one of them gave up space in his personal locker to store the retro.”46 Once in orbit, Discovery astronauts attached the retroreflector to the inside of the forward left side hatch window. The plan called for the shuttle to maneuver on its left side to position the retroreflector directly over the Maui ground site. At that point, the Maui beam director would fire a low-power (4-watt) blue-green argon-ion laser, which would strike the retroreflector and reflect back to the ground, where the adaptive optics system would measure the amount of distortion in the beam caused by atmospheric turbulence. Once scientists had this information in hand, they imaged the beam spot and knew they could compensate a laser beam using the adaptive optics system. However, for this experiment, there was no requirement to send a compensated beam back up to the shuttle. This was a closed-loop experiment but did not involve correction of an outgoing beam. It was an experiment to acquire accurate data on the amount of distortion in the return beam traveling from the shuttle to the ground and to compensate the resultant beam image, but not to compensate an outgoing beam.47 The plan was sound, but the execution was not—at least not on the first try. On 20 June, when the shuttle was orbiting 200 miles above Maui, an operator error caused the Discovery to roll onto its right side instead of its left. The post-mission operations report stated that this error was caused by “an incorrect data format programmed into the universal pointing display. Strategic Defense Initiative

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Figure 11. Schematic of ACE shuttle Discovery experiment conducted

on 21 June 1985.

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The target altitude was entered in feet, not in the required units of nautical miles.” This resulted in the retroreflector facing out into deep space instead of down to the Maui site. Even though the shuttle was pointed in the wrong direction, the Maui team fired its laser on schedule. The low-power beam hit the right side of the shuttle, but caused no damage to the spacecraft; the astronauts reported seeing the beam outside the cockpit window.48 Failure of the first shuttle test strained the patience of some officials in the Pentagon. Tom Meyer received a call from Weinberger’s executive officer demanding to know, “Why didn’t it work?” Meyer reassured him that the software problem was being fixed and the entire Lincoln Lab/Air Force team was confident that the next test would produce the desired results.49 Meyer’s credibility would soon be put to the test. The next day, the shuttle’s navigation software performed on cue and banked the Discovery spacecraft onto its left side so the retroreflector faced Maui. But now there was a problem on the ground: winds gusting from 55–80 mph increased atmospheric turbulence, making it more difficult to track the shuttle and raising concerns about the ground optical system, which would be vulnerable to wind damage while the dome protecting it was open for the experiment. Fortunately, conditions improved just enough to meet minimum safety standards, and the test went forward. The beam left Earth as a narrow ray of light a mere quarter of an inch (a little over half a centimeter) wide. Passing through the atmosphere, it expanded to nearly 30 feet (9.1 meters) by the time it hit the shuttle’s retroreflector, covering the device’s entire surface and more. The portion that was reflected back to earth was measured for wavefront distortion, and that information was used to correct the image of the retroreflector (bright spot on shuttle). The return beam also provided input to an optical device that tracked the shuttle.50 Department of Defense and Air Force officials were excited about the success of the test. General Abrahamson told the news media, “This is an important step in a series of steps that will prove we can effectively shoot lasers from the ground into space without suffering unacceptable atmospheric losses.” One of the more promising signs was the fact that the shuttle had been traveling at 17,000 miles (27,000 kilometers) an hour when engaged by the laser—several hundred mph faster than a nuclear warhead. It was not unreasonable to speculate that it would someday be possible to

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build a defense system with enough precision to intercept slower-moving space targets such as missiles and warheads.51 The 1985 shuttle test was the first to propagate a laser from the ground to a spacecraft. Although this was an important step forward, the wavefront distortion data it acquired were not completely integrated into an adaptive optics system—the experiment had not attempted to send an outgoing compensated beam from the ground back up to the shuttle. Phase three of the ACE experiments would take on that challenge.52 Several months after the shuttle test, Lincoln Lab scientists on Maui under the direction of Darryl Greenwood began the third phase of the ACE. It consisted of four separate launches of Terrier-Malamute two-stage sounding rockets—at a cost of $750,000 each—developed by a Sandia National Laboratory team headed by Richard Eno. Each rocket took off from the Navy’s Barking Sands launch site on the island of Kauai and reached its apogee of 372 miles (599 kilometers) as it passed south of the Maui site. The rockets’ altitude was roughly three times that of the altitude of the lowest earth-orbiting satellite and twice that of the shuttle Discovery’s orbit during the SDIO experiment—making them realistic targets for testing the capability of Lincoln’s adaptive optics system under operational conditions.53 The purpose of the experiment was to compensate a laser beam traveling from the ground to the rocket. That required sending a 4-watt argonion blue illuminator laser from the Maui site to a retroreflector on the nose of the rocket. The reflected beam returned to the ground, where distortions caused by atmospheric turbulence were measured. These in turn drove the settings on the 69-channel deformable mirror. The plan called for a second outgoing “scoring” green laser beam (1 watt) to reflect off the deformable mirror and strike a diagnostic array of 20 sensors aligned in a row near the center of the rocket. Those sensors would measure the quality of the scoring beam to determine if it had been compensated—properly corrected—as it moved through the atmosphere to the rocket.54 Scientists aimed the second (compensated) beam along the same path that the first beam had traveled to hit the retroreflector. (The direction of the outgoing beam automatically took into account point-ahead angle.) Between the time the first beam returned to Earth and the second beam was transmitted to the rocket, the rocket had moved forward slightly. The second laser would thus hit a detector array in the middle of the rocket

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Photo 31. The Atmospheric Compensation Experiment demonstrated the first compensated laser beam from the ground to rockets in space. At left is the Terrier-Malamute two-stage sounding rocket, at center is a laser beam transmitted from the Maui site to the rocket, and at right is a schematic showing the rocket’s flight path.

rather than on its nose, because the rocket had moved slightly forward so the array now occupied the position where the retroreflector had been previously located a fraction of a second earlier.55 The ACE sounding rocket experiments were 75 percent successful. After launch of the first rocket on 27 September 1985, the Maui ground station’s tracking system malfunctioned and failed to acquire the missile. Although launch of the first rocket was flawless, the inability to track it meant the mission had to be aborted. Since tracking was a critical element for directing the laser to the rocket, the Maui ground team never projected a beam to target.56 Lincoln’s Dan Murphy was in charge of the experiments for sounding Strategic Defense Initiative

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rockets 2, 3, and 4. Each rocket launched successfully and was accurately tracked during its 10-minute flight before it crashed into the ocean 496 miles (793 kilometers) downrange from its launch point. (The plan did not call for the rockets to be recovered.) One of the major improvements for this test was that Lincoln had developed a faster and more accurate digital computer for processing wavefront measurements to replace the Itek analog computer used in previous experiments.57 Greenwood and Primmerman reported all three rocket tests clearly showed “a dramatic increase in irradiance when the beam is compensated. The ACE sounding rocket tests were the first to demonstrate atmospheric compensation of a beam propagating from the ground to space.” Also, SDIO officials told the press that the experiments furthered the understanding of physics in terms of “projecting high-power, ground based lasers through the atmosphere to space for application to a ballistic missile defense.” DARPA officials were pleased and encouraged. Secretary Weinberger sent a congratulatory message to the director of Lincoln Lab, praising the ACE team for conducting “the first successful demonstration of the propagation of a compensated visible laser beam from ground to space at Maui on 27 Sept 1985. This result is a significant achievement which supports the feasibility of SDI.” Phase three produced more evidence that adaptive optics worked under realworld conditions. The sounding rocket experiments were completed and the resulting data processed by the end of 1985; this marked the end of the atmospheric compensation experiments conducted by Lincoln Laboratory.58 There was no immediate follow-on program to the ACE experiments. The adaptive optics system used on Maui was subsequently transferred to the Mount Wilson Observatory and used to conduct astronomical experiments to acquire improved images of stars, planets, galaxies, and other space images—a prime example of technology transfer by the military to the civilian sector, in which Mount Wilson benefited from the state-of-theart technology and realized considerable cost savings.59 Not everyone agreed that Lincoln Lab, the Air Force, and other government agencies were making significant progress with lasers and adaptive optics. Critics pounded away at the weakness of SDIO’s vision, calling for directed-energy weapons as the ultimate ballistic missile defense weapon. They argued it would be decades at least before these “pie-in-the-sky” weapons could be deployed. The American Physical Society and the Union

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of Concerned Scientist led the charge, claiming that Star Wars was unrealistic, technically immature, and easy to defeat using relatively simple countermeasures. The Union of Concerned Scientists was an independent nonprofit organization that assessed the impact of technology on society and carried substantial weight among scientists outside the government.60 Although many physicists outside the Defense Department expressed pessimism about the success of SDIO, they did not have access to all the facts. During the 1980s, most adaptive optics research was classified, as was much laser research. The announcement of adaptive optics laser guide star progress at the American Astronomical Society’s meeting in Seattle in 1991 was an eyeopener to astronomers and other scientists, some of whom had a hard time accepting that the military had led the way on laser guide stars.61 A second consideration that critics did not always take into account was that it is not unusual for laboratories to experience more failures than successes, given the nature of scientific research. In most cases, it took large financial investments and decades of work to accomplish a major scientific breakthrough. There was no such thing as instant scientific success, especially when large, complex military systems were involved. A good example was the Air Force’s development of the Airborne Laser Laboratory. During the 1970s and early 1980s, critics insisted that the system would never work. For 13 years they were right, but in 1983 the ALL succeeded in shooting down five air-to-air missiles over the China Lake test range in California. This success influenced the decision to proceed with the development of a second-generation airborne laser, which is under way today.62 A third issue critics did not anticipate was that SDIO evolved more into a political venture than a scientific enterprise, and as such had significant and lasting consequences for the entire world. Opponents of strategic defense technologies in the 1980s had no way of predicting that SDIO’s commitment to developing a ballistic missile defense system would contribute to the demise of the Soviet Union and the end of the Cold War. At the Reykjavik Summit in October 1986, Ronald Reagan and Mikhail Gorbachev addressed the sensitive issue of arms reduction of ballistic missiles. Gorbachev asked Reagan to abandon SDI, but Reagan refused, because he believed that this new defensive strategy would be a military insurance policy against future Soviet aggression. The truth was that the struggling Soviet economy was too weak to match the huge U.S. financial Strategic Defense Initiative

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investments in SDIO, and the Soviets knew it. Severe economic instability in the Soviet Union led to political unrest in the late 1980s that changed the course of that nation dramatically. By June 1987 Gorbachev had introduced perestroika to move the Soviet Union away from the traditional communist model of a planned and centrally controlled economy. Gorbachev believed perestroika, in combination with glasnost or political openness, would lead to the revitalization of the Soviet Union. But his economic and political reforms failed. By December 1991 the Soviet Union had splintered into 15 separate and independent republics.63 At a conference at Princeton University in February 1993, former Soviet foreign minister Alexander Bessmertnykh declared that the inability of the Soviet Union to develop economically and sustain its own SDI program contributed greatly to its downfall. When Reagan died in June 2004, many around the world praised him most for his tough rhetoric and unswerving stand against the Soviet Union. Gennady Gerasimov, one of the top spokesmen for the Soviet foreign ministry in the 1980s, remembered the powerful impact Reagan’s SDI program had on the balance of world power. Gerasimov recalled that “Reagan bolstered the U.S. military might to ruin the Soviet Union, and he achieved his goal.” Describing SDI as a form of “successful blackmail,” Gerasimov explained, “The Soviet Union tried to keep up pace with the U.S. military buildup, but the Soviet economy couldn’t endure such competition.” Even though SDI never deployed a single piece of operational hardware, its specter hastened the collapse of the Soviet Union.64 Although many believed that SDI contributed to the demise of the Soviet Union, others argued that the country collapsed naturally under its own deteriorating economic conditions. Since the 1970s, the Soviet Union had suffered a steady decline in its economy. Gorbachev tried to reverse this trend through economic reform, but that change did not begin to take root until long after he was forced out of office. The Soviet Union continued to maintain a robust research and development program, but it never created its own ballistic defense program to compete on the same level as SDI.65 One other criticism of SDI was that it cost too much. But the DoD argued that when put in perspective, SDI’s costs were rather modest and consumed only a small fraction of the federal budget. For example, in fiscal year 1989, the federal budget totaled $1,119.0 billion. The DoD spent $282.4 billion or about 25 percent of the federal budget. SDI’s budget was $3.8 billion—0.34 of

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one percent of the overall federal budget. Of course, these funds were spent primarily on research; any operational weapons systems to come out of the program (none had been built yet) would cost significantly more.66 Regardless of the Soviet Union’s response to SDI, and in spite of the criticism that SDI would never work, the Air Force and Lincoln Laboratory pressed on. After the ACE experiments, Lincoln personnel became heavily involved in a space satellite experiment called LACE, which stood for LowPower Atmospheric Compensation Experiment.

Low-Power Atmospheric Compensation Experiment Lou Marquet and his directed-energy group at SDIO started planning for LACE in the mid-1980s. On 7 April 1984, the shuttle Challenger launched from its cargo bay NASA’s Long Duration Exposure Facility (LDEF) satellite. The original plan had called for the Challenger to retrieve the LDEF satellite in 1986, strip it of its experimental hardware, and turn it into a satellite platform for LACE, which would be launched from a future shuttle flight. But the Challenger disaster of 28 January 1986, in which seven crew members died, intervened. When shuttle launches were put on hold pending an investigation of the disaster, deployment of LACE was delayed and LDEF was left in orbit, leaving LACE without a vehicle to fly on. Consequently, SDIO decided to deploy LACE on its own satellite and not wait for LDEF or the shuttle. It would take nearly 4 years before LACE was ready to be launched into space aboard an expendable Delta rocket.67 LACE was the last part (the ground-to-space phase) of Lincoln Lab’s Short-Wavelength Adaptive Techniques or SWAT program, which explored ways to compensate for atmospheric distortions. The Naval Research Laboratory in Washington, DC, built the LACE satellite, which took 3 years. LACE experiments were similar to the ACE program, except that a laser beam engaged the LACE satellite at a lower altitude than the ACE sounding rockets. LACE’s cross-sky velocities were also greater, making it more difficult to track.68 The LACE plan called for Lincoln Lab scientists to demonstrate that a laser beam propagated from the ground to a satellite could be compensated for atmospheric turbulence. To accomplish that first required measuring Strategic Defense Initiative

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Photo 32. Technicians prepare the LACE satellite for launch on 14 February

1990. The square sensor array located in the center of the satellite measured the intensity of the compensated scoring beam.

wavefront distortions in one of the lasers used in the experiment—called a beacon light—which was projected from a beam director on the ground and reflected from the LACE target satellite back to the ground, where information on the beam’s makeup could be analyzed. Based on the data analysis, Lincoln’s 241-channel SWAT adaptive optics system would make the required adjustments on its deformable mirror so it would pre-distort an outgoing laser beam—designated the scoring beam—that could then be sent from the ground back up to the satellite. If scientists could show that a compensated beam was feasible, then SDIO would be a step closer to the enabling technology it needed to develop a powerful ballistic missile defense system.69 LACE experienced numerous delays because of technical and administrative problems. Launches scheduled for August 1989, December 1989,

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January 1990, and 8 February 1990 were all canceled for various reasons. For example, the 8 February launch delay occurred because a contractor employee dropped a 4-inch spacecraft connector tool into a constricted area between the protective shroud of the rocket and the LACE satellite. Why the tool was not tethered to the worker as required by standard operating procedures was never fully explained. One Air Force officer held the contractor (McDonnell Douglas) responsible because “quality assurance was not vigilant.” The dropped tool caused no damage to any of the satellite components. But because it lodged in an inaccessible place, technicians had to remove a detector array panel and other components to retrieve it. That delayed the launch of LACE by 6 days.70 On 14 February 1990 at 11:15 a.m., a Delta II rocket lifted off smoothly from Pad 17B at Cape Canaveral Air Force Station and launched the 3,175pound (1,428.8-kilogram) LACE satellite into a 547-kilometer (340-mile) circular orbit over the Indian Ocean. Once in orbit, the $130 million LACE satellite served as a target for a laser beam fired from the ground. The goal of the experiment was to verify the ability of the ground-based adaptive optics hardware to correct for atmospheric turbulence and then to send the corrected or compensated laser beam from the ground to the target spot on LACE. Two of the most important components of the satellite were the retroreflector beacon and the diagnostic detector array, called the sensor array subsystem.71 Dan Murphy, Lincoln Lab’s principal investigator for LACE, explained that the retroreflector was made up of an array of 252 cornercube retroreflectors—each an inch in diameter—precisely packed together and arranged in different positions so light from the ground of any frequency striking the array from any direction would reflect back to its source on the ground. Mounted at the end of a lightweight boom in front of the satellite, the retroreflector represented the correct point-ahead distance from the “sweet spot” of the detector array, which was located at the center of the LACE satellite.72 A continuous wavelength argon-ion laser transmitted from the Maui site illuminated the retroreflector as it passed overhead. It also served as a tracker. When the beam exited the beam director, it measured only 2.5 centimeters (1 inch) in diameter. By the time it reached the LACE satellite, the beam had expanded to 15 meters (16.5 yards) in diameter. As in the earlier ACE tests, the beam flooded the entire retroreflector, making it Strategic Defense Initiative

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Figure 12. The Low-Power Atmospheric Compensation Experiment (LACE) demonstrated for the first time a compensated laser beam transmitted from the ground to a low-earth-orbiting satellite.

relatively easy to hit the target and get a reflected beam transmitted back to the Maui site. A wavefront sensor on the ground measured distortions in the reflected beam and, based on those measurements, adjusted the surface of the deformable mirror. A second beam—the outgoing scoring beam— traveled along the same path of atmospheric turbulence as the first beam, which had reflected off the satellite less than a second earlier. In the time it took light to make the round trip from the satellite to the ground and back to the satellite, the body of the satellite had moved forward to occupy the previous location of the retroreflector. That meant that the scoring beam hit the detector array, a 4-meter (4.4-yard) square target board located in the center of the body of the satellite. Two hundred sensors in the detector array measured the intensity of the beam on the target board and transmitted the data to the ground station on Maui for analysis.73

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Figure 13. The LACE satellite deployed three booms: the retro-reflector boom (lower right), a counterweight boom for balance (left), and a gravity gradient boom (center) to keep the sensor array pointed down facing the Earth.

This process—sending the first beam to the retroreflector and back, changing the deformable mirror settings, and then sending a compensated beam back to the LACE satellite—made up the closed-loop feature of the SWAT adaptive optics system. Most experiments lasted under 2 minutes, which was the viewing time of the satellite as it passed above Maui once every 24 hours. For that brief period the adaptive optics system was continually receiving feedback and making up-to-date corrections to the deformable mirror, thereby allowing a compensated beam to propagate through the atmosphere to the detector array. This was the first cooperative atmospheric compensation of a laser beam propagating to a satellite.74 Although Lincoln Laboratory ran the LACE SWAT experiments, Starfire Optical Range responded to Lincoln’s request for assistance on short notice once the LACE satellite was in orbit. Lincoln was concerned Strategic Defense Initiative

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that the cross section of the LACE cornercube array might not be positioned correctly, which could jeopardize the success of the experiments. To evaluate the situation, an SOR team used a laser to illuminate the satellite as it passed over the Kirtland site and imaged the array. Results confirmed that the array was properly positioned. The Naval Research Laboratory— sponsor of the Lincoln’s LACE—sent a letter of appreciation to the SOR team applauding the timeliness of their work.75 The LACE satellite in the work done thus far was a cooperative target. However, under hostile conditions, an operator would not have this luxury— an enemy would not install retroreflectors on its missiles or satellites. Some other technique would have to be found to measure atmospheric turbulence in order to accurately aim a beam from the ground to an enemy satellite or missile. Thus, a second part of the LACE experiments involved using the satellite as an uncooperative target and using a Rayleigh laser artificial guide star to sample atmospheric turbulence and help direct a compensated beam from the ground to hit the LACE satellite. This was a more difficult experiment than using LACE as a cooperative target. Nevertheless, Lincoln did succeed in establishing a synthetic beacon using a dye laser and sending a compensated laser beam from the ground to the satellite. That was the first synthetic beacon compensation of a laser beam propagating to a satellite. The LACE team found that the quality of the compensated beam was higher when using the cooperative target, because the adaptive optics system sampled the entire path of atmospheric turbulence from the ground to the satellite. When the adaptive optics system relied on the synthetic beacon, which focused much lower in the sky (at altitudes between 4 and 8 kilometers), not all the atmospheric turbulence from the ground to LACE was sampled. Consequently, a greater degree of compensation could be applied to the beam when using more atmospheric turbulence data collected during the cooperative targeting of LACE. LACE took place from February 1990 to April 1991. Its completion marked the end of the SWAT program.76 The LACE program involved approximately 50 experiments. For the first time, in the summer of 1990, an adaptive optics system demonstrated it could send a compensated laser beam from the ground to a low earthorbiting satellite. Results repeatedly showed that when the adaptive optics system was turned on and used LACE as either a cooperative or uncooperative target, the compensated beam was tighter and displayed a higher

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Figure 14. The spike represents a tight compensated beam profile, a

significant improvement over an uncompensated beam.

intensity than an uncompensated beam. After LACE, Dan Murphy wrote: “The ability of adaptive optics systems to compensate for atmospheric turbulence by using cooperative beacons is by now well established.”77 Shortly after the launch of LACE, Colonel William F. Browning, SDI’s space experiments program manager, commented on how he envisioned LACE fitting into the bigger strategic picture. “These are key technologies for developing a ground-based laser system,” Browning told the news media. “If we get rid of the distortion in the atmosphere and get good accuracy with the laser coming off a mirror, it is a major step in our program to develop directed-energy weapons.”78 Although LACE proved a success, the progress Browning predicted stalled because of changing circumstances at the national level. DARPA and SDIO had invested heavily in adaptive optics research for nearly a decade through the ACE, SWAT, and LACE programs. Lincoln Lab considered these three efforts their most important contributions to the advancement Strategic Defense Initiative

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of adaptive optics. However, once these programs were over, a major shift occurred in SDIO’s priorities. In 1991 SDIO cancelled its ground-based laser program in order to devote the bulk of its decreasing financial resources to space-based laser weapon systems and more conventional ground-based kinetic weapon systems. The result was a drastic reduction in SDIO funding for directed-energy research. From 1987 through 1989, SDIO funded directedenergy research at the rate of nearly $1 billion per year. Funding dropped to $300 million in 1990 and to $60 million in 1991. With the end of the Cold War and the perceived end to the Soviet threat, President George H. W. Bush reduced the scope of President Reagan’s missile defense program. In its place, Bush promoted a limited missile defense architecture called Theater Missile Defense. Reflecting the shift to this new strategy, Secretary of Defense Les Aspin in May 1993 renamed SDIO the Ballistic Missile Defense Organization or BMDO. On 2 January 2002, Secretary of Defense Donald Rumsfeld renamed BMDO the Missile Defense Agency or MDA.79 The Theater High Altitude Area Defense (THAAD) system was an integral part of the theater missile ground-based defense system, designed to intercept missiles in either the atmosphere or outer space. THAAD is part of the upper-tier layered defense system, while other systems, such as the Army’s Patriot Missile and the Navy Area Theater Missile Defense System, are responsible for lower-tier missile defense. As Defense Department priorities gravitated away from SDI, so did the need to develop adaptive optics systems to support ground-based laser programs. Interest was turning to kinetic energy weapons, which did not require adaptive optics. Neither did space-based weapons have a need for adaptive optics to correct for beam distortions, because in the vacuum of space there was no atmospheric turbulence to distort a laser beam.80 With the restructuring of SDIO, funding for adaptive optics research dropped severely in the 1990s. However, by then adaptive optics technology had matured sufficiently to be applied to operational weapon systems. One of the most prominent examples of this is the Airborne Laser, designed to shoot down Scud missiles in their boost stage. For imaging, nearly every new large telescope in the world beginning in the 1990s came equipped with adaptive optics. The 3.5-meter telescope at Starfire Optical Range and the 3.67-meter AEOS telescope on Maui were two premier Air Force telescopes that reaped the benefits of over two decades of adaptive optics research.

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Airborne Laser

By the early 1990s, the Air Force, DARPA, Lincoln Laboratory, the Navy, and a number of independent contractors had been actively engaged in adaptive optics research for two decades. During that time, there were many impressive technical accomplishments in this relatively new field of science. The military suspected early on that adaptive optics, if it worked, would represent a critical enabling technology for future Air Force missions—improving images of objects in space and thus strengthening the Air Force’s ability to monitor the activities of satellites and missiles. As it turned out, military research in this area also benefited astronomers around the world. Another goal of adaptive optics research was to perfect compensation techniques in order to produce powerful coherent beams of light that would be the kill mechanism of future ground-based and airborne directed-energy weapons. The Air Force was optimistic that this could be done, because for 13 years it had developed and tested the Airborne Laser Laboratory or ALL. This modified NKC-135 research aircraft was essentially a laboratory in the sky that operated a high-power CO2 laser in flight. In 1983 the ALL shot down five AIM-9B “Sidewinder” missiles over the Navy’s China Lake Test Range in California, thereby proving that an airborne laser could function in an operational environment. By the early 1990s, the Air

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Force had proposed a second-generation Airborne Laser or ABL to be ready for duty in the early 21st century. ABL would be a critical component of the nation’s multilayered missile defense system. Originally, it was designed to intercept only short- and medium-range theater ballistic missiles. Later, it was expanded to engage a full range of enemy ballistic missile threats— theater and intercontinental ballistic missiles—during any phase (boost, midcourse, or terminal) of their flight.1 A missile is most vulnerable during boost phase, the first few minutes after launch when it climbs slowly, moves along a predictable course, and gives off a bright, hot exhaust, making it relatively easy to track. At that stage the missile is also at risk because it is loaded with pressurized oxygen and kerosene. A powerful laser beam hitting the fuel tanks could heat the metal skin of the missile enough to cause it to collapse or rupture. As an initial stress fracture in the metal grows larger, it quickly “unzips” the missile, causing it to break up. Or the laser could ignite fuel vapors, causing the missile to explode. At that point, nuclear, biological, chemical, or conventional explosive payloads onboard the missile would fall on the enemy’s homeland (a condition known as fratricide), thereby not causing an immediate danger or threat to friendly ground troops positioned hundreds of miles away. Also, plans called for an airborne laser system to perform its mission in a standoff mode while flying over friendly air space to reduce the chances of casualties to air crews.2 Air Force leaders felt the time was right to begin development of an ABL that could become the country’s first operational laser weapon. Hans Mark, former secretary of the Air Force under President Carter and director of defense research and development under President Clinton, supported this goal. He pointed to two recent technical achievements that accounted for a revival of interest in the ABL. One was the development of the shortwavelength 1.3-micron chemical oxygen iodine laser (COIL), which could deliver an intense beam of continuous energy over hundreds of miles to a target such as a boosting Scud missile.3 The other was adaptive optics. Mark firmly believed that the advancement of wavefront sensors, high-speed computers, and deformable mirrors made it possible to equip an ABL with an adaptive optics system that would be capable of significantly reducing the damaging effects of atmospheric turbulence on a high-power COIL beam propagating from an aircraft flying high above the clouds to a target hundreds of kilometers away.4

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Although many in the military bet adaptive optics would be a key ingredient of any successful directed-energy weapon, most adaptive optics research focused on theoretical studies and laboratory experiments conducted under controlled conditions. By the 1990s there was more pressure from the leadership to move adaptive optics off the drawing board and into the operational arena by developing an airborne laser weapon. Meeting that challenge was more difficult than first expected, both technically and financially. It was extremely time-consuming and difficult to integrate adaptive optics into the beam control system (all the functions required to direct the high-energy laser beam from the laser device to the target) and then combine that system with all the other pieces making up a laser weapon system.5

Second-Generation Airborne Laser The end of the Cold War temporarily created the perception that global nuclear conflict was no longer likely. But a growing threat emerged in the 1990s, involving ballistic missiles in the hands of terrorist groups and rogue nations, such as North Korea, Iraq, and Iran. One of the lessons learned from the first Gulf War was that the United States had only a limited capacity to protect itself and its allies from theater ballistic missiles, specifically Scud missiles. National security planners feared that terrorist groups and hostile nations—especially in the Middle East and Asia—were working hard to develop the capabilities of their missiles for delivering nuclear, biological, and chemical warheads.6 On 15 March 2004, Air Force Lieutenant General Henry A. Obering III, director of the Missile Defense Agency, testified before the Strategic Forces Subcommittee of the House Armed Services Committee. Obering outlined the severity of the new threat when he told the committee: “There were nearly 100 foreign ballistic missile launches around the world in 2004.” That number was up from previous years. Citing North Korea and Iran as two of the countries most likely to resort to nuclear ballistic missile strikes, the general argued that the United States must field an effective ballistic missile defense program as “a direct response to these dangers.” Development of an airborne laser weapon offered one military option to counter this growing Airborne Laser

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tactical and strategic ballistic missile threat—consisting mainly, but not only, of Scud missiles.7 Ground- and sea-based kinetic-energy interceptors formed the existing foundation of the nation’s ballistic missile defense system. But Obering said that the Air Force was also willing to take higher risks to develop a laser weapon system in the hope of gaining higher battlefield payoffs in the future. Obering told the committee that he was impressed by the progress of the ABL program under way at Edwards Air Force Base in California. He was convinced that the “revolutionary potential” of the ABL technology was “so significant, that it is worth both the investment and our patience.” Obering went on to inform the committee that “We have established the Airborne Laser as the primary boost phase defense element.” What he neglected to say was that the ABL was the nation’s only boost-phase defense system under development.8 Eight years prior to Obering’s remarks, in November 1996, Air Force Chief of Staff General Ronald R. Fogleman had announced the award of a $1.1 billion contract to Boeing (Washington, DC and Seattle, Washington), TRW (now Northrop Grumman Space Technology in Redondo Beach, California), and Lockheed Martin Space Systems Company (Sunnyvale, California) to develop the ABL. From the start, it was marketed as an entirely new class of weapon that would transform the battlefield of the 21st century. Secretary of the Air Force Sheila E. Widnall described it as “the most revolutionary weapon in the last 40 years.” The Missile Defense Agency (MDA) in Arlington, Virginia, is the program manager for ABL and oversees the contractor team. MDA is responsible for all of the country’s missile defense programs. At Kirtland Air Force Base, the ABL System Program Office develops performance requirements, provides guidance to the contractors, and monitors the day-to-day progress and shortcomings of the ABL program. The job of the contractors, working with military scientists and engineers, is to develop a weapon that can fire high-power lasers at the speed of light from an aircraft over a range of several hundred miles to intercept and destroy ballistic missiles in their boost phase. Since its inception, ABL has been a gigantic high-risk undertaking that has posed some tough scientific and technological challenges. The uncertainty of getting ABL to work and the program’s ever-escalating price tag have attracted a considerable number of critics over the years.9

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Each contractor had precisely defined responsibilities for putting the complicated ABL mosaic together. Organizing this was no easy job, because at some point all the separate components of this complex system—detection and tracking devices, four onboard lasers, infrared sensors, adaptive optics, and a rotating turret, to mention only a few—had to be integrated into a single, workable system. This final engineering integration phase plagued the program and led to repeated delays in testing, first on the ground and then in the air. Although significant technical progress has been made since 1996 on the various individual hardware components of the ABL, it still has a way to go before it can be considered operational. Although General Obering was optimistic about the future of ABL, he realistically reported “it is not out of the woods yet.”10 Colonel Ellen Pawlikowski, director of the ABL system program office in 2004, underscored engineering integration as the biggest challenge for the ABL team. In November 2004, she declared that the “pure complexity” of ABL and the large number of components accounted for delays. “[I]t’s really been the engineering challenge and integration challenge over the last couple of years,” the colonel said in response to a question from a reporter in November 2004, “that’s been just enormous.” She pointed out that there were “thousands of feet of plumbing in the laser and close to a hundred different valves and different fittings and everything and just putting that together and testing it has been a real challenge for us.” The first ABL flight to shoot down missiles was originally scheduled for 2002, but that has been pushed back to no earlier than 2009.11 From the beginning, the ABL System Program Office has counted on contractors working with Air Force military personnel and civil-service scientists to meet these challenges. Boeing has led the ABL contractor team and is responsible for building and modifying the large airborne laser 747400 freighter aircraft—called YAL-1A for prototype attack laser, model 1A—so it can accommodate all the parts of the ABL. Boeing is responsible for developing the ABL battle-management system, which covers surveillance, command, control, communications, and computers and intelligence functions. The battle management system uses infrared sensors to find and track a boosting missile traveling at about 1,500 miles (2,424 kilometers) per hour or 4.2 miles per second and then tells the system when and in what direction the laser beam should be fired to intercept the missile. Boeing’s Airborne Laser

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Figure 15. Schematic of the Airborne Laser.

final and most demanding responsibility is the monumental task of integrating all subsystems making up the weapon system.12 Northrop Grumman’s main job is to develop and verify the performance specifications of the six laser modules that generate the high-power megawatt-class chemical oxygen iodine laser (COIL). The company is also in charge of building the beacon illuminator laser (BILL), a solid-state laser that gathers atmospheric turbulence measurements for the adaptive optics system onboard the ABL. Lockheed Martin is responsible for developing the beam control/fire control system that acquires and tracks the target, compensates for atmospheric turbulence in order to produce a high-quality beam, and accurately points the COIL beam at the target.13 In December 1999, the ABL aircraft rolled off Boeing’s assembly line in Everett, Washington. In January 2000, it arrived at Boeing’s Modification Center in Wichita, Kansas. There the aircraft underwent 2 years of modifications to make room for the hardware of the ABL weapon system. Changes included removing the nose of the plane and replacing it with a Lockheed Martin 14,000-pound rotating turret. The turret is where the laser beam exits the aircraft.14 The modified ABL made its first test flight on 18 July 2004. After 14 successful flight tests, the plane flew to Edwards Air Force Base. There the

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ABL was consigned to a hangar. Once all the separate components of the system—such as the COIL laser modules, beam control system, and turret—have been tested individually to meet operational specifications, they will be installed on the ABL for ground and flight-testing.15 COIL turned out to be the brute-force directed-energy laser selected for the ABL to shoot down missiles at long ranges. Invented by a team of scientists at the Air Force Weapons Laboratory in November 1977, COIL went through many incremental upgrades in the laboratory over the next 20 years that scaled the device up to higher power levels—from a few watts of power to the kilowatt and eventually the megawatt level. AFWL operated the first supersonic flow COIL in 1984. By the 1990s, COIL had sufficient power to destroy a variety of targets and had become the laser of choice for the ABL.16 COIL had other attractive features besides its high power. First, it was lighter. COIL contained six modules (located in the rear of the ABL, three on each side) working together to generate a large amount of energy through a spontaneous chemical reaction. Thus it could produce a beam without large, heavy external energy sources (electrical devices, flashlamps, or other lasers) to excite and sustain a lasing medium to produce a beam. The chemical reaction would do that. That was a distinct advantage, because an external energy source—a weight and volume factor—was eliminated from the ABL equation and did not need to be carried on the ABL aircraft to generate the COIL beam. Also, COIL components were made of advanced materials—plastics, composites, and titanium—that resulted in significant weight reductions. Second, COIL is an efficient short-wavelength laser that operates at 1.315 microns, making it an excellent candidate for the ABL. This wavelength is determined by the makeup of the iodine laser gain medium. Because it exhibits a short wavelength at a good atmospheric transmission window, the atmosphere does not readily absorb COIL’s beam as much as it would with a longer-wavelength laser. As a result, COIL slices through the air rather easily as the beam is not severely distorted by the effects of thermal blooming. (The wavelength is determined by the makeup of the iodine laser gain medium.) However, COIL is more susceptible to atmospheric turbulence, especially at lower altitudes. Third, as a shortwave laser, COIL does not require large optics, requiring only a 1.5-meter diameter primary mirror. Smaller optics mean less weight and bulk, important considerations for an airborne laser. Also, less diffraction means increased power on target.17 Airborne Laser

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COIL is a continuous-wave laser that, once turned on, stays on, to project photons in a strong, steady stream of light to provide the maximum amount of energy on target—unlike pulsed lasers, which are turned on and off and do not deliver nonstop laser energy on target. Iodine, the COIL lasing medium, transfers its chemical power into billions of photons. Generating that light requires precisely the right mixture of a variety of fuels. The Airborne Laser System Program Office described how these fuels interact to produce a COIL beam: Chlorine gas is injected into an extremely fine spray of Mixed Base Hydrogen Peroxide (MHP), a mixture of Basic Hydrogen Peroxide (BHP) and three salts—sodium, potassium and lithium hydroxides. When the chlorine and MHP interact, excited oxygen atoms are produced. The excited oxygen atoms are then mixed with iodine atoms. The extra energy is transferred from the oxygen to the iodine atoms. When the excited iodine atoms return to their ground state, photons [packets of light] are given off which produce the laser beam.18 Northrop Grumman Space Technology (formerly TRW) built the first COIL module and finished testing it at its Capistrano test site in California in January 2002. In March 2002, that single-unit module produced 118 percent of its expected beam output—but that alone was not enough power to destroy a ballistic missile. The Air Force figured it would take six modules linked together to generate a megawatt-class beam capable of destroying a missile. Over the next two and a half years, Northrop Grumman built the remaining COIL modules—each about the size of a pickup truck—and then installed them on a 747-200 aircraft that served as a simulated flight testbed. This old, no-longer-in-service 747 was kept in the ABL System Integration Laboratory at Edwards Air Force Base. ABL workers configured COIL in the junked 747 in the same way that the system would be installed later in the real ABL aircraft. It took up nearly two-thirds of the interior space on the aircraft. For safety reasons, the ABL team installed a 4,862-pound (2,188-kilogram) bulkhead to ensure that any potential chemical leaks during the operation of the COIL system could not reach the crew located in the forward section of the aircraft.19

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Early in the afternoon of 10 November 2004, all six COIL modules were fired simultaneously to produce COIL’s first light—the first time the laser device produced sufficient photons to produce a beam. The beam was directed into a metal calorimeter, where measurements showed the temperature rose sufficiently “to validate that laser power was generated.” MDA hailed this event as a landmark achievement and a much-needed boost to the overall ABL program. Although the lasing lasted less than a second, Colonel Pawlikowski stressed the importance of COIL first light because it verified the physics for the design of the COIL laser was correct. In other words, the laser worked. She explained, “this was our verification we had the right physics in order to produce the medium required to actually create and sustain a megawatt class laser beam.” Future testing called for a gradual increase in laser power and lasing time.20 The testing conducted during the next year turned out to be important. General Obering announced on 6 December 2005 that COIL had reached its 2005 “knowledge point” by “firing long enough with sufficient power to prove it is technically capable of destroying boost-phase ballistic missiles.” To reach that milestone, a team of ABL scientists had fired the Northrop Grumman-built COIL over 70 times between 10 November and 6 December inside the System Integration Lab. The first few firings lasted for less than a second, but firings were incrementally increased until at the end of the test series they exceeded the full duration needed to destroy a ballistic missile.21 No matter how well COIL performed in terms of generating a powerful laser beam inside the ABL aircraft, that solved only half the problem of delivering a quality beam with sufficient energy on target. The other half— using adaptive optics to tailor the beam to the right shape and quality before it exits the aircraft—is in many ways the most important aspect of the ABL system. “Marrying those two [COIL and the ABL beam control system] over the next several years,” Obering predicted, “is a major technical hurdle that I feel confident we will be able to overcome.” Once that happens, the next step will be for the ABL to shoot down a missile in its boost stage to demonstrate the lethality of the airborne system. “We plan to accomplish [the shootdown],” the general stated, “in the 2008 timeframe under the current schedule.” Everyone knew that adaptive optics was a make-or-break technology for the ABL. Bob Cooper, head of the ABL independent review Airborne Laser

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Photo 33. Polishing of the ABL turret’s conformal mirror at Brashear’s

Pittsburgh plant. Photo courtesy of Jim Mayo.

group, declared that the ABL was one of the most complex weapon systems ever attempted. As he put it, “You wouldn’t be able to do the program at all unless you had a very, very sophisticated and successful adaptive optics capability built into it.”22 Adaptive optics is a key part of the ABL beam control/fire control system consisting of 127 optics (mirrors, lenses, and windows) that work together to steer the COIL beam from the rear of the aircraft, where it is produced, through the length of the fuselage to the nose of the airplane. Each highly polished mirror is coated with special protective material that forms a durable and highly reflective optical surface. This ensures that the high-energy laser COIL is not absorbed by the mirror but rather efficiently reflected on to the next mirror. Without such coatings, the intense heat from the COIL beam would destroy the mirror. In the 1970s and 1980s, before such coatings were available, mirrors used on the Airborne Laser Laboratory were water-cooled to dissipate the heat from its high-energy laser beam. However, since then, major improvements have been achieved

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Photo 34. ABL project consultant Jim Mayo (left) of Northrop Grumman and Brashear’s master optician Mark Young inspect ABL’s primary mirror. Photo courtesy of Jim Mayo.

in the development of durable mirror coating and polishing techniques, eliminating the need for water-cooled mirrors.23 Inside the nose of the ABL aircraft is the 7-ton (6.4 metric ton) rotating turret housing a 12.2-inch (0.31-meter) secondary mirror and a lightweight 59-inch (1.5 meter) primary mirror, which make up the ABL’s beam director telescope. Corning built the primary mirror—made of ultra-low-expansion fused silica and coated with gold—large enough to collect weak laser illuminator returns from the target. As the COIL beam strikes the secondary mirror, it is expanded onto the surface of the larger primary mirror. Upon reflection from the primary mirror, the beam is 150 centimeters in diameter. It then passes through the turret’s 300-pound transparent conformal window (shaped to replace the nose of the aircraft) and is projected to its target. Traditional business rivals Contraves-Brashear Systems (now the Brashear Division of the L3 Corporation), Corning, and the German company Heraeus pooled their knowledge and resources to manufacture Airborne Laser

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the 300-pound optical-quality fused-silica domed window, the largest ever built, with stringent transmission requirements to enable the beam to pass through without being absorbed. However, before the COIL can be fired, a number of procedures must be completed by three other independent lasers onboard the ABL.24 In a typical attack scenario, the ABL will fly at an altitude of 40,000 feet, hundreds of miles from enemy missile launch sites. At that altitude— nearly 8 miles—the ABL would be flying above the worst turbulence, which exists up to an altitude of 4 miles. When a missile is launched, the ABL’s 360-degree surveillance system, consisting of six infrared Search and Track (IRST) sensors—two on each side, one at the front, and one at the rear— will detect it. Built by Lockheed Martin, the sensors are modeled after the ones used on the Navy’s F-14 Tomcat fighter aircraft. The IRST collects preliminary tracking data on the missile and sends it to the ABL’s battle management system, which makes more precise tracking corrections with the help of the Active Ranging System or ARS, mounted atop the fuselage.25 Using data on missile location from the IRST, the ARS points its 11.5micron continuous wavelength carbon dioxide laser in the direction of the missile rising off its launch pad. The ARS is the first laser to fire during an ABL mission. Once it bounces off the missile, its return signal is processed aboard the ABL to provide the range to the target. Knowing the precise distance to target—which is continuously changing because both the ABL and missile are moving—is critical in obtaining uninterrupted track of the target. Once the ABL’s tracking system has locked on to the missile, two other lasers begin to operate to prepare the COIL laser to engage its target.26 One of those two lasers is the Track Illumination Laser or TILL, built by Raytheon, a subcontractor to Lockheed Martin. This solid-state ytterbium: yttrium aluminum garnet (Yb:YAG) diode-pumped laser works at a wavelength of 1.03 microns with an output power in the kilowatt range. The TILL is a 5-meter pulsed beam that will be fired from the ABL and aimed at the nose of the missile. Its width makes it relatively easy to illuminate the nose. The beam is then reflected back to the ABL, where sensitive cameras remain focused on the nose. Information from the return TILL beam is used as input to the imaging tracker. The TILL’s information on the missile’s speed and elevation is critical for determining where the high-power COIL laser should be aimed.27

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Figure 16. Three different lasers make up the Airborne Laser system. The

aircraft illuminates the target using low-power illuminator lasers, one for tracking and the other to collect atmospheric turbulence data. The turbulence information is then fed into an adaptive optics system aboard the aircraft. The adaptive optics system compensates the outgoing COIL high-energy beam, turning it into a high quality, coherent beam that is capable of delivering maximum destructive energy on target.

In March 2001, Raytheon achieved first light with TILL at its laser test center in El Segundo, California. In November 2002, Raytheon delivered the TILL to the ABL program.28 While TILL performs its tracking functions, another laser known as the Beacon Illumination Laser or BILL is operating to gather critical wavefront error information for the ABL’s adaptive optics system. BILL is a 1.064-micron pulsed neodymium: yttrium aluminum garnet (Nd:YAG) laser in the kilowatt range, whose primary job is to obtain measurements of atmospheric turbulence between the ABL aircraft and the target. Like the TILL, the BILL is a diode-pumped solid-state laser. Airborne Laser

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Northrop Grumman built and delivered the BILL to Lockheed Martin’s test facility in Sunnyvale, California, to undergo preliminary testing in May 2003. Those laboratory tests to verify the performance specifications of the beam control system—laid out on the test center’s floor to replicate how the beam control system would be configured in the ABL aircraft—did not involve the turret and its telescope or the full-scale COIL. Using a lower power surrogate laser instead provided a margin of safety to ground operations. In April 2004, Lockheed Martin announced testing had successfully demonstrated that the beam control system could point and focus the laser beam after it made its way through the entire length of the system.29 In an engagement, the ABL would send the BILL beam to reflect off the front end of the missile. This reflected light serves as a beacon or guide star for the adaptive optics system. When the beam returns to the ABL it is fed into a wavefront sensor (manufactured by Adaptive Optics Associates in Cambridge, Massachusetts), which measures the amount of distortion on the received wavefront. An elaborate computer and software system— equivalent to the combined computing power of 130 personal computers, executing over 72 billion instructions per second—processes the information (utilizing phase reconstruction algorithms), which is then used to send electrical signals to make tiny changes to the surface of a deformable mirror, located in the beam transfer assembly unit just behind the turret of the ABL, which adjusts the COIL beam to compensate for the atmospheric turbulence it will encounter on its way to the target. The ABL adaptive optics system is designed to correct for phase-only aberrations in the outgoing laser beam sent to the target.30 The flight path of the laser on its way to the missile is continuously changing, and so is atmospheric turbulence. The BILL constantly feeds turbulence measurements to a wavefront sensor. Meanwhile, the compensated COIL beam moves toward the target along the same path as the BILL return beam. Although it has been compensated to reduce the effects of atmospheric turbulence, the COIL beam does not hit the target at the same spot as the BILL beam. Because the missile moves forward a few feet in the time it takes the BILL beam to make its round trip and the COIL beam to reach the missile, the COIL beam strikes the missile a few feet back from where the BILL first illuminated it (about the middle to rear of the missile).31 The BILL used on the ABL is a direct descendant of the laser guide

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star technique demonstrated by SOR and Lincoln Laboratory in the 1980s. While the earliest guide stars focused a laser beam on a predetermined point in the atmosphere, the BILL had the more difficult challenge of focusing its horizontal beam on a moving target hundreds of miles away. But the principle remained the same: the BILL beam, reflected off the target missile—just as the earlier guide stars produced backscatter from their focused points in the sky and carries back information about atmospheric turbulence, which enables a deformable mirror to pre-distort an outgoing beam to compensate in advance for the turbulence the beam will encounter on its way to the target.32 That deformable mirror is only one of three used in the ABL beam control system. The other two address other problems, inside the aircraft, that also affect the COIL beam wavefront. Xinetics, an optical system company run by Mark Ealey in Devins, Massachusetts, manufactured all three mirrors for the ABL. Ealey, a likeable and enterprising individual, had developed a good portion of his adaptive optics expertise while working for Itek in the 1980s before forming Xinetics in 1993. His company is one of only a few capable of supplying the military with deformable mirrors for its weapon systems and telescopes.33 Although the deformable mirrors served exclusively to adjust the COIL beam, all three lasers—TILL, BILL, and COIL—shared other mirrors in the beam control system. Because the three lasers operated at different wavelengths, they could simultaneously reflect off the primary and secondary mirrors and pass through the turret window without interfering with one another. When the COIL beam is first produced it does not exhibit a perfectly flat wavefront. Every startup induces “local loop” vibrations, jitter, and other distortions. During flight, the airplane flexes and vibrates, and the laser’s journey through the plane to the turret introduces additional vibrations and jitter. Two other mirrors, a beam cleanup deformable mirror and a focus offload deformable mirror, correct for these distortions. The latter cleans up distortions caused by the heat generated in producing the beam. All the local loop corrections are made before sending the beam to the mirror that compensates for turbulence outside the plane.34 The beam control system that transfers the COIL beam to the front of the aircraft, and corrects for distortions encountered on the way, is the work Airborne Laser

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of Ken Billman and his seven-man Lockheed Martin team—consisting of Bruce Horwitz, Ross Blankinship, David Stubbs, Alan Duncan, Lothar Bandermann, Rich Holmes, and Steve Daigneault—which was responsible for designing, building, and testing the complex ABL beam control/ fire control system. Billman’s group devised a complicated electro-optical system made up of hundreds of mechanical and electrical parts—steering and deformable mirrors, sensors, lasers, trackers, and more. Failure of any one part could cause the entire system to shut down.35 Billman, who taught physics at MIT earlier in his career, is immersed in his work. He looks and acts like a scientist, taking his time to respond to even the most routine questions as precisely as possible. Solving difficult technical problems is what inspires him. He is a detail man, a perfectionist, who leaves nothing to chance. Over the past few years, his energy has been directed at making the ABL beam control system a practical reality. He recognizes that “good ideas do not always translate into workable systems.” It is clear that, in spite of all the frustrations associated with the ABL beam control system, Billman is determined to make it work. He believes strongly in the capacity of the system to produce a quality beam; otherwise, as he put it, he would have “walked away from the program a long time ago.”36 When asked why he was chosen to head the ABL beam control system, Billman responded that a big part of it was because of his experience while serving as chief scientist with the Ground-Based Free Electron Laser Technology Integration Experiment in the 1980s. The Army wanted to develop a free electron laser ballistic missile defense system that could shoot down missiles in midcourse and reentry phases (about 13–20 minutes and 3 minutes, respectively) and won SDIO’s support for the program.37 The ABL beam control and adaptive optics system moved forward systematically, and the Missile Defense Agency reported on 1 August 2005 that 8 months of tests aboard the ABL aircraft to measure the effectiveness of the beam control and adaptive optics system had been a success, which “demonstrated the performance of the ABL’s sophisticated battle management and beam control/fire control systems.” What still needed to happen was the integration of the beam control and adaptive optics system with the high-power COIL. That testing was not scheduled to occur until 2009 or later.38 In 2005 the ABL moved from California back to Wichita to undergo airframe modifications to strengthen the aircraft so it can carry the six

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heavy high-energy laser modules. While in Kansas, the ABL undertook the Low-Power System Integration-Active testing program—in which, Boeing reported, ABL “demonstrated the ability to locate a ballistic missile target, track the target with simulated return from its target illuminator laser, and then compensate for distortions on the path to target using simulated return from the ABL’s beacon illuminator laser.” ABL flight testing designed to intercept a target, Boeing predicted, would take place in 2009.39

Airborne Laser/Adaptive Optics Experiments Readying the adaptive optics system to be integrated onto the ABL involved many complications. During the 1990s the Air Force’s Phillips Laboratory and then the Air Force Research Laboratory’s Directed Energy Directorate at Kirtland Air Force Base conducted atmospheric turbulence experiments to prove the feasibility of adaptive optics for the ABL. Many scientists, as well as members of Congress, wanted to acquire more experimental data defining the effects of atmospheric turbulence on a laser beam before spending large sums of money on an untried adaptive optics system. This was normal front-end risk reduction and proof-of-concept for the development of any major weapon system. Experimental data on atmospheric turbulence and its effect on a laser beam would provide DoD leadership with a solid scientific foundation to assess the benefit, cost, and risk of acquiring an ABL weapon and all its components, including adaptive optics.40 Adaptive optics systems had already worked well for imaging applications and for ground-based laser systems at Phillips Lab’s Starfire Optical Range. Between August and October 1992, SOR scientists conducted the Horizontal Path Experiment or HoPE, seeking to define the effects of atmospheric turbulence on a laser beam traveling horizontally a few feet off the ground, where the strongest turbulence existed. The thinking went that if laser power, wavelengths, apertures, and distances could be scaled at ground level to simulate conditions a laser beam would encounter at higher altitudes, then the test would be a good indicator of how a beam would react to turbulence at the higher altitudes where the Air Force intended to operate the ABL.41 HoPE used two laser beams. Two miles downrange from SOR was a beacon/receiver site that projected a horizontal outgoing beam to an Airborne Laser

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adaptive optics system set up at SOR. That beam served as a light beacon that fed into a wavefront sensor in the SOR adaptive optics system. The sensor measured phase aberrations in the beam, and that information was used to adjust the surface of a deformable mirror. The adaptive optics system at SOR then sent a precompensated outgoing beam back to the 2-mile receiver site. There measurements were made to determine if the beam had been corrected. Results showed that the improvement in beam quality was good, but not outstanding. The adaptive optics system used in these experiments was designed to transmit vertical paths of light, and was not designed to deal with the higher levels of fluctuation (scintillation) that a horizontal beam encountered near the ground. Nevertheless, HoPE was an important first step. Next came a bigger experiment known as the Airborne Laser Experiment or ABLEX.42 Also in 1992, Lincoln Laboratory began conducting a more extensive set of experiments—similar to HoPE—at its Firepond Optical Research facility in Westford, Massachusetts. The Firepond experiments used Lincoln’s 241-channel Short-Wavelength Adaptive Techniques or SWAT adaptive optics system (used in earlier SDI experiments) in conjunction with a 1.2-meter telescope. This system was designed to demonstrate the ability to propagate a laser beam horizontally long-range through a turbulent atmosphere. Hardware for this test series integrated “all the components that make up a flight system [for an ABL theater ballistic defense scenario] including tracking, pointing, illumination, and adaptive optics.” Lincoln’s Firepond test program was another example that showed existing adaptive optics systems were well suited to support the ABL program. Moreover, the Firepond adaptive optics system was better at correcting for distortions in the beam than HoPE had been.43

Airborne Laser Experiment (ABLEX) Over the years, the Air Force Geophysics Laboratory at Hanscom Air Force Base, Massachusetts—now part of the Air Force Research Laboratory’s Space Vehicles Directorate—had been a leader in conducting experiments on the effect of atmospheric turbulence on a laser beam propagating in a nearly vertical direction. This information was valuable for assessing the

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feasibility of using ground-based lasers to image space objects or, possibly, to intercept missiles or satellites. For vertically directed laser beams, most distortions occur within a few miles of the telescope’s receiving or transmitting aperture. To better define the turbulence profile, Geophysics Lab scientists launched balloons to travel straight up along a vertical path. These government scientists “pioneered balloon-borne high-bandwidth-sensitive temperature probes that could be used to measure turbulence at altitudes up to 30 kilometers.” A large share of these balloon flights occurred over Maui and White Sands Missile Range. As one observer noted, “The Geophysics Laboratory developed models of turbulence from these data, including the Clear1 model that was adopted as the basis for the turbulence requirements for the ABL program.” However, the ABL program also needed to understand how a laser beam propagating horizontally would be affected by turbulence. To acquire that information, Phillips Laboratory scientists used a number of different aircraft.44 ABLEX, conceived by Phillips Lab scientists in winter 1992, was the first in a series of atmospheric tests directed to assess the feasibility of adaptive optics technologies in aircraft. Funded by the Ballistic Missile Defense Organization, ABLEX flight experiments took place during December 1992 and January 1993. The experiments consisted of ten night-time aerial missions, two over White Sands Missile Range and eight over central Montana.45 Carried out by a team of Phillips Lab scientists led by Dr. Larry Weaver, the tests involved propagating a low-power 0.53-micron Nd:YAG laser beam between two aircraft in flight. A Learjet, named the High Altitude Reconnaissance Platform (HARP) and operated by Aeromet Corporation of Tulsa, Oklahoma, transmitted a laser beam to an NC-135 diagnostic aircraft called Argus, operated by Phillips Laboratory’s Flight Test Branch. The ABLEX laser beam served as a light beacon, similar to the BILL laser used later in the ABL program. As the ABLEX beam completed its journey through the atmosphere, it was projected onto an 85-centimeter-diameter receiver on the Argus aircraft, which served as a substitute for the ABL aircraft. ABL planned to have a 1.5-meter diameter aperture. Argus had an optical system—not an adaptive optics system to make beam corrections— that imaged the beam’s scintillation pattern onto a focal array. This pattern was recorded and used to compute the scintillation limit on ABL adaptive optics performance.46 Airborne Laser

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Figure 17. The Airborne Laser Experiment (ABLEX) measured the effects

of atmospheric turbulence on a laser beam transmitted from the Harp to the Argus aircraft.

Argus flew at altitudes from 35,000 to 50,000 feet—above, below, and through the tropopause—depending on the test. (The tropopause is the upper region of the troposphere, which extends about 7 miles upward from the ground.) These were the altitudes where ABL engagements against enemy targets most likely would occur. At these altitudes, the air turbulence was active and constantly changing. The phase aberrations in the beam could change hundreds of times each second. For most tests, the range the beam traveled from the HARP to Argus varied from 100 to 200 kilometers, representing realistic engagement scenarios for a future ABL.47 The purpose of ABLEX was to assess the performance limits of adaptive optics technologies designed for phase-only compensation of a laser beam by conducting aircraft laser propagation measurements to better understand upper atmospheric turbulence characteristics. A beam fired from an

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airborne laser would encounter temperature fluctuations in the atmosphere producing a form of optical turbulence resulting in scintillation patterns in the beam, resembling the twinkling of a star. Starlight does not twinkle until it encounters turbulence that imparts phase aberrations on the light beam. At the high altitudes where the airborne laser will operate, the beam will experience much less turbulence than it would at lower altitudes, where the air is denser and more disruptive to a laser beam. However, because the ABL is designed to attack during a missile’s boost phase, the laser beam must travel long distances through the atmosphere almost horizontally. Even though the turbulence is weaker at higher altitudes, its cumulative effects can be significant.48 ABLEX was a scaled experiment, meaning it was designed in such a way that the low-power beam transmitted over a range of 200 kilometers would experience the same optical effects as the high-power COIL beam would encounter traveling hundreds of kilometers. With experimental parameters chosen to scale to some of the most stressing ABL engagements, ABLEX recorded scintillation patterns resulting from the beam moving through atmospheric turbulence. These measurements demonstrated there were no physics limitations to the performance of a phase-only compensation adaptive optics system for the ABL system. Russ Butts, a Phillips Lab scientist who worked on ABLEX, explained the significance of the experiment: By measuring the irradiance distribution of the beam across an 80-centimeter aperture on the receiving aircraft [Argus], the performance with perfect phase compensation (perfect adaptive optics) could be calculated. Real adaptive optics systems do not achieve perfect compensation, of course, but the experiment [ABLEX] established that the physics limits of phase compensation with high-altitude turbulence was as expected. The physics limit of phase compensation was determined to yield Strehl ratios from 0.7 to 0.8. Those were extremely good measurements, considering a Strehl ratio of 1.0 represents perfection.49 In fact, the impact of turbulence-induced scintillation on the ABLEX laser beam was somewhat less than expected, which was a positive sign. Airborne Laser

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Prior to the ABLEX tests there was concern that turbulence would limit the Strehl values to a small number, meaning that an adaptive optics system could not make the required improvements to beam quality. However, average Strehl values for the ABLEX tests turned out to be 0.84, with a range from 0.72 to 0.98 —which meant that atmospheric turbulence was not as debilitating as anticipated and adaptive optics systems were sufficiently advanced to help correct for phase aberrations in a high-energy laser beam. As the final report stated, “ABLEX demonstrated that there are no significant fundamental limitations to the performance of a phase-only compensation system [adaptive optics] in an ABL weapon system.” The ABLEX results were highly encouraging and provided strong evidence for the feasibility of building an effective ABL adaptive optics system.50 ABLEX and other studies gave credibility to the idea of a strategic airborne laser. One of the most serious shortcomings of the earlier Airborne Laser Laboratory was that it had a range of only a few kilometers. Major General Don Lamberson, who had led the ALL program in the 1970s and served on the Air Force Scientific Advisory Board in the 1980s and 1990s, knew that for the ABL to be successfully deployed, its range would have to be increased to meet the missions of the 21st century. That required a beam that was close to diffraction limited so that a small, intense laser spot could be placed on target at a range of hundreds of kilometers. “The breakthrough which allowed us to get extended ranges that mean something in the strategic world,” Lamberson recalled in 2002, “was primarily adaptive optics.” Although adaptive optics would not be able to produce a perfect beam, Lamberson believed it could clean up a beam to approach 70 percent of diffraction limited, which would be sufficient to disrupt or destroy targets at long ranges.51

Airborne Laser Extended Atmospheric Characterization Experiment The follow-on program to ABLEX was the $18 million Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE). This series of tests, conducted from February through June 1995, collected the most complete and precise set of data on the effects of stratospheric

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turbulence on horizontal laser beam propagation to date. It utilized “a much richer suite of instruments” than ABLEX and recorded “every turbulence effect that was thought to be important for ABL performance.” ABLEX took the same types of measurements as ABLEX and added “highbandwidth scintillometry . . . as well as WFS [wavefront sensor] data, full aperture wavefront tilt, and far-field imaging.” All this provided data that validated high-altitude laser propagation models needed to predict optical degradations in a laser beam.52 An important goal of ABLE ACE was to take measurements that would “anchor the propagation codes in regimes of interest to ABL, so they could be used with confidence in the design process” of an ABL adaptive optics system. Real-world data were “essential for validating laser beam propagation models and simulation tools,” which was a fundamental part of the process that had to be completed in order to design an adaptive optics and beam control system customized for the ABL. The codes mathematically predicted how a beam would be distorted by different levels of atmospheric turbulence. Without accurate ABLE ACE turbulence measurements, scientists would have had to rely much more on guesswork and unproven formulas.53 To collect all this data, a 35-person ABLE ACE crew flew 28 sorties totaling 124 flight hours over 4 months. The team, headed by Lieutenant Colonel Shawn O’Keefe of Phillips Laboratory’s ABL Technology Division, sampled the atmosphere in a variety of conditions over several different sites, including the United States mainland, Alaska, the Pacific, Japan, and South Korea. One of the reasons the Korean peninsula was chosen was that it was a potential threat area where no extensive data existed on air turbulence over long horizontal distances. In general, ABLE ACE encountered and collected data on stronger turbulence regimes than ABLEX experiments. ABLE ACE experiments deliberately flew through the worst atmosphere in order to collect the most accurate turbulence information.54 Scientists predicted ABLE ACE data would show how a laser beam traveling horizontally would be affected by air turbulence. Two test aircraft flying in parallel at altitudes varying from 35,000 to 50,000 feet and separated by 20 to 200 kilometers were critical to the success of the ABLE ACE experiments. This experimental setup simulated planned ABL flight scenarios, as ABL was projected to operate between 39,000 and 46,000 feet, substantially higher than commercial airliners and fighter aircraft. This Airborne Laser

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region of the atmosphere included the lower stratosphere, where the effects of atmospheric turbulence on laser beam propagation were not fully understood. The goal was to expand the turbulence database needed to design an adaptive optics system for the ABL.55 One of the aircraft, a Gulfstream II, transmitted a horizontal lowpower laser beam (a 6-watt frequency doubled Nd:YAG) to the receiver aircraft, which carried sophisticated optical and electronic instrumentation, including a 79-centimeter aperture telescope. Six sensors measured distortions on the laser beam. Another sensor recorded the strength of the turbulence the beam passed through. As with ABLEX, the design of ABLE ACE involved scaled optical propagation experiments, meaning the corruptive effects of atmospheric turbulence for ABLE ACE were the same as the atmospheric turbulence effects the ABL would experience. In short, the idea behind ABLE ACE was to validate the feasibility of an adaptive optics system before the Air Force committed to funding an adaptive optics demonstrator system for the ABL.56 ABLE ACE flight experiments captured over 250 gigabytes of optical data that underwent extensive analysis. This information formed the foundation of an invaluable database on atmospheric turbulence at high altitudes that confirmed that there were no physics limits on designing an adaptive optics system for the ABL. The final technical report condensed the findings from the ABLE ACE experiments into two general conclusions. First: “The atmosphere is, for optical purposes, essentially Kolmogorov. We observed no persistent, unexpected high-altitude propagation phenomena that would preclude an ABL system.” And second: “Wave optics propagation codes . . . are well suited for ABL design and performance prediction.” In sum, it should be possible to design an adaptive optics system for the ABL aircraft that would be able to compensate for atmospheric turbulence so a high-energy laser could pass through the atmosphere without being distorted and weakened and deliver sufficient energy to disable a missile in its boost phase.57 Even though ABLEX and ABLE ACE were successful, there remained skeptics in Congress and elsewhere who insisted more data were needed before moving ahead with the risky development phase of the ABL—with its price tag of billions of dollars for a technology that had yet to prove that it could work in a combat environment. By the mid to late 1990s, ABL was

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Photo 35. Phillips Laboratory’s Captain Mike Ching and Dr. Mark Kramer

inspect the ABLE ACE telescope receiver and sensor package on the Argus C-135E aircraft.

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the second largest weapon system acquisition program in the Air Force (the F-22 Raptor advanced tactical fighter was first)—highly visible and subject to close scrutiny.58 Congress wanted to make sure that every precaution was taken to ensure the technical and financial success of the ABL program. Consequently, a number of checks and balances were imposed upon the ABL. The House Armed Services Committee relied on feedback from the Office of the Secretary of Defense’s Program Analysis and Evaluation (PA&E) panel of independent analysts to determine if the Air Force was on the right track. PA&E required the Air Force to demonstrate the viability of the ABL beam control system through a series of scaled-down beam control tests as part of the Advanced Concepts Testbed (ACT) program, carried out from North Oscura Peak at White Sands Missile Range. Many saw ACT as a technological insurance policy for the results derived from ABLEX and ABLE, which would err on the side of caution before Congress would give its authorization for the Air Force to proceed with the next stage of the ABL program.59

North Oscura Peak Poised 3,000 feet above the desert floor at the north end of White Sands Missile Range in southern New Mexico—near where Robert Oppenheimer and his Los Alamos team of scientists detonated the world’s first atomic bomb on 16 July 1945—is North Oscura Peak (NOP). This remote site is the home of the Air Force Research Laboratory’s unique and sophisticated beam control facility. It was here at NOP that a capable lineup of government scientists, led by Russ Butts and Mark Kramer from AFRL’s Directed Energy Directorate, worked under rigorous field conditions to implement the goals of the Advanced Concepts Testbed research program designed to replicate a beam control system similar to the one proposed to be used on the ABL.60 Kramer, who was the chief systems engineer for ACT, explained that the main purpose of the NOP beam control work was to put together a closescale testbed that would resemble the design and function of the beam control system that would actually be installed in the ABL aircraft. Using the testbed, scientists would test how well the NOP beam control system could correct for atmospheric disturbance. The goal of the NOP testing was to validate the

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Photo 36. North Oscura Peak in southern New Mexico was the site of a

series of laser, beam control, and adaptive optics testing in preparation for the Airborne Laser program.

ABL beam control design codes on a scaled testbed. That would increase confidence in Congress that a full-scale ABL beam control system would operate properly once installed in the ABL aircraft. What Phillips Laboratory wanted to show most was that an integrated laser and adaptive optics system would be able to correct for distortions in a beam caused by atmospheric turbulence and thereby improve the Strehl ratio by a factor of two or more. That meant improving the quality of the beam so it would deliver the maximum amount of laser energy on a very small target spot. In the end, Congress and the Air Force wanted the NOP beam findings to either support or refute the claim that the ABL beam control approach was viable.61 It took a team of about 20 people, military and civilians, nearly 2 years to ready the NOP site and to get the adaptive optics and beam control hardware up and running. The centerpiece of NOP was a 1-meter telescope situated at the top of the peak with a bird’s-eye view of anything that flew above the valley floor. From this vantage point, the NOP telescope was Airborne Laser

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capable of tracking aircraft and missiles flying over White Sands Missile Range. In addition to the telescope, the NOP facility housed two large clean rooms. One contained the tracking and adaptive optics system, consisting of a Shack-Hartman wavefront sensor and a 349-actuator deformable mirror. The second was where the laser operated. Test personnel monitored operational consoles and computer systems from a separate control room. Kramer and his group replaced or upgraded beam control components including processors, sensors, the laser and adaptive optics system, and the telemetry system.62 Testing of the adaptive optics and beam control system in summer 2000 took place under the Non-cooperative Dynamic Compensation Experiment or NoDyCE. “Non-cooperative Dynamic” referred to a moving target that gave off no laser light for NOP to collect and diagnose. The target was a Cessna Caravan aircraft, leased and operated by Lincoln Laboratory, with a scaled silhouette of a missile affixed to a target board on the side of the plane that measured 1 x 2.5 meters and contained 1,536 sensors that measured the quality and shape of a pulsed neodymium: yttrium lithium fluoride (Nd:YLF) laser beam, as well as the amount of energy it deposited on target. Most testing took place between 2:00 and 6:00 a.m. The aircraft flew at an altitude of 11,000 feet along a 40–50 kilometer arc downrange from NOP. There were over 15 NoDyCE flights with six to eight laser test passes on each flight.63 The NoDyCE tests sought to measure beam control performance over a wide range of atmospheric turbulence conditions. The results were used to aid in validating the ABL design code predictions for the scaled test using the Cessna aircraft against the measured performance of a weapons beam control system that used adaptive optics at NOP. In other words, would computer code predictions show the same beam profile on target as the real-world compensated beam sent from NOP to the Cessna?64 NoDyCE used three lasers. The first was a 10-watt low-power Nd:YAG pulsed laser that tracked the target by illuminating the tip of the missile silhouette on the side of the Cessna aircraft. It measured about 2 meters in diameter at the target. Track processors used the image of the illuminated tip of the missile silhouette to point both a tip-tilt mirror and the telescope at the target. Once NOP tracked the target, the next step was to employ the adaptive optics systems to form a tight, round beam on the target.65

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For this purpose, scientists used a second laser, a Nd:YLF, to illuminate a spot 50 centimeters in diameter on the missile silhouette. A wavefront sensor measured the optical distortions in the atmosphere along the path traveled by the Nd:YLF laser from the NOP telescope to the target silhouette on the Cessna. Based on these atmospheric distortion measurements, a high-performance computer determined the precise amount of deformations to apply to a deformable mirror to “fix” the atmospheric distortion. These fixes ensured that a third laser (also a Nd:YLF), or scoring beam, exited the NOP telescope so its outbound path to the target exactly retraced the inbound path of the beam from the Cessna to the NOP telescope. In that way, the outbound path of the scoring laser beam would cancel out atmospheric distortions, resulting in maximum energy deposited on target.66 The scoring beam laser was a product of the changes made by the adaptive optics system. Scientists used this third laser to score the beam control performance as the beam reflected off the deformable mirror and formed a small round spot on the missile silhouette. Sensors detected and assessed the beam’s quality, spot size, and intensity on target. All these processes involving the three lasers and adaptive optics took place thousands of times per second. Although the three NOP lasers were low-power devices, the techniques derived from the NOP tests will be used with the high-energy COIL laser and associated beam control system planned for the ABL.67 The NoDyCE testing ended on 1 September 2000; Kramer described it as “immensely successful.” The NOP beacon lasers and beam control system’s adaptive optics provided high-order correction for atmospheric disturbances as the scoring laser beam propagated over long horizontal distances (40–50 km) from NOP to its target. Captain Steve Ford, who worked on this project, remarked, “We’ve found the performance [of the beam control system] better than we expected.” One of the most important outcomes was that the NoDyCE tests demonstrated “up to a four-fold improvement in concentrated energy-on-target,” which was a strong indicator that the design of the beam control system was mature and reliable enough to direct, place, and hold a small tight laser spot on target for six seconds, in spite of the adverse effects of the atmosphere. The testing at NOP had validated the ABL design code predictions. In the process, NoDyCE satisfied the congressional mandate for testing key enabling beam control technologies before the Air Force was given authority to proceed with the full-scale ABL beam control system.68 Airborne Laser

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ABL Star At the same time the ACT work was underway at NOP, the Air Force focused on satisfying a second congressional mandate: to validate computer design codes for the ABL beam control system when exposed to more realistic flight scenarios than the ones conducted at NOP. To accomplish this, the Air Force initiated the ABL Star program in FY 2000, a worldwide campaign to collect more data on atmospheric turbulence, from the Middle East and the area around Korea, during three seasons (fall, winter, and spring)—to help determine whether ABL adaptive optics could deal effectively with the turbulence it would encounter in those two areas. ABL Star experiments took place from October 1999 to June 2000.69 Given all the previous programs that had collected atmospheric turbulence data, why was there still a need to go out and collect more? The answer was that some of the PA&E panel members were vocal ABL critics who claimed that the previous body of turbulence information from ABLEX, ABLE ACE, and ACT was still suspect. (Some were convinced that a space-based laser system was superior to ABL.) The PA&E skeptics contended the earlier turbulence data understated the problem; they thought the turbulence levels would be much higher. Although this might not have been the best scientific approach, members of the PA&E wanted to make doubly sure the beam control and adaptive optics system would work under the worst atmospheric turbulence conditions. According to Larry Weaver, who led an 18-man scientific team for this project, the ABL Star program set out to resolve the issue once and for all by having the Argus aircraft fly 43 missions collecting 296 hours of atmospheric data.70 An important part of ABL Star was to gather data that would confirm the 2XClear1 model—an empirical model of the strength of turbulence as a function of altitude that was used to design and predict the performance of the ABL adaptive optics system. The goal was for the system to operate satisfactorily 85 percent of the time against a variety of atmospheric environments. Only 15 percent of the time would the effects of the atmosphere be so harsh and unforgiving that the adaptive optics system could not direct a high quality laser beam through the air to destroy a distant target, such as a Scud missile in its boost stage. Even in the 15 percent of unsuccessful attempts, the beam control system was expected to be

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Photo 37. Argus aircraft on the ramp at Doha, Qatar, during ABL Star.

able to make some adjustments to the beam, so that, although its quality would be reduced, this could be partially overcome by increasing its dwell time on target.71 The ABL Star team used three methods for measuring turbulence at various altitudes. Two of these methods used sophisticated sensors to measure atmospheric conditions along a horizontal path, flown by Argus, similar to the path a laser beam would travel. One used a stellar scintillometer, an optical sensor that measured the fluctuating intensity of starlight (twinkle) in a narrow optical band; the other used an anemometer to measure temperature fluctuations. The third method involved launching balloons to measure small-scale temperature changes and turbulence along a vertical path.72 The scintillometer took measurements along a slant path that simulated ABL engagement angles. It enabled researchers to estimate the strength of turbulence by measuring turbulence-induced fluctuations in the intensity of starlight. The anemometer, mounted under the nose of the Argus aircraft, consisted of two four-pronged wires protruding into the air that sampled airflow along the flight path. It could measure temperature changes of 1/1000 degree. Research balloons collected similar temperature change data. All this information expanded the optical turbulence database and increased confidence in the design of the ABL beam control system.73 Airborne Laser

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After analyzing the data from the ABL Star testing, AFRL’s Directed Energy Directorate concluded that the design of the ABL adaptive optics system was valid. The data model 2XClear1 had proven accurate, and there was no need to change the design of the ABL beam control system. Lieutenant Colonel Richard Bagnell, who headed the Airborne Laser Technologies Branch at Kirtland Air Force Base, summed it up best when he stated, “We’ve found the turbulence at airborne laser flight altitudes appears to be as expected. The turbulent values we found . . . support the contention that the airborne laser, as designed, can perform its mission very effectively.” ABL Star expanded the upper atmospheric database, which contributed greatly to perfecting integrated optical path measurement techniques. The scintillometer and balloon data showed close agreement. The ABL system program office also declared the ABL Star testing an unqualified success.74 Although it was a military research program, ABL Star’s success in collecting atmospheric turbulence data did not go unnoticed in the scientific community at large, as the International Test and Evaluation Association recognized the work of the ABL Star scintillometer test team. In a ceremony held in September 2000 in Hershey, Pennsylvania, the association presented its annual Special Achievement Award to the Air Force scientists who participated in the ABL Star experiments. The award read, “The outstanding results allayed the fears of the Office of the Secretary of Defense and Congress resulting in the Airborne Laser staying on schedule and on cost, avoiding hundreds of millions of dollars in threatened delays.”75 HoPE, ABLEX, ABLE ACE, ACT/NoDyCE, and ABL Star were all designed for one purpose: to validate the performance of an adaptive optics system as a critical part of the ABL beam control system. The results established the technical feasibility of an ABL beam control system. The Air Force could now proceed with confidence to integrate and test the components of the ABL. Another experiment that showed that a laser could be fired quickly to engage one target after another occurred at White Sands Missile Range in September 2000, when a ground-based tactical high-energy laser shot two Katyusha rockets within a second of one another. The ABL has not yet been perfected, but is making progress against difficult system engineering integration problems. When the ABL shoots down its first missile, its success will depend to a large degree on the performance of its adaptive optics system.76

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Two of the Air Force’s most senior leaders were optimistic that the ABL would succeed. Secretary of the Air Force James G. Roche and Chief of Staff of the Air Force General John P. Jumper, who served during President George W. Bush’s administration, were united in their support for ABL. Roche said, “It’s worth doing the ABL systems engineering and taking the risks.” Both men believed it was important for the Air Force to stick with the program as long as there was a reasonable chance for it to work. Roche predicted that if ABL worked, the results would be dramatic in their effect on the future of the nation, not only for engaging missiles, but for locating launch sites, providing target information, and possibly performing future space missions.77

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3.5-Meter Military Telescope Complex Starfire Optical Range, New Mexico

The application of adaptive optics to the Airborne Laser program brought closer the day this revolutionary weapon system could be introduced into the Air Force operational inventory. But that was not the only mission that the Air Force envisioned for adaptive optics technology. Surveillance and high-resolution imaging of space objects using largeaperture, ground-based telescopes was another high-priority use for adaptive optics. To achieve that goal, the Air Force moved forward with the development of two state-of-the-art telescopes: the 3.5-meter (11.5-foot) telescope at Starfire Optical Range (SOR) and the 3.67-meter (12.04-foot) Advanced Electro-Optical System or AEOS on Maui. The origins of the 3.5-meter telescope went back to events at the Air Force Weapons Laboratory. Shortly after the installation of the 1.5-meter telescope at SOR in May 1987, that apparatus, with its closed-loop adaptive optics system, was able to consistently produce high-quality compensated images of space objects. Although the telescope’s performance was very good, Fugate realized in the fall of 1987 that he could achieve even higher

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resolution images of space objects—enough to see objects the size of basketballs hundreds of miles away—by building a new telescope with a bigger aperture. Larger telescopes need even more help from adaptive optics, and so do telescopes imaging faint space objects. Without adaptive optics, a 3.5-meter, 4-meter, or even 8-meter telescope would produce the same resolution image as a 15-centimeter backyard device.1 To improve its space imaging and laser propagation techniques, SOR planned to develop a new 3.5-meter telescope as its principal research tool. Improved imaging had some obvious near-term military benefits, but the Air Force also believed that larger telescopes had the potential to advance optical capabilities for a ground-based laser antisatellite system, if required for the nation’s defense in the future. Other potential missions included laser communications (between a ground station and a spacecraft) and power beaming (to illuminate a satellite’s solar panels to provide the external energy needed to boost it from low to geosynchronous orbit). Whatever their mission, bigger telescopes would require a reliable adaptive optics system to work at their peak potential. SOR’s long-term vision was to demonstrate the usefulness of adaptive optics and artificial beacon technologies for high-payoff operational applications.2 Fugate knew that he would need the support of Pete Avizonis, technical advisor to the director of the Air Force Weapons Laboratory’s Advanced Radiation Technology Office (ARTO), to acquire a bigger telescope. This would be a hard sell, especially since Fugate was proposing a new telescope that would have a primary mirror with nearly five and one-half times the light collecting area of the lab’s recently acquired 1.5-meter telescope. Realizing he would have an uphill fight on his hands, Fugate made an appointment to see Avizonis. Deciding to take the most direct approach, Fugate walked into Avizonis’s office and told the brusque but savvy and well-connected technocrat, “We are going to need a bigger telescope.” Avizonis didn’t flinch easily. Fugate recalled that his plan of attack “didn’t go over too well and basically to be blunt, I got thrown out, but I kept at it!”3 Fugate periodically went back to see Avizonis but did not make any progress. Avizonis and the AFWL commander at the time, Colonel J. P. Amor, believed that a 3.5-meter telescope would be too expensive at a time when laboratory budgets were tight. Outside sources of funding, readily available during the flush times of Reagan’s Strategic Defense Initiative Organization,

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were fading as the military threat from the Soviet Union declined. No one in the Department of Defense had built a telescope as big as 3.5 meters, and Avizonis felt that Fugate was trying to push the state of the art too quickly. Avizonis continued to ask the piercing question that Fugate did not want to hear, “do we really need bigger telescopes?” Although Fugate felt he “got beat up” every time he tried to make his case to Avizonis, he persisted.4 Eventually, Fugate adjusted his approach and recruited support from technical experts outside the laboratory. He asked Jim Mayo, an expert on telescopes and large optics who had retired from the Air Force in 1985, to examine the feasibility of a larger telescope for SOR and any related engineering issues. Mayo was employed as a contractor in charge of the Optical Mechanical Engineering Department for Logicon RDA in Albuquerque.5 Mayo set to work in the fall of 1987 preparing a point paper on the assets and liabilities of building a bigger telescope for SOR. His position was that the lab should invest in a 4-meter telescope that could conduct “groundbased experimental projects involving satellite tracking, imaging, and other activities.” A few months later, Mayo briefed his findings to Fugate, Avizonis, and other Weapons Laboratory personnel. Topics included the design and construction of the primary and secondary mirrors, mirror cells, mounts and optical design, site and facilities issues, system integration, and final assembly and checkout of the proposed new telescope. In addition, he addressed costs and scheduling, areas he knew could become deal breakers. Although Mayo’s presentation was persuasive, Avizonis wanted more time to weigh the pros and cons of such a costly enterprise.6 In the meantime, Fugate continued to argue to Avizonis—and to anyone else who would listen—that the laboratory had a responsibility to step up to the next level and take bold, calculated risks to promote progress in science and technology. But it took Fugate nearly a year to convince Avizonis to back the 3.5-meter telescope.7 It helped to be able to show Avizonis the excellent progress the 1.5-meter telescope had made in laser beacon experiments. At every opportunity, Fugate arranged for Avizonis and other key lab leaders to observe the 1.5-meter experiments at SOR. The high-definition images produced there did a great deal to establish SOR’s credibility. Those eyewitness accounts at SOR made an exceptionally strong and lasting impression on lab management, validating that Fugate and his team knew what they were doing.8 3.5-Meter Military Telescope Complex

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In essence, the SOR team was achieving substantive results as opposed to just flashing some fancy words on a slide presentation describing what could be done to demonstrate technical progress. It was the essential differentiation between planning and doing. Fugate’s team was producing things, building hardware, achieving results, and making a powerful impression by surpassing technical goals on a regular basis. There was no disputing the historical record. That made a huge difference in eventually obtaining support and approval for a larger telescope from the AFWL leadership, as well as from the higher levels of the Air Force.9 An important part of Fugate’s sales pitch was that the advancement of adaptive optics was a very good reason for moving ahead with the building of bigger telescopes. The two technologies together, Fugate believed, would have enormous military utility, “one that would give you a kind of resolution and angular diffraction that was useful both for imaging as well as for projecting [laser] energy.” But he cautioned that there were no plans to associate the 3.5-meter telescope with a weapon-class laser. Planned laser beam experiments would involve only a few watts of power and were aimed at understanding how a beam could be compensated when transmitted from the ground through turbulent atmosphere. “Acquisition, tracking, and point-ahead problems,” according to Fugate, “as well as getting the adaptive optics to work right, complicated the issue of propagating highenergy lasers.” Low-power laser experiments with the new telescope would, however, produce data with potential long-range military applications and enable the Air Force to investigate the scientific and technical problems of acquisition and tracking, as well as the effects of atmospheric turbulence on imaging and laser beam propagation.10 Locating the best possible site for the 3.5-meter telescope was a question that came up early in the planning process and that worried Avizonis. Fugate and laser scientist Barry Hogge looked at the possibility of installing it at a higher elevation and better seeing location than the existing SOR site. A new location offered the potential of a light beam encountering less atmospheric turbulence, making the job of the adaptive optics system somewhat easier.11 Fugate and Dr. Don Walters from the Naval Post Graduate School in Monterey, California, an expert in measuring atmospheric turbulence with ground-based telescopes, walked a ridgeline in the Manzano Mountains just east of SOR to look for a possible home for the new telescope. The main

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advantage of the Manzano site was that it was 1,500 feet higher than SOR at 6,240 feet. But field tests showed the elevation gain did not help significantly. Walters set up small telescopes at SOR and at the proposed new site, and simultaneously collected turbulence measurements from both. Seeing conditions at the Manzano location were better than SOR’s only 20 percent of the time. The lab considered that nothing less than an 80 percent improvement would justify constructing an expensive new site.12 Other reasons also worked against establishing a new site. The U.S. Forest Service controlled the Manzano land and had stringent rules, regulations, and environmental requirements affecting building a road into the site—erosion control, drainage, sewage, electricity, water lines, and so on. And neither the Forest Service nor Kirtland Air Force Base had the resources to provide year-round security, emergency medical service, or fire protection at the secluded location. Building a new site would cost 30 percent more than staying at SOR. Consequently, because of money issues, unresolved logistical support problems, and the fact that there were no significant improvements in seeing conditions at the proposed Manzano site, the lab decided to construct the new 3.5-meter telescope at SOR.13 Another decision Fugate faced was what type of primary mirror should be used for the 3.5-meter telescope and who should design and build it. Roger Angel at the University of Arizona in Tucson was working on an innovative mirror-making technique known as spin casting, which was less expensive and took less time than conventional manufacturing methods, which cast a flat piece of glass and then ground its surface down to the required parabolic shape—an arduous and time-consuming process. Because a spun-cast mirror cooled to nearly its desired shape, grinding was kept to a minimum. Angel also had pioneered a stressed-lap (computerdriven) polishing procedure that smoothed out a mirror’s surface more quickly and precisely than any other system available.14 Fugate had heard and read about Angel’s work, but he had never met the man, who was in charge of the University of Arizona’s Steward Observatory Mirror Laboratory (SOML), located under the stands of the university’s football stadium, which he referred to as his “glass casting factory.” Fugate arranged a meeting with Angel to discuss building a 3.5-meter mirror. Angel was interested, but Fugate traveled to Tucson with some reservations, because he was entering a university campus, where people did 3.5-Meter Military Telescope Complex

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not always see eye-to-eye with military researchers. Fugate did not think he would receive a warm reception, but Angel immediately put him at ease.15 From the start, Fugate and Angel began forming a mutually beneficial scientific business partnership. Both were engaged in something of a highstakes game. Fugate was taking a gutsy risk that Angel could deliver a large spun-cast mirror that would meet rigorous polishing specifications and become the centerpiece of SOR’s optical research program. Fugate liked taking calculated risks and doing things neither he nor anybody else had done before. “I think Roger and I,” Fugate reminisced, “kind of hit it off in that regard.”16 Angel was also at risk in the sense that he knew he had to convince Fugate he could deliver on fabricating the 3.5-meter primary mirror in a timely fashion using a manufacturing technique that had not yet been universally accepted in the scientific community. Always on the lookout for ways to attract new funding for his university research projects, Angel looked at Fugate as a source of government money to help him advance his mirror-building operation. Someday he hoped to build 8-meter mirrors. In short, the Fugate/Angel relationship was a win-win situation for both men. If everything worked as planned, Roger Angel would get his research funding, and Bob Fugate would get a 3.5-meter mirror for SOR.17 Fugate was willing to take a chance on spin casting and stressed-lap polishing, both new techniques, for a couple of reasons. As Fugate explained it, “I think the main thing was Roger’s credibility. In this case, the very first time I met Roger, I locked on immediately to his credibility and his brilliance, his creativity—it just kind of shines through. He had done his homework on spin casting and polishing techniques.” In addition, Angel already had two other orders in hand to build 3.5-meter mirrors. One was cast in 1988 for the Apache Point Observatory in Sunspot, New Mexico—a privately owned facility in the mountains above the town of Alamogordo adjacent to the Air Force’s Sacramento Peak Solar Observatory. Apache Point is supported by the Astrophysical Research Consortium, consisting of six universities (New Mexico State, Johns Hopkins, Chicago, Princeton, Washington, and Colorado) and the Institute for Advanced Studies. The other, also built in 1988, was for the 3.5-meter WIYN telescope (for Wisconsin, Indiana, Yale, National Optical Astronomy Observatory) at Kitt Peak Observatories in the Quinlan Mountains, an hour and a half drive southwest of Tucson.18

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Knowing that Angel already had plans to cast two other 3.5-meter mirrors, Fugate thought it would be a perfect opportunity for him to get into the queue and have Angel make a third 3.5-meter mirror for SOR. As the spin-casting schedule evolved, the plan called for the first two mirrors to be built before Fugate’s mirror would be cast. Fugate’s mirror was third on the schedule—and thus would benefit from any lessons learned in making the first two mirrors. As Angel later said, “We had already cast two of these things, so we knew what we were doing. We had a track record.” The fact that the Air Force would benefit from the experience Angel would gain working on the Apache Point and WIYN mirrors was a strong selling point for Angel. SOML was also the only facility in the world at the time that was spin casting lightweight honeycomb mirrors.19 Angel told Fugate and the AFWL commander Colonel John Otten that the Air Force would be in an enviable position to “cash in” on all the technology others had paid for—Apache Point and WIYN—in the making of the first two honeycomb 3.5-meter mirrors. This was an extraordinarily strong selling point for Angel, and gradually he was also able to convince AFWL to invest in helping him develop and perfect his relatively new stressed-lap polishing technique, on the grounds that it would benefit both Angel and the Air Force.20 After his initial meeting with Angel, Fugate arranged for Avizonis to visit Angel’s operation in Arizona and observe the first 3.5-meter blank fabricated in the SOML facility. Avizonis was impressed by what he saw. By the time he left, he felt more confident than ever that AFWL should invest in its own 3.5-meter mirror.21 Before committing to the 3.5-meter mirror, Avizonis formed an ad hoc 3.5-Meter Telescope Mirror Assessment Committee headed by Ray Wick, one of AFWL’s most experienced scientists in the field of directed energy, to determine the mirror size and who would build the mirror. Avizonis asked the committee to compare the pros and cons of Roger Angel’s spun-cast honeycomb borosilicate mirror with a machine light-weighted Zerodur solid glass mirror, most likely to be manufactured by the respected glassmaker Schott Optical Glass Inc. in Mainz, Germany. Jim Mayo, who was familiar with both Angel’s and Schott’s work, served as technical advisor to the group and prepared much of the analysis and the final report.22 Wick reported the committee’s findings to Avizonis on 14 September 3.5-Meter Military Telescope Complex

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1988. He wrote that the “technical risks were nearly equally distributed between these two materials [borosilicate and Zerodur].” Given that, the committee recommended that “programmatical issues as well as cost and schedule should be the determining factors in selecting the 3.5-meter mirror.” Although it was a close call, Avizonis chose Angel’s team at SOML. Avizonis and the committee recognized the risk involved in relying on such a new manufacturing process, but they realized two mirrors had already been built and a significant amount of money could be saved. They also believed that SOML could build the mirror on schedule and polish it in less time than any other vendor.23 After Avizonis chose SOML, he called Mayo into his office to express concern about ensuring the program succeeded. Mayo had worked with Avizonis for 10 years as a military officer assigned to the Weapons Lab and later on and off as a contractor. Avizonis was demanding, paid attention to detail, was often impatient, and showed little tolerance for poor performance. His dynamic management style was punctuated with occasional outbursts directed at the lab’s division and branch chiefs as well as scientists and engineers. But everything he did was in the best interest of the lab. Above all, he had a stellar record for getting things done. When Avizonis asked Mayo to serve as the lab’s senior optics advisor for the new 3.5-meter telescope, Mayo did not hesitate. He knew working with Avizonis would be challenging, but he also realized he would have an opportunity to contribute to the development of the Air Force’s most advanced telescope.24 Mayo was comfortable in his new assignment because he knew he would be working with many of the people he had served with before at the lab during his active duty days. He and Fugate, for instance, had worked in the same division in the lab in the early to mid-1980s, where they developed good rapport. Mayo also had a good working relationship with Otten— and with Captain Rich Miller, who served as project officer for much of the 3.5-meter telescope efforts. Over the next four years Mayo spent most of his time “practically living at SOML and Contraves Corporation who was selected to construct the 3.5-meter telescope.” At those two locations, he provided technical advice, monitored progress, and prepared technical reports and assessments that served as a basis for lab decision-making.25 SOML’s first step in November 1988 was to prepare a mold for SOR’s 3.5-meter primary mirror. Angel and one of his students, John M. Hill, had

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Figure 18. Cross section of the 3.5-meter parabolic mirror blank. The front

plate of the mirror is a layer of glass 1.25 inches thick. The vertical lines in the center section are the half-inch-thick glass cell walls that form a honeycomb structure throughout the mirror. A 1-inch glass layer at the bottom makes up the mirror’s back plate.

begun working in the late 1970s on the preliminary design of a honeycomb mold for a light-weight parabolic mirror. They bolted hexagon-shaped solid cores, made of ceramic-like material that could withstand intense heat, to a flat, circular metal plate that made up the base of the mold. For the 3.5-meter mirror there were 308 of these cores. They stood upright and measured about 8 inches in diameter and between a foot and a foot and a half high depending on location—the higher cores at the outer edges and the shortest at the center, with a one-half inch space between them.26 Once the cores were in place, technicians placed chunks of low-expansion borosilicate glass (similar to Pyrex), each weighing about 5–10 kilograms, on top of the 308 cores. By calculating the area and depth of the mirror, SOML scientists determined with mathematical precision the amount of glass for insertion into the mold that would be required to make a 3.5-meter mirror. Each chunk of glass was weighed before being placed in the mirror mold to ensure that all the chunks of glass added up to the total calculated weight for the 3.5-meter mirror. Ohara, a Japanese company, provided the glass referred to as Ohara E6 borosilicate. The chunks of glass formed an irregular surface across the top of the cores. Next the glassfilled mold was placed in a 1,170 degrees Centigrade two-story furnace that melted the glass to about the consistency of molasses. It flowed downward under the force of gravity, filled the half-inch spaces between the cores, and settled to the bottom of the mold.27 As the glass melted, the mirror mold spun at 9.277 rpms. Centrifugal force pushed the molten glass outward to form a rough parabolic-shaped primary mirror called the mirror blank. The molten glass rose high enough 3.5-Meter Military Telescope Complex

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Photo 38. Fabrication of the primary mirror began with precise weighing

of each piece of low-expansion borosilicate glass, manufactured by Ohara of Japan, to ensure exactly the correct volume of melted glass to fill the mirror mold.

above the core walls to form the mirror faceplate or front surface. It took nearly 6 weeks for the mirror to cool and for the glass to anneal or settle into its final concave shape. (In comparison, it took over a year to cool a more conventional solid-glass mirror.) As the glass cooled, it became rigid and gained strength. The next procedure was to remove the 308 cores still embedded in the mirror.28 Removing the cores was a critical step. The glass that cooled at the bottom of the mirror formed a 1-inch-thick back plate. Holes were drilled into this back plate, and water was injected at high pressure into each of the 308 cores trapped in the glass mirror, until each core was dissolved; the waste material was then extracted through the holes. This messy ordeal took a couple of weeks to complete. It left behind 308 empty cells spread over the entire area of the mirror, each with six half-inch-thick glass walls,

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Photo 39. Captain Richard Miller of the Air Force Weapons

Laboratory placed the last piece of glass into the mirror mold before the 10-meter diameter oven was closed to heat, melt, and spin the glass into its concave shape.

in a strong but lightweight honeycomb structure. Removing the cores not only lowered the weight of the mirror. Left in place, they would have heated and cooled (and expanded and contracted) at different rates from the glass, which would disrupt the homogeneity of the mirror and induce additional stress, adversely affecting the mirror’s reflectivity qualities.29 Angel’s spin-casting process fashioned a concave mirror for SOR weighing only 4,500 pounds, compared to 18,000 pounds for a conventional mirror. Although Angel’s mirror was lightweight—air accounted for roughly 70 percent of its volume—its honeycomb structure made it just as strong as a solid glass mirror that weighed four times as much. Later, when the mirror was installed on the 3.5-meter telescope at SOR, 56 computer-driven actuators prevented the large mirror from sagging under the pull of gravity, so it could maintain its shape as it changed positions during operation. (When 3.5-Meter Military Telescope Complex

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Photo 40. The primary mirror after cooling, still in the mirror mold within the open oven at SOML in Tucson.

the mirror faces straight upward, gravity exerts more force on its edges, flattening it a few thousands of an inch—enough to exceed optical tolerances. When the mirror faces the horizon, the force of gravity pulls it out of shape to resemble a potato chip rather than a smooth, uniform parabola.30 The back plate and honeycomb cells made up two of the three structural components of the 3.5-meter primary mirror. The top, called the front plate or face sheet, consisted of a 1¼-inch layer of spun glass. This deeply concave front surface collected and reflected incoming light, the essential purpose of the mirror. The spin-casting technology that shaped the surface offered an important advantage, because less glass had to be ground off at various locations and depths across the mirror’s surface. Precision grinding took 2 to 3 years on average for conventional solid-glass mirrors. It was also expensive, costing about $30,000 in 1991 dollars to grind out a ton of glass.31 A lighter mirror also made possible a lighter-weight mirror cell and

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Photo 41. Close-up of the cooled primary mirror, ready to be removed from its mold. Note the honeycomb-hexagon configuration on the mirror’s surface.

telescope mount and support system, which in turn allowed the telescope to rotate more quickly to any point in the sky with less powerful torque motors. Honeycomb mirrors were actively ventilated, which helped avoid another problem: turbulence eddies above the mirror surface and around the telescope caused by temperature differences between the glass and the surrounding air, which distorts the incoming light and spoils the image. A thick solid-glass mirror takes a long time to heat up or cool down to match the temperature of the surrounding air. Since the faceplate of the honeycomb mirror was 1¼ inches thick, and the walls of honeycomb cells were only half an inch thick, the entire mirror structure’s temperature could change quickly when exposed to the temperature airflow circulating in and around the primary mirror. But Angel’s team devised a system of fans, vents, and exhaust ducts that circulated air at just the right temperature through the honeycomb cells of the primary mirror to rapidly lower or elevate its temperature.32 3.5-Meter Military Telescope Complex

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Photo 42. A technician engaged in acid etching to remove surface stress on the back plate of the 3.5-meter mirror after it was removed from its mold. Distributed over the back plate were 308 holes where water was injected at high pressure to dissolve the cores and form the final honeycomb mirror structure.

A solid glass mirror also does not exhibit a uniform temperature over its entire surface: the back may not have the same temperature as the front, and the middle will usually not have the same temperature as the edges. This can cause the surface of the mirror to bend and produce a blurred image. The honeycomb mirror’s ventilation system could correct this problem as well. Angel’s system was able to maintain the primary mirror glass and ambient air temperatures to within a few tenths of a degree Centigrade once the telescope was up and running.33 The honeycomb structure and airflow system were the factors that convinced the Air Force to choose SOML in the first place. Only 7 months after spin casting began, the mirror blank was finished. On 28 June 1989,

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the AFWL commander led a small group of senior lab officials to Tucson to observe as Angel’s team lifted the lid off the furnace. The red-hot, glowing 3.5-meter mirror, shaped and sized as advertised, more than satisfied their expectations.34 Once the mirror was cast and cooled and the cores were removed, the next step was to polish the faceplate. Polishing did not get under way until early 1991. The mirror had to cool for at least 6 weeks, and AFWL and SOML had to negotiate the final polishing specifications. But the main cause of delay was the need to move a heavy piece of equipment into place. Before the stressed-lap polishing could begin, a Large Optics Generation machine (also called a Campbell Generator), equipped with high-speed diamond finishing wheels, had to do the preliminary grinding of the mirror’s surface. The device had to be moved a couple of blocks from the Optical Sciences Center on the University of Arizona campus to SOML and set up and tested.35 AFWL also needed a plan for synchronizing all the other components—not just the primary mirror—that would make up the 3.5 telescope facility. Contracts had to be awarded for building the telescope gimbal, mounts, and yoke, a secondary mirror, an ice chilling plant to cool the temperatures around the telescope, and more laboratory floor space to support the operation of the telescope. All this took time. Once all the parts of the telescope were built and installed at SOR, the Air Force proclaimed, the 3.5 would be the largest telescope in the DoD, the fifth largest in the United States, and the twelfth largest in the world.36 Angel pioneered the techniques for spin casting and stressed-lap polishing large honeycombed primary mirrors. He first applied these procedures in 1989, when his SOML team built and polished a 1.8-meter primary mirror used on the Vatican Advanced Technology Telescope on Mount Graham, 75 miles northeast of Tucson. Ten Jesuit astronomers spend part of each year working at SOML and Mount Graham. Certainly the Roman Catholic Church must have been pleased that a higher power from above had intervened to assign an Arizona “Angel” to build the primary mirror for the Vatican telescope.37 Angel’s computer-controlled polishing device consisted of a diskshaped polishing tool, called a lap, that measured 1.2 meters in diameter and weighed over a thousand pounds. On its underside was a 2-inch aluminum 3.5-Meter Military Telescope Complex

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Photo 43. The stressed-lap polisher during calibration testing on a small spun-cast mirror in preparation for polishing the much larger 3.5-meter SOR mirror. The polisher rubbed a mixture of water and fine grit onto the surface to smooth it.

plate with polishing pads attached at regular intervals. A computer calculated the exact position of the lap at all times as it moved over the mirror surface. Since the mirror was the shape of a parabola rather than a sphere, the stressed lap used 18 force actuators that bent the pliable aluminum plate into the proper configuration as it moved, so it could precisely conform to the required figure of the mirror surface. The lap glided smoothly from one location to another over the entire curved mirror surface every 60 seconds. A system of steel bands attached to the aluminum plate and stepper motors bent the aluminum plate just enough to conform to the required shape, changing the angle of the plate up to 1,000 times a second, so it would conform to the mirror surface without damaging it.38 Not everyone was convinced that Angel’s new polishing technique would work. For example, Burke E. Nelson, an optical fabrication expert with Logicon RDA, visited Angel on 1 September 1988 to observe his

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Photo 44. Roger Angel pioneered the spin casting and stressed-lap polisher techniques. In the background is a stressed-lap polisher smoothing the surface of a large primary mirror at SOML.

mirror-making operation. Nelson reported to Wick’s ad hoc committee, “The spin casting facility is very well thought out and carefully engineered,” but said that he had doubts about the stressed-lap polishing procedure. He did not believe the technique, “promising as it may be, is in anywhere near the state of development that would allow it to be chosen as the primary polishing approach to the 3.5-meter optic.” In the end, Avizonis overruled Nelson’s recommendation and opted to take a calculated risk by endorsing Angel’s innovative stressed-lap polishing technique.39 By 21 November 1991, the polishing process was complete. The mirror met its contract specifications. The surface was “precisely polished to 21 nanometers, or 3,000 times thinner than a human hair.” That was an extraordinary technical accomplishment; the uniformity of the mirror surface was nearly perfect. Moreover, the stressed-lap polishing technique— nearly 100 times faster than conventional methods—was a major triumph 3.5-Meter Military Telescope Complex

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representing a technological first for such a large mirror. Angel’s know-how and the Air Force’s financial and technical support helped ensure the successful transition of the stressed-lap polishing process from the laboratory to the real world.40 After polishing, the 3.5-meter mirror had to be coated to provide the required reflective surface. In the 19th century, mirrors were usually coated with silver, which had a high initial reflectivity of about 94 to 96 percent. But silver tarnished rapidly, and its reflectivity level dropped to about 40 to 60 percent after only a few months. Tarnished silver also blocked out shortwavelength light. By the early 1930s, aluminum had replaced silver as the best mirror coating. John Strong, an optical scientist from the California Institute of Technology, had developed a vacuum-deposit process that placed an aluminum layer of just the right thickness on top of a glass surface. This process was used to coat SOR’s 3.5-meter mirror.41 Coating took place at Kitt Peak’s coating facility, not far from SOML. There technicians placed the polished mirror inside a vacuum chamber. After several days of cleaning and other preparation, an electrical current was sent through pure aluminum coils inside the chamber, which caused the aluminum to evaporate quickly. In 30 seconds, aluminum coated everything in the vacuum chamber, including the mirror surface. The even aluminum coating adhered tightly to the glass, providing high optical quality and a reflectivity level between 90 and 92 percent. After exhaustive inspections, the mirror was trucked back to SOML, where it was inspected again and carefully packed on a truck. Surrounded by airbags, vibration dampeners, tension rods, and other protective gear, the mirror arrived safely at SOR in a large rectangular crate on 8 April 1993, ending a 5-year effort to acquire the Air Force’s largest telescope.42 The primary mirror, though a major milestone, was only one piece of a larger puzzle that remained to be perfected before the new telescope could produce sharp images. Many things still needed to happen, including building the telescope and its support structure, erecting buildings at the SOR site, and acquiring the adaptive optics system from Hughes Danbury Optical Systems in Connecticut. All these activities had to be coordinated in terms of scheduling, funding, and delivery of an acceptable product that met strict technical specifications. Not until all these actions were completed could the 3.5-meter telescope system be considered fully operational.43

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The large mirror would work in tandem with the telescope’s 14-inch secondary mirror. The job of the secondary mirror was to collect the light reflecting off the primary mirror and direct it to a tertiary mirror, which sent the light to the coudé room directly underneath the telescope, where it was directed to the adaptive optics system and imaging camera (also referred to as a science camera). In the coudé room, a wavefront sensor would assess the quality of the light and make the correct settings on a deformable mirror so sharp images could be captured by a camera.44 Contraves USA Corporation of Pittsburgh designed and built the secondary mirror, telescope mount, gimbal structures, coudé optics, and control system. The company had a long history in the telescope-making business and had worked with AFWL on SOR’s 1.5-meter telescope. By the end of November 1992 Contraves had fabricated a high-quality secondary mirror, but the company encountered a problem in delivering the mirror to SOR.45 Contraves shipped the secondary mirror by truck from its plant in Pittsburgh to SOR. The shipping container included the mirror mounted to the mirror cell, which held the mirror in place by flexures or matchsticksized steel rods. This was an accepted way of shipment, but to reduce the risk of damage from shock impact during transport some believed it would have been safer to pack the mirror separately in a padded metal case. Once at its destination, the mirror could then be mounted to its support cell.46 After the mirror arrived in late 1992, Mayo drove out to SOR to inspect it. He found the mirror and cell out of the shipping crate and sitting on a workbench. Two of the flexures were bent, indicating the mirror had received a severe shock sometime during shipment. Upon further scrutiny, he found three fractures in the mirror. “One of these fractures,” Mayo reported, “was propagating all the way up to the face [reflecting surface] of the mirror”—a serious defect that could impair the mirror’s performance.47 The lab notified Contraves, and the company sent two technicians to retrieve the mirror for a thorough inspection and damage assessment. For the return trip to Pittsburgh, the Contraves technicians packed the mirror in a foam-padded aluminum briefcase for extra protection. The precious cargo was to be hand-carried aboard a commercial airliner back to Pittsburgh. The two technicians transported the mirror from SOR in a rented SUV and parked it in front of La Quinta Hotel on Yale Boulevard 3.5-Meter Military Telescope Complex

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in Albuquerque, less than a half mile from the airport, planning to take a morning flight to Pittsburgh. They left the briefcase with the mirror locked inside the SUV.48 Unfortunately, the Contraves employees used poor judgment and made the mistake of locking the briefcase with the mirror for safekeeping inside the SUV and left it overnight. That evening, someone broke into the SUV, stole the briefcase, and took it across the street to a vacant lot to check it out. There the thieves opened the briefcase in hopes of finding some valuable treasure that would fetch high dollars. The problem was that the culprits were baffled by what they found. Having no idea what the mirror was, they figured there was no marketable cash value for the stolen merchandise. Consequently, they abandoned the briefcase and the mirror in the vacant lot, just a block from the hotel. Luckily, a passerby discovered it the next day and turned it over to the security police at Kirtland. From there the mirror eventually made its way to Fugate, its rightful owner.49 Mayo was called to SOR again on 19 January 1993 to conduct another inspection of the secondary mirror. He, Fugate, and others soon discovered the silver-coated mirror surface had received a few scratches and a small chip on its outer edge. Mayo carefully examined the three fractures found earlier and pronounced that they had not propagated further, which was encouraging news. For a second time, the mirror was packed in its padded briefcase in preparation for its trip back to Contraves for inspection and repair.50 This time Mayo—accompanied by Captain Chuck Villamarin, who had taken over as the 3.5-meter telescope project officer from Captain Rich Miller—personally escorted the mirror to the contractor. Mayo and Miller boarded US Air Flight 420 on the morning of 20 January 1993, wrapped the briefcase with the carefully padded mirror inside in a blanket, stored it in the overhead compartment for safekeeping directly above Mayo’s head, and brought it safely back to Pittsburgh. Contraves inspected the mirror and declared that the damage was minor and repairable.51 The contractor ground out the defects, recoated the mirror’s surface, and returned it to SOR, where it was installed on the 3.5-meter telescope and tested. As a long-term solution, Contraves built a new secondary mirror at no expense to the government. It was delivered and installed in 1997.52 Contraves was also responsible for manufacturing the telescope support structure, including the inner gimbal, the base, and the yoke or outer

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gimbal, a U-shaped steel structure resembling a two-prong fork. That contract began on 6 September 1989. The inner gimbal was an open rectangular steel frame that attached to the yoke’s two tines. Installed at the bottom of the gimbal was the primary mirror. At the top was the secondary mirror, supported by a four-vane “spider” configuration affixed to a truss on the telescope mount frame. The inner gimbal could be moved up and down so the primary mirror could be set at the desired elevation angle to observe space objects low or high above the horizon. The yoke rested on a telescope base equipped with a mechanical bearing that allowed the telescope to rotate smoothly and point toward the desired azimuth. Contraves designed the support structure and control system of the 3.5-meter telescope as a modified version of the 1.5-meter telescope the company had built earlier for SOR, which was based in part on an earlier NASA system called MOMS (Mobile Optical Measurement System).53 By summer 1992, Contraves had built and tested all the systems— including computer hardware and software, coudé mirrors, and electronic interfaces—for which it was responsible. The 3.5-meter telescope stood 37 feet high and weighed approximately 125 tons. In November 1992, Contraves installed the gimbal on the telescope. After several months of testing, the Air Force formally accepted the Contraves telescope—minus Angel’s primary mirror—on 15 March 1993.54 At the same time that Contraves was building the secondary mirror and telescope support superstructure, a number of construction projects were feverishly under way to prepare the SOR site for the eventual installation of the telescope. On 23 October 1990, K. L. House Construction Company of Albuquerque broke ground on SOR’s mechanical building, located 1,000 feet downhill from the telescope. The building contained large ice-making machines and a small propane boiler. Its purpose was to lower or raise the telescope’s primary mirror temperature as needed to match the surrounding air temperature and prevent the local turbulence and distortion that a temperature differential could cause.55 When cool air was needed to circulate around the telescope and the laboratory rooms adjacent to the telescope, the mechanical building functioned as a big ice house. During the day, when the telescope was not in use, the plant made large quantities of ice and stored it in a 30-foot-deep hole underneath the building that could store up to 4.5 million pounds of ice. The plant was far 3.5-Meter Military Telescope Complex

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Photo 45. The first 1/16-scale model of the 3.5-meter telescope designed and

built by Contraves.

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enough downhill that the heat generated during ice making would not thermally contaminate the air around the telescope. A closed-cycle system passed water over the ice and piped the chilled water up to the telescope. There, fans blew air over the chilled water, much like in a car’s radiator system, and the cool air adjusted the mirror surface temperature.56 If the telescope (and its adjacent optical laboratories) needed to be warmed instead of cooled, the mechanical building could crank up its propane-fired boiler, capable of generating 2 million BTUs, and pipe hot water up the hill. Hot and cold water could be mixed to reach the precise temperature control settings. After a year of work, the contractor completed construction of the mechanical building at a cost of $1.84 million. In January 1992, the government officially accepted the building, but it took several more months to install and test the cooling and heating units. By September 1992, the facility, not a high-tech enterprise but essential to the telescope’s design, was up and running.57 Two other major construction projects took place on top of the SOR hill. In June 1991, another Albuquerque company, Bradbury and Stamm Construction, began work on a 15,000-square-foot research laboratory and control building located next to the 3.5-meter telescope. Part of the new complex was to be located one level below the telescope. Here, in a large coudé room that housed the adaptive optics system, light from the telescope would be analyzed to measure the extent of distortions in the wavefront. That information was vital for adjusting the settings on the deformable mirror. Building the research and support facility, which included electronic and instrumentation laboratories, was a fairly straightforward construction project that reached completion in the fall of 1992. Also in 1991, the contractor had begun excavating a site on top of the hill for the reinforced concrete foundation of the 3.5-meter telescope. This project was more difficult; the contractor had to remove all the dirt down to bedrock. A 700-ton concrete pier would be poured to sit on top of the foundation. A steel telescope base would rest on top of the pier, and the telescope yoke would rest on the base. Foundation, pier, and base would make up an immovable tower of concrete and steel to support the telescope.58 In preparation for pouring the concrete, hundreds of holes were drilled into the granite bedrock, up to 60 feet deep, to accept steel reinforcing rods. Each rod was glued into its designated hole, which firmly anchored the 3.5-Meter Military Telescope Complex

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Photo 46. The concrete octagonal base for the 3.5-meter telescope (left

foreground) and for the new laboratory and control facilities (center) during construction. The 1.5-meter telescope originally located on the side of the hill at SOR was later relocated to the smaller concrete base under construction (right center). Top center is the shiny silver dome protecting the 1.0-meter beam director.

concrete foundation and pier to the bedrock. Several tons of rebar were tied together to add strength to the concrete in the foundation and pier. This support structure was completely isolated from other parts of the facility, virtually eliminating unwanted vibrations in the telescope base. On 12 September 1991, George Abrahamson, the chief scientist of the Air Force, tossed the first shovel-full of concrete into the foundation forms. When Abrahamson and a small group of other dignitaries moved aside, workers in hard hats began pouring 300 cubic yards of concrete, which dried and cured over the next few days to form the literally rock-solid telescope foundation.59 Another big construction project vital to the success of the 3.5-meter telescope was the fabrication of a large metal dome to protect the telescope and its support equipment from the weather. In spring 1991, the government

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awarded a contract to Coast Steel Fabricators of Port Coquitlam, British Columbia, to design and build the dome. Coast Steel had built the domes for both W. M. Keck Telescopes on Mauna Kea in Hawaii. It took the contractor only 18 months to complete fabrication of the large dome project for the 3.5-meter telescope at SOR.60 Until then, most telescope domes had been designed with a narrow slit for viewing. But air passing over the slit could produce unwanted turbulence, caused by temperature changes and wind, resulting in blurred images. Another problem was that the only way to view moving objects in the sky was to rotate the entire dome with the telescope, which caused vibrations that also degraded images. In contrast, the 3.5-meter telescope’s dome opened completely; only the telescope moved to track objects. The telescope was exposed to the outside air, facilitating thermal equilibrium and reducing turbulence in the surrounding air. The stationary dome also meant fewer vibrations as only the telescope moved to follow satellites across the sky. Thus, fewer corrections would have to be made by the telescope’s adaptive optics system. This was ideal for tracking satellites, one of the main reasons the design was chosen. The best time to track satellites was when SOR was in darkness—just after dusk or before dawn—while a satellite high overhead was still in sunlight and could reflect the sun’s light to the ground.61 A second advantage was that when the dome was open the telescope had an unobstructed 360-degree view of the horizon. And it could move quickly. It revolved on its base at a maximum azimuthal (horizontal) angular velocity of 10.8 degrees per second—turning full circle in just over half a minute—and could move up and down at 5 degrees of elevation per second. Satellite tracking requires such high slew rates, especially in the azimuthal axis of an altitude/azimuth mount system. However, there was a major disadvantage to an open dome: extremely high winds could interrupt operations or damage the telescope.62 The distance from the floor of the dome to the apex of its roof measured 37 feet. That provided sufficient clearance so the telescope could rotate 360 degrees with the dome closed. This allowed operational tests and routine maintenance to be conducted on the telescope without exposing it to the weather outside.63 The dome was put together in such a way that the roof and walls 3.5-Meter Military Telescope Complex

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Figure 19. Dome of the 3.5-meter telescope at Starfire Optical Range. On the left, the walls and roof are fully extended in the closed position. On the right, they are fully retracted.

collapsed vertically in a controlled fashion to open the dome and expose the telescope. Two shutters made up the center section of the roof. Each shutter slid away from the center, leaving an opening 35 feet in diameter. Then the roof could be lowered farther to follow the path of the collapsing side walls of the dome. The dome walls consisted of three tiers of concentric rings stacked on top of one another, resembling an old-fashioned collapsible drinking cup carried on camping trips. The bottom ring was 67 feet in diameter and 8.5 feet tall. The middle ring was 69 feet in diameter and 8.5 feet tall. The uppermost ring was the largest, with a diameter of 71 feet and a height of 9.5 feet. When the telescope dome opened, the second ring retracted and slid down behind the first ring, and the third ring slid down behind the second ring. A system of cables and pulleys driven by variablespeed motors lowered the walls. When fully retracted, the walls stood 10 feet high, leaving the telescope a panoramic view of the heavens.64 The outer dome wall, exposed to the weather, was made of 0.1575-inch aluminum plate. Its highly reflective surface kept it as close as possible to the temperature of the ambient air. A thinner aluminum sheet, measuring

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Photo 47. The 3.5-meter telescope dome at Starfire Optical Range consisted of three retractable concentric walls and a 15 degree sloped roof.

0.0508 inch thick, made up the inner wall. Between the two walls was a 6-inch gap that allowed forced air flow to circulate to control the temperature. The double-wall design helped achieve temperature equilibrium and get the best performance out of the telescope.65 The dome weighed 143,000 pounds. Eight steel box girders supported the roof. In the closed position, the structure could withstand winds of up to 120 miles per hour and snow loads of up to 20 pounds per square foot. When the wind blew at 60 miles per hour, the dome walls could be raised without damaging the structure.66 Fugate and others had to juggle many tasks to plan, design, build, and integrate all the pieces of the 3.5-meter telescope site. There was a heavy administrative burden that required constant attention to assess the progress of many different contractors and ensure they kept their time schedules and met their technical milestones. A wide range of budget, safety, 3.5-Meter Military Telescope Complex

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and security matters also consumed big chunks of time each week. By late 1992 and early 1993 the individual parts of this labor-intensive project had started to come together to shape one unified site. That effort was more than a full-time job for Fugate and his 75-member staff of physicists, electrical and mechanical engineers, computer scientists, mathematicians, laser technicians, and even a weatherman and astronomer, as well as the electricians, welders, machinists, and plumbers who kept the facilities and equipment running. They monitored progress at the site during the day and stayed into the early morning hours many times each month conducting imaging experiments on the 1.5-meter telescope. Those were hectic and fulfilling times, demanding both physical and mental stamina. By the end of 1992, there were visible signs of progress at SOR. The mechanical cooling and heating plant was operational. All the concrete work for the telescope’s support structure—foundation, pier, and floor— had been completed. The dome had been built and installed. The new laboratory and control facility adjacent to the telescope was finished. In October, Contraves began installing the telescope inside the dome—minus the primary mirror. And in August 1993, a large crane lowered the primary mirror through the top of the dome into position onto the 3.5-meter telescope.67 The primary mirror arrived at SOR on 7 April 1993. Between then and its installation, the telescope and its gimbal were put to good use. The first step in making the telescope operational was to demonstrate that its 125-ton gimbal system could point to and follow the path of a fast-moving satellite. This was accomplished using a small 12-inch acquisition telescope, also constructed by Contraves, and an unintensified acquisition camera bolted to the steel frame of the 3.5-meter telescope. The camera was boresighted with the 3.5-meter telescope so the camera and telescope saw the same object. The small diameter satellite appeared as a dot on the camera—but it would verify that the mechanical gimbal of the 3.5-meter telescope structure could follow the path of a low-earth-orbiting satellite.68 On 12 May 1993, the 3.5-meter telescope and its 12-inch telescope and acquisition camera succeeded in tracking several low-earth-orbiting satellites, 600 miles above the Earth’s surface. At that time there was no primary mirror on the 3.5-meter telescope and there was no adaptive optics system, since that system had not yet been built. Major John Anderson at SOR explained the excitement surrounding the night’s events: “Absolute mount

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Photo 48.

A large crane carefully lowers the 3.5-meter telescope through the roof of its protective aluminum dome at Starfire Optical Range.

positions were calibrated in less than an hour by pointing first at a known position in the Sandia Mountains, then at a known star, immediately after which the gimbal successfully tracked a rocket body. That night over 30 objects were tracked, including rocket bodies, COSMOS satellites, and the LACE satellite.” The system that controlled the 3.5-meter telescope’s gimbal was an upgraded version of the one used on the 1.5-meter telescope.69 The installation of the primary mirror in August 1993 went smoothly, but once in place the mirror had to undergo fine tuning. The biggest problem was making mounting adjustments to the primary mirror so it aligned properly with the secondary mirror, which took several months. Because of the polishing process used on the mirror surface, “the optical axis was not exactly centered geometrically.” To correct that imperfection, which is present to some degree in nearly all large mirrors, the mirror had to be 3.5-Meter Military Telescope Complex

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Photo 49. Bob Fugate (lower right) looks up and admires the newly installed

3.5-meter telescope at Starfire Optical Range. At top right, a 12-inch telescope and unintensified acquisition camera are mounted on the main telescope’s head ring, used to hold the secondary mirror in place.

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moved a few millimeters from where it was supposed to be mounted. Also, the 56 actuators used to maintain the shape of the large primary mirror (so it would not sag under its own weight) had to be checked to make sure they operated according to specifications. Once these two tasks were completed, the telescope was ready to begin conducting preliminary tracking and imaging experiments.70 First light acquired by the 3.5-meter telescope using its primary mirror occurred on 10 February 1994. (First light meant the telescope could collect light from a space object and make an image of it.) Using a photometrics camera, 1- and 4-minute exposures were taken of NGC4147, a tight globular cluster of stars at the edge of the Milky Way, 55,000 light years from Earth. Images were also obtained of NGC3583, a spiral galaxy millions of light years away. The telescope collected the natural light given off by these bodies in space and sent the light directly to a camera. There was still no adaptive optics system installed on the telescope. But the images showed that the 3.5-meter telescope could detect very dim objects—roughly a million times dimmer than what can be seen by the human eye—in distant space.71 Two weeks later, on 24 February during a full moon, a series of short exposures captured images of bright stars. Fugate was pleased that all the telescope components and subsystems were working in unison. He was especially proud that “The thermal environment behaved very well during these first observations as well as the active control of the primary mirror. The temperature difference between any two points on the mirror’s surface was within a few tenths of a degree.” During that time, the 3.5-meter telescope also located and imaged three low-earth-orbiting satellites for the first time. That feat set a world record for the 3.5-meter telescope as the largest aperture telescope ever to track and image low-earth-orbiting satellites. The telescope had made a promising start.72 From March 1993, when the Air Force accepted the 3.5-meter telescope from Contraves, until late spring 1994, the telescope underwent several tests and upgrades in addition to the installation of the primary mirror—much like a shake-down cruise. Not only did SOR technicians and scientists continually fine-tune the telescope, they also conducted numerous imaging experiments, even though it had no adaptive optics system yet.73 The DoD’s largest telescope had been up and running (minus the adaptive optics) for over a year before the official dedication ceremony took 3.5-Meter Military Telescope Complex

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Photo 50. Starfire Optical Range, looking west. In center at the top of the hill is the 3.5-meter telescope inside its closed aluminum dome. To the right of it is the 1.0-meter beam director, the same one that Lincoln Lab used for its first sodium guide star experiment at White Sands Missile Range in the mid1980s. At the lower left, on the side of the hill, is the 1.5-meter telescope. To the left of the 3.5-meter telescope is the concrete base that would become the new location of the 1.5-meter telescope in 2000.

place on 18 May 1994. It had been over 6 years since Fugate first walked into Avizonis’s office to argue the need for the telescope. That early vision turned into an official reality when a small group of Air Force leaders and distinguished visitors gathered at SOR for the dedication ceremony. George Abrahamson, the Air Force chief scientist, who worked in the Pentagon, traveled to SOR and cut the ceremonial ribbon as the dome of the 3.5-meter telescope silently retracted to expose the Air Force’s impressive new stateof-the-art telescope with the theme song from 2001: A Space Odyssey playing in the background.74

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Not everyone who wanted to be at the dedication was able to attend. U.S. Senator Jeff Bingaman of New Mexico regretted that pressing Senate business kept him in Washington. But in a letter honoring the dedication of the 3.5-meter telescope, Bingaman wrote: “This dedication marks a momentous event in astronomical research. Primarily developed for military application, the Starfire Telescope now becomes available for use by a broad range of research institutions. The use of adaptive optics to extend the clarity of ground based telescopes will help broaden our knowledge of the heavens.” What Bingaman was referring to was a prime example of technology transfer from the military to the civilian astronomy community. His endorsement once again attested to Fugate and his associates’ ability to get things done in spite of great odds.75 The telescope soon achieved another milestone, in support of the Air Force’s man-made space object identification mission. U.S. Space Command cataloged detected space objects and shared the information with selected military, civilian, and scientific agencies. In December 1994, the new SOR telescope, using a charge-coupled device (CCD) array developed by Phillips and Lincoln laboratories, successfully acquired high-resolution satellite images for the first time. That work was part of the Large Aperture Speckle Experiment, which used a Daytime Optical Near-Infrared System with a fast charge-coupled device camera array to produce the images.76 Since the adaptive optics system was not yet installed, the initial satellite images had to go through computer post-processing. Previously, smallaperture telescopes could not passively (without adaptive optics) acquire sharp images of very dim space objects just before sunrise and after sunset. However, the new telescope’s larger aperture “demonstrated the utility of a passive daylight satellite imaging system . . . for high resolution satellite imaging experiments.” The Large Aperture Speckle Experiment represented the first steps toward developing a night or daytime imaging capability for the Air Force.77 Through the May dedication ceremony, the Air Force had funded the entire 3.5-meter telescope project at a cost of $27 million, spread over 6 years. The money came entirely out of the annual Air Force science and technology budget. More than half of that amount was spent on the design, fabrication, and installation of the telescope. The primary mirror cost $5 million, and the remaining components of the telescope—gimbal, yoke, 3.5-Meter Military Telescope Complex

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base, secondary mirror, and so on—amounted to $10.5 million. Another $11.5 million went for construction of the mechanical building, the laboratory and control facilities adjacent to the telescope, the dome enclosing the telescope, and other support facilities.78 The $27 million did not include the price of the adaptive optics system, which was installed in 1997. Part of the reason for the nearly 4-year delay in installing the adaptive optics system was the convoluted financial connection between the building of the 3.5-meter telescope and the AEOS telescope. In May 1993 the Air Force decided as a cost-saving measure to contract with Hughes Danbury Optical Systems in Connecticut for the building of two identical adaptive optics systems, one for the 3.5-meter SOR telescope and the other for the 3.67-meter AEOS telescope under construction at Maui (see chapter 11). As Fugate put it, in terms of adaptive optics, “These two programs were joined at the hip.” He was not favorably impressed with this joint acquisition arrangement, believing developing two turnkey adaptive optics systems simultaneously would delay the delivery of SOR’s system. Too many unforeseen problems could arise in building a complicated adaptive optics system, and there was little leeway to deviate from the rigid design if problems did occur. Because there was a lot of money and politics involved, contract negotiations dragged on for a couple of years. Even after the contract was awarded on 22 August 1994, there were recurring design problems that required constant attention and changes to ensure all technical specifications would be met.79 As expected, problems persisted during the design and manufacturing phases of the adaptive optics system for the 3.5-meter telescope. Those problems were never completely resolved, and Hughes did not end up providing an integrated adaptive optics system to SOR. However, Xinetics, a Hughes subcontractor, did fabricate a high quality state-of-the-art deformable mirror with 941 actuators and delivered it to SOR in December 1996. Mark Ealey, who had gained valuable experience working on optical systems at Itek in the 1980s, had founded Xinetics in 1994. The $4.5 million deformable mirror—the heart of the adaptive optics system for the 3.5-meter telescope— was one of the first deformable mirrors made by Ealey’s company. (Some critics considered the $4.5 million awarded to Hughes excessive, because only about $1 million went to Xinetics to build the deformable mirror.) Lincoln Laboratory also contributed by providing a high-speed wavefront sensor camera, another critical part of SOR’s adaptive optics system.80

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So what the Air Force and SOR wound up with at the end of 1996 was an incomplete adaptive optics system. Overall, some believed Hughes was a disappointment in fulfilling its obligation to develop a workable SOR adaptive optics system. The contractor was behind schedule, over cost (final payment for the two adaptive optics system skyrocketed to $45 million), and the hardware it delivered, such as the wavefront sensor, failed to meet performance specifications. Consequently, Fugate and his team took a bold step to correct that situation by drawing upon their collective scientific and engineering know-how to build, in-house, the remaining components of the partially completed Hughes adaptive optics system. A dedicated core group of about 15 individuals worked long hours at SOR to design and build the adaptive optics processing electronics, including all the processing boards, a Shack-Hartman wavefront sensor with 30 subapertures across the diameter (the primary mirror had 800 subapertures), as well as the coudé relay path optics (most of these mirrors were 14–16 inches in diameter) used to move the beam and other optics that interfaced with the deformable mirror. With the exception of the deformable mirror and the wavefront camera, Fugate’s team designed, built, and integrated all the parts and subsystems of the adaptive optics system. Much of the work involved customizing the electronics to be responsive to SOR’s special research and experimental parameters. The SOR adaptive optics system turned out to be very different from the turnkey system designed for AEOS on Maui. According to Fugate, the SOR in-house effort “sped up things enormously.”81 In spring 1997 the pace did pick up substantially at SOR as work began on installation of the adaptive optics system in a laboratory located one level below the 3.5-meter telescope. That work lasted into December. Xinetics’s deformable mirror worked reasonably well with only a few expected minor glitches. The 10-inch-diameter mirror consisted of a 1-millimeter-thick piece of ultra-low-expansion glass that could bend to various degrees depending on the amount of voltage delivered to each of 941 actuators on its back. Only 7 millimeters separated actuators from one another. The deformable mirror for the 3.5-meter telescope was similar, but not identical, to the 241-actuator deformable mirror used with SOR’s earlier 1.5-meter telescope.82 While work progressed on the adaptive optics installation, another important optical improvement was made to the 3.5-meter telescope. Contraves built a new secondary mirror for SOR to replace the earlier 3.5-Meter Military Telescope Complex

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damaged mirror, and SOR workers installed it in June 1997. That involved tilting the apex of the telescope down to give workers access to the secondary mirror; they then unbolted the old mirror and fastened the new one in its place. Although not a major scientific accomplishment, addition of the new secondary mirror was important because it was superior to the first slightly damaged secondary mirror and would improve the performance of the 3.5-meter telescope.83 With the new secondary mirror and adaptive optics system installed, the 3.5-meter telescope achieved first light at one o’clock in the morning on 17 September 1997. The first target to be imaged was a bright star named Kappa-Pegasus. Viewed without adaptive optics, Kappa-Pegasus appeared as a single blurred image. However, when the SOR experimenters closed the loop on the adaptive optics system, Lieutenant Colonel John Anderson, an Air Force scientist who was present, excitedly proclaimed that the image of the star “improved immediately.” In addition, what appeared as a blurry single star without adaptive optics had changed dramatically when the adaptive optics was turned on, revealing, for the first time, two stars instead of one. That discovery of a binary star promptly established the value of the 3.5-meter telescope’s adaptive optics system. Obtaining an instantaneous high-quality compensated image on the first image was a huge accomplishment. The 3.5-meter telescope detected and imaged several other stars that night, duplicating the high resolution of the first image each time.84 Over the years that followed, the 3.5-meter telescope in combination with its adaptive optics system continued to be adjusted. Part of that work involved repeating experiments carried out earlier by the 1.5-meter telescope and its adaptive optics system. The goal was to image the same astronomical bodies using the 3.5-meter and 1.5-meter telescopes, and then compare the quality of the two. Resolution, as predicted, was much better with the 3.5-meter telescope—on average, 2.3 times better. That in itself was good reason to justify the Air Force’s decision to build the larger 3.5-meter telescope in the first place.85 The best images captured by the 1.5-meter telescope would never be as good as the best images captured by the 3.5-meter telescope using the same or comparable adaptive optics systems. As long as adaptive optics could correct for atmospheric turbulence, the telescope with the bigger aperture would always produce a better image than a smaller aperture telescope with

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Photo 51. Adaptive optics makes a clear difference: Comparison of images of

the same low-earth-orbiting satellite, SEASAT, taken from Starfire Optical Range in 1993 with the 1.5-meter telescope (top row) and in 1999 with the 3.5meter telescope (bottom row). Top row left is a turbulence-blurred image taken without adaptive optics; top center is a raw image obtained using adaptive optics; top right is the same image enhanced by computer postprocessing. The bottom row contains images of the same satellite: again, without adaptive optics (left), with adaptive optics (center), and with adaptive optics and post-processing (right).

adaptive optics. Moreover, that was why the 3.5-meter ground-based telescope could rival the resolution quality of images acquired by the smalleraperture 2.4-meter Hubble Space Telescope. The adaptive optics system for the 3.5-meter telescope could correct for at best about 96 percent of distortions in the light it received, while the Hubble, operating in space, did not have to contend with atmospheric distortion at all. But the ground-based telescope, with its larger aperture, could produce images that approached the resolution level of the smaller Hubble telescope, even though it had to contend with some residual distortion. In some limited cases under ideal seeing conditions, the 3.5-meter telescope could image very bright stars with better 3.5-Meter Military Telescope Complex

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resolution than the Hubble. And it could do that operating from the ground, a much less expensive enterprise than sustaining the Hubble in space.86 With the reliable performance of the 3.5-meter telescope, SOR was turning into a world-class center for adaptive optics. Both civilian astronomers and military researchers recognized the adaptive optics system at SOR as the most complex and most advanced in the world. Its reliable performance showed that adaptive optics worked not only in theory but also in practice. SOR has built a unique archive of high-resolution images with excellent Strehl ratios between 0.5 and 0.8 at short wavelengths (0.8 microns in the visible part of the spectrum) for stars and other astronomical bodies. On the nights of 12 January and 23 February 1998, for instance, the 3.5-meter telescope viewed and imaged single and close binary stars. SOR scientists reported: “We found that compensation with adaptive optics yielded an approximately 70-to-1 improvement in Strehl ratios over uncompensated long exposures.” That had never been done before with any other telescope, including the Hubble.87 Other laser energy projection experiments showed that a satellite could be tracked and that a compensated low-power laser beam of good quality could be directed from the ground to intercept a low-earth-orbiting satellite. It was more difficult to focus a laser beam on a satellite than to image the satellite. In 2002, for the first time, SOR conducted a target beacon experiment that used sunlight reflected from a satellite as the beacon to drive the adaptive optics system of the 3.5-meter telescope. The telescope’s wavefront sensor measured distortions in the beacon and made the necessary settings on the deformable mirror to correct for atmospheric turbulence. Then the telescope projected a 1.064-micron compensated laser beam in the point-ahead direction of a very small angle of 50 microradians. The beam struck a retroreflector on the satellite and was quickly scanned onboard the satellite to measure its compensated beam profile. The beam profile signal was then transmitted through telemetry to the ground and collected by the 1-meter beam director located 145 feet from the 3.5-meter telescope on the top of the hill at SOR.88 The beam director recorded the intensity profile of the beam to determine whether the beam was of good quality. In this case, results showed that the low-power laser beam was 10 times better than an uncompensated beam, demonstrating that the adaptive optics system, working in combination with the 3.5-meter telescope, was able to project a compensated and coherent beam

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from the ground to a satellite. That suggested that a future, scaled-up experiment using a high-power laser could produce similar results.89 Although it took nearly 10 years to move from concept to operation, the 3.5-meter telescope aided by an adaptive optics system proved almost at once to be a reliable enabling technology. As was the case with laser guide stars in the 1980s, the Air Force led the way in advancing imaging techniques to produce high quality images of space objects that were of immediate interest to the military and to astronomers all over the world. In addition to improvements in imaging, the combination of adaptive optics and the 3.5-meter telescope achieved significant improvements in propagating a low-power laser beam through space to intercept a target and laid the foundation for similar work with high-power lasers that might someday be used in ground-based laser antisatellite and ballistic defense missions. The 3.5-meter telescope and its adaptive optics hardware transformed SOR into a world-class research center destined to shape the nation’s defense posture now and in the future. In spite of the tremendous progress that had been made, scientists agreed that adaptive optics was still in its infancy—the best was yet to come. As civil servants, military, and contractor scientists worked together for the Air Force, the men and women at SOR occupied a special niche in the scientific community. Their world was different from academia, as they aimed to take their scientific findings one step further by applying them to practical, operational Air Force systems—an aspect of the research that many of the Air Force’s dedicated cadre of civilian and military scientists found deeply satisfying.90 Although senior Air Force officials had supported research at SOR, General Lester L. Lyles, commander of Air Force Materiel Command from April 2000 through October 2003, pointed out that because of the complexity of the science some high officials were still a little skeptical about whether the research would lead to useful applications. Listening to a briefing in the Pentagon did not have nearly the same effect as seeing operations at SOR first-hand.91 In 2002, Lyles invited James G. Roche, secretary of the Air Force, and General John P. Jumper, chief of staff of the Air Force, to visit SOR. Fugate briefed the two highest leaders in the Air Force on the capabilities of the 3.5-meter telescope and adaptive optics system. He followed with a spectacular demonstration of the firing of a visible blue-green laser into the pitch-black 3.5-Meter Military Telescope Complex

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night sky. Both men were impressed by Fugate’s demonstration. That was a real turning point, according to Lyles, who recalled, “From that point on, I was convinced that Roche and Jumper became even stronger champions of adaptive optics.” Roche later commented that he and Jumper had been completely sold on Fugate’s work and its potential benefits to the Air Force.92 Other influential people were also sold. Ron M. Sega, a former astronaut who served as director of defense research and engineering in the Office of the Secretary of Defense from 2001to 2005, had always believed that DoD considered adaptive optics research a credible program. He recalled that there was a general recognition that “[a]daptive optics research was a good investment—there was not a lot of debate on the value of adaptive optics.” Part of the reason for that was that by the start of the 21st century more than 20 countries had satellites in space, and the DoD needed to know on “what is out there.” Adaptive optics systems were a means to satisfy that need by capturing high-resolution images that helped analysts identify the function of different satellites and other objects in space. Sega declared the sustained support in terms of money and resources for adaptive optics research had been instrumental in bringing “stability to the scientific process that allowed the work to continue without any major interruptions.”93 In 2003, Fugate was one of six recipients of the Presidential Rank Award for his work in adaptive optics. That honor placed him in the top 1 percent of senior civilian executives in the federal government. In his acceptance remarks, Fugate turned back the pages of history to recognize and praise General Hap Arnold and Theodore von Kármán for their foresight and courage after the Second World War in laying the foundation that the future of airpower depended on a long-term investment in science and technology. The Air Force’s commitment to research remained firm over the next 50 years as it passed from one generation of Air Force leaders to the next. In 2003, General Jumper and Secretary Roche publicly reaffirmed their support for the advancement of science and technology as an enduring and fundamental tenet of Air Force strategic planning.94 Fugate made two other significant points about his career with the Air Force. At the personal level, he said gratefully, “I have done things I could never have done in academia or industry.” Equally important, he recognized the fundamental element of scientific success in adaptive optics: “our accomplishments come from a team effort.”95

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3.67-Meter Military Telescope Complex Maui, Hawaii

The 3.5-meter (11.5-foot) telescope developed for SOR was the Department of Defense’s largest and most advanced operational telescope for most of the 1990s. But toward the end of the decade, the Starfire telescope would be surpassed in size by the slightly larger AEOS telescope installed on the summit of Haleakala in July 1997; it became fully operational in 2000. The new Maui telescope, with its primary mirror diameter measuring at 3.67 meters (12.04 feet), barely exceeded the diameter of the 3.5-meter telescope at SOR. The telescopes were closely connected, as AEOS was built on the basic design philosophy and incorporated lessons learned from the 3.5-meter telescope. Management and operation of the two telescopes were the responsibility of the Air Force Research Laboratory’s Directed Energy (DE) Directorate, located at Kirtland. Although the Air Force now had two comparable-sized, 3-meterclass telescopes, the missions of the two telescopes are fundamentally different. The SOR telescope is used primarily as a sophisticated scientific research instrument to advance the state of the art for imaging of space objects, adaptive optics, and laser beam control and propagation. The

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Maui telescope has a dual responsibility. Besides being used for research, it provides real-time imaging support to operational units, namely U.S. Space Command (USSPACECOM), headquartered at Peterson Air Force Base, Colorado, and the Air Force Space Command (AFSPC) established on 1 September 1982 and also located at Peterson. USSPACECOM, established on 23 September 1985, disbanded on 1 October 2002. Its responsibilities transferred to the newly created U.S. Strategic Command (USSTRATCOM) at Offutt Air Force Base in Omaha, Nebraska. USSTRATCOM oversees a global network of satellite command and control functions. Hence, even though the SOR and Maui telescopes are similar in some cases, their operations and workloads are not the same. In short, SOR is a research site, while Maui’s primary role is to support day-to-day Air Force space object identification missions. Originally, justification for that mission was precisely spelled out in USSPACECOM’s Space Object Identification Statement of Need, 14–89.1 AEOS detects, tracks, identifies, and images artificial objects in space, such as satellites and missiles. Today, this is the essence of the Air Force’s space situational awareness mission. AEOS is a contributing sensor supporting the military’s space surveillance network and intelligence-gathering customers, who are involved in satellite mission payload assessment. AFSPC and USSTRATCOM want to know the exact location of satellites, space debris, and other objects at any time. The Air Force also wants to be able to predict where each satellite will be located at a specific time in the future and the mission of those satellites.2 USSTRATCOM and a number of U.S. intelligence agencies, including the National Air and Space Intelligence Center at Wright-Patterson Air Force Base, Ohio, use Maui space surveillance data to collect and assess other information about satellites and missiles—such as friend or foe, operational status, spectrum, stability, and intent. For example, an image of a satellite showing no solar panels might suggest the satellite is nuclearpowered. The Directed Energy detachment responsible for managing the Maui telescope is the only unit within the Air Force Research Laboratory assigned a continuing operational mission.3 The Maui telescope is a major contributor to the space surveillance network, which has 19 observation sites (radars and optical telescopes) worldwide that keep track of satellites, missiles, and space debris. AMOS

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originally opened in August 1966 as the Advanced Research Projects Agency’s Midcourse Optical Observatory Station, to collect optical measurements on ICBMs launched from Vandenberg Air Force Base, California, to the Kwajalein Atoll in the Pacific. Another project, Maui’s Ground-Based Electro-Optical Deep Surveillance System (GEODSS), can look 3,000 to 23,000 miles into space to observe communications, weather, and surveillance satellites that move in geosynchronous orbit (at the same speed as the Earth’s rotation). One of the functions of satellites in geosynchronous orbit is early detection of missile and space launches for the Air Force Defense Support Program.4 Before (and even after) electro-optical systems became available, the Air Force relied on radar as the primary method of space surveillance. Unlike optical telescopes, radar can penetrate clouds and operate during poor weather. But it cannot provide the sharpness and detail of a telescope—especially a large-aperture telescope enhanced with adaptive optics, like AEOS.5 Nonetheless, radar remained the Air Force’s preferred choice for ground-based space surveillance. Radar sites involved large financial investments in hardware and personnel as well as sensitive political considerations, and they vastly outnumbered electro-optical sites at Maui, SOR, White Sands Missile Range (near Socorro, New Mexico), and Diego Garcia in the Indian Ocean, which for the near future, at least, will serve as a complement to radar surveillance. Once AEOS proved itself, most became convinced of the value of electro-optical systems; but their expense makes it unlikely that they will soon replace radar.6 AEOS tracks satellites in low-earth orbit as well as sub-orbital vehicles, such as missiles launched from Vandenberg Air Force Base’s Western Test Range and Navy missiles launched from Barking Sands Missile Range on the island of Kauai. It is responsible for collecting data on space objects in a designated portion of the Pacific sky and transmitting that information to AFSPC and to USSTRATCOM—usually providing about 100 image sets per month, each set containing about six image frames of a satellite at the beginning, middle, and end of its flyover. Only the best images are sent to AFSPC; most remain stored on Maui. AFSPC gathers data from Maui and a number of other sources and records the time and position of each space object into a comprehensive catalog. This serves as 3.67-Meter Military Telescope Complex

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an invaluable reference guide because it lists the identity and location of all man-made space objects viewed by the Air Force and other services.7 At the heart of the Maui operation is the Maui Space Surveillance Complex (MSSC). It includes AEOS and nine other state-of-the-art telescopes on the 10,023-foot summit of Haleakala. Most of the telescopes atop the mountain, which make up the Maui Space Surveillance System or MSSS, belong to AFRL’s Detachment 15. Detachment 3, 18th Space Surveillance Squadron, controls the three GEODSS telescopes for AFSPC.8 The summit of Haleakala resembles a barren moonscape covered with reddish-brown lava rock where only a few native plants struggle to survive. However, this site is an ideal year-round viewing environment and is considered by most astronomers and military scientists to be one of the best in the world. Its dry and stable climate permits telescopes to operate 70 percent of the year. The telescopes do not operate in fog, rain, extreme overcast, or when winds exceed 35 miles per hour. Located high above the cloud cover (typically about 7,000 feet), which blocks out the light and air pollution from the towns below, the MSSC offers near-pristine conditions for observing astronomical bodies and man-made space objects in suborbital, near-earth, and deep space orbits. In sum, it is a near-perfect site for a ground-based electro-optical telescope system. Haleakala was also chosen as the site for the Advanced Solar Telescope because of its favorable daytime seeing conditions.9 Because the Maui site is about 4,000 feet higher than SOR, it has a less turbulent atmosphere to contend with. The ocean surrounding Maui helps keep temperatures stable, which also reduces turbulence. In addition, SOR’s proximity to Albuquerque—a city of nearly 500,000 people—means the night sky is brighter and faint objects are more difficult to detect. Thus, the AEOS telescope on Maui does not have to push its adaptive optics system as hard because there is usually less distortion to be corrected than at SOR.10 Two technical and administrative facilities located at the base of the mountain, in the Maui Research and Technology Park in Kihei, support the operation of the MSSS telescopes. The first is Premier Place, which provides office space, meeting rooms, and a technical library for AFRL’s Detachment 15—and for Boeing, the site’s prime contractor, and subcontractors Textron, Trex, and Oceanit, who are responsible for managing and operating the AMOS site. A large portion of the work at Premier Place addresses mission

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planning and scheduling and data analysis. Across the street is the Maui High Performance Computing Center (MHPCC), one of only a handful of DoD national high-performance computer centers. In 2001, MHPCC ranked as the twelfth largest supercomputer in the world.11 MHPCC is a leader in image post-processing techniques; it has developed algorithms and software that enhance the clarity of optical images provided by the telescopes on top of the mountain. Images are transmitted from the telescopes via a fiber optics link and then digitally enhanced, making it possible to recognize objects as small as an astronaut’s glove. That is done by running the images through a complicated series of algorithms developed by MHPCC computer scientists.12 Although AMOS is first and foremost a military enterprise, research is not limited to Air Force scientists. The Air Force aggressively pursues a plan to attract first-rate scientists from universities, commercial companies, private scientific organizations, and government agencies to use the unique combinations of telescopes, adaptive optics, and data processing facilities at AMOS. AFRL’s Office of Scientific Research and the National Science Foundation play leading roles in sponsoring and financing outside researchers to work at Maui.13 AEOS capitalized on SOR’s design experience and technical expertise when building the 3.67-meter telescope. That approach reduced technical risks throughout the development process. But why did the Air Force decide to build AEOS in the first place?14 AEOS had its origins in the mid-1980s, when the Air Force considered developing a ground-based laser antisatellite capability to counter potential threats from the Soviet Union. Mainly for political and economic reasons, the Air Force eventually abandoned the idea of developing a highpower ground-based laser antisatellite system. But Rome Air Development Center (RADC), which then managed Maui’s AMOS site, was pushing for approval to develop a 4-meter telescope that would improve the Air Force’s ability to track satellites and obtain high-resolution images of a range of space objects. Since the mid-1960s, Maui had relied on a 1.6-meter telescope and two 1.2-meter telescopes to conduct space surveillance.15 In April 1986, RADC convened a workshop to discuss telescope upgrades at AMOS. The consensus there was that the telescopes at the Maui site, by then more than 20 years old, should be replaced. All agreed that the technology 3.67-Meter Military Telescope Complex

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was available to build a bigger telescope. Getting the Air Force to finance such a project would be difficult, but the workshop was an important first step that led to initiating contacts with the Strategic Defense Initiative Organization and the Hawaii congressional delegation to gain their support.16 Based on findings from the workshop, RADC made a proposal in September 1986 for a world-class 4-meter telescope at Maui to be called the AMOS Large Optical Facility Testbed. The Air Force could not afford to lag behind progress in the field, RADC argued. As Jim Mayo, the Logicon RDA contractor who advised the Air Force on the building of new telescopes, put it, “That was just the nature of the beast—bigger was always better!” Bigger telescopes could collect more light and track and image dimmer objects, such as satellites. The proposed new telescope would be able to do better space surveillance, but it was not intended for antisatellite missions.17 In fall 1986 RADC presented a briefing to SDIO on the technical merits of a new and improved telescope at Maui. But SDIO rejected the proposal, mainly because of its projected cost ($100 million), and the plan was put on hold over the next three years.18 In summer 1989, RADC changed its strategy by coming up with a less costly plan for an $18 million telescope, AEOS, that would use light-weight optics (thinner mirrors) and other new technologies to reduce costs, and suggested that the costs be shared by three organizations—SDIO, AFSPC, and the Air Force’s antisatellite planning group—as a way to lessen the financial burden on a single agency. RADC argued that AEOS, fitted with adaptive optics, would greatly outperform Maui’s aging 1.6-meter workhorse and offer two to three times better resolution and six to eight times better light collecting capability. In January 1990, RADC briefed its headquarters, the Electronic Systems Division at Hanscom Air Force Base near Boston, which supported the proposal. In addition, a congressional delegation—led by Hawaii elected officials—traveled to Maui to review the AEOS proposal and to inspect the Haleakala site.19 The original funding plan did not work out. In February 1990, the antisatellite planning group backed out of supporting AEOS because their requirements changed. The group claimed it lacked sufficient funding, did not have a real requirement for an AEOS telescope, and had other, higherpriority projects to support. At the same time, AFSPC said it had no firm requirement for a 4-meter telescope. And SDIO still said the cost was too

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high. But Senator Daniel K. Inouye of Hawaii stepped forward to instill new life into the stagnant AEOS program.20 Inouye, chairman of the Senate Defense Appropriations Subcommittee, was impressed by the advantages of AEOS outlined in a March 1990 paper prepared by AMOS contractors Avco and Textron Defense Systems in response to questions posed by Peter Lennon on behalf of the Appropriations Subcommittee. The paper addressed the issues of AEOS costs (now revised to an estimated $26 million), requirements, missions, and users. The paper argued that AEOS could become the greatest satellite tracking telescope in the world, if it was built at Maui. Inouye viewed AEOS as a unique opportunity and a “win-win” situation that would strengthen U.S. defense and at the same time bring high-tech business to Hawaii, attract federal funding, create high-paying jobs, and diversify the economy to free Hawaii from its dependence on tourism and agriculture. Inouye became a strong and tireless advocate for AEOS.21 Funding for AEOS did not follow the usual process. In preparing its annual budget, the Air Force “racked and stacked” (prioritized) all its research and development programs and submitted the entire package to the Pentagon and the White House for submission to Congress. Congressionally mandated money or “add-on” dollars funded specific programs not included in the Air Force budget but added during congressional consideration of the executive branch’s proposals. Senator Inouye took full advantage of the federal budgetary add-on procedures to fund AEOS. Inouye could propose AEOS as a legitimate and much-needed space tracking and imaging program, but he did not have the authority to act in isolation on this matter. For the add-on dollars to be earmarked for AEOS, Congress had to vote to approve and disburse that money annually. Over the years, Congress consistently did support the AEOS with add-on funding.22 Money was not the only issue that affected AEOS. A shakeup in Air Force Systems Command in June 1990 resulted in the management of the Maui site shifting from the Rome Air Development Center to the Air Force Weapons Laboratory at Kirtland. This meant that after years of work leading the effort to promote the AEOS telescope enterprise, RADC suddenly found itself completely removed from AEOS. By November, Colonel John Otten, commander of the Weapons Lab, had formed a small advisory team composed of fewer than a dozen lab personnel, assisted by Jim Mayo of 3.67-Meter Military Telescope Complex

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Logicon RDA as the primary technical advisor, to prepare specifications for the AEOS telescope, spelling out all the precontractual work that had to be completed before money could be committed for contracts to design and build the telescope. Mayo had acquired a great deal of knowledge about telescopes during a long and distinguished career as a research and development officer in the Air Force. More recently he had served as the principal civilian contractor technical advisor on the design of SOR’s 3.5-meter telescope, which became the basic design blueprint for AEOS. Mayo played a prominent role in both the SOR and AEOS telescope programs. He was the only person who remained with AEOS from its conceptual phase in the late 1980s until it became fully operational in 2000. His presence added a strong sense of stability, continuity, and direction to the program.23 Innately curious, Mayo is a man whose interests extend far beyond science and technology. He has an abiding interest in history, photography, and music. Affable, gregarious, and pleasant describe only one side of Mayo’s personality. The other side reflects a steadfast concern for scientific detail, which accounts for his intensity and enthusiastic commitment to getting it right when it comes to the design, development, construction, and operation of telescopes. Recognized today as a leading expert in his field, Mayo, as a young Air Force captain in 1968, held the distinction of being the first graduate of the University of Arizona’s Optical Sciences Center in 1968. By the end of 1990 Mayo and others on the review team had witnessed several key changes affecting the future of AEOS. By that time Senator Inouye had convinced the Air Force and Congress of the value of AEOS. The senator also was politically connected and effective in selling the “dualuse” concept to support military missions at the same time as astronomical research, an efficient use of taxpayer dollars. Universities, which had neither the funding to build AEOS-type sites nor the experience to manage them, would benefit immensely.24 The Department of Defense Appropriations Act of 1991 allocated $14.95 million over two years to start the acquisition of a 4-meter telescope, moving AEOS from the debate phase to the action phase. Another Air Force Systems Command reorganization to streamline research and development activities led to the establishment of Phillips Laboratory at Kirtland on 13 December 1990 as one of four new super labs in the Air Force. Phillips, commanded by Colonel Peter Marchiando, picked up responsibility for AEOS from the now

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Photo 52.

Jim Mayo’s technical expertise and decades of experience with telescopes contributed a great deal to the success of the SOR and AEOS 3.5-meter telescopes.

inactivated Air Force Weapons Laboratory. Phillips’s chief scientist, Joseph Janni, recalled that was a critically important turning point because Phillips Lab became the “implementer” to assure the AEOS telescope and its associated adaptive optics would be ready as quickly as possible.25 Although responsibility for AEOS shifted from the Weapons Laboratory to Phillips Laboratory, the AEOS advisory team headed by Captain Rich Miller remained in place. For several months the team had been addressing design issues including tracking, imaging, jitter, field of view, weight, electronics, and size of mirrors. By the end of January 1991, the team had decided on preliminary specifications. AEOS would support the Air Force’s space surveillance mission but would not operate as a laser antisatellite weapon.26 3.67-Meter Military Telescope Complex

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Until early 1991, the AEOS plan called for a 4-meter telescope, an expensive undertaking. But the AEOS review committee learned that a manufactured but unused large mirror blank might be available. A 25,000pound Zerodur mirror blank had been built for the Army’s Ground-Based Free Electron Laser Technology Integration Experiment, better known as GBFELTIE. The Army was intent on taking the lead among the military services in developing an antiballistic missile defense system by building and developing the costly GBFELTIE system at White Sands Missile Range in New Mexico. But the program eventually shut down because of insufficient funding, technical problems, and political sensitivities associated with building a high-energy laser ground-based antiballistic missile system. The Zerodur mirror remained in storage in Germany, where it was manufactured, collecting dust instead of light from space.27 The AEOS advisory team reasoned that if AEOS could acquire the mirror blank it could save substantial money and time—enough to make it worth accepting the 3.67-meter Zerodur instead of acquiring a 4-meter mirror. Once the Phillips Lab commander approved that approach, Bill Thompson began exploring the possibilities of transferring the Zerodur mirror blank from the Army to the Air Force.28 In March 1991 another bright young officer, Lieutenant Rich Elder, replaced Miller as the head of the AEOS review team, which continued working through 1991 on design specifications. One requirement was for AEOS to include a centralized coudé room with an adaptive optics system located below the telescope floor. Compensated light from the coudé room could then be distributed to any one of seven optics experimental suites radiating away from it like spokes on a wheel. One of the advantages of this setup was that a scientist could conduct experiments on an optical beam in one room while another was simultaneously setting up equipment in the next. Oddly, there was no formal provision in the initial AEOS design for building the adaptive optics system to be installed in the coudé room.29 Although there was no adaptive optics development program at that time, it was “always in the back of people’s minds,” according to Mayo and others working on the program. The plan was to build the telescope first, and then, when funding became available, the adaptive optics. One advantage of this approach was that the funding could be spread out several years. So to some financial conservatives faced with coming up with the dollars,

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it made better financial sense to build the telescope first and then add the adaptive optics later.30 Meanwhile, Elder and Mayo visited Schott Glass Works representatives in Mainz, Germany, in May 1991 to inspect the 25,000-pound Zerodur mirror blank. They agreed that it could be modified to fit AEOS specifications. But it would have to be cut in such a fashion that it would create a thinner mirror to meet the AEOS’s 10,000-pound weight specification. After Thompson finalized the transfer of the Zerodur blank from the Army to the Air Force, it was wire-sawed into two halves at Schott. One half was machine-generated to form a thin, curved 3.67-meter meniscus primary mirror—approximately 6 inches thick over its entire diameter—for the AEOS telescope. The other half of the blank was stored in Danbury, Connecticut, and later moved to Kirtland, where it remains today.31 In August 1991, Phillips Laboratory hosted a pre-proposal conference at Kirtland to inform contract bidders about the AEOS program and status. Fifteen perspective vendors attended to listen to the Air Force’s plan and had an opportunity to ask questions and to acquire contract information that would be useful to them in preparing bids. By this time the AEOS team had defined most of the technical specifications, but one issue remained.32 There were serious discussions about building the AEOS telescope foundation (also referred to as seismic mass or base) strong enough to support a heavier 8-meter telescope to be prepared for any future upgrade. Inouye supported the idea, because he believed that as technology progressed, bigger telescopes would be needed and that building a more expensive and heavier-duty telescope base now would save money in the long run. No doubt, part of Inouye’s motivation was to get as much infrastructure in place early in the game as possible to assure that Maui remained a leading contender for the next-generation telescope and that federal dollars would continue to fuel the Hawaii economy.33 Bolstering the Hawaii economy was a legitimate role for the federal government. Building the larger foundation made technical sense. But one major drawback was that the dome to house the 3.67-meter telescope would have to be redesigned to be much bigger, with a much bigger price tag, to house an 8-meter telescope. There was also limited space atop Haleakala, which worked against building a second telescope bigger than AEOS some time in the future. Sensitive religious, cultural, and environmental issues 3.67-Meter Military Telescope Complex

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Figure 20. Schematic of the AEOS 3.67-meter telescope and dome,

courtesy of Jim Mayo and Pat Cavanee.

also entered the debate. The mountain was considered sacred ground by many in the indigenous population, who looked upon more construction as desecration. Environmentalists objected to building on volcanic rifts and vents and worried about the threat to endangered plants and archeological sites. Logic, however, dictated that building a larger telescope base from the start was the right way to proceed.34 But lack of funding ruled out construction of the larger structure. Most Americans perceived that the Soviet threat had receded since 1989 and believed the defense budget should be shrinking rather than growing. And some officials argued it would be more cost-effective to wait and build a new 8-meter telescope foundation when the time came, even if that meant tearing down the 3.67-meter structure and starting over. Another possibility was that an agreement might be hammered out among Air Force officials, religious leaders, and environmentalists to find an alternate site on the mountain when the time came to build a bigger telescope. In that case the 3.67-meter telescope would not be demolished but would coexist with the new telescope.35

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In the end, the Air Force compromised and decided to build only the foundation and the pier (also referred to as the pedestal or cone) as the only two structural components to support an 8-meter telescope. The rest of the facility (azimuth base and mounting ring, azimuth yoke base, inner gimbal, dome roof, floor, and walls) were built for a 3.67-meter telescope. The immense pancake-shaped foundation, resting on Haleakala’s volcanic rock, was constructed in a continuous pour and measured a hefty 7 feet thick and nearly 147 feet in diameter. Rising 18 feet out of the foundation was a massive steel pier support structure that turned out to be the most expensive part of the construction project.36 Once approval was granted to build a foundation and pier to support an 8-meter telescope base, the Air Force awarded a $19.3 million dollar contract on 13 December 1991 to Contraves USA (now the Brashear Division of L3 Corporation) to build the AEOS 3.67-meter telescope. Contraves had designed and built the 1.5- and 3.5-meter telescopes for SOR, and the Air Force was confident it would turn out a quality telescope this time. There was still no plan for an adaptive optics system. Contraves’s job was to build only the telescope, complete with the primary and secondary mirrors.37 Also, by the end of 1991, plans were under way to ship the cut mirror blank from Germany to the United States. Elder and Mayo met with officials from Zeiss in Oberkochen, Germany, to arrange for a customized steel shipping container to protect the blank during transport. Five months later, Elder and Mayo, accompanied by Colonel Otten, Chief Master Sergeant Jim Augustine, and Steve Miller of Contraves, returned to Germany to inspect and accept the mirror blank from Schott. The mirror blank was loaded on a C-5B aircraft and flown from Rhein-Main Air Force Base near Frankfurt to Pittsburgh, Pennsylvania. There Contraves took possession of it and transported it to its nearby Keystone Commons facilities at Turtle Creek, where it would be machined to the design specifications of the AEOS telescope.38 The Air Force approved Contraves’s telescope design during a preliminary design review in May 1992 and again at the critical design review in summer 1993. Work began on manufacturing hardware components for the telescope. The Air Force assigned two key people to direct and monitor progress. Dr. John R. Kenemuth, an optics expert from Phillips Lab, became the technical director of AEOS in December 1993. His job was to assure that AEOS met all technical specifications. Lieutenant Colonel Jim McNally, also 3.67-Meter Military Telescope Complex

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Photo 53. Schott’s 3.67-meter mirror blank packed for shipment in a steel shipping crate in Mainz, Germany. Photo courtesy of Jim Mayo.

from Phillips Lab and armed with a PhD in optics, became the program manager for AEOS in early 1994. He was responsible for managing all the political and administrative program duties associated with AEOS, as well as managing construction on top of the mountain. The Air Force also had to finalize a leasing agreement with the University of Hawaii, which owned the land on top of the mountain, before construction could start.39 It took a bit of arm twisting by Colonel Lanny Larson, who led Phillips Laboratory’s Laser and Imaging Directorate, to persuade Kenemuth to take the job as Maui tech director. Kenemuth prided himself on being first and foremost a research scientist, and managing AEOS did not appeal to him. He had spent a good portion of his career in the laboratory trenches, studying laser propagation and thermal blooming in the atmosphere. That work involved all sorts of deformable mirrors. Much of his research focused on identifying stress points on individual actuators in deformable mirrors, as

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Photo 54. The crew that transported the AEOS mirror blank in a C-5B

aircraft from Germany to Pittsburgh. Left to right: Captain Mark Clifford, Jim Augustine, Jim Mayo, Rick Elder, and Steve Miller. Photo courtesy of Jim Mayo.

well as looking for solutions to reduce the size, weight, and electrical drive requirements of the actuator and ways to drive the complement of actuators to achieve the best results.40 Kenemuth also looked at ways to improve mirror coatings to minimize heat buildup; that work contributed to the transition from metal to silicon coatings. Better low-absorption coatings could eliminate the need for water-cooled mirrors, an important consideration for building highpower lasers. Kenemuth was a pioneer in the field of deformable mirrors, working closely with contractors such as Itek, Pratt & Whitney, Hughes, and others on how to fabricate a better mirror. In sum, Kenemuth’s experimental work, especially in the area of deformable mirrors and how they integrated with wavefront sensors and control systems, played a key role in 3.67-Meter Military Telescope Complex

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maturing adaptive optics technologies. Giving all this up in order to take on administrative duties was unappealing. But eventually the importance of the mission outweighed his preference for doing bench science.41 As it turned out, Kenemuth was just as effective in his role as director as he had been as a research scientist. One of his most important contributions was producing a state-of-the-art adaptive optics system for the AEOS telescope. Three years after the first funding of AEOS, Kenemuth’s first priority in the early months of 1994 was to define the technical specifications for an adaptive optics system, the most complex yet to be developed. On 22 August 1994, Phillips Laboratory awarded a $15-million, 3-year contract to Hughes Danbury Optical Systems to design and build the adaptive optics system. Kenemuth worked closely with Hughes optics engineering personnel to ensure that all the critical technical specifications were precisely defined and understood. The system was to consist of a wavefront sensor, a high-speed processor, and a deformable mirror with 941 actuators. Hughes subcontracted Xinetics to build the mirror, which had the most actuators of any built up to that time.42 Hughes was required to provide two identical adaptive optics systems— one for the 3.5-meter telescope that had been installed at SOR in 1993, and the other for AEOS. The Air Force expected this would save at least $2 million in costs for design, fabrication, spare parts, and maintenance. The goal was to make the AEOS system from an SOR template. Plans called for the contractor to deliver the AEOS adaptive optics system by summer 1997.43 While Kenemuth oversaw the adaptive optics effort, McNally focused on working with state officials and finalizing the AEOS facility contract. On 26 August 1994, the Hawaii Department of Land and Natural Resources issued a site permit to the Air Force that authorized construction at the top of Haleakala. Three days later, the Army Corps of Engineers, responsible for all construction on the mountain, issued a contract for $19 million to Kiewit Pacific Inc. of Honolulu to construct the 41,000-square-foot AEOS facility. Before that could happen, design of the facility by the Hawaii-based Gima-Yoshimor Architects Inc. had to be completed; that took 7 months. On 15 April 1995, Senator Inouye presided over the AEOS groundbreaking ceremony that officially signified the start of the construction.44 Meanwhile, Contraves had completed factory testing of the AEOS telescope at its plant in Turtle Creek by the end of 1996. It had taken Contraves

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nearly 5 years to complete the telescope. For the test, the 250,000-pound telescope was assembled on a special pier in the plant’s high-bay area. There it underwent rigorous tests of its fit, alignment, slew, start/stop, and control functions to simulate how it would operate at Haleakala. (The test did not include adaptive optics system or full wavefront testing.) The Air Force concurred with Contraves’s test results and confirmed that the telescope met its design and operating requirements. Next the contractor disassembled the telescope and shipped all the components except the primary mirror to Vancouver, Washington, to await shipment by barge to Maui. Thomas Trucking of Pittsburgh transported the telescope, which arrived in Vancouver in January 1997.45 While the rest of the components traveled to the Pacific coast, Tom Thomas, president of Thomas Trucking, drove the primary mirror, safely ensconced in a steel protective crate, to Tucson, Arizona, where it remained for 11 days at Davis-Monthan Air Force Base. The delay in Tucson was attributed to the National Optical Astronomical Observatory (NOAO) at Kitt Peak not being ready to accept the mirror because of a schedule mixup. The mirror finally left Davis-Monthan on the morning of 31 January and arrived at Kitt Peak a few hours later. There it received the reflective coating it needed to become a working mirror. Mayo, who had monitored and certified the coating operation for the SOR 3.5-meter telescope primary mirror years earlier, performed the same service for AEOS. The coating process began on 3 February and ended three days later. A 100-nanometer layer of aluminum weighing only 3 grams was deposited over the entire surface of the mirror. On 7 February the newly coated mirror was crated and trucked to Vancouver, where it joined the other telescope components already awaiting shipment to Maui.46 The telescope traveled across the Pacific by barge and arrived at the port of Kahului on Maui in late March 1997. Then it was assembled, moved to the top of the mountain, and installed in its large protective dome, which had been built by Comsat RSI of Fairfax, Virginia, and assembled at the company’s facility 60 miles south of Dallas.47 Originally, assembly was to take place inside the protective dome on top of Haleakala. However, the area inside the dome was too small to do that safely and efficiently. The AEOS team rented a C&H Sugar Company warehouse in Puunene, not far from the Kahului airport. The warehouse 3.67-Meter Military Telescope Complex

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had plenty of floor space and a high ceiling so portable cranes could lift various parts of the telescope into place. Not only was the rent cheap, but the facility was only 5 minutes from the main highway that led up the mountain. The downside was that it was not an optically clean environment; the air was filled with dust and sugar particles. It was also extremely hot, with temperatures in the 90s and humidity at 70 to 90 percent on most days. But the AEOS team made the best of the situation.48 The telescope was in the sugar warehouse only for the first 2 weeks of April. Once the primary mirror and operational mirror cell had been integrated, they were crated and loaded on a truck to be moved to their permanent home. The truck departed the warehouse late in the evening of 15 April, maneuvered its way up the steep and winding mountain road without incident, and arrived at the AEOS site 2½ hours later at 1:00 the next morning.49 Weeks prior to the telescope’s arrival, work had been under way to prepare the site. To accomplish that work required a giant Campbell Demag 300-ton crane that had been shipped by sea from Vancouver, Washington, to Maui by Sause Marine Services. Getting the huge crane up the mountain on 4 April using a heavy-duty tow truck was no quick and easy chore. But once in place, the crane began lifting and lowering sections of the telescope down through the 40-foot opening in the center of the roof of the AEOS dome. The heaviest lift occurred on 7 April, when the crane picked up the 92,000-pound telescope base and guided it flawlessly through the dome opening onto the telescope pier on the floor of the dome. Reinforced steel bolts secured the base to the pier, forming an immovable vertical concrete structure to support the telescope’s 60,000-pound yoke, the trunnion box (which swings in the yoke to provide elevation change for the telescope), and most importantly, the primary mirror and its cell assembly.50 On the morning of 16 April, the primary mirror and its support system—the “eye” that made up the most critical and most expensive part of the telescope—arrived atop Haleakala and was carefully lifted into place on the telescope pier. Six days later, the telescope’s truss and inner gimbal were the final components lowered through the dome roof and bolted onto the telescope yoke already positioned inside the dome. By 5:30 p.m. on 22 April 1997, the installation was complete. Jim Mayo grabbed a camera and snapped the first picture of Maui’s newest and most advanced telescope.51

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Photo 55. The huge Campbell Demag TC 1200 crane—with pulling assistance from a tow truck—on the road to the AEOS facility atop Haleakala on 4 April 1997. Photo courtesy of Jim Mayo.

The assembly and installation of the 3.67-meter telescope was the culmination of over 6 1/2 years of hard work by Air Force laboratory personnel and contractors. And from a political perspective there was little doubt that Senator Inouye played a central role in making AEOS happen. His constant efforts to push the project forward, along with his financial acumen and skill in getting funding, solidified the AEOS project. So by the summer of 1997, those who had worked on AEOS waited with great anticipation for the dedication ceremony of the Air Force’s largest telescope.52 The AEOS dedication took place on Saturday, 5 July 1997, on Haleakala. It was a fittingly gorgeous day. The guest list was impressive, headed by General Ronald R. Fogleman, chief of staff of the Air Force. He was accompanied by Major General Richard R. Paul, commander of the Air Force Research Laboratory, who was responsible for all Air Force research and development programs. Representing Hawaii were Senator Inouye and Representatives Neil Abercrombie and Patsy T. Mink. Hawaii Governor 3.67-Meter Military Telescope Complex

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It was a major logistical operation getting all the telescope components into the dome in the right sequence. Photo 56. (left) A crane lifts the 46-ton telescope base 60 feet to the floor inside the dome. Photo 57. (right) The inner gimbal assembly/trunnion box is ready to be lowered into the dome. Photos courtesy of Jim Mayo.

Benjamin J. Cayetano also attended this important event, destined to have a positive economic impact on his state.53 Speakers had nothing but high praise for AEOS and its potential. “Today marks a milestone to go forward to the 21st century,” General Fogleman told the crowd of over 200 onlookers. “This facility is important for the nation’s security and will aid in space object identification, which is an important step in maintaining space security now and in the future.”

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Photo 58. Dedication of the Air Force’s 3.67-meter Advanced Electro-Optical System (AEOS) on 5 July 1997 at Haleakala, Hawaii. Left to right: U.S. Senator Daniel K. Inouye from Hawaii; Hawaii Governor Benjamin J. Cayetano; General Ronald R. Fogleman, Air Force chief of staff; Major General Richard R. Paul, commander of the Air Force Research Laboratory; and U.S. Representatives Neil Abercrombie and Patsy Mink of Hawaii.

Senator Inouye weighed in proudly with a strong endorsement of the $165 million AEOS telescope system, which he described as a national treasure. “This is the key to the next century. This is a partnership between the Air Force and the Hawaiian people, and I commend the Air Force on their sensitivities of the sacred mountain and the cultural needs of Maui.”54 When the highly reflective 40-foot-high and 90-foot-diameter aluminum dome retracted in only 6 minutes to unveil the telescope—the primary mirror still covered with a dull blue protective coating—the crowd came to life with cheers and applause. Although the telescope was not fully operational yet—it was like a new car that still had to be detailed before it was ready for delivery to its owner—the azimuth and elevation mechanisms worked to perfection. So did the drive motors that rapidly slewed 3.67-Meter Military Telescope Complex

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Photo 59. Contraves designed and built the 3.67-meter

telescope installed at Maui in April 1997.

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the telescope at a rate of 18 degrees per second in azimuth and 5 degrees per second in elevation, to the delight of the guests. While the crowd roared approval as the giant telescope rotated, Lee Greenwood’s “Proud to be an American” reverberated against the deep blue Maui sky. It was a proud and satisfying moment for all to savor, especially those at all levels who had endured the highs and lows of the AEOS project along every step of its development.55 The work to transform AEOS into a fully operational optical resource would take another 3 years. It included “jitter measurement, telescope subsystem integration, telescope and primary mirror air purge review, secondary mirror installation and checkout, coating inspections, sensor interfaces, drawings review, primary mirror actuator debugging, and wavefront sensor calibration.” And, probably most importantly, the adaptive optics system still had to be installed, tested, and integrated with the telescope. Without adaptive optics, the 3.67-meter telescope would be just one big light collector that could not produce the high-resolution images that the DoD needed.56 The immediate goal was to achieve first light and to show that the telescope would work. Since the coudé room and its adaptive optics system were not yet operational, first light would occur using two acquisition sensors— the 24-inch Large Aperture Acquisition Telescope (LAAT) and the 8-inch Large Field Acquisition Telescope (LFAT), bore sighted with the AEOS telescope—mounted on the telescope gimbal. As Mayo explained, “First light for the full-aperture telescope would have to be achieved using a commercially available off-the-shelf detector” rather than using the telescope’s science camera with the yet-to-be-completed adaptive optics system.57 Seeing conditions were excellent over Haleakala on the night of 26 September 1997, when the AEOS team decided to observe several wellknown astronomical objects including the Ring Nebula M57 in Lyra, 1,500 light years from Earth. Mayo, one in a small group of scientists and technicians standing around the telescope imaging console, described what followed. “The telescope was directed toward the ring nebula. The view in the LAAT was unusually impressive, with the stars down to about 15th magnitude being plainly visible in the field. Then the ring came into view on the main telescope screen and its appearance was spectacular. There were a few seconds of silence then a nearly simultaneously exaltation from the 3.67-Meter Military Telescope Complex

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Photo 60. The AEOS dome (at far right), with its 3.67-meter telescope

protruding through the roof, dominates the Air Force telescope landscape atop Haleakala. In the center of the photo is the dome housing the 1.6-meter telescope, equipped in the early 1980s with the Air Force’s first adaptive optics system, called the Compensated Imaging System.

team. FIRST LIGHT!!! The journey down the long road was over at last.” Although that first light image did not produce any new information about Ring Nebula M57, it did demonstrate the high-quality imaging capability of the AEOS telescope. Expectations were that once the adaptive optics system was mated to the telescope, images would be obtained that would far surpass the first-light images.58 After the installation of the AEOS telescope on Haleakala, the dedication ceremony, and first light, the next big step was to work with Hughes Danbury to get the adaptive optics system integrated with the telescope. Kenemuth, one of the key players in this process, described his responsibilities as “to expeditiously develop the requirements, specifications, and procurement package for the most complex adaptive optics system yet to be

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Photo 61. This first-light image of the doughnut-shaped M57-Ring Nebula

was produced by AEOS telescope without using adaptive optics.

developed at the time.” To better deal with this heavy workload, Kenemuth moved from Albuquerque to Maui in April 1997 and remained there until December 1999.59 Rusty Hughes, who worked for Trex Enterprises (a subcontractor of Boeing, the Maui site contractor) was the responsible engineer for the AEOS adaptive optics system. He had climbed through the ranks, gaining experience and know-how as an electronic technician maintaining the adaptive optics compensated imaging system on the 1.6-meter telescope at Maui in the early 1980s. When the 1.6-meter adaptive optics system shut down in late 1996, he moved over to the AEOS adaptive optics project. Hughes, softspoken and smart, is a capable hands-on individual who learned the intricacies of the AEOS adaptive optics from the ground up when he spent 11 months in Danbury, Connecticut, working with the Hughes engineers who built the system to get it ready for integration with the AEOS telescope. He maintained and fine-tuned the finicky AEOS adaptive optics system like a 3.67-Meter Military Telescope Complex

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top-flight car mechanic with a Ferrari. When the adaptive optics failed to operate as advertised at Maui, most first turned to Rusty Hughes and his crew to fix the problem.60 The “dual buy” plan, under which the contractor would design and build two identical adaptive optics systems, one for SOR and one for AEOS, unraveled as both projects moved forward. Rene Abreu served as the chief engineer for the team of 70 people at Hughes Danbury responsible for the SOR and AEOS adaptive optics systems. The complex enterprise ended up taking 5 years to complete instead of the 3 years stipulated in the August 1994 contract. As mentioned in chapter 10, the SOR team became impatient with the contractor delivery delays and in the end took it upon themselves to get Hughes to deliver individual components rather than an integrated system. They then took the parts and customized them into an adaptive optics system that best met their experimental research needs. That was not a turnkey operation, but was a more flexible adaptive optics system that could be modified from time to time depending on particular research requirements at SOR.61 What Hughes delivered to SOR was only a partial order. The contractor did not provide a reconstructor; SOR built its own high-speed processor to digest distortion measurements provided by the wavefront sensor. Hughes also did not deliver an entire wavefront sensor. It provided the CCD (charge-coupled device) camera—an important component, built by Lincoln Laboratory—but SOR built the other parts, such as the optical bench and lens array, itself. Hughes did not deliver a science camera to capture the compensated image. It did provide the deformable mirror, but SOR tested it and integrated it into the adaptive optics system. The contractor also did not perform site acceptance testing at SOR.62 While SOR was busy tailoring, assembling, integrating, and testing its adaptive optics system on site, Hughes shifted its attention to completing its turnkey adaptive optics system for AEOS. One of the problems the contractor faced was that the software incorporated into the AEOS adaptive optics system was very complicated—consisting of “a couple of hundred thousand lines of computer code, which is a huge number,” as Abreu explained it. Most people who worked at Maui did not completely understand the inner workings of the software. As the brain behind the system, the sophisticated software package allowed an operator to control the adaptive optics much in the same way he would operate a video game. That meant an operator did

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not have to know all the details of the software. After AEOS was installed and a problem came up with the software, Maui scientists had to go back to the experts at Hughes who had developed it—a time-consuming process that caused delays.63 Another technical issue was the 28.8-centimeter diameter deformable mirror provided by Xinetics, which had some minor flaws. On the back of the mirror were 941 actuators spaced 9 millimeters apart—the same number as on SOR’s deformable mirror. Five of the 941 actuators failed to respond to electrical signals to move and change the front surface of the mirror. Some claimed that this deficiency slightly degraded the resolution of the image. Others contended that five bad actuators—less than 1 percent of the total—did not make much difference.64 Rene Abreu and others at Hughes were concerned about the quality of the deformable mirror delivered to SOR. To find out how it would perform in the field, Abreu and his coworker, Ralph Pringle, traveled to SOR in 1998 to decide the fate of the five dead actuators. They conducted a series of closed-loop experiments at SOR using the deformable mirror with five of 941 actuators electrically disabled. Experimental results showed that the compensated images displayed Strehl numbers of 0.75 and 0.80, which was very good. That confirmed to Abreu and Pringle that five dead actuators made no appreciable difference in the mirror’s performance. Eventually, to be on the safe side, AEOS purchased a spare deformable mirror from Xinetics with all 941 actuators operating properly so it could replace the original deformable mirror sometime in the future.65 Hughes encountered one other important technical challenge in developing the AEOS adaptive optics system. It was difficult for the contractor to get the wavefront sensor to operate at a rate of 5,000 frames per second (Hz)—a very high rate—and generate an array of numbers that represented the distorted phase of the wavefront. Sensing the wavefront phase at 5,000 Hz would provide accurate data that could be relayed to the reconstructor, which then computed and sent the correct electrical signals to the deformable mirror. However, operating at 5,000 Hz was pushing the state of the art for high-speed processing. Hughes had to settle on a more practical 2,500 Hz system. As it turned out, that rate was sufficient to generate high-resolution images.66 After completing its factory acceptance testing (February 1999) in 3.67-Meter Military Telescope Complex

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Connecticut, the contractor (by that time Raytheon had taken over Hughes) delivered the AEOS adaptive optics system to Maui in March 1999. Rene Abreu described the system as follows: The heart of the . . . adaptive optics system comprises two optical sensors (the Wavefront Sensor [WFS] and Tracker) and two adaptive optical components (the Deformable Mirror [DM] and the Tilt Control Mirror), Local Processing Electronics to process and condition the error signals from the sensors and Real-Time Reconstructor to convert the WFS signals into DM control commands. Wrapped around these are optics to condition the optical radiation from the target and relay it from the telescope to the AO components and imagers or science instruments; mechanical structure to keep the optics and subsystems aligned; electrical infrastructure and optical fiber and other networks; command and control computers and software; and interfaces with the rest of the observatory. All of these were designed to work in unison with the observatory, under the control of a single operator.67 The final cost to the government for the adaptive optics system amounted to $54 million, more than three and a half times the price in the original contract awarded to Hughes. Cost overruns and technical difficulties resulted in Hughes expanding its original production timetable from 3 to 5 years. (In comparison, the SOR team successfully operated its 941-actuator adaptive optics system in September 1997.) Not only did it take more time to build the AEOS system, but the government ended up paying considerably more money than originally anticipated.68 In some ways this was to be expected. The complex system and cuttingedge technology required a learn-as-you-go approach. Although the theoretical basis for adaptive optics was sound, the technologies needed to make the system work changed frequently as the process of building the system moved forward. As mentioned in connection with the Airborne Laser program (see chapter 9), the biggest engineering challenge lies in integrating the various components of a system. That was equally true for the adaptive optics venture. Other problems also arose when the design of the adaptive

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Photo 62. The AEOS adaptive optics system was built by Hughes Danbury

Optical Systems and delivered to Maui in spring 1999.

optics system lagged behind the design of the AEOS facility. As Kenemuth described it, “the coudé room had been designed and built without any consideration for the specifics of the adaptive optics system. The confined space in the coudé room imposed significant constraints and complications on the AEOS adaptive optics system design.”69 In some cases the individual components tested at Danbury and Maui were not the same. For example, during factory acceptance testing at Danbury, the contractor used a different visible imaging camera than the one shipped to Maui. The camera used in Danbury produced images with a Strehl of 0.7, which was considered very high, but the camera used in Hawaii did not perform quite as well. The main difference between the camera performance at the factory and the Maui site was the problem of the overall integration of the telescope and the adaptive optics system.70 Scientists at Maui were aware of all the complications involved in fabricating the AEOS adaptive optics system, and most were satisfied with 3.67-Meter Military Telescope Complex

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the contractor’s performance. In spite of all the setbacks and delays, on 29 July 1999 the contractor and AEOS team closed the loop on the adaptive optics system for the first time. The result was a dramatic shift from an initial blur to a sharp image of a space object representing a 30-fold improvement in resolution. The AEOS turnkey adaptive optics performed at a level comparable to the SOR adaptive optics. Lewis C. Roberts Jr. and Christopher R. Neyman, two young AEOS scientists involved in the workings of the system, reported, “The AEOS adaptive optics system is one of the highest order systems in the world; as such, it offers an unprecedented opportunity: Lessons learned here can be applied to the next generation of high-order adaptive optics systems on the giant telescopes (>10 meters) currently being planned.”71 Contractor personnel along with Lewis, Neyman, Hughes, and many others inspected, tested, and learned how to operate the system for 11 months after its delivery. The consensus was that the system met contract specifications and produced extremely high-quality images of satellites and other space objects. Once the contractor turned over the AEOS adaptive optics system to the Maui site, AEOS became fully operational in February 2000. In a letter to Raytheon dated 16 January 2001, the Air Force praised the adaptive optics contractor for its “success in the design, fabrication, installation, and test of the AEOS system and Visible Imager.” The letter went on to define success “as seen in the consistently outstanding imagery produced by the system.” Those images included binary stars, and the moons of Jupiter and Saturn. But many also concluded the system was “not perfect” and that the adaptive optics could perform even better once all the bugs were worked out.72 There was room for improvement in several areas. For example, personnel from the contractor assembled and tested the system and taught Maui employees how to operate it. But they left the island in February 2000. Some thought that was a mistake, given the complexity of this one-of-a-kind program, and felt that the contractor—whose name by then had changed to Raytheon Optical Systems Inc. and then to Goodrich) should have been retained as a consultant in case problems arose. Instead, Trex (as a subcontractor to Boeing, the AMOS site contractor) was given full responsibility to operate and maintain AEOS; no supporting or consulting arrangement with Hughes was made. Kenemuth and others reasoned that the contractor

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who designed and built the system, and who was most familiar with its operation, should have been readily available to advise on its maintenance and the correction of problems. According to Kenemuth, in the long run the Air Force “would have saved money and achieved better performance by having ready access to the expertise of the Hughes personnel.”73 Although the contractor did not receive a follow-on contract to support and consult on the operation and maintenance of the AEOS adaptive optics system, the company believed it had delivered a quality product even though it was late and over cost. Rene Abreu and his team produced the most advanced adaptive optics system in existence at the time, and they were justifiably proud of the job they had done. They pointed to the testing at the Maui site, and pointed out that the government had few complaints about the system’s performance, described in detail in the contractor’s site acceptance test report. The government officially accepted the system in February 2000. Everyone recognized that the next generation of adaptive optics for AEOS would be even better, but for the time being the Hughes system had pushed the state of the art to the point where AEOS was consistently producing high-quality images of a variety of space objects to satisfy the operational needs of AFSPC and USSTRATCOM.74 For the most part, the quality of images collected at AEOS and SOR were comparable. Producing a high-resolution image in the visible spectrum depended on a number of variables. One advantage AEOS had was that it was at a higher altitude and usually encountered less atmospheric turbulence than SOR. That meant the AEOS adaptive optics did not have to work as hard, because there were fewer distortions to compensate for in the beam. However, SOR’s adaptive optics system was more flexible and could be more finely tuned. One of the defining features of the SOR adaptive optics system was that government and military scientists built and ran it. If something broke, the people at SOR could make the repairs. It was not unusual for SOR to acquire Strehl numbers in the 0.7 to 0.8 range when observing stars and other astronomical objects. AEOS also produced high Strehl numbers, depending on seeing conditions, and was considered the best operational telescope for tracking satellites and other man-made objects. Rusty Hughes pointed out that AEOS consistently acquired Strehl readings of 0.38 to 0.40 and produced images that were a big improvement over those from the compensated imaging system mounted on the older 1.6-meter telescope at Maui.75 3.67-Meter Military Telescope Complex

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Although AEOS’s adaptive optics worked well, a technique known as post-processing could take high-quality AEOS images and make them even better. Post-processing is a computer cleanup technique using sophisticated algorithms to remove blurring. As a general rule of thumb, AEOS adaptive optics can improve the resolution of a blurred image by a factor of up to 30. In an image of a satellite, that would mean the individual pieces making up the solar panels could be clearly seen. By using post-processing, the image can be improved again by a factor of 2, removing residual blur to provide even sharper detail. Post-processing also can be used to remove blurring from images collected by telescopes that are not equipped with adaptive optics, but such images typically have much lower resolution.76 Post-processing goes back to the early 1990s. Prior to that time, images were captured on videotape, which did not lend itself to the process. But then CCD cameras came into use, producing digital images that could be enhanced by a computer. A team of military and civilian scientists led the initial post-processing research and development effort at Phillips Laboratory. At the start, it consisted of two young Air Force captains, Chuck Matson and Mike Roggemann, and two civilian government scientists, Marsha Fox and Dave Tyler. Using the 1.6-meter telescope at Maui, the team captured images, with and without adaptive optics, during the terminator phase—just after dusk and before dawn, when the viewed object is outside Earth’s shadow and the viewing telescope is in the dark—and improved their resolution with post-processing. The speed was slow by today’s standards: it usually took several hours to clean up the images.77 By 1994, John Gonglewski and other Phillips Lab scientists, along with contractors from Rockwell Power Systems and Thermo Trex Corporation, had made a major technical breakthrough at Maui with the design, development, and deployment of ADONIS, the AMOS Daytime Optical NearInfrared Imaging System. ADONIS, which also worked in conjunction with the 1.6-meter telescope, could record and post-process images of lowearth-orbiting satellites, using a Knox-Thompson reconstruction algorithm, during daylight hours as well as during the terminator phase. Not only was observation time increased to 14 hours a day, but ADONIS could provide Air Force customers with high-resolution post-processed images in minutes instead of hours. Many target satellites for which AFSPC and USSPACECOM wanted images were active only during daytime hours.78

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Still further improvements in hardware and software led from ADONIS to a new system called GEMINI, which could image satellites in the visible, long-, and mid-infrared wavelengths. GEMINI had two components: a camera system mounted on the side of the 1.6-meter telescope, and a computer to control the camera and to process the data it collected. The system could collect light on two cameras simultaneously, thus permitting improved image-processing algorithms to take advantage of simultaneous measurements of images and wavefronts. Technical difficulties initially prevented effective use of both cameras, and the GEMINI system has been operated primarily in the single-camera mode. Captain Bruce Stribling of Phillips Lab was the primary driver behind the design and acquisition of the GEMINI system. Like its predecessor, GEMINI could collect and process images of space images during daylight hours as well as during the terminator phase. GEMINI’s visible sensor, developed by Lincoln Lab, could record images at a rate of up to 250 frames per second. It took less than a minute to process the images, a notable speed improvement over ADONIS.79 The next major step forward in imaging processing at Maui was possible because of the supercomputers at the Maui High Performance Computing Center (MHPCC) located 30 miles from the summit of Haleakala in the town of Kihei. Chuck Matson, who participated in that program, explained the importance of MHPCC: A fiber optic link was put into place between the MSSS and MHPCC in 1998 to enable fast data transfer between the imaging sensors at the MSSS and the high-speed computers at MHPCC. By using the MHPCC computers, the image processing time was cut down to less than a second. In addition, the next generation of imaging algorithms—called non-linear iterative algorithms—could be used to process the MSSS raw images to generate even higher quality image reconstructions than possible with standard algorithms. Nonlinear iterative algorithms tend to take several orders of magnitude more time to generate a processed image than do the standard image processing algorithms, making them less useful when images are needed immediately. Fortunately, recent supercomputer acquisitions have made it possible to generate a processed image with these nonlinear iterative algorithms in just a few seconds. 3.67-Meter Military Telescope Complex

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Photo 63. The image of the Hubble Space Telescope on the left was acquired by the AEOS 3.67-meter telescope using adaptive optics. At right is the post-processed version.

The Air Force made the MHPCC available to selected scientists from universities, private industry, and other government agencies to pursue research to advance post-processing of space images.80 Air Force civilian and military scientists on Maui became the foremost experts in the science needed to obtain higher-resolution images quickly, exploiting state-of-the-art computational hardware, and developing algorithms that resulted in faster post-processing times. Adequate funding also played a significant role. As Joe Janni, former chief scientist at Phillips Laboratory, put it, “The overwhelming majority of image postprocess progress at AMOS has been made through the Air Force Office of Scientific Research funding. The progress could not been achieved without it.” Today, images obtained from the 1.6-meter and 3.67-meter telescopes on Maui are delivered to Air Force customers post-processed. The revealing image above of the Hubble Space Telescope attests to the quality and value of post-processing.81

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Figure 21. The evolution of telescopes, shown at the same relative scale. Left to right: 75-cm NASA telescope, 1.5-meter (1985) and 3.5-meter (1990) telescopes at Starfire Optical Range, and 3.67-meter AEOS telescope (1995) on Maui.

The 3.67-meter telescope on Maui was the third major telescope developed by the Air Force since the mid-1980s. Two of these—the 1.5-meter and 3.5-meter telescopes at SOR—are used as precision light-collecting instruments to conduct a variety of research and technology activities to advance Air Force imaging and beam propagation missions. The Air Force’s largest telescope, the 3.67-meter AEOS on Maui, conducts operational missions on nearly a daily basis to support space object identification taskings from AFSPC and USSTRATCOM. The illustration below reveals the evolution of all three of the Air Force’s most recent telescopes. By the year 2000, the AEOS complex on Maui had become the Air Force’s premier operational site for tracking and imaging satellites and other man-made objects in space. Planning, designing, building, and installing the 3.67-meter telescope with all its auxiliary equipment—and making it all work together as a reliable operational system—was a huge undertaking that took years to complete. Key to the entire enterprise was the development of an adaptive optics system. Although the AEOS adaptive optics system encountered problems along the way, by 2000 it had become identified as one of 3.67-Meter Military Telescope Complex

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the most advanced compensated imaging systems in the world for tracking and producing high-resolution images of objects in space. Post-processing advances in the 1990s also had a tremendous impact in terms of improving the resolution of all images produced at Maui. As with most complex scientific ventures, the tendency is for the technical breakthroughs and the innovative design and performance of hardware to take center stage in terms of defining success. But the other essential components of success are the brainpower and determination of a talented group of individuals, who collectively defined the direction and value of science and technology. They first conceived the hardware and then made it reality. In the case of AEOS, the leaders at all levels were a team of competent Air Force military, civilian, and contract scientists. They emerged from the Air Force laboratory system to break new ground and pave the way for the deployment of the most advanced military electro-optical imaging system in the world today.

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t w e lv e

Sodium Guide Star Laser The Future

At the Jasons’ 1982 summer session in La Jolla, Will Happer from Princeton presented the revolutionary concept that the mesospheric sodium layer could be used to generate a high-altitude artificial guide star for use with an adaptive optics telescope. He proposed using a specially tuned yellow laser beam to excite the sodium atoms in the mesosphere to induce resonance fluorescence (glow)—the sodium atom emits a photon at the same wavelength as was absorbed—to create a high-altitude artificial star. The use of this artificial star would make it possible for an adaptive optics system to improve space-object images generated from the collection of light transmitted through the atmosphere by removing the effects of turbulence. The Rayleigh guide star serves the same purpose. But it uses reflected backscatter (not fluorescence), from a laser focused at a lower altitude (10–15 kilometers rather than 90 kilometers). And it is more vulnerable to the problem of focal anisoplanatism. Light from both types of artificial star falls to Earth in a conical path—unlike light from much more distant natural stars, which travels a cylindrical path (see figures 5 and 6). The difference

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between cone and cylinder, and the way that affects a guide star’s ability to mimic a natural star, is called focus anisoplanatism (see chapter 4 for a detailed discussion). Sodium guide stars are less affected by it than Rayleigh guide stars—their light, coming from farther away, falls in a more nearly parallel path. Focus anisoplanatism limits the ability of adaptive optics to sharpen images; the larger the telescope, the worse the problem. With everlarger telescopes appearing on the scene, with apertures as wide as 3 or even 10 meters, a solution was needed.1 Generating a bright enough guide star to produce photons in sufficient numbers from the sodium layer—90 kilometers up and about 10 kilometers thick, with a density of about 5,000 sodium atoms per cubic centimeter—to operate an adaptive optics telescope was easier said than done. To a large degree, it was impractical to make a sodium laser directly using sodium atoms as the laser media. The main problem was the difficulty in achieving efficient pumping of the sodium atom to obtain the required population inversion for lasing.2 Lincoln Laboratory scientists led the way in the 1980s experimenting with dye lasers operating at the sodium wavelength (see chapter 6). But dye was difficult to work with and could be unstable and outright dangerous to handle and store. In the mid-1980s, research moved toward development of solid-state sodium-wavelength lasers using a technique called sumfrequency mixing. Lincoln’s Aram Mooradian led this effort and demonstrated that by combining the two wavelengths at 1.064 and 1.319 microns (the two strongest lasing lines of neodymium-doped: yttrium aluminum garnet or Nd:YAG in a nonlinear crystal (lithium niobate), a third wavelength could be produced for sodium D2a-line resonance (0.589159 microns) excitation. Mooradian and his team built a small laboratory low-power laser to prove his theory, which laid the groundwork for the development of sodium-wavelength laser guide star systems in the 1990s and beyond.3 In 1986 Tom Jeys, who had been on the faculty of Rice University, took a position at Lincoln Laboratory. Jeys’s research took Mooradian’s concepts to the next level. Jeys built the first high-power solid-state laser system that demonstrated a practical source of sodium resonance radiation that could be used for guide star applications. More specifically, Jeys was the first to demonstrate he could get to the “center of the tuning curve”—as opposed to the edges—for generating the 1.064- and 1.319-micron laser wavelengths,

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which combined to produce a quality 0.589-micron sodium-wavelength beam capable of tuning exactly to the sodium D2-line resonance while having sufficient power for mesospheric sodium guide star excitation. At the time, sodium-wavelength laser work was classified. Bob Fugate marveled, “You could not even say the word sodium on the phone!”4 The Air Force funded Jeys to develop a sodium-wavelength laser system that could be used to create a sodium guide star. At that time the Air Force was more interested in using guide stars to perfect ground-based laser antisatellite missions than for improving space imaging. Jeys designed a pulsed laser system that was built by Continuum Inc. By pumping two Nd:YAG crystals with a flashlamp, two lasers were generated—one at 1.064 microns and the other at 1.319 microns. The two lasers were then combined in a lithium triborate crystal to produce a 0.589-micron sodium-wavelength laser with 20 watts of average power. In March 1991, Jeys delivered his system to the Air Force at SOR. There the sodium-wavelength laser system underwent a rigorous series of tests to determine if it could operate reliably when mounted to a telescope and exposed to atmospheric turbulence and everchanging weather conditions.5 Once at SOR, Jeys’s laser system was used in a number of experiments in conjunction with the 1.0-meter auxiliary beam director. But early in the testing it became clear that there were fundamental shortcomings with the system. First, the laser was not very efficient; it took a lot of external power to generate the two flash-lamp-pumped lasers. The flash lamps generated a great deal of undesirable heat on the Nd:YAG rods, which severely reduced beam power and quality. The system needed extensive maintenance. The weak beam excited fewer sodium atoms when it reached the mesosphere, resulting in a weaker guide star. Second, Jeys’s “mode-locked” pulsed laser system was complicated and difficult to operate in a reliable fashion. There were unresolved problems getting the laser to consistently deliver 15–20 watts of average power. Despite the problems, SOR was able to obtain and analyze return photon flux from the mesospheric sodium layer and, for the first time, measure important properties of a laser-generated sodium guide star as it related to the degree of distortion caused by atmospheric turbulence.6 The SOR experiments provided data to help prove that Mooradian’s concept and Jeys’s laser worked. Although the first solid-state laser system was validated, the hard part was building a sodium-wavelength laser system that Sodium Guide Star Laser

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would work in the real world, reliably and with sufficient power. It would take another 10 years before Craig Denman and his small team at Kirtland would take that step. As Denman pointed out, his 50-watt system, developed in 2004, was “the first to be packaged for mounting on the side of a telescope and to be fully automated for operation from a remote console.”7 By the late 1990s, Fugate realized that, with the newly acquired 3.5-meter telescope installed and operating at SOR, there was an urgent need to develop a dependable sodium-wavelength laser system. It was clear from analysis and experiment that a sodium guide star was superior to a Rayleigh guide star. With the introduction in the 1990s of larger and larger telescopes throughout the world, the high-altitude mesospheric sodium guide star was considered the preferred method for best adaptive optics performance. Resonance fluorescence from sodium atoms in the mesosphere created the highest and brightest artificial guide stars, which sampled the largest portion of the atmosphere within the field of view of the telescope. As a result, Fugate approached Earl Good, director of the Directed Energy Directorate of the Air Force Research Laboratory at Kirtland Air Force Base, and his chief scientist, Bill Baker, to gain their support for a sodium-wavelength laser guide star program at SOR.8 Fugate insisted that the man to run that program was Craig Denman, the most qualified person in the Air Force Research Laboratory in terms of knowledge and experience for building advanced laser systems. Denman had developed a laser system in 1996 that “demonstrated a world-record linewidth of less than 1.5 Hertz at 25 watts at 1.064 microns,” the same wavelength of one of the two lasers that later would combine to produce a sodium-wavelength laser. Good and Baker concurred and asked Fugate to arrange for Denman to make a presentation to them outlining how he planned to build a laser for sodium guide star excitation.9 At the time of his meeting with Good and Baker, Denman was working in the Directed Energy Directorate’s Laser Division. As a civil service scientist with the Air Force since 1984, he had honed his technical skills and earned a reputation as being good with his hands, especially in building intricate electro-optical devices. He was adept at transforming his concepts into hardware that would work. Self-assured but not overbearing, he exhibited a quiet and steady sense of confidence that allowed him to embrace the most difficult technical challenges that came his way. His strong resolve to

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Photo 64. Craig Denman led the sodium-wavelength laser guide star research program at the Air Force Research Laboratory in Albuquerque, New Mexico.

find solutions to complex problems was the fuel that kept him going. Like Fugate, he was not deterred by the potential for failure—he simply eliminated that from his thinking. In many ways, Denman’s greatest strength was his scientific and technical curiosity and versatility, which motivated him to design the car and assemble all the parts so that when he turned the key the vehicle drove away smoothly without any operating problems.10 Denman, who had earned a BS in physics from the University of San Diego and a PhD in experimental laser physics from the University of New Mexico, presented a compelling argument to Good and Baker in December 2000 that he could build a sodium-wavelength laser. At the time, Denman was the laboratory program manager for a large fiber laser research program called LITE, which stood for Laser Integration Technology program. That program, cofounded by Denman in 1998, focused primarily on advancing “fiber laser technology, diode-laser pumps, micro-optics, coherent beam combining, and packaging.” Impressed with Denman’s technical expertise Sodium Guide Star Laser

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and coolness, Good made the decision on the spot to relieve Denman of his current duties as the LITE program manager so he could devote all his time to developing a program that could generate a reliable sodium-wavelength laser. That laser would become an integral part of the sodium guide star program at SOR. Good gave Denman about $700,000 to get started.11 Money had always been a problem, as Fugate earlier had been only partially successful in securing funding for a sodium-wavelength laser program. A few years prior to the Good meeting, Fugate had been able to acquire $200,000 from Howard Schlossberg at the Air Force Office of Scientific Research outside Washington, DC to conduct basic research on sodium-wavelength guide star lasers. Fugate used part of that money to hire John M. Telle and Peter W. Milonni from Los Alamos National Laboratory to start preliminary studies. They concentrated primarily on the theoretical and modeling aspects of mesospheric physics and the effects that different laser characteristics might have on the brightness of the guide star—primarily, whether pulsed or continuous-wave lasers were more efficient. Their work laid the theoretical groundwork, but it would be left to Denman and his team to build an operational sodium-wavelength guide star laser system. Denman’s team exhibited a dogged determinism in applying the well-understood concepts of laser design and nonlinear frequency conversion, along with a fair share of trial and error.12 In the short term, the military believed that the development of a sodium-wavelength laser guide star would support the Air Force’s space situational awareness mission. The goal was for the guide star, combined with adaptive optics, to enable large ground-based telescopes to produce high-resolution images of space objects. This would enable the military to identify any man-made object in space as friend or foe. A reliable sodiumwavelength laser guide star system also offered the potential of enabling ground-based telescopes to generate high-resolution images comparable to those produced by space telescopes like Hubble, but at much less cost. The Air Force expected that sodium-wavelength laser guide star adaptive optics might contribute to ground-based offensive counter space laser systems to intercept hostile satellites or missiles.13 Denman’s first step was to find a suitable area for a laboratory. In January 2001, he acquired enough floor space in Hangar 760 at Kirtland—a facility originally built to support the Air Force Weapons Laboratory’s

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first airborne laser program—to begin putting his laboratory together. It would take time and considerable effort to get the sodium lab up and running. Denman had to design the lab’s physical layout—including a clean room—as well as the laser, and order and assemble equipment such as optical benches, electronics, computers, and optical components. Nine months later, in October 2001, Denman moved his desk in, and the sodium laboratory was complete.14 Progress after that was swift. By the end of May 2002, Denman and his team—made up of Paul D. Hillman, Joshua C. Bienfang, Captain Brent W. Grimes, John M. Telle, and Gerald T. Moore, all assigned to the Air Force Research Lab’s Directed Energy Directorate—had built and demonstrated a laboratory sodium-wavelength laser on an optics table that produced 6 watts of yellow sodium light. Denman described that accomplishment as a major turning point: At this point in time others had already demonstrated mixing in a lithium triborate crystal to get the yellow wavelength. What we had proved was that we could build a high-power injector-locked 1319nm [nanometer—one millionth of a millimeter] laser and that multiwatt powers at the yellow wavelength were possible. Up to this point, 1319nm single-frequency lasers only existed at powers less than 350mW [milliwatt—one thousandth of a watt] and no one had ever built an injection-locked 1319nm laser and no one had ever made the yellow wavelength continuous wave using a solid state nonlinear material over about 400mW. So our effort to this point was truly ground breaking.15 That accomplishment exceeded most colleagues’ expectations. In early 2002, Denman had attended a conference sponsored by the Center for Adaptive Optics at the University of California, Santa Cruz. Astronomers were interested in the possibility of applying Denman’s sodium-wavelength laser guide star work for generating higher resolution images of astronomical bodies. They expected he would produce at most 2 to 3 watts of sodium light, and few expected a breakthrough soon. The Air Force Scientific Advisory Board, responsible for evaluating programs at AFRL, also told Denman they expected it would take a long time for his work to bear fruit. Sodium Guide Star Laser

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But Denman ignored all these predictions that he was chasing an unsolvable problem. He had confidence in himself and his team.16 Even though Lincoln Lab had already built expensive pulsed dye lasers to generate a sodium-wavelength laser in the 1980s at White Sands Missile Range (see chapter 6), they were inefficient, produced low power (1–3 watts, continuous wave) and poor beam quality, and required a large chilling system to dissipate the heat buildup. The dye was also dangerously flammable. Denman’s alternative to dye lasers was to build a solid-state and continuous wavelength sodium-wavelength laser—described as a doubly resonant sum-frequency laser. This appealed to military scientists and astronomers as a safer, cheaper, and more reliable choice. The challenge was to get the laser to work reliably at multiple watts and to demonstrate that it could produce a sodium guide star of sufficient brightness. Denman and his team succeeded at that.17 Everyone’s reaction to Denman’s first demonstrated 6-watt laser in May 2002 was favorable. They could not quite believe it, but Denman’s evidence was indisputable. Military scientists and astronomers alike were astonished that Denman and his team had been able to develop a 6-watt laboratory demonstration of a sodium-wavelength laser in less than 6 months. The team next set to work building a sodium-wavelength laser that would generate 15 to 20 watts. Denman and his team were optimistic, but many experts were decidedly pessimistic, including the Air Force Scientific Advisory Board, which did not think a sodium-wavelength laser delivering 20 watts of energy was possible. Scaling from 6 to 20 watts—over three times as much output power—was simply viewed as too great a leap.18 Building a 20-watt sodium-wavelength laser at 0.589 microns required precision and patience. The key was based on “sum-frequency mixing two injection-locked Nd:YAG lasers in the lithium triborate crystal inside a doubly resonant external cavity.” Denman designed the system, assisted by Paul D. Hillman, a physicist, and Josh Bienfang, a post-doctoral researcher in physics who had earned his PhD at the University of New Mexico under Denman. Unfortunately, Bienfang left in July 2002 to take a job at the National Institute of Standards and Technology in Gaithersburg, Maryland.19 To produce sodium-wavelength light, Denman first had to build two continuous-wave Nd:YAG solid-state infrared lasers at different wavelengths—one at a wavelength of 1.064 microns and a power level of 24 watts,

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the other at 1.319 microns and 15 watts. The two would then be combined to generate yellow light at the desired wavelength of 0.589 microns. To make each laser, Denman relied on small diode laser bars to pump or excite the neodymium atoms contained in Brewster-cut Nd:YAG rods (solid crystals) measuring only 67 mm long and 1.6 mm in diameter. The rods served as the lasing material. Years before, Denman had developed the technology for high-power single-frequency lasers at 1.064 microns, referred to as injection-locked lasers, similar to what he would need for the new system. But Denman also would need to build a 1.319-micron injection-locked laser, a wavelength that had not been demonstrated before based on injection-locking technology. His challenge was that he needed both the 1.064micron laser and the 1.319-micron laser to be mixed together to arrive at the desired sodium-wavelength of 0.589 microns.20 Denman was able to use diode pumps to excite the laser medium—a more effective technology than the flash lamps Jeys had to rely on in his earlier work. Diodes are much better because they greatly reduce the amount of heat in the system, making it easier to run at high power. Diode lasers were also more reliable and generated higher quality yellow light. In addition, Denman’s injection-locked lasers and sum-frequency configuration allowed him to produce a single-frequency output that could be precisely locked to the sodium D2a resonance, while Jeys’s system produced a “comb” of frequencies spanning the expected Doppler-broadened mesospheric sodium D2a resonance. As Jeys described it, Denman had developed a much more sophisticated laser system and a turnkey operation.21 By summer 2002, the team had built and assembled the hardware for the 1.064-micron and 1.319-micron lasers. Denman and Hillman next turned their attention to building, testing, and operating a doubly resonant optical cavity, basically a resonator containing a small nonlinear lithium triborate crystal measuring 20 x 5 x 5 millimeters. The two lasers were combined by a dichroic mirror and directed into the cavity. When they interacted with the lithium triborate crystal, 20 watts of 0.589-micron sodium light was generated (through a second-order nonlinear optical process called sum-frequency generation) and extracted from the cavity. The process was completed successfully for the first time in October 2002. At the time, 20 watts was a world-record power level for a diode-pumped and continuous-wave solid-state sodium-wavelength laser. The highest Sodium Guide Star Laser

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Figure 22. Two injection-locked lasers at 1.064 microns and 1.319 microns

combine in a sum frequency generation (SFG) cavity to produce a 20-watt, 0.589-micron sodium-wavelength laser. A beam director (far right) projects the laser to the mesosphere to excite sodium atoms. The photon return from the mesosphere is collected by a receiving telescope on the ground.

single output measurement in Denman’s laboratory was 22.5 watts. Why two Nd:YAG wavelengths have just the required amount of tunability to produce the third wavelength with just the right amount of tunability for resonance with the sodium D2a and D2b transitions has been explained as a “fortuitous accident of nature.”22 After the 0.589-micron beam exits the cavity, a beam director sends it up through the sodium layer in the mesosphere. As the beam passes through, sodium atoms in its path absorb photons, raising their energy level and becoming resonantly excited. As each atom then returns to its normal energy level, it emits a photon of the same wavelength as the beam that struck it—fluorescence. The beam’s path through the sodium layer is parallel, and so is the path back to Earth of the fluorescence it produces; when it hits the telescope, it produces a small, circular spot.23 The more powerful the laser, the more photons it emits—and thus the more atoms it can affect in the sodium layer and the brighter the resulting guide star. The guide star emits fluorescence in all directions. The

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Photo 65. The Air Force laboratory team responsible for building and demonstrating the 20-watt sodium guide star laser system. Left to right: Gerald Moore, James Carr, Brent Grimes, Paul Hillman, Joshua Bienfang, Craig Denman, and John Telle. Photo was taken circa July 2002.

fluorescence, or light, that travels back to Earth is collected by a telescope and sent to a wavefront sensor, which measures the amount of distortion in it (distortion induced by the atmospheric turbulence through which it traveled). That information is then used by an adaptive optics system to make corrections to the surface of a deformable mirror that alters the wavefront to compensate for the distortion.24 Reaching the 20-watt milestone for a reliable, all solid-state, continuouswave laser for sodium guide star excitation was an amazing feat. No one had done it before, even though contractors and university researchers had been trying to for nearly 20 years. This accomplishment took on even more meaning for the Air Force because its team of in-house scientists had achieved this major technological breakthrough. There were no contractors involved in the 20-watt work. Denman had led a highly qualified and motivated team of strictly government and military scientists and technicians Sodium Guide Star Laser

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who had moved from theory to practical application and actually built and demonstrated a high-quality sodium beam. It was a great example of what an independent Air Force laboratory team could do. Moreover, the Air Force exclusively funded this important research effort at a relatively modest cost, but the return on the dollar was huge in terms of the revolutionary nature of the contribution made. In April 2006, the “Continuous Wave Sodium Beacon Excitation Source” was patented. Because Denman and his associates were government employees, the patent was assigned to the United States Air Force.25 The Air Force Scientific Advisory Board (SAB) recognized the Denman team’s work in December 2002. In a feedback session to the Air Force Research Laboratory, the board said producing the 20-watt laser was “phenomenal,” especially considering that the effort took less than 2 years—and admitted that its 2001 prediction that it was unlikely that the team would succeed had been wrong. Now the SAB offered only glowing praise: “World-class seems inadequate to describe recent results at SOR. Superb technical leadership combined with highly talented and motivated people.” The team’s success “enables a new level of atmospheric compensation performance.”26 The next step was to take the 20-watt sodium-wavelength laser system out of the laboratory and operate it at the SOR site to see how bright a guide star could be produced and whether the system would perform reliably. The system was moved to SOR in November 2002. It consisted of four aluminum boxes, each measuring 2 x 2 feet—one that housed the 1319nm laser, one for the 1064nm laser, a third for the sum-frequency generator, and the fourth for the sodium transition lock. There was no duplicate or backup for this one-of-a-kind system, and there were only a few spare parts.27 Denman’s team installed the laser system in the coudé room below SOR’s 1.0-meter auxiliary beam director. The plan was to launch the beam from the coudé room up through the beam director, which would transmit the beam to the sodium layer in the mesosphere. Because the beam director’s mirrors are reflection-coated for optimization in the near infrared, their reflectivity in the sodium wavelength is poor—about 60 percent— leaving typically only about 11.5 watts of power propagating to the sky. Additional power losses as the beam travels to the mesosphere can vary depending on atmospheric conditions.28

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Photo 66. The 20-watt sodium guide star laser system consisted of a four-box

configuration containing complex optical and laser-generating hardware. A 20-watt 589 nm laser output beam is propagating horizontally in the lower half of the photo.

The first experiments took place in November 2002 and were witnessed by members of the SAB, who were deeply impressed. Once the beam excited a column of atoms in the sodium layer, resonance photons were collected by SOR’s 3.5-meter telescope and observed in its coudé room. Initial test results were encouraging: each square centimeter on the surface of the telescope’s primary mirror collected about 800 photons per second—the equivalent of light from a magnitude 7 star, which could not be seen by the naked eye. For the entire surface of the mirror, that added up to 100 million photons per second. Denman’s sodium-wavelength laser guide star system had proven its effectiveness in real-world conditions and produced a guide star of record brightness per watt of illumination.29 Subsequent sky testing of the 20-watt system took place during the spring and summer of 2003. Tom Jeys, who had pioneered the sodium solid state laser work at Lincoln Laboratory, had heard about Denman’s laser but was not totally convinced that it worked as advertised until he observed it Sodium Guide Star Laser

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Photo 67. A 4-inch-diameter sodium-wavelength laser beam is fired from

Starfire Optical Range’s 1.0-meter auxiliary beam director (far right). The 3.5-meter telescope (center) collects photons returned from the sodium layer in the mesosphere.

first-hand at SOR. Jeys had been able to get a couple of hundred of return photons/cm2/sec with his earlier pulsed sodium frequency laser. His photon return number was consistent with sodium dye laser systems used on Lawrence Livermore National Laboratory’s Lick Telescope in California and the 10-meter Keck Telescope at Mauna Kea, Hawaii.30 When Jeys observed the 20-watt SOR operation, he absolutely was amazed by the results: many hundreds of sodium photons per square centimeter per second. For tests that occurred in July 2003, the outgoing laser beam was compensated for atmospheric turbulence by an adaptive optics system before the beam was fired. That resulted in a smaller beam diameter in the mesosphere, more concentrated power in the excitation column, and a brighter guide star. Also, a circularly polarized beam was later used that produced an even brighter guide star. The maximum photon return measured 1,015 photons/cm2/sec and was obtained using only about 8 watts of power of circularly polarized light. In other words, Denman’s

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sodium-wavelength laser guide star system produced about 10 times more photons per watt—brighter returns—than the photon return achieved by any pulsed sodium dye system had ever done. Astronomy requirements were about 150–300 photons/cm2/sec to acquire good images. Jeys was overwhelmed by what he saw and was extremely complimentary of the groundbreaking work by Denman and his team.31 The success of the 20-watt sodium guide star laser system prompted Bob Fugate to abandon a hybrid system that he had proposed earlier that had involved using Rayleigh and sodium guide stars at the same time. Once Denman had successfully produced a 20-watt laser, Fugate realized that there was no need for a complex and expensive hybrid guide star system. Instead, Fugate asked Denman in January 2003 if he could build a 50-watt sodium guide star system. In theory, such a system could achieve a return of 5,000 or more photons/cm2/sec. Denman said yes.32 The new system took a year longer to develop than the 20-watt system had. In addition to achieving a 50-watt power level, it had to be remotely operable and mounted directly on SOR’s 3.5-meter telescope. As in the 20-watt system, two injection-locked lasers were combined to produce a single sodium-wavelength laser. But this time the 1.064-micron laser had to be scaled up to 80 watts and the 1.319-micron laser to 60 watts. Both levels would create new world records.33 Denman again served as technical leader, laser and optics designer, as well as overall project manager. Although two capable scientists had left his team in summer 2002, Josh Bienfang and Brent Grimes, Denman was confident his team could solve the tasks at hand of achieving higher beam output power.34 Denman was not disappointed. Paul Hillman worked on critical modeling and power scaling problems connected to the 50-watt system. Joe Preston, a computer programmer working for the Boeing Corporation at SOR, refined the complex algorithms required to run the totally automated 50-watt system. Tim Rogers, another Boeing employee, helped assemble electronic and optical components. Gerry Moore continued to provide insight into the theory of the sum-frequency conversion process. Fugate visited the sodium lab in Hangar 760 almost every week to check on progress and offer ideas and encouragement. Air Force teamwork, with support from the Lab’s senior leadership, ensured that the 50-watt system was developed in a relatively short time.35 Sodium Guide Star Laser

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Many other activities had begun to allow the 50-watt system to be mounted on the 3.5-meter telescope when it was ready. Denman recalled those busy times: A specially designed projection telescope for the 50-watt system was being prepared by Dr. Imelda De La Rue and Dr. James M. Spinhirne [a contractor with the Boeing Corporation] for mounting along the side of the 3.5-meter telescope and above the laser. This projection telescope had to be completed and already mounted to the telescope before the 50-watt system could be mounted to the 3.5-meter telescope. Additionally, John Telle, a team member from the start, began to devote his time to the study of the mesospheric sodium physics to engage as the devil’s advocate and assist Dr. Jack Drummond with the analysis of the sky test data obtained from the 20-watt sodium guide star laser. Drummond, who arrived at SOR in 1991, was the only astronomer assigned to the program. He would take the lead in measuring and analyzing the photon return during sky testing of the 50-watt system.36 Denman and his team set to work in April 2003 designing and purchasing hardware for a 50-watt system. Although similar in principle to the earlier 20-watt system, the new system was completely redesigned. Besides its greater power, the new system also had to be remotely controlled and automated while remaining robust enough for direct mounting to the side of the 3.5-meter telescope. That was a tall order by anyone’s technical yardstick. Fifty watts was an imposing technical hurdle to overcome, but the effort would be worth it if it worked. More output power in terms of wattage meant the outgoing beam would create more photon radiance of the sodium layer, which in turn would generate a brighter guide star.37 In fall 2004 Denman’s team, in the laboratory in Hangar 760, demonstrated 50 watts of power at the sodium-wavelength of 0.589 microns for the first time. That was a world-shattering record for output power for a continuous-wavelength single-frequency solid-state sodium-wavelength laser. As Denman explained it, “We devised, in house, the first computer-automated all-solid-state sodium guide star laser system that would work with Starfire’s 3.5-meter telescope.” The 50-watt laser produced a photon return from the

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sodium layer that was ten times as efficient (per watt of illumination) and about four times as powerful as any sodium guide star system in existence. It seemed clear that this breakthrough had potentially revolutionary applications for the military, but, as Denman said, it was also “an enabling technology for large ground-based adaptive optical telescopes worldwide.”38 Once the 50-watt system proved itself in the laboratory, the next step was to mount it on SOR’s 3.5-meter telescope. In just over one and a half years, Denman’s team had designed, built, tested, and installed it. Once the system was in place, a series of sky tests followed in 2005 and 2006 to validate the system’s performance under a variety of power levels and atmospheric conditions. Scientists at SOR were eager to observe the sodium flux return produced by different beam output power levels under a variety of atmospheric conditions.39 As had happened 2 years earlier with the introduction of the 20-watt system, members of the Air Force Scientific Advisory Board were anxious to observe the more powerful system. In November 2004, Denman told the board that the 50-watt system was fully automated. One of the main advantages of automation was the system could be run by nontechnical staff, freeing up time for test directors and scientists to attend to other duties. Denman told the SAB that the new system would also produce a brighter sodium guide star than the proven 20-watt system. During their visit to SOR in late November, SAB members watched as a yellow laser beam projected from the 3.5-meter telescope traveled into the heavens and disappeared into the deep black space. The event erased any remaining reservations about the practicality of the 50-watt system and confirmed the SAB’s judgment that Denman and his team were performing world-class science.40 The SAB later described the guide star laser work at SOR as the “best in the world,” praised the professionalism and commitment of the team, and said the work would enable “a new level of performance for ground based imaging and HEL [high-energy laser] propagation.” This had been achieved at the relatively modest cost of $3 million. Air Force leaders believed the new technology had the potential to transform future Air Force missions.41 The 20-watt system had used the SOR beam director to project the laser into the mesosphere. However, the automated 50-watt system depended on a 20-cm projection telescope attached to the side of the 3.5-meter telescope to send the beam. The beam when it hit the sodium layer in the mesosphere Sodium Guide Star Laser

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was approximately 1.5 meters in diameter, limited in size only by the degree of atmospheric turbulence. To make accurate measurements possible, the smaller telescope was located 3.1 meters from the optical axis of the 3.5-meter telescope so the two telescopes were always looking in exactly the same direction.42 Guide star photon return differs depending on the time of year. The density of sodium atoms in the mesosphere varies according to season, usually reaching a maximum in late November and a minimum around June. Sodium density (and, if all else remains constant, guide star brightness) is about four times greater in the fall than in the spring—and five times or greater during the Leonid meteor showers, which last several days. Every 33 years the comet responsible for the Leonid meteor showers, TempelTuttle, passes through our solar system. It leaves the most debris as it passes through the solar system, but some debris is strewn over much of its orbit. Meteorites from the comet’s debris path burn as they enter the Earth’s atmosphere, replenishing the sodium atoms in the mesosphere. This is believed to be the primary source of mesospheric sodium. The seasonal fluctuations in sodium density are thought to be primarily due to lunar and solar tidal forces and the tilt of the Earth’s axis with respect to the sun.43 Jack D. Drummond, the astronomer assigned to the SOR sky test team, measured the photon return for every sky test using the 20- and 50-watt systems. To calculate the number of sodium photons delivered from the mesosphere to the SOR telescope, he compared the brightness of known stars to the sodium guide star. He placed a narrow-band wavelength filter in front of a CCD camera, allowing only those photons with wavelengths near that of the guide star photons to be detected. Images from known stars and the sodium guide star appear as circular bright spots (where the photons reside) on the CCD camera. By comparing the known brightness levels of light from these stars with that of light from a sodium guide star, Drummond could calculate the guide star’s photon count. This was a fairly routine procedure used by astronomers and other researchers to measure brightness.44 Results kept improving throughout the sky testing of the 50-watt system at SOR in 2005 and 2006. Beam output power played a dominant role in the success of the sky testing, because it has an approximately linear relation to guide star brightness: if beam output power doubles, so does the sodium return. The new system’s initial operation and integration with

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Photo 68. A small telescope attached to the side of Starfire Optical Range’s 3.5-meter telescope projects a sodium-wavelength laser beam generated by the 50-watt system to excite sodium atoms in the mesosphere. The light returning from the mesosphere, which made up the sodium guide star, is collected by the 3.5-meter telescope. Light from a sodium guide star is similar to the twinkle of light from a natural star, except that it is not quite bright enough to be seen by the naked eye, although the bright outgoing beam can be easily observed.

SOR’s telescope had some normal growing pains. Operating the system to produce its highest power output often caused the sum frequency generation to become unstable. “This was eventually remedied,” Denman said, “once a defective optic was identified and minor changes were made but, up to that point, sky test operations continued at lower operating power levels.” Scientists first used a 20-watt beam produced by the 50-watt system to interact with sodium atoms in the mesosphere. It was not until fall 2006 that the full power range up to 50 watts was available on a consistent basis.45 In January 2005, excitation of the sodium guide star using a linear polarized 20-watt beam deposited 1,015 photons every second on every Sodium Guide Star Laser

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square centimeter of the primary mirror’s surface. As scientists learned more about mesospheric sodium physics and the relation between the laser beam properties and the guide star excitation efficiency, higher photon measurements were achieved. For example, in September 2005, the ability to operate with a circularly polarized beam was achieved, and the number of photons per square centimeter per second had climbed to 2,460 using the 20-watt beam—a record-breaking level. Earlier sky tests of the 20-watt system had already demonstrated that a circularly polarized beam could as much as double guide star photon return.46 As SOR personnel became more familiar with the intricacies of the 50-watt system, beam output power moved up from 20 watts to 30 watts. The peak sodium flux return occurred on 16 November 2005, when a 30-watt circularly polarized beam produced by the 50-watt system generated sodium photon flux at the D2a resonance of 7,000 photons per second to every square centimeter of the 3.5-meter telescope’s primary mirror, an astonishingly high number. Even while operating far below its full power capacity of 50 watts, SOR’s 30-watt guide star laser had “far greater power than any other laser in use for astronomy,” according to Drummond.47 For the first 6 months of 2006, Denman’s team focused on adjusting the system to operate at full capacity. By early summer, the system was operating routinely, and by the end of the summer Lieutenant Quoc Vo had been assigned as the first official operator of the 50-watt system. The system required less maintenance by this time; only minor adjustments were needed before each monthly test. Though the system could produce 52 watts immediately after maintenance, it was generally capable of routine power levels up to 40 watts.48 On 8 May 2006, a 50-watt outgoing laser generated a guide star that, because of the seasonal low in sodium density, returned only 2,000 photons/cm2/sec to the 3.5-meter telescope. On 30 May, a 30-watt beam produced a return of about 1,200 photons/cm2/sec—low in comparison to the previous November’s 7,000. Denman said the May numbers were “a bit surprising although consistent with the seasonal fluctuations in sodium density in the mesosphere.” By 19 September 2006, a 50-watt beam could generate a guide star with photon returns of about 3,500 photons/cm2/sec or about 70 photons/cm2/sec/watt.49 Over the previous 2 years, Denman and his team had worked on many

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of the details required to integrate the 50-watt system with the telescope to reach optimal performance. Sky tests were performed at least 2 weeks out of every month. The short periods between tests were used to make changes to the system and prepare for the next tests, as well as to analyze the previous week’s data, model the mesospheric sodium physics, and design new experiments.50 The brightness of the sodium guide star continued to amaze the SOR team and astronomers at observatories worldwide. Not only was the photon return efficiency (radiance per watt) far higher than that of any other guide star, but the SOR laser had about four times more power. As good as those results were, Denman, Hillman, and Telle began exploring ways to increase the brightness of the sodium guide star even more. The next approach they wanted to try was an outgoing laser with two frequencies instead of one.51 The two-frequency experiments proposed by Denman and his team would use both the prototype 20-watt system and the telescope-mounted 50-watt system. The 20-watt system was placed in a laboratory two floors below the 3.5-meter telescope, where its beam was expanded to a 4-inch diameter and then launched through a long tube to an outside turning mirror, which pointed the beam straight up into the sky toward the same target as the 50-watt beam. The 50-watt system’s beam position could then be fine-tuned to overlap exactly with the 20-watt system’s beam in the mesosphere. The 50-watt system was tuned to the sodium D2a resonance while the 20-watt system was tuned to the D2b resonance. When the two beams converged and entered the sodium layer in the mesosphere a twofrequency guide star would be created.52 Denman and his team conducted an experiment to test this concept on 29 September 2006. Denman reported that the experimental results demonstrated that by combining 10 watts [created by the 20-watt system] from the D2b resonant beam with 40 watts [created by the 50-watt system] from the D2a resonant beam that a guide star could be produced with a 1.6 times higher brightness over the guide star produced only from the 40-watt D2a resonant beam. The guide star created measured an extraordinary sodium photon return of 10,000 photons/cm2/sec. That same night using the D2a resonant beam at 40 watts generated a guide star with a photon Sodium Guide Star Laser

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return of about 5,800 photons/cm2/sec. The brightness increase by using the additional 10 watts from the D2b resonant beam was a little more than the 1.6 times factor. This result was spectacular for the team, for the experiment proved them correct that guide star efficiency could be greatly improved with the addition of just a small amount of power at the D2b resonance frequency.53 With the 50-watt system now operating at its highest power level, one additional sky test was scheduled to coincide with the fall peak of the mesospheric sodium density. On 21 November 2006, a 40-watt beam—created by the 50-watt system—produced a guide star with a measured photon return of 12,000 photons/cm2/sec (about 300 photons/cm2/sec/watt). That return was equivalent to the brightness of a magnitude 4 star—a medium bright star that can be seen by the naked eye—which was considered an exceptionally bright return for a sodium guide star laser and represented another world record. Drummond marveled that “12,000 photons are 100 times more light produced by any observatory using a laser guide star.” Denman speculated that if a full 50-watt D2a had been used instead of the 40-watt beam, “then a return of 15,000 photons/cm2/sec might have been produced and . . . an even more mind boggling thought was that if a second D2b resonant beam was used along with a 50-watt D2a beam, then over 24,000 photons/cm2/sec might have been produced!”54 These results ushered in an unprecedented level of adaptive optics telescope capability. The Air Force research team had set a standard of performance that observatories would incorporate in the designs of future adaptive optics telescopes. Denman and his team led the effort, as private companies had not invested in this type of research. Drummond commented, “Craig Denman is the reason why the sodium guide star laser system works. He can do everything from design conception to ordering parts, turning the screws, and putting the entire system together so it works. He can do it all!”55 Denman and his team set a new high mark for guide star brightness and performance. As he and his associates reported their findings at scientific conferences, many were skeptical at first. But upon closer examination of the results, most in the field gave high praise to Denman and his team. In assessing the future role and direction of sodium-wavelength laser

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Photo 69.

Two lasers launched simultaneously from SOR’s 3.5-meter telescope facility (one from the telescope and one from a laboratory below the telescope) converge at the sodium layer in the mesosphere. Sodium Guide Star Laser

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guide stars, Drummond and others predicted, “Eventually, some may shift to the Denman type system in place of dye.” That was a powerful statement, because even the solid-state guide star laser systems currently being built by industry for observatories worldwide have exhibited guide star brightness efficiency no greater than those using dye laser systems. By 2007, the consensus was that Denman’s system was the wave of the future for sodiumwavelength laser guide stars for military and astronomical applications. The trick was going to be designing and building these complex systems to meet the varying pulse-format conditions that the larger telescope applications might demand.56 In spite of the success of the 20- and 50-watt systems at SOR, some problems remained to be solved. Laser guide star performance had outpaced the performance of SOR’s adaptive optics. To extract the maximum benefit from the guide star system, it was time to give the SOR adaptive optics system, which was over 10 years old, a complete overhaul.57 That turned out to be a tough challenge. The adaptive optics system was a test bed for ideas, and the sodium guide star part had to coexist with the fully functional natural guide star adaptive optic system working with the 3.5-meter telescope. But components of the adaptive optics system were laid deep in the coudé room two floors below the telescope, and much light was lost in moving from the telescope’s primary mirror through a series of mirrors to the coudé room where it could be integrated into the adaptive optics system. It was not unusual to recover in the coudé room only about 15 percent of the light collected by the telescope’s primary mirror. This loss contributed to the inefficiency of the sodium guide star adaptive optics system, and the SOR team realized that more light was needed to produce higherresolution images of dim space objects.58 The current system was optimized for use with natural guide stars— such as stars, planets, and galaxies. But it needed a complete redesign to optimize its ability to work with the sodium guide stars. Components including the wavefront sensor, CCD camera, and mirrors and coatings had to be replaced with new, state-of-the-art hardware—for example, a wavefront sensor with “better reference files” and “a lenslet array of the proper size.” The Air Force Research Laboratory began the overhaul in 2007. To go with the new adaptive optics system there would also be a new multifrequency sodium guide star system. Expected completion date for the new

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system was 2009. Once that occurs, Drummond confidently predicted, the new adaptive optics integrated with the sodium guide star laser “will produce images to blow everyone away!”59 The revolutionary nature of the extraordinary accomplishments of Denman and his team has elevated them to a unique position in the world of science and technology. They succeeded in taking sodium guide star laser research from the realm of theory to practical application, and distinguished themselves from colleagues conducting similar research in academia and private industry. Team members have worked so well together that they have been able to accomplish in 6 years what industry and universities have been unable to achieve in 20. Realistic expectations are that by 2010, the combination of multifrequency guide star laser systems and a refurbished adaptive optics system at Starfire Optical Range will create higher-resolution images of even fainter space objects from the 3.5-meter telescope. An improved sodium guide star system will certainly be invaluable to the Air Force’s space mission. As in the past, leading this movement into the future will be the Air Force Research Laboratory’s team of dedicated civilian and military scientists.

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Conclusion

From the late 1960s to the present, the United States Air Force has played a leading role in the development of the revolutionary technology of adaptive optics. The Air Force laboratory system served as the focal point for pioneering research energized by the brainpower and persistence of an extremely competent team of military and civil service scientists. This distinguished group—working in obscurity for large portions of their careers because of classification restrictions—successfully advanced adaptive optics technology while assigned to a number of Air Force organizations throughout the country. Heading the list performing this groundbreaking work over the last four decades was the Air Force Research Laboratory and its predecessor organizations: Phillips Laboratory, the Air Force Weapons Laboratory, Rome Laboratory, and Rome Air Development Center. Two civilian components that made major contributions to this Air Force team were the Defense Advanced Research Projects Agency and the Massachusetts Institute of Technology’s Lincoln Laboratory, one of several Department of Defense Federally Funded Research and Development Centers chartered to assist the government in strategic scientific planning and research. And finally, in the 1980s, with more and more of the nation’s defense policy emphasis shifting to space, the Strategic Defense Initiative Organization became another important member of the adaptive optics team. People in these organizations had a grand vision and made a difference. Although there was no one person who single-handedly invented

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and advanced adaptive optics, the Air Force’s scientific cadre were out in front of the pack, solving enormously complex problems relating to the development of sophisticated optics and beam control systems, laser guide stars, wavefront sensors, high-speed processors, deformable mirrors, lasers with good beam quality, and much more, in order to remove the distorting effects of atmospheric turbulence on light waves. Their scientific contributions have had a profound effect on current and future Air Force missions, and many of their findings have also benefited the astronomy community. It is not an exaggeration to label this group of military and government scientists, armed with imagination and daring, as trailblazers and pioneers. They possessed a firm belief that they could get the job done in spite of the odds that they faced, and devised real-world atmospheric compensation techniques and new hardware leading to the production of high-resolution images of space objects, as well as compensated laser beams propagating through the atmosphere. What drove the Air Force’s commitment to adaptive optics was the overriding concern to meet its space object identification mission by generating the best possible images. Senior military strategists viewed space as the battleground of the future, and they envisioned collection of high-resolution images as the cornerstone of the Air Force’s space situational awareness mission. In addition, in preparation for potential future antisatellite missions, the Air Force wanted to be ready to strengthen its space control mission of offensive and counter-space operations. Both tasks depended upon advancing adaptive optics—a critical component of any future airborne or ground-based laser weapon system. It was in the best interest of DoD to initiate research and development programs designed to better understand atmospheric turbulence and how it affected light waves, and then to build adaptive optics systems that were capable of compensating for distortions in light to perform decisive imaging and beam propagation missions vital to the nation’s defense. The Department of Defense had designated the Air Force to develop and integrate adaptive optics technology into an operational system. The Air Force received unfailing support from the Department of Defense and the Defense Advanced Research Projects Agency, which sustained a heavy financial investment in the development of adaptive optics. That steady flow of money was one reason for the success of the adaptive optics research

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program. Funding not only paid for the salaries of scientists and theoretical and experimental programs, it also built the military’s largest telescopes and optical support facilities at Starfire Optical Range in New Mexico and the Air Force Maui Optical and Supercomputing Site in Hawaii. These modern observatory sites directly contributed to the success of the Air Force adaptive optics program. Without these large telescopes, the pace of adaptive optics research would have been greatly diminished.1 Money had a powerful effect and partially explained why government scientists were ahead of university researchers on adaptive optics. Sufficient funding allowed research programs to flourish from one year to the next. That was vitally important to many highly qualified scientists working in the Air Force laboratory system. One of the advantages of working for a military lab was that scientists had state-of-the-art facilities and equipment at their disposal. Knowing modern equipment was available, and was likely to be periodically upgraded or replaced, was an attractive incentive for scientists to pursue a career with the government. Another distinctive trait that separated military scientists from university researchers was that the former were driven by the importance of the military mission. The stakes were simply different. Scientists working for the military tended to have an engineering outlook that focused on applying scientific principles to hardware in order to deploy operational systems. In some ways, they were driven by a greater sense of real-world urgency to keep ahead of our adversaries by moving theoretical concepts off the drawing board into the realm of operational combat systems. On the other hand, military and civilian scientists employed by the government did not have the academic freedom of university scientists to choose their specific research goals or conduct independent research just for the sake of knowledge. Those were just the rules of the game as the government defined what research programs military and civilian employees would work on, depending on military needs, and expected a practical return on its investment in the form of better weaponry. Because senior leadership believed in the value of scientific research as one of the pillars of the nation’s strategic military policy, DoD’s annual research and development budget has shown a pattern, for the most part, over the last four decades, of holding its own or increasing. In those few years when the research programs experienced cuts, it was usually temporary. Conclusion

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Although there were fairly rigid restrictions on what government scientists could work on, there were exceptions. The Defense Advanced Research Projects Agency offered military and government scientists an opportunity, and seed money with very few strings attached, to pursue high-risk basic research projects that might have the chance to be developed and transitioned to operational forces. DARPA was willing to take those risks—fully realizing there would be more failures than successes—if even a few of the scientists they sponsored achieved truly revolutionary breakthroughs. DARPA itself played a predominant role in initiating innovative scientific concepts and distributed a large share of its dollars to Air Force laboratories and private contractors to carry out the heavy work of experimental research. Revolutionary technology did not come about easily or cheaply. And in most cases it took an extraordinary amount of time. Galileo’s telescope, early in the 17th century, created a truly revolutionary moment, because human beings could see heavenly bodies more clearly, including objects that they were unable to see with the naked eye. Four centuries later, adaptive optics occupies a distinguished position in science that rivals the telescope in magnitude of importance. Galileo’s telescope could not remotely compare to today’s large, computer-driven telescopes, equipped with adaptive optics, which can penetrate deep into the universe and produce extraordinary highresolution images of a vast assortment of celestial bodies. Alex Roland, a respected historian of science and technology, in his book Strategic Computing, concluded that DARPA’s massive investment in developing strategic supercomputing failed. He wrote, “Strategic computing never achieved the machine intelligence it had promised.”2 But that was not the case with adaptive optics research, a good portion of which was funded by DARPA. Adaptive optics stood out as a shining beacon in the convoluted landscape of complex technology that over time demonstrated the practical payoffs of sustained research and development in the military to ultimately support the airman, soldier, and sailor on the modern battlefield. DARPA funding had a stabilizing influence on adaptive optics research. For example, in the mid-1980s it funded the Air Force Weapons Laboratory’s research that led to the first Rayleigh guide star system, as well as Lincoln Laboratory’s experiment at White Sands Missile Range, which proved the concept of a sodium laser guide star. Both projects made a tremendous contribution to the advancement of adaptive optics technology. One former

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DARPA director emphasized that it required some “real magic” to close the loop and make adaptive optics work. Adaptive optics was decades in the making, but the end product has been worth the wait. The Strategic Defense Initiative Organization provided another source of funding to encourage military and civilian scientists to come up with innovative technologies to reinvigorate the nation’s space defense capabilities. SDIO funds paid or helped pay for such projects as Lincoln Lab’s short-wavelength atmospheric compensation experiments on Maui and the Weapons Lab’s 1.5-meter telescope at Starfire Optical Range. The Air Force deserves a great deal of credit for leading the way in advancing adaptive optics. As one distinguished university physicist pointed out, the military throughout history has always pushed technology and merits more recognition than it usually receives, especially from the academic community. Some have claimed there is a sort of snootiness in science that sees academics as the cream of humanity, but one should remember that the first applications envisioned by the Dutch when the telescope was invented in 1608 were military in nature; the people who sponsored Galileo were the departments of defense of rapacious Italian dukes. The Air Force recognized the difficult challenge of compensated imaging from the beginning and stepped up to the task. It did this through the exceptional leadership and superior scientific ability of Bob Fugate and Craig Denman at the Air Force Weapons Lab and Air Force Research Laboratory; Ray Urtz and Don Hanson at Rome Air Development Center and later at Rome Laboratory; Darryl Greenwood and Chuck Primmerman at Lincoln Laboratory; Lou Marquet and Tom Meyer at the Strategic Defense Initiative Organization; Rett Benedict at DARPA; David Fried and Jim Mayo in the private sector; and many other “scholar-warriors.” Not only are they first-class scientists, but nearly everyone was motivated by an underlying sense of patriotism to succeed in developing the most effective technology to serve the nation’s defense. For the most part, these scientists tended to be low-key but intense and focused, dedicated investigators always striving for the next scientific breakthrough. There was seldom loud applause or enormous monetary reward for their deeds. Among themselves, they knew who were the real movers and shakers, but outside their guarded community they were relatively unknown. Conclusion

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Most of all, the government team of military, civilian, and contractor scientists believed they faced big challenges and that their work was making a difference. Although it was a team effort, each individual had a unique opportunity to make a lasting contribution. However, there was no one clean line of uninterrupted progress. Research moved forward in a number of different directions at the same time, with good days and bad days, before meaningful progress could be made. Sometimes progress was measured in leaps and bounds and monumental breakthroughs. But more often, research appeared to move forward at a painfully slow pace, and even regress in some cases, before it could be righted and inch forward again. Moreover, government scientists found themselves working in a military closed society that attracted some criticism from outside scientists. Ann Finkbeiner, in her recent book The Jasons: The Secret History of Science’s Postwar Elite,3 pointed out that many academics were troubled that the military was conducting adaptive optics research in secret for many years, thereby denying other scientists vital scientific data. However, abiding by strict classification guidelines in matters affecting national security was the normal way for the government to conduct business. DoD made the investments in people, telescopes, and support facilities in order to exploit adaptive optics technology for military purposes, not to broaden the scientific community’s knowledge. Emphasis in the military labs was on both theory and application, which went counter to the customary way progress evolved in the sciences. Generally, universities are heavily focused on the development of theory, with industry or the military then applying those theoretical principles to the building of practical, marketable operational systems. In 1991, with the demise of the Soviet Union well under way, the Air Force declassified much of its adaptive optics findings and shared them with civilian astronomers—a major watershed and a prime example of technology transfer from the military to universities and the private sector. At first, civilian scientists were overwhelmed to learn about the scientific progress the Air Force had accomplished in advancing adaptive optics. Some were even more amazed that the military was willing to share that critical information with them. From that point on, the Air Force has continued to share its adaptive optics research findings with astronomers. Astronomers have been able to build upon the military’s scientific contributions and expertise to advance their own independent research.

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In addition, the Air Force has collaborated with astronomers by giving them access to the large telescope facilities at the Air Force Maui Optical and Supercomputing Site at Maui and Starfire Optical Range in New Mexico. This “dual use” approach of opening expensive scientific facilities to two different research groups not only has benefited the astronomy community but has turned out to be a cost-effective use of taxpayer dollars. This trend has led to more cooperative and interdisciplinary research that draws its scientific expertise from a diversity of institutions including the military, federally funded laboratories, universities, and the private sector. After the 1991 declassification meeting in Seattle, astronomers working at universities and at consortium-run observatories around the world had high praise for the Air Force’s scientific achievements in adaptive optics. Most university scientists applauded the quality of work conducted by Air Force scientists. The Center for Adaptive Optics at the University of California, Santa Cruz, the National Science Foundation, the University of Chicago, the University of Hawaii, the University of New Mexico, the University of Arizona, the University of Illinois, the Imperial College (London), W. M. Keck Observatory, Gemini Observatory, Mount Wilson Observatory, the European Southern Observatory, and the Max Planck Institute for Astronomy were just a few of the institutions that recognized Air Force scientists for their groundbreaking work. Evidence of that trend was the positive reception of a flood of papers in the open literature authored by government scientists after their work was declassified in 1991. As one veteran civilian laboratory scientist assessed it, “The astronomy community would not be where it is today if it wasn’t for the military research and development of adaptive optics for surveillance purposes.” Moreover, the Jasons, senior scientists who advised the government on scientific matters and were recruited mostly from universities, praised the government’s adaptive optics researchers.4 Most Jason members believed the military’s work on adaptive optics and the electronic battlefield ranked among the top scientific accomplishments of the era. For example, Freeman Dyson of Princeton University, one of the longest-serving Jasons, declared that his evaluation of the government’s adaptive optics research was the most serious work he ever did as a Jason. In many ways, the successful development of adaptive optics was a direct outgrowth of military decisions made after World War II. At the Conclusion

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urging of General Hap Arnold and Theodore von Kármán, the government began to systematically invest in military laboratories as an insurance policy for winning the next war. The DoD recruited scientists through the military services and the civil service personnel system as well as contracting work from private industry and universities. Military civil service career scientists represented a new breed of government scientists who led a diversity of high-tech programs aimed at satisfying specific military needs. Pulling together a capable scientific workforce did not occur overnight but evolved and grew over time. DoD scientists found themselves part of a unique culture, divorced from the traditional work settings of academia and private industry, with a strong sense of teamwork and an emphasis on practical results.5 The Department of Defense funded and supported the military labs hoping for groundbreaking research that would lead to advanced weapon systems. Progress in adaptive optics was similar to other DoD programs. David H. DeVorkin, in Science with a Vengeance: How the Military Created the US Space Sciences After World War II, declared, “[R]ocket exploration of the upper atmosphere began in the U.S. Department of Defense largely because of the increasing importance of missiles and the expectation of very high altitude flight. It was imperative to know the medium through which such missiles and craft would fly and the environmental conditions they would encounter.”6 Gaining a better understanding of the atmosphere was also important in advancing the performance of high-velocity jet aircraft that led to the breaking of the sound barrier by Air Force pilot Chuck Yeager on 14 October 1947. The same held true for adaptive optics. It was important for DoD to understand atmospheric turbulence as the first step in developing an adaptive optics system for use with large telescopes. In this case the emphasis was not on spacecraft moving through the atmosphere but on the more elusive concept of how photons passed through it and were affected by turbulence. Once the concept of atmospheric turbulence was defined and better understood, attention shifted to building the hardware for an adaptive optics system. DoD established a cadre of scientists to explore the possibilities of adaptive optics and provided the bulk of the funding, facilities, hardware, program management, and leadership to transform adaptive optics from an abstract concept to a successful enabling technology.

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The future of adaptive optics looks extremely promising. While the last four decades of research and experimentation built the foundation, adaptive optics systems are likely to grow exponentially in the coming decade. As one scientist predicted, “We have only scratched the surface in terms of the potential of adaptive optics. What lies ahead are even higher resolution images of space objects captured on a routine basis and the potential capability to send compensated laser beams from the ground to intercept and disable target satellites and missiles.” The ability to capture better images of space objects from the ground is almost inevitable. A recent article in Aviation Week & Space Technology reported that many astronomers and NASA officials believe that ground-based adaptive optics systems will eventually replace the need for space-based telescopes and that, in the near future “adaptive optics of very large ground-based telescopes probably will be able to produce resolutions equal or better than Hubble can deliver.”7 But this prediction applied only to visual wavelengths; space-based telescopes will still be needed to image in those wavelength bands (X-rays, ultraviolet, and medium- and long-range infrared) that do not transmit through the atmosphere. Adaptive optics is a revolutionary technology that has successfully transitioned from the laboratory to the operational arena, supporting space object identification, high-energy laser beam propagation, and airborne laser missions. Adaptive optics systems have become a critical component of nearly every large telescope constructed in recent years. Research continues to evolve and promises even greater technical breakthroughs in the years ahead. In over 40 years of research, the program has developed deep roots in the Department of Defense but has also spread widely into the civilian scientific community. At the Air Force Research Laboratory, work continues to make possible the advanced imaging and laser beam systems that United States national security will require in the future.

Conclusion

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List of Intervie ws The major interviews listed here were sometimes followed up by brief conversations on the phone or in person. Name

Date

Location

Abrahamson, James A.

15 June 2005

Herndon, Virginia

Abreu, Rene

2 November 2006

Danbury, Connecticut (phone interview)

Albertine, John R.

30 November 2004

Annapolis, Maryland (phone interview)

Albertine, John R.

3 December 2004

Annapolis, Maryland (phone interview)

Angel, J. Roger P.

14 September 2004

Tucson, Arizona

Augustine, Janet C.

30 August 2006

Maui, Hawaii

Benedict, Rettig, Jr.

28 October 2002

Albuquerque, New Mexico

Billman, Kenneth W.

7 April 2005

Sunnyvale, California (phone interview)

Billman, Kenneth W.

22 April 2005

Albuquerque, New Mexico

Bowker, J. Kent

23 January 2004

Salem, Massachusetts

Cooper, Robert S.

18 May 2005

Greenbelt, Maryland

Cusack, James W.

20 November 2002

Rome, New York

Denman, Craig A.

19 December 2006

Albuquerque, New Mexico

Dimiduk, David P.

10 February 2005

Albuquerque, New Mexico

349

Name

Date

Location

Drummond, Jack D.

9 March 2007

Albuquerque, New Mexico

Duff, Edward A.

5 April 2004

Albuquerque, New Mexico

Ealey, Mark A.

23 January 2004

Devens, Massachusetts

Eberhart, Ralph E.

18 December 2007

Alexandria, Virginia

Ellerbroek, Brent L.

11 July 2007

Pasadena, California

Fried, David L.

2 April 2003

Monterey, California

Frieman, Edward A.

8 February 2006

La Jolla, California

Fugate, Robert Q.

16 December 2002

Albuquerque, New Mexico

Fugate, Robert Q.

21 April 2003

Albuquerque, New Mexico

Fugate, Robert Q.

14 May 2003

Albuquerque, New Mexico

Fugate, Robert Q.

27 February 2004

Albuquerque, New Mexico

Fugate, Robert Q.

5 April 2004

Albuquerque, New Mexico

Fugate, Robert Q.

23 September 2005

Albuquerque, New Mexico

Fugate, Robert Q.

9 January 2006

Albuquerque, New Mexico

Fugate, Robert Q.

13 December 2006

Albuquerque, New Mexico

Good, R. Earl

31 October 2002

Albuquerque, New Mexico

Greenwood, Darryl P.

21 January 2004

Lexington, Massachusetts

Greenwood, Darryl P.

10 February 2005

Lexington, Massachusetts (phone interview)

Hanson, Donald W.

19 November 2002

Dayton, Ohio

Happer, William

29 September 2005

Princeton, New Jersey

Hardy, John W.

20 January 2004

Lexington, Massachusetts

Higgs, Charles

21 January 2004

Lexington, Massachusetts

Hogge, Charles B.

10 October 2002

Albuquerque, New Mexico

Hughes, Rusty

30 August 2006

Maui, Hawaii

Hunt, Scott

30 August 2006

Maui, Hawaii

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Name

Date

Location

Hutchin, Richard A.

17 April 2003

Albuquerque, New Mexico

Infosino, Charles J.

15 April 2004

Arlington, Virginia

Janni, Joseph F.

29 August 2006

Maui, Hawaii

Jeys, Thomas H.

26 February 2007

Lexington, Massachusetts (phone interview)

Kenemuth, John R.

5 March 2002

Albuquerque, New Mexico

Kenemuth, John R.

22 September 2006

Albuquerque, New Mexico

Kramer, Mark A.

30 October 2000

Albuquerque, New Mexico

Lamberson, Donald L.

1 December 2002

Albuquerque, New Mexico

Lyles, Lester L.

25 September 2007

Washington, DC

Marek, J. Raley

28 February 2002

Maui, Hawaii

Marquet, Louis C.

18 February 2004

Sarasota, Florida

Marquet, Louis C.

22 December 2004

Sarasota, Florida (phone interview)

Matson, Charles L.

17 November 2006

Albuquerque, New Mexico

Max, Claire E.

18 August 2005

Santa Cruz, California

Mayo, James W. III

14 January 2004

Albuquerque, New Mexico

Mayo, James W. III

9 January 2006

Albuquerque, New Mexico

Mayo, James W. III

10 January 2006

Albuquerque, New Mexico

Mayo, James W. III

30 May 2006

Albuquerque, New Mexico

Mayo, James W. III

28 September 2006

Albuquerque, New Mexico

Mayo, James W. III

30 March 2007

Albuquerque, New Mexico

McNally, James L.

23 August 2006

Albuquerque, New Mexico

McNiel, Samuel L.

28 February 2002

Maui, Hawaii

Medrano, Robert S.

28 February 2002

Maui, Hawaii

Meyer, Thomas W.

6 December 2004

Albuquerque, New Mexico

List of Interviews

351

Name

Date

Location

Meyer, Thomas W.

20 January 2005

Albuquerque, New Mexico (phone interview)

Murphy, Daniel V.

22 January 2004

Lexington, Massachusetts

Nelson, Jerry E.

18 August 2005

Santa Cruz, California

Neyman, Christopher R.

31 August 2006

Kamuela, Hawaii

Nielsen, Paul D.

19 November 2002

Dayton, Ohio

O’Niell, Malcolm R.

14 December 2007

Vienna, Virginia (phone interview)

Otten, Leonard John III

9 June 2004

Albuquerque, New Mexico

Pearson, James E.

17 February 2004

Raleigh, North Carolina

Primmerman, Charles A.

22 January 2004

Lexington, Massachusetts

Primmerman, Charles A.

10 December 2004

Lexington, Massachusetts (phone interview)

Primmerman, Charles A.

21 December 2004

Lexington, Massachusetts (phone interview)

Rich, John C.

7 October 2004

Albuquerque, New Mexico

Roberts, Lewis C., Jr.

29 August 2006

Maui, Hawaii

Roche, James G.

17 December 2007

Arlington, Virginia

Russell, John J.

7 July 2004

Albuquerque, New Mexico

Sega, Ronald M.

7 November 2007

Denver, Colorado

Skolnick, Alfred

13 April 2004

Arlington, Virginia

Snodgrass, Joshua D.

1 March 2002

Maui, Hawaii

Sturdevant, Rick W.

30 March 2007

Colorado Springs, Colorado (phone interview)

Sturdevant, Rick W.

12 February 2008

Colorado Springs, Colorado (phone interview)

352

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Name

Date

Location

Tether, Anthony J.

19 May 2005

Arlington, Virginia

Thompson, Thomas W.

20 November 2002

Rome, New York

Thompson, Thomas W.

29 May 2003

Rome, New York (phone interview)

Thompson, William E.

25 October 2000

Albuquerque, New Mexico

Thompson, William E.

9 October 2002

Albuquerque, New Mexico

Thompson, William E.

11 February 2003

Albuquerque, New Mexico

Tyler, Glenn A.

10 July 2007

Anaheim, California

Urtz, Raymond P.

20 November 2002

Rome, New York

Urtz, Raymond P.

27 March 2003

Rome, New York (phone interview)

Van Citters, G. Wayne

14 April 2004

Arlington, Virginia

Vyce, Jay Richard

20 January 2004

Lexington, Massachusetts

Walter, Robert F.

15 November 2002

Albuquerque, New Mexico

Walter, Robert F.

25 March 2005

Albuquerque, New Mexico

Weaver, Lawrence D.

6 November 2000

Albuquerque, New Mexico

White, Dale R.

1 March 2002

Maui, Hawaii

Wyant, James C.

15 September 2004

Tucson, Arizona

List of Interviews

353

Notes

Introduction 1. The biggest refracting telescope today is the University of Chicago’s 1-meter Yerkes telescope in Williams Bay, Wisconsin, built in 1897. The largest reflecting telescopes are the twin 10-meter (32.8 feet) Keck telescopes, which tower eight stories high and became operational in May 1993 and October 1996. Both are located atop Mauna Kea on the island of Hawaii. Even bigger telescopes are planned for the future. The Thirty Meter Telescope, a joint effort by Caltech, the University of California, and the Association of Canadian Universities for Research in Astronomy, will be able to see objects in space one tenth as bright as those detected by the Keck telescopes. 2. An adaptive optics system works with an extremely small field of view where turbulence is the same throughout the viewing angle. Because an adaptive optics system compensates for atmospheric turbulence along a very narrow line of sight to the viewing object—analogous to tunnel vision or looking through a soda straw—the system is not suited for producing wide-angle or panoramic images.

Chapter One 1. The Russian word Sputnik meant traveling companion of the Earth—see Paul Dickson, Sputnik: The Shock of the Century (New York: Walker Publishing Company, 2001), p. 12. Defense Advanced Research Projects Agency, http://www. darpa.mil (accessed 27 November 2002); William J. Perry, “Defense Advanced Research Projects Agency: Technology Transition,” internal report, January 1997, p. 9; Jonathan E. Lewis, Spy Capitalism: Itek and the CIA (New Haven: Yale University Press, 2002), pp. 46–63.

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2. Laika, the first animal launched into orbit, died in space when her air supply ran out. Curtis Peebles, High Frontier: The United States Air Force and the Military Space Program (Washington, DC: U.S. Government Printing Office, 1997), p. 9; Donald R. Baucom, “Eisenhower and Ballistic Missile Defense: The Formative Years, 1944–1961,” Air Power History, Winter 2004, p. 10. 3. Peebles, High Frontier, p. 9. 4. Ibid.; Baucom, “Eisenhower and Ballistic Missile Defense,” p. 10. 5. Freedom’s Sentinel in Space, CD-ROM, National Reconnaissance Office, Office of the Historian, 2000; Walter A. McDougall, The Heavens and the Earth: A Political History of the Space Age (New York: Basic Books, 1985), pp. 123, 131, 134, 142, 146–148; James R. Killian Jr., Sputnik, Scientists, and Eisenhower (Cambridge: The MIT Press, 1977), pp. xvii, 2–12; Peebles, High Frontier, pp. 8–9. 6. One of the educational reforms Congress passed was the National Defense Education Act, which set aside money for scholarships for students to become math and science teachers. Paul Donnelly, ed., The Itek News: Special Tenth Anniversary Issue, 1957–1967 (Lexington, MA: Itek, n.d., ca. September 1967), pp. 1–12; Dickson, Sputnik: The Shock of the Century, pp. 225–231. 7. The first edition of the PSSC Physics high school textbook was published in 1960. Notes to author from James W. Mayo III, Northrop Grumman, 13 May 2004; Lawrence S. Lerner, “An Outstanding and Inspiring Book, Strongly Recommended,” The Textbook Letter, May–June 1992, http://www. textbookleague.org (accessed 20 April 2005); Lester F. Rentmeester, “Open Skies Policy and the Origin of the U.S. Space Program,” Air Power History, Summer 2004, p. 43. 8. Killian, Sputnik, Scientists, and Eisenhower, pp. 2–3. 9. Eisenhower’s appointment of Killian was a deliberate move to include a representative at the highest levels of government to promote the value of science and technology. Killian, Sputnik, Scientists, and Eisenhower, pp. 3, 120; Matt Bille and Erika Lishock, The First Space Race (College Station, TX: Texas A&M University Press, 2004), pp. 118–119; Eric Pace, “James Killian, 83, Science Adviser, Dies,” The New York Times, 31 January 1988. 10. Major General John Bruce Medaris was determined for years that the Army should be responsible for developing missile boosters for getting America’s first satellite into space. The Army reasoned that rocket technology was an extension of artillery technology. Von Braun, who worked to develop the German V-2 rocket at Peenemuende during World War II, came to the United States after the war as part of Operation Paperclip, which tested about 100 German V-2 rockets at White Sands Missile Range, New Mexico. Von Braun became one of the most influential figures on the American

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|   Notes to pages 2–5

space team. Killian, Sputnik, Scientists, and Eisenhower, pp. 119–120; Loyd S. Swenson Jr., James M. Grimwood, and Charles C. Alexander, This New Ocean: A History of Project Mercury (Washington, DC: U.S. Government Printing Office, 1966), p. 29. 11. Although the Navy did not launch America’s first satellite, it succeeded in launching Vanguard I, the second U.S. satellite placed in orbit, on 17 March 1958. The satellite weighed only 3.5 pounds and measured 6.4 inches in diameter. Soviet Premier Nikita Khrushchev mockingly referred to Vanguard I as “the grapefruit satellite.” Swenson, Grimwood, and Alexander, This New Ocean, pp. 23–26. 12. Jupiter-C, a knockoff of the German V-2 rocket used in World War II, was originally designed and built in the United States as a high-performance test rocket. While the Jupiter-C made up the first stage of the launch vehicle, stages 2, 3, and 4 consisted of Sergeant rocket engines. Swenson, Grimwood, and Alexander, This New Ocean, pp. 121–122; John W. Finney, “Satellite Takes 114-Minute Orbit,” The New York Times, 1 February 1958; Richard Witkin, “Plan for Space Vehicle Shaped as Joint Service Project in ’54,” The New York Times, 1 February 1958; Felix Belair Jr., “Success Attained: At His Georgia Retreat Eisenhower Gives News of Ascent,” The New York Times, 1 February 1958; McDougall, The Heavens and the Earth, p. 168; Bille and Lishock, The First Space Race, p. 128; William E. Burrows, This New Ocean: The Story of the First Space Age (New York: The Modern Library, 1999), pp. 205–211. 13. Bille and Lishock, The First Space Race, pp. 128, 135; Department of Astronautics, National Air and Space Museum, Smithsonian Institution, “Explorer-I and Jupiter-C: The First United States Satellite and Space Launch Vehicle,” http://www.hq.nasagov/pao/History/sputnik,expinfo.html, 23 June 2005. 14. Gregory W. Pedlow and Donald E. Welzenbach, The CIA and the U-2 Program: 1954–1974 (Washington, DC: Center for the Study of Intelligence, Central Intelligence Agency, 1992), pp. 60, 74, 96–97, 110. 15. Ibid.; Rentmeester, “Open Skies Policy,” pp. 42–43; Curtis Peebles, Guardians: Strategic Reconnaissance Satellites (Novato, CA: Presidio Press, 1987), pp. 30–31; Philip Taubman, Secret Empire: Eisenhower, the CIA, and the Hidden Story of America’s Space Espionage (New York: Simon & Shuster, 2003), p. 230. 16. Pedlow and Welzenback, The CIA and the U-2 Program, pp. 176–181. 17. Dwayne A. Day, John M. Logsdon, and Brian Latell, eds., Eye in the Sky: The Story of the CORONA Spy Satellite (Washington, DC: Smithsonian

Notes to pages 6–9

357

Institution Press, 1998), pp. 144–145; Pedlow and Welzenbach, The CIA and the U-2 Program, pp. 99–100, 111–112. 18. Kevin C. Ruffner, ed., CORONA: America’s First Satellite Program (Washington, DC: Center for the Study of Intelligence, Central Intelligence Agency, 1995) pp. 3–11; Day, Logsdon, and Latell, Eye in the Sky, pp. 5–9. 19. In March 1954, RAND released its report Project Feed Back, which endorsed the concept and technical practicality of building and using reconnaissance satellites in space. Ruffner, CORONA, p. 5; Taubman, Secret Empire, pp. 212–238. 20. NRO was an ultra-secret organization that denied its own existence. The joke was that the letters NRO stood for “Never Revealed Openly.” Ruffner, CORONA, pp. 3–11; Day, Logsdon, and Latell, Eye in the Sky, pp. 148–150. 21. There were two stories about how the name CORONA evolved. At an early meeting, Bissell asked his staff for suggestions on what to name the program. One person in the room pointed to the paper ring from his Corona cigar, while another supposedly took the name from a Corona typewriter. Ritland, as a colonel, had served as Bissell’s deputy for the U-2 program. Ruffner, CORONA, p. 5; Taubman, Secret Empire, pp. 212–238. 22. One part of the WS-117 program was called SAMOS, for Satellite and Missile Observation System. SAMOS satellites launched in the early 1960s evaluated the feasibility of collecting electromagnetic reconnaissance data. That process involved scanning film electronically in orbit and then transmitting the information to ground stations. However, results showed that the existing technology was not mature enough to make the system work. Ruffner, CORONA, p. 12; Taubman, Secret Empire, pp. 194, 224–226, 233, 238. 23. R. Cargill Hall, “The Air Force Agena: A Case Study in Early Spacecraft Technology,” in Technology and the Air Force: A Retrospective Assessment, eds. Jacob Neufeld, George M. Watson Jr., and David Chenoweth (Washington, DC: Air Force History and Museums Program, 1997), p. 239; F. Dow Smith, “The Design and Engineering of Corona’s Optics,” in Corona Between the Sun and the Earth: The First NRO Reconnaissance Eye in Space, ed. Robert A. McDonald (Bethesda, MD: The American Society for Photogrammetry and Remote Sensing, 1997), pp. 111–120. 24. Defense Advanced Research Projects Agency, “Bridging The Gap Powered By Ideas,” February 2005, pp. 1–4. 25. Perry, “Defense Advanced Research Projects Agency,” p. 9. 26. The United States more than doubled its research and development budget between 1957 and 1961, to $9 million annually. Defense Advanced Research

358

|   Notes to pages 9–12

Projects Agency, “Bridging The Gap,” pp. 1, 5, 7; Killian, Sputnik, Scientists, and Eisenhower, pp. 127–129; Paul B. Stares, The Militarization of Space: U.S. Policy, 1945–1984 (Ithaca: Cornell University Press, 1985), pp. 22–44. 27. R. Cargill Hall, “Civil-Military Relations in America’s Early Space Program,” in The U.S. Air Force in Space: 1945 to the Twenty-First Century, eds. R. Cargill Hall and Jacob Neufeld (Washington, DC: U.S. Government Printing Office, 1998), pp. 19–31; David N. Spires, “The Air Force and Military Space Missions: The Critical Years, 1957–1961,” in The U.S. Air Force in Space, ed. Hall and Neufeld, pp. 32–45; Perry, “Defense Advanced Research Projects Agency,” p. 9. 28. Interview with Rettig Benedict Jr., vice president of the Space and Directed Energy Division, Schafer Corporation, and former director of the shortwavelength laser program at DARPA, 28 October 2002; Richard H. Van Atta, Michael J. Lippitz, Jasper Lupo, Rob Mahoney, and Jack H. Nunn, “Transformation and Transition: DARPA’s Role in Fostering an Emerging Revolution in Military Affairs, Volume 1—Overall Assessment” (Alexandria, VA: Institute for Defense Analyses, 2003), p. S-3; Defense Advanced Research Projects Agency, “Bridging The Gap,” pp. 5–6; McDougall, The Heavens and the Earth, pp. 141–156, 167–169. 29. Interview with Benedict, 28 October 2002; Van Atta, et al., “Transformation and Transition,” p. S-3; Defense Advanced Research Projects Agency, “Bridging The Gap,” pp. 5–6; McDougall, The Heavens and the Earth, pp. 141–156, 167–169; Tom Junod, “Defense Advanced Research Projects Agency (DARPA),” Esquire, December 2003, pp. 183–188. 30. Interview with Benedict, 28 October 2002; interview with Raymond P. Urtz, director, Rome Research Site, 20 November 2002; interview with Louis C. Marquet, formerly of Lincoln Laboratory, DARPA, and SDIO, 18 February 2004; Defense Advanced Research Projects Agency, http://www.darpa.mil (accessed 12 December 2002); Perry, “Defense Advanced Research Projects Agency,” pp. 26–27. 31. Interview with Urtz, 20 November 2002; interview with Benedict, 28 October 2002; Defense Advanced Research Projects Agency, “Bridging the Gap,” p. 6. 32. Interview with Benedict, 28 October 2002; interview with Urtz, 20 November 2002; Rome Air Development Center, “Compensated Imaging Video Production” (unpublished script, n.d., archives of Air Force Research Laboratory, Kirtland Air Force Base, NM); John Gribbin, The Scientists: A History of Science Told Through the Lives of Its Greatest Inventors (New York: Random House, 2002), pp. 85–86.

Notes to pages 12–14

359

33. Interview with John C. Rich (Colonel, USAF, Retired), former commander of the Air Force Avionics Laboratory and Air Force Weapons Laboratory, 7 October 2004; interview with Lester L. Lyles (General, USAF, Retired), former commander of Air Force Materiel Command, 25 September 2007. 34. Interview with Urtz, 20 November 2002; interview with John W. Hardy, former Itek adaptive optics engineer, 20 January 2004. 35. Interview with Urtz, 20 November 2002; interview with Hardy, 20 January 2004; Peebles, Guardians, pp. 366–375. 36. Interview with Urtz, 20 November 2002; interview with Hardy, 20 January 2004; nomination for Harold Brown Award for Raymond P. Urtz Jr., Rome Air Development Center, 1981. 37. Interview with Anthony J. Tether, director, Defense Advanced Research Projects Agency, 19 May 2005; Rettig Benedict, e-mail message to author, 4 June 2003. 38. Benedict, e-mail message to author, 4 June 2003. 39. This is referred to as the “shower door” effect, whereby a hand or face pressed against the inside of the shower door can be easily seen from a distance outside of the shower door. Images of ground objects taken from space generally are better than images of space objects taken from the ground with telescopes not equipped with adaptive optics. Depending on turbulence conditions, conservatively speaking, images of ground objects taken from cameras in space are at least two to three times better than images of space objects taken from the ground. Most of the time, images of ground objects are eight to ten times clearer. Benedict, e-mail message to author, 4 June 2003; notes to author from John W. Hardy, 23 January 2004, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 40. Interview with Benedict, 28 October 2002; interview with William E. Thompson, technical advisor to the Air Force Laboratory/Directed Energy Financial and Program Management Division and former program manager, Ground-Based Laser Technology Program, 11 February 2003.

Chapter Two 1. Arthur H. Guenther, ed., International Trends in Adaptive Optics (Bellingham, WA: SPIE Press, 2002), pp. 542–544. 2. Most airline passengers have experienced a bumpy ride caused by the effects of velocity turbulence, random fluctuations in the velocity field, rather than thermal turbulence, which degrades light waves and makes images

360

|   Notes to pages 14–18

blurry. Interview with Benedict, 28 October 2002; interview with Urtz, 20 November 2002; interview with Donald W. Hanson, director, Air Force Research Laboratory Sensors Directorate, 19 November 2002; Glenn A. Tyler, Paul H. Merritt, Robert Q. Fugate, and Terry J. Brennan, “Adaptive Optics: Theory and Applications” (Technical Report AFRL-DE-PS-TR-1998–1054, Pt.1, the Optical Sciences Company, December 1999), pp. 2–8; Raymond P. Urtz Jr. and James W. Justice, “Compensated Imaging” (paper presented at the Optical Society of America Topical Meeting on Imaging in Astronomy, Harvard University, 18–20 June 1975); Francois Roddier, ed., Adaptive Optics in Astronomy (Cambridge, England: Cambridge University Press, 1999), p. 9; Robert Q. Fugate, “Laser Beacon Adaptive Optics,” Optics and Photonics News, June 1993, pp.14–19. 3. Interview with Benedict, 28 October 2002; interview with Urtz, 20 November 2002; interview with Hanson, 19 November 2002; Tyler et al., “Adaptive Optics,” pp. 2–8; Urtz and Justice, “Compensated Imaging”; Roddier, ed., Adaptive Optics in Astronomy, p. 9; Fugate, “Laser Beacon Adaptive Optics,” pp. 14–19; interview with Robert Q. Fugate, technical director, Starfire Optical Range, 16 December 2002; John W. Hardy, “Adaptive Optics,” Scientific American, June 1994, pp. 60–65. 4. Robert K. Tyson, Principles of Adaptive Optics (Boston: Academic Press, 1997), p. 3. 5. A short-wavelength oxygen-iodine laser is about 10 times more sensitive to atmospheric turbulence than a long-wavelength CO2 laser. Interview with Benedict, 28 October 2002; interview with Charles B. Hogge, AFRL, Directed Energy Directorate, 10 October 2002; interview with Urtz, 20 November 2002; interview with Hanson, 19 November 2002; interview with Robert S. Cooper, former director, DARPA, 18 May 2005; interview with Leonard John Otten III (Colonel, USAF, Retired), former commander, Weapons Laboratory, 9 June 2004; Roger Angel and Bob Fugate, “Adaptive Optics,” Science, 21 April 2000, pp. 455–456; Center for Adaptive Optics, http://www.cfao.ucolick.org. 6. Interview with Hogge, 10 October 2002; interview with Urtz, 20 November 2002; interview with Hanson, 19 November 2002; interview with Cooper, 18 May 2005; Angel and Fugate, “Adaptive Optics,” pp. 455–456. 7. Interview with Cooper, 18 May 2005; interview with Hanson, 19 November 2002; Hardy, “Adaptive Optics,” p. 65; Corey S. Powell, “Mirroring the Cosmos,” Scientific American, November 1991, pp. 115, 121; Tony Reichhardt, “Seeing Stars,” Air & Space, March 1996, pp. 68–69.

Notes to pages 18–20

361

8. Interview with Urtz, 20 November 2002; Raymond P. Urtz, e-mail message to author, 26 March 2003; Theodore H. Maiman, The Laser Odyssey (Blaine, WA: Laser Press, 2000), pp. 57–103; Greg Friedman, “Inventing the Light Fantastic: Ted Maiman and the World’s First Laser,” OE Reports, August 2000, p. 5. 9. Interviews with Urtz, 20 November 2002 and 27 March 2003; interview with Tether, 19 May 2005; Urtz, e-mail message to author, 26 March 2003; Tyler et al., “Adaptive Optics,” p. 2. 10. Interviews with Urtz, 20 November 2002 and 27 March 2003; Urtz, e-mail message to author, 26 March 2003; Tyler et al., “Adaptive Optics,” p. 2. 11. The mission of RADC in the mid-1960s was to “plan, formulate, present and execute the Air Force Systems Command Exploratory Development Programs in the electromagnetic areas of: transmission and reception; information processing display; reliability and compatibility; ground based surveillance; ground communications; intelligence; instrumentation and test; and related advanced development programs.” See Thomas W. Thompson, History of the Rome Air Development Center, Griffiss Air Force Base, New York: 1 January 1965–30 June 1965 (Griffiss Air Force Base, NY: Rome Air Development Center, 1965), p.1; interview with Hanson, 19 November 2002; David L. Fried, “My Recollection of Who Did What in the Early Development of Adaptive Optics” (unpublished manuscript in Fried files, September 1992); Phillip J. Klass, “Adaptive Optics Evaluated as Laser Aid,” Aviation Week & Space Technology, 24 August 1981, pp. 61–63, 65. 12. Comments by William E. Thompson to proposed “Questions for Gen. Nielsen,” 15 November 2002, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; Barry Hogge, “Beam Control: A Critical Part of a High Energy Laser,” briefing, 21 March 2001, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 13. Interview with Hanson, 19 November 2002; Raymond P. Urtz Jr., “Personal History—Biographical Data,” n.d., archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; USAF Biography, Raymond P. Urtz, January 2001. 14. Interview with Richard A. Hutchin, CEO, Optical Physics Company, 17 April 2003; interview with Hardy, 20 January 2004; interview with Thomas W. Thompson, Air Force Research Laboratory, Information Directorate, 29 May 2003. 15. Interview with Hanson, 19 November 2002; interview with Benedict, 28 October 2002; Charles B. Hogge, “Adaptive Optics in High Energy Laser Systems,” in Adaptive Optics and Short Wavelength Sources, ed. Stephen F.

362

|   Notes to pages 20–23

Jacobs, Murry Sargent III, and Marlan O. Scully (Reading, MA: AddisonWesley Publishing Company, 1978), pp. 55–66. 16. Interview with Hanson, 19 November 2002; interview with Benedict, 28 October 2002. 17. Interview with Hanson, 19 November 2002; interview with Benedict, 28 October 2002; interview with Urtz, 20 November 2002; “Development of ‘PATS’ Station Is Announced,” Newsreview (Air Force Systems Command), February 1968; Robert K. Tyson, Introduction to Adaptive Optics (Bellingham, WA: SPIE Press, 2000), pp. 2–3. 18. Interview with Hanson, 19 November 2002; interview with Urtz, 20 November 2002; RADC Technical Facilities Register (Technical Report RADC-TR-82–212), January 1983; “RADC Unveils PATS At Verona Test Annex,” Wave Guide (Griffiss Air Force Base newspaper), 7 March 1968. 19. Interview with Urtz, 20 November 2002; Urtz and Justice, “Compensated Imaging”; Thompson, History of the Rome Air Development Center, p. 26; Tyson, Introduction to Adaptive Optics, pp. 71–72. 20. Bob Hafnagel at Perkin-Elmer came up with the idea of shadow imaging. Interview with Urtz, 20 November 2002; Urtz and Justice, “Compensated Imaging”; Thompson, History of the Rome Air Development Center, p. 26; Tyson, Introduction to Adaptive Optics, pp. 71–72. 21. Interview with Urtz, 20 November 2002; Urtz and Justice, “Compensated Imaging”; Thompson, History of the Rome Air Development Center, p. 26; Tyson, Introduction to Adaptive Optics, pp. 71–72; “Amplitude Scintillation Study” (RADC Technical Report TR-68–416), December 1968; “Rome Lasers Studying Atmospheric Disturbances,” AFSC News Review, June 1967, p. 6; Thomas W. Thompson, The Fifty-Year Role of the United States Air Force in Advancing Information Technology: A History of the Rome, New York Ground Electronics Laboratory (Lewiston, NY: The Edwin Mellen Press, 2004), pp. 45–46. 22. Later in 1973, Rome also worked closely with Robert Lawrence at the National Oceanic and Atmospheric Administration, whose research aircraft flew 100 miles off the coast of San Diego to measure atmospheric turbulence at various altitudes. Interview with Urtz, 20 November 2002; Urtz and Justice, “Compensated Imaging”; Thompson, History of the Rome Air Development Center, p. 26; Tyson, Introduction to Adaptive Optics, pp. 71–72; “Amplitude Scintillation Study” (RADC Technical Report TR-68–416, December 1968); “Rome Lasers Studying Atmospheric Disturbances,” AFSC News Review, June 1967, p. 6; Thompson, The Fifty-Year Role of the United States Air Force in Advancing Information Technology, pp. 45–46; Peter Blankman, “Just a ‘Lamp’ from a B-57,” Utica Observer-Dispatch, 24 March 1968.

Notes to pages 23–26

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23. Interview with Urtz, 20 November 2002; Emily L. Tuck, “They’re Back: Area Persons Report Seeing UFO’s in Sky,” Daily Sentinel (Rome, NY), 16 March 1968. 24. Interview with Hanson, 19 November 2002; interview with Urtz, 20 November 2002; interview with Hardy, 20 January 2004. 25. Paul Donnelly, ed., The Itek News, September 1957; notes to author from John Hardy, 20 January 2004; Jonathan E. Lewis, Spy Capitalism: Itek and the CIA (New Haven: Yale University Press, 2002), pp. 2, 37–40. 26. The RAND Corporation (its name derived from the term research and development) is a nonprofit research organization made up of civilian scientists and engineers that advises public and private decision-makers on a variety of topics, including national defense. RAND began as a special project under contract to Douglas Aircraft Company in December 1945. In 1948, it became an independent think tank headquartered in Santa Monica, California. RAND provided the Army Air Forces and then the Air Force with scientific research and development assessments to better define the types of technology that would be needed to fight the wars of the future. Donnelly, The Itek News; Curtis Peebles, The CORONA Project: America’s First Spy Satellites (Annapolis, MD: Naval Institute Press, 1997), pp. 2–3. See also Lewis, Spy Capitalism, and Phillip Taubman, Secret Empire: Eisenhower, The CIA, and The Hidden Story of America’s Space Espionage (New York: Simon & Shuster, 2003). 27. Donnelly, The Itek News; Curtis Peebles, The CORONA Project: America’s First Spy Satellites (Annapolis, MD: Naval Institute Press, 1997), pp. 2–3. See also Lewis, Spy Capitalism, and Taubman, Secret Empire. 28. Donnelly, The Itek News; Peebles, The CORONA Project, pp. 11–13; R. Cargill Hall, “Post War Strategic Reconnaissance and the Genesis of Project Corona,” in Corona Between the Sun and the Earth: The First NRO Reconnaissance Eye in the Sky, ed. Robert A. McDonald (Bethesda, MD: American Society for Photogrammetry and Remote Sensing, 1997), pp. 36–37, 48. 29. Donnelly, The Itek News; F. Dow Smith, “History of Optics at Itek,” Applied Optics, December 1972, pp. 2729–2738; F. Dow Smith, “The Design and Engineering of Corona’s Optics,” in Corona Between the Sun and the Earth: The First NRO Reconnaissance Eye in Space, ed. Robert A. McDonald (Bethesda, MD: The American Society for Photogrammetry and Remote Sensing, 1997), pp. 111–120. 30. Thor missiles were intermediate-range ballistic missiles (IRBMs), and Atlas missiles were intercontinental ballistic missiles (ICBMs). Interview with Hardy, 20 January 2004; Donnelly, The Itek News; Kevin C. Ruffner, ed.,

364

|   Notes to pages 26–29

CORONA: America’s First Satellite Program (Washington, DC: Center for the Study of Intelligence, Central Intelligence Agency, 1995), pp. 4, 10–11. 31. Ruffner, CORONA, pp. xiii–xiv, 2, 22–24; “Spies That Fly,” NOVA, PBS, transcript updated for 24 February 2004 rebroadcast; Freedom’s Sentinel in Space (CD-ROM, The National Reconnaissance Office); Smith, “The Design and Engineering of Corona’s Optics,” pp. 111–120. 32. Interview with Hanson, 19 November 2002; interview with Urtz, 20 November 2002; interview with Benedict, 28 October 2002; interview with Hutchin, 17 April 2003. 33. Interview with Benedict, 28 October 2002; interview with Jay Richard Vyce, former director of marketing at Itek, 20 January 2004; interview with Hardy, 20 January 2004; interview with Charles Higgs, Lincoln Laboratory, 21 January 2004; notes to author from Hardy, 20 January 2004. 34. Interview with Benedict, 28 October 2002; interview with Vyce, 20 January 2004; interview with Hardy, 20 January 2004; interview with Higgs, 21 January 2004; notes to author from Hardy, 20 January 2004. 35. Interview with Hutchin, 17 April 2003; interview with Mark A. Ealey, president of Xinetics Inc., 23 January 2004; interview with Benedict, 28 October 2002. 36. Interview with Hardy, 20 January 2004; notes to author from Hardy, 20 January 2004; biographical information by John Hardy, 23 January 2004, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 37. Interview with Hanson, 19 November 2002; interview with Hutchin, 17 April 2003; interview with Hardy, 20 January 2004; John Hardy, “Space Object Imaging from the Earth’s Surface” (Itek Technical Report 72-35911), 30 November 1972; J. R. Vyce, “Space Object Identification [SOI] and Re-entry Vehicle Observation [RVO] Briefing Preparation,” memorandum, 21 June 1972, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; notes to author from Hardy, 20 January 2004; Lewis, Spy Capitalism, pp. 1–3. 38. Interview with Vyce, 20 January 2004; interview with Hardy, 20 January 2004; notes to author from Hardy, 23 January 2004. 39. Interview with Vyce, 20 January 2004; interview with Hardy, 20 January 2004; interview with Benedict, 28 October 2002; notes to author from Hardy, 23 January 2004. 40. Interview with Vyce, 20 January 2004; interview with Hardy, 20 January 2004; notes to author from Hardy, 23 January 2004.

Notes to pages 30–33

365

41. Interview with Hanson, 19 November 2002; Sir Isaac Newton, Opticks or a Treatise of the Reflections, Defractions, Inflections & Colours of Light, first published in 1704 (New York: Dover Publication, 1979), p. 111. 42. H. W. Babcock, “The Possibility of Compensating Astronomical Seeing,” Astronomical Society of the Pacific, October 1953, pp. 229–236; Tyson, Introduction to Adaptive Optics, pp. 5, 33. 43. Interview with Hogge, 10 October 2002; interview with Urtz, 27 March 2003; V. I. Tatarskii, Wave Propagation in a Turbulent Medium, translated by R. A. Silverman (New York: McGraw-Hill, 1961). 44. Interview with Hardy, 20 January 2004; Babcock, “The Possibility of Compensating Astronomical Seeing,” pp. 229–236; Horace W. Babcock, “Adaptive Optics Revisited,” Science, 20 July 1990, p. 253; John W. Hardy, Adaptive Optics for Astronomical Telescopes (New York: Oxford University Press, 1998), pp.12–13; Rettig Benedict Jr., James B. Breckinridge, and David Fried, “Atmospheric-Compensation Technology,” Journal of the Optical Society of America, January 1994, pp. 255–260. 45. Interview with Hanson, 19 November 2002; interview with James C. Wyant, University of Arizona, College of Optical Sciences, 15 September 2004; Benedict, Breckinridge, and Fried, “Atmospheric-Compensation Technology,” pp. 255–260; notes to author from Hardy, 23 January 2004; Hardy, Adaptive Optics for Astronomical Telescopes, p. 18; John W. Hardy, Real-Time Wavefront Correction System, U.S. Patent 3,923,400, filed 16 January 1973 and issued 2 December 1975. 46. Itek originally tried using a bismuth silicon oxide crystal to make the wavefront corrections, but the crystal was unable to transmit an adequate amount of light and had only a very limited range of phase correction. Interview with Hardy, 20 January 2004; interview with Wyant, 15 September 2004; interview with Hutchin, 17 April 2003; Tyler et al., “Adaptive Optics,” pp. 8–9; Tyson, Introduction to Adaptive Optics, pp. 5, 19; J. C. Wyant, “White Light Extended Source Shearing Interferometer,” Applied Optics, January 1974, pp. 200–202; SPIE, http://www.spie.org; Hardy, Adaptive Optics for Astronomical Telescopes, p. 18. 47. There are four types of deformable mirrors. One is a segmented mirror made up of small identical mirrors butted up against one another. Its disadvantage is that there is a fitting error where each mirror segment meets its neighbor, causing minute irregularities on the surface. A second type of mirror—the most widely preferred—is a continuous-surface deformable mirror with a flexible, continuous facesheet that responds as a single unit. A third type is a bimorph mirror consisting of an electrode sandwiched between piezoelectric wafers. In addition, Marcel Golet at Perkin-Elmer proposed a membrane

366

|   Notes to pages 33–35

deformable mirror; it never worked very well, but it was a competitor to Itek’s early deformable mirror. See Roddier, Adaptive Optics in Astronomy, pp. 70–73. Interview with Hardy, 20 January 2004; Tyler et al., “Adaptive Optics,” pp. 8–9; Tyson, Introduction to Adaptive Optics, pp. 5, 19; SPIE, http://www.spie.org; Hardy, Adaptive Optics for Astronomical Telescopes, p. 18. 48. Interview with Hardy, 20 January 2004; interview with Hanson, 19 November 2002; interview with Vyce, 20 January 2004; David L. Fried, “Adaptive Optics Development: A 30-Year Personal Perspective,” Proceedings of SPIE: Laser Weapons Technology II, 16–17 April 2001, p. 7; “Take Twinkle Out Of Stars? New Photo Device to Eliminate Atmospheric Distortions,” The San Diego Union, 16 June 1975; Tyler et al., “Adaptive Optics,” p. 6; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 18–19, 181; Hardy, “Adaptive Optics,” pp. 60–65; Mark A. Ealey and John F. Washeba, “Continuous Facesheet Low Voltage Deformable Mirrors,” Optical Engineering, October 1990, pp. 1191–1198. 49. Interview with Hardy, 20 January 2004; interview with Hanson, 19 November 2002; interview with Vyce, 20 January 2004; Fried, “Adaptive Optics Development,” p. 7; “Take Twinkle Out Of Stars?”; Tyler et al., “Adaptive Optics,” p. 6; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 18–19, 181; Hardy, “Adaptive Optics,” pp. 60–65; Ealey and Washeba, “Continuous Facesheet Low Voltage Deformable Mirrors,” pp. 1191–1198. 50. Interview with Hardy, 20 January 2004; interview with Hanson, 19 November 2002; interview with Vyce, 20 January 2004; Fried, “Adaptive Optics Development,” p. 7; “Take Twinkle Out Of Stars?”; Tyler et al., “Adaptive Optics,” p. 6; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 18–19, 181; Hardy, “Adaptive Optics,” pp. 60–65; Ealey and Washeba, “Continuous Facesheet Low Voltage Deformable Mirrors,” pp. 1191–1198; Robert Q. Fugate, “Laser Guide Star Adaptive Optics For Compensated Imaging,” in The Infrared and Electo-Optical Systems Handbook: Emerging Systems and Technologies, Vol. 8, ed. Stanley R. Robinson (Bellingham, WA: SPIE Optical Engineering Press, 1993), p. 135. 51. Tyler et al., “Adaptive Optics,” p. 5. 52. Interview with Ealey, 23 January 2004. 53. Robert K. Tyson and Peter B. Ulrich, “Adaptive Optics,” in The Infrared and Electo-Optical Systems Handbook: Emerging Systems and Technologies, Vol. 8, ed. Robinson, p. 167. 54. Interview with William Thompson, 9 October 2002; interview with Hogge, 10 October 2002; Tyler et al., “Adaptive Optics,” p. 20.

Notes to pages 36–39

367

Chapter Three 1. Interview with Urtz, 20 November 2002. 2. Interview with Urtz, 20 November 2002; “Dr. Donald W. Hanson,” U.S. Air Force Biographies, October 2000. 3. Interview with Urtz, 20 November 2002; “Dr. Donald W. Hanson.” 4. Interview with Urtz, 20 November 2002; interview with Hutchin, 17 April 2003; interview with Hardy, 20 January 2004. 5. Interview with David L. Fried, mathematician and former CEO of the Optical Sciences Company, 2 April 2003; interview with Hutchin, 17 April 2003; interview with Hardy, 20 January 2004; interview with Thomas W. Meyer (Colonel, USAF, Retired), formerly with the Strategic Defense Initiative Organization, 6 December 2004. 6. For some laboratory experiments, the light passed through a piece of plate glass that distorted the wavefront to simulate the effects of atmospheric turbulence. The goal was to determine if the distortions could be removed using adaptive optics. Interview with Hanson, 19 November 2002; “RTAC I: Informal Operating Instructions for RTAC Feasibility Model,” n.d.; Patrick J. Martone, “Use of Adaptive Optics in Visible Wavelength C3I Systems” (Technical Report RADC-TR-82–265, Rome Air Development Center, October 1982), pp. 1–8. 7. Hardy, Joseph Lefebvre, and Steven Moody (all assigned to the Optical Systems Division of Itek) worked full time to develop RTAC technology. Interview with Hardy, 20 January 2004; John W. Hardy, Adaptive Optics for Astronomical Telescopes (New York: Oxford University Press, 1998), pp. 18–19; John W. Hardy, “Adaptive Optics,” Scientific American, June 1994, p. 63; John Hardy, “Compensated Imaging,” paper presented at the 14th Winter Colloquium on Quantum Electronics, Snowbird, Utah, January 1984. 8. Just a little over 2 years after Hardy demonstrated the first closed-loop RTAC adaptive optics system, S. L. McCall, T. R. Brown, and A. Passner of Bell Laboratories in Murry Hill, New Jersey, demonstrated the first closedloop adaptive optics system using a telescope in February 1976. They used a 14-inch aperture on a 36-inch telescope at Princeton University Observatory to actively correct for atmospheric phase aberrations when capturing images of the star Sirius. For details, see S. L McCall, T. R. Brown, and A. Passner, “Improved Optical Stellar Image Using a Real-Time Phase-Correction System: Initial Results,” The Astrophysical Journal, 15 January 1977, pp. 463–468. Interview with Hardy, 20 January 2004; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 18–19; Hardy, “Adaptive Optics,” p. 63; Hardy, “Compensated Imaging.”

368

|   Notes to pages 41–45

9. Interview with Hanson, 19 November 2002; Horace W. Babcock, “Adaptive Optics Revisited” (Bellingham, WA: SPIE Milestone Series 92: 2), p. 253. 10. Interview with Hanson, 19 November 2002; Babcock, “Adaptive Optics Revisited,” p. 253. 11. Donald Hanson, e-mail message to author, 23 December 2002; Glenn A. Tyler, Paul Merritt, Robert Q. Fugate, and Terry J. Brennan, “Adaptive Optics: Theory and Applications” (Technical Report AFRL-DE-PS-TR-1998–1054, Pt.1, The Optical Sciences Company, December 1999), pp. 8–9. 12. Interview with Hanson, 19 November 2002; interview with Hardy, 20 January 2004. 13. Interview with Hanson, 19 November 2002; interview with Higgs, 21 January 2004; Donald Hanson, “Field Tests of RTAC” (scientific notebook entry), 14 February 1974; John Hardy, “Initial Tests on RTAC at Verona,” memorandum to D. C. Smith, 7 June 1974; Tyler et al., “Adaptive Optics,” pp. 8–9; Rettig Benedict, Jr., James B. Breckinridge, and David Fried, “Atmospheric-Compensation Technology,” Journal of the Optical Society of America, January 1994, pp. 255–260. 14. John W. Hardy, Julius Feinleib, and James C. Wyant, “Real-Time Phase Correction of Optical Imaging Systems,” paper presented at a meeting of the Optical Society of America, University of Colorado, Boulder, CO, 9–11 July 1974; Benedict, Breckinridge, and Fried, “Atmospheric-Compensation Technology,” pp. 255–260. 15. Ray Urtz and James Justice presented a paper at Harvard University in 1975, addressing atmospheric turbulence and techniques for compensating for real-time wavefront errors. See Raymond P. Urtz Jr. and James W. Justice, “Compensated Imaging,” paper presented at the Optical Society of America Topical Meeting on Imaging in Astronomy, Harvard University, 12 June 1975. Interview with Marquet, 18 February 2004; Martone, “Use of Adaptive Optics,” p. 9. 16. Interview with Benedict, 28 October 2002; interview with Hanson, 19 November 2002; interview with Tether, 19 May 2005; Hardy, “Adaptive Optics,” pp. 60–61; “Take Twinkle Out Of Stars?”; “Telescope Spurs Hope For Clearer Images,” The News and Observer (Raleigh, North Carolina), 16 June 1975. 17. Interview with Benedict, 28 October 2002; interview with Urtz, 20 November 2002; Fried, “Adaptive Optics Development,” pp. 1, 12; Corinna Wu, “Supernormal Vision,” Science News, 15 November 1997, http:// www.sciencenews.org/sn_arc97/11_15_97/bob1.htm (accessed 14 May 2002). 18. Interview with Hardy, 20 January 2004.

Notes to pages 46–49

369

19. In 1977, Itek’s RTAC was tested on Harvard’s 1.55-meter telescope. Interview with Hardy, 20 January 2004; interview with Hanson, 19 November 2002; interview with Urtz, 20 November 2002; interview with Benedict, 28 October 2002. 20. Interview with Hanson, 19 November 2002; Hardy, “Adaptive Optics,” p. 63. 21. The original name of AMOS stood until 1977, when it was renamed the Air Force Maui Optical Station. Today, AMOS stands for the Air Force Maui Optical and Supercomputing Site. Before the arrival of the CIS, the 1.6-meter telescope used radar to acquire images of satellites. Those were generally poor-resolution images. Interview with Hanson, 19 November 2002; Hardy, “Adaptive Optics,” p. 63; Raymond P. Urtz, “Compensated Imaging Program History,” information paper, 6 January 2003, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; notes to author from John Hardy, 19 January 2004. 22. Interview with Hanson, 19 November 2002; Hardy, “Adaptive Optics,” p. 63; Urtz, “Compensated Imaging Program History”; notes to author from Hardy, 19 January 2004; interview with Hutchin, 17 April 2003. 23. Later, under a separate contract to Perkin-Elmer, Bob Hufnagel showed that it was impractical to design a membrane mirror. Interview with Hanson, 19 November 2002; interview with Fried, 2 April 2003; interview with Hardy, 20 January 2004; Fried, “My Recollection of Who Did What in the Early Development of Adaptive Optics,” unpublished manuscript in Fried files, September 1992; Itek Optical Systems, “Compensated Imaging System Operation and Maintenance Manual: Volume I—System and Hardware Description, Installation, and Maintenance,” November 1981, p. 2–3. 24. In 1979 Richard Hudgin changed his name to Hutchin because it seemed easier for clients to pronounce and remember. Interview with Hanson, 19 November 2002; interview with Fried, 2 April 2003; interview with Hardy, 20 January 2004; Fried, “My Recollection of Who Did What”; Itek Optical Systems, “Compensated Imaging System Operation and Maintenance Manual.” 25. Interview with Hanson, 19 November 2002; interview with Fried, 2 April 2003; interview with Hardy, 20 January 2004; Fried, “My Recollection of Who Did What”; Itek Optical Systems, “Compensated Imaging System Operation and Maintenance Manual”; Urtz, “Compensated Imaging Program History.” 26. In a related program, Rome started work in 1976 on the High Altitude Large Optics program to develop new techniques for fabricating large lightweight mirrors to be placed in space for a number of laser-related missions. Interview with Hanson, 19 November 2002; interview with Fried, 2 April 2003; interview with Hardy, 20 January 2004; interview with Urtz, 20 November 2002; Fried,

370

|   Notes to pages 49–52

“My Recollection of Who Did What”; Itek Optical Systems, “Compensated Imaging System Operation and Maintenance Manual”; Urtz, “Compensated Imaging Program History”; George H. Heilmeier (director, Defense Research Projects Agency), “Defense Advanced Research Projects Agency [ARPA] Plans for the ARPA Maui Optical Station [AMOS],” letter to Commander, Rome Air Development Center, Griffiss Air Force Base, 1 April 1976; Donald Hanson, e-mail message to author, 5 February 2003. 27. Interview with Urtz, 20 November 2002; Hardy, Adaptive Optics for Astronomical Telescopes, p. 21. 28. Interview with Hardy, 20 January 2004; notes to author from Hardy (subject: AO Questions), 19 January 2004; Itek Optical Systems, “Compensated Imaging System Operation and Maintenance Manual,” pp. 2:1–2:22. 29. Urtz and Justice, “Compensated Imaging,” 12 June 1975; Urtz, “Compensated Imaging Program History”; Martone, “Use of Adaptive Optics,” pp. 9–11, 19–20; Hardy, “Adaptive Optics,” p. 61. 30. Interview with Hanson, 19 November 2002. 31. Notes to author from Jim Mayo, 19 January 2007. 32. Notes to author from Jim Mayo, 19 January 2007; Tyler et al., “Adaptive Optics,” p. 9; Urtz, “Compensated Imaging Program History.” 33. Interview with Urtz, 20 November 2002. 34. Interview with Hanson, 19 November 2002. 35. Interview with Hanson, 19 November 2002; “FY 82 Accomplishments” (Technical Report RADC-TR-82–1, RADC Electronic Systems Division, Griffiss Air Force Base, NY, December 1982), pp. 8–9; Hardy, “Adaptive Optics,” p. 63. 36. Interview with Hanson, 19 November 2002; interview with Hutchin, 17 April 2003; “FY 82 Accomplishments,” pp. 8–9; Hardy, “Adaptive Optics,” p. 63; Thomas W. Thompson, The Fifty-Year Role of the United States Air Force in Advancing Information Technology: A History of the Rome, New York Ground Electronics Laboratory (Lewiston, NY: The Edwin Mellen Press, 2004), p. 47. 37. Interview with Urtz, 20 November 2002. 38. Rome Air Development Center, “Compensated Imaging Video Production,” undated script; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 20–24; Thomas W. Thompson, History of the Rome Air Development Center, Griffiss Air Force Base, New York: 1 January 1965–30 June 1965 (Griffiss Air Force Base, NY: Rome Air Development Center, 1965), p. 27; Michael Lloyd-Hart, “Taking the Twinkle Out of Starlight,” IEEE Spectrum, December 2003, p. 25. Notes to pages 53–57

371

39. Interview with Hutchin, 17 April 2003; Rome Air Development Center, “Compensated Imaging Video Production”; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 20–24; Thompson, History of the Rome Air Development Center, p. 27; Lloyd-Hart, “Taking the Twinkle Out of Starlight,” p. 25; Benedict, Breckinridge, and Fried, “AtmosphericCompensation Technology,” pp. 255–260. 40. Interview with Urtz, 20 November 2002; interview with Hanson, 19 November 2002; interview with Hogge, 10 October 2002; interview with Hutchin, 17 April 2003; interview with Wyant, 15 September 2004; Rome Air Development Center, “Compensated Imaging Video Production”; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 20–24; Thompson, History of the Rome Air Development Center, p. 27; Lloyd-Hart, “Taking the Twinkle Out of Starlight,” p. 25; Benedict, Breckinridge, and Fried, “AtmosphericCompensation Technology,” pp. 255–260; Thompson, History of the Rome Air Development Center, pp. 27–28. 41. Interview with Urtz, 20 November 2002; interview with Hanson, 19 November 2002; interview with Hogge, 10 October 2002; interview with Hutchin, 17 April 2003; interview with Wyant, 15 September 2004; Rome Air Development Center, “Compensated Imaging Video Production”; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 20–24; Thompson, History of the Rome Air Development Center, p. 27; Lloyd-Hart, “Taking the Twinkle Out of Starlight,” p. 25; Benedict, Breckinridge, and Fried, “AtmosphericCompensation Technology,” pp. 255–260; Thompson, History of the Rome Air Development Center, pp. 27–28. 42. Interview with Hanson, 19 November 2002. 43. Interview with Hanson, 19 November 2002. 44. Interview with Hardy, 20 January 2004; nomination for Harold Brown Award for Raymond P. Urtz Jr., Rome Air Development Center, 1981. 45. Nomination for Harold Brown Award for Raymond P. Urtz Jr. 46. Nomination for Harold Brown Award for Raymond P. Urtz Jr. 47. Interview with Urtz, 20 November 2002; interview with Major General Paul D. Nielsen, commander, Air Force Research Laboratory, 19 November 2002. 48. Interview with Urtz, 20 November 2002; interview with Hanson, 12 November 2002; Hardy, Adaptive Optics for Astronomical Telescopes, pp. 21, 24; Hardy, “Compensated Imaging.” 49. Notes to author from Hardy, 20 January 2004. 50. Interview with Urtz, 20 November 2002; interview with Hanson, 19 November 2002. 51. Interview with Nielsen, 19 November 2002; background paper on the ARPA Maui Optical Station (AMOS), from the files of Ray Urtz, n.d.; background

372

|   Notes to pages 58–62

paper on Maui site, n.d., in Phillips Research Site archives; DoD Dictionary of Military Terms, http://www.dtic.mil/doctrine/jel/doddict (accessed 15 January 2009). 52. Jim Mayo, “WPAFB/AFAL 1960s and 1970s Atmospheric Turbulence Measurements and Compensation Research Input for R. Duffner,” notes, September 2004; Air Force Avionics Laboratory (brochure, Air Force Avionics Laboratory, Research and Technology Division, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio, 1 October 1965), pp. 8–11. 53. Mayo, “WPAFB/AFAL 1960s and 1970s Atmospheric Turbulence”; Air Force Avionics Laboratory. 54. At the height of the Strategic Defense Initiative (SDI) in the 1980s, Itek did venture into directed energy, working on developing a liquid-cooled deformable mirror that could accommodate a high-energy laser beam. But that effort did not progress very far because of the uncertainty of a strong commitment by SDI to directed energy, especially when funding dried up with de-emphasis on SDI and the end of the Cold War. Interview with Ealey, 23 January 2004; interview with Higgs, 21 January 2004; interview with Tether, 19 May 2005. 55. By the mid-1990s the mirror manufacturing business had changed considerably for contractors. Because of the cyclical nature of the directedenergy marketplace, United Technologies Optical Systems (UTOS) went out of business in 1995. In February 1996, Itek was bought out by Hughes Danbury Optical Systems. That left the door open for Xinetics (formed in 1993) to assume the roles previous carried out by Itek and UTOS. Xinetics produced deformable mirrors for both imaging and directed-energy applications and quickly became the military’s foremost supplier of mirrors. The company built the mirrors for the Space-Based Laser, the 3.5-meter telescope at Starfire Optical Range, the 3.67-meter Advanced Electro-Optical System telescope at Maui, and the new Airborne Laser. Despite these accomplishments, Ealey related that only about 15% of his business was devoted to deformable mirrors because there was not enough demand to sustain higher levels. Interview with Ealey, 23 January 2004; interview with Higgs, 21 January 2004; interview with Tether, 19 May 2005; Mark A. Ealey, “Large Optics in the 21st Century: A Transition from Discrete Manufacturing to Highly Integrated Techniques,” Proceedings of SPIE, March 8–15, 2003, pp. 4:1705–4:1716.

Chapter Four 1. Interview with William Thompson, 11 February 2003; interview with Urtz, 20 November 2002.

Notes to pages 63–65

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2. Interview with William Thompson, 11 February 2003; interview with Urtz, 20 November 2002. 3. Interview with William Thompson, 11 February 2003; interview with Fugate, 16 December 2002. 4. Interview with William Thompson, 11 February 2002; interview with Lyles, 25 September 2007; Phillips Laboratory, Lasers and Imaging Directorate, “Adaptive Optics Imaging Technology Supports Weapons and Surveillance Needs,” briefing, 18 June 1993. 5. Interview with William Thompson, 11 February 2002; interview with Hogge, 10 October 2002; interview with Benedict, 28 October 2002; Roger H. Ressmeyer, “Robert Q. Fugate: Starfire’s Magician Optician,” Sky & Telescope, May 1994, pp. 21–22; John W. Hardy, “Adaptive Optics,” Scientific American, June 1994, pp. 60–61. 6. Interview with Fugate, 21 April 2003; Greg Peisert, “Robert Fugate” (remarks, Miami Valley Astronomical Society meeting, Miami, Ohio, September 1999). 7. Interview with Fugate, 21 April 2003. 8. Interview with Fugate, 21 April 2003. 9. Interview with Fugate, 21 April 2003; USAF biography, Robert Q. Fugate, September 2000; Jim Babcock, “Star Light, Image Bright: Ex-Resident Perfects Laser Technology,” Dayton Daily News, 4 September 1991. 10. Interview with Fugate, 21 April 2003; Mark Sincell, “Making the Stars Stand Still,” Astronomy, June 2000, pp. 43–47. 11. Interview with William Thompson, 9 October 2002; interview with Otten, 9 June 2004; interview with John J. Russell (Colonel, USAF, Retired), University of New Mexico, Department of Mechanical Engineering, 7 July 2004; Peisert, “Robert Fugate.” 12. Interview with William Thompson, 9 October 2002; interview with Otten, 9 June 2004; interview with Russell, 7 July 2004; Peisert, “Robert Fugate.” 13. Interview with William Thompson, 9 October 2002; interview with Otten, 9 June 2004; interview with Russell, 7 July 2004; interview with Hogge, 10 October 2002; interview with Paul D. Nielsen, 19 November 2002; interview with R. Earl Good, director, Directed Energy Directorate, Air Force Research Laboratory, 10 December 2002; Peisert, “Robert Fugate.” 14. Interview with Meyer, 6 December 2004. 15. Interview with Fugate, 21 April 2003. 16. There was never any interest in using an adaptive optics system for the ALL because of the long wavelength of its CO2 laser, which was not significantly

374

|   Notes to pages 66–72

affected by atmospheric turbulence or thermal blooming at short firing ranges. Interviews with Fugate, 16 December 2002 and 21 April 2003. 17. John Rich, former commander of the Air Force Avionics Laboratory and Air Force Weapons Laboratory, believed Fugate needed to move from the Avionics Laboratory to the Weapons Laboratory, where he would get better support and funding for the type of research he wanted to conduct. Interview with Rich, 7 October 2004; interviews with Fugate, 16 December 2002 and 21 April 2003. 18. Interview with Fugate, 21 April 2003. 19. Interview with Fugate, 21 April 2003; Nomination for Giller Award, Robert Q. Fugate, Air Force Weapons Laboratory, n.d., ca. 1984. 20. Interview with Fugate, 21 April 2003. 21. Interview with Benedict, 28 October 2002; interview with William Thompson, 9 October 2002. 22. Interview with Benedict, 28 October 2002; interview with William Thompson, 9 October 2002. 23. Interview with Benedict, 28 October 2002; William Thompson, “Assessment and Recommendations: Desirability of Modifications to Current Classification and Public Release Policies for Adaptive Optics and Artificial Beacon Technologies,” Phillips Laboratory, Lasers and Imaging, 11 March 1991, pp. 7–8. 24. Interview with Benedict, 28 October 2002; interview with Hutchin, 17 April 2003; interview with Benedict, 3 March 2003; interview with Hanson, 7 March 2003; Rettig Benedict, Jr., James B. Breckinridge, and David Fried, “Atmospheric-Compensation Technology,” Journal of the Optical Society of America, January 1994, pp. 255–260; John W. Hardy, Adaptive Optics for Astronomical Telescopes (New York: Oxford University Press, 1998), p. 217; Malcolm Browne, “Anti-Missile Technology Delights Astronomers,” The New York Times, 6 August 1991. 25. Interview with Benedict, 28 October 2002; interview with Hutchin, 17 April 2003; interview with Benedict, 3 March 2003; interview with Hanson, 7 March 2003; Benedict, Breckinridge, and Fried, “AtmosphericCompensation Technology,” pp. 255–260; Robert K. Tyson, Introduction to Adaptive Optics, (Bellingham, WA: SPIE Press, 2000), p. 9. 26. Interview with Fugate, 16 December 2002; interview with Hutchin, 17 April 2003; Benedict, Breckinridge, and Fried, “AtmosphericCompensation Technology,” pp. 255–260; David L. Fried, “Adaptive Optics Development: A 30-Year Personal Perspective,” Proceedings of SPIE: Laser Weapons Technology II, 16–17 April 2001, p. 11; Robert Q. Fugate and

Notes to pages 72–75

375

Walter J. Wild, “Untwinkling the Stars: Part I,” Sky & Telescope, May 1994, pp. 24–31; Hardy, Adaptive Optics for Astronomical Telescopes, p. 218; Adaptive Optics Associates, http://www.aoainc.com (accessed 16 June 2004); Ronald A. Humphreys, Lee C. Bradley, and Jay Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” Lincoln Laboratory Journal, Spring 1992, p. 46; Ronald R. Parenti, Robert H. Kingston, and Charles Higgs, “High-Energy Lasers and Laser Propagation,” Lincoln Laboratory Journal (Special Issue on Ballistic Missile Defense), 2002, p. 233. 27. Interview with Fugate, 16 December 2002; interview with Hutchin, 17 April 2003; Benedict, Breckinridge, and Fried, “AtmosphericCompensation Technology,” pp. 255–260; Fried, “Adaptive Optics Development,” p. 11; Fugate and Wild, “Untwinkling the Stars: Part I,” pp. 24–31; Hardy, Adaptive Optics for Astronomical Telescopes, p. 218; Adaptive Optics Associates; Humphreys, Bradley, and Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” p. 46; Parenti, Kingston, and Higgs, “High-Energy Lasers and Laser Propagation,” p. 233; Richard A. Hutchin and J. Richard Vyce, letter to the editor, Physics Today, 17 August 1992; Richard A. Hutchin, “History and Physical Principles of Lodestar Technology,” briefing to the Optical Society of America, 8 November 1991. 28. Interviews with Benedict, 28 October 2002 and 3 March 2003; interview with Hanson, 7 March 2003; interview with Hutchin, 17 April 2003; interview with Fried, 2 April 2003; interview with Tether, 19 May 2005; Francois Roddier, Adaptive Optics in Astronomy (Cambridge, UK: Cambridge University Press, 1999), p. 265. 29. Interviews with Benedict, 28 October 2002 and 3 March 2003; interview with Hanson, 7 March 2003; interview with Hutchin, 17 April 2003; interview with Fried, 2 April 2003; interview with Tether, 19 May 2005; Roddier, Adaptive Optics in Astronomy, p. 265. 30. Interviews with Benedict, 28 October 2002 and 3 March 2003; interview with Hanson, 7 March 2003; interview with Hutchin, 17 April 2003; interview with Fried, 2 April 2003; interview with Tether, 19 May 2005; interview with Fugate, 16 December 2002; interview with William Thompson, 9 October 2002; Roddier, Adaptive Optics in Astronomy, p. 265; Benedict, Breckinridge, and Fried, “Atmospheric-Compensation Technology,” pp. 255–260; Robert Q. Fugate, David L. Fried, George A. Ameer, Bruce R. Boeke, Steven L. Browne, Phillip R. Roberts, Raymond E. Ruane, Glenn A. Tyler, and Lawrence M. Wopat, “Measurement of Atmospheric Wavefront Distortion Using Scattered Light from a Laser Guide-Star,” Nature, 12 September 1991, pp. 144–146.

376

|   Notes to pages 75–76

31. Interview with Fugate, 16 December 2002; interview with Benedict, 28 October 2002. 32. Interview with Fugate, 16 December 2002; interview with Benedict, 28 October 2002; interview with Fried, 2 April 2003; Graham P. Collins, “Making Stars to See Stars: DOD Adaptive Optics Work Is Declassified,” Physics Today, February 1992, pp. 17–21. 33. The word focal comes from the fact that the laser beam is focused at a finite range. Interview with Benedict, 28 October 2003; interview with Fugate, 16 December 2002; interview with William Thompson, 9 October, 2002; Roddier, Adaptive Optics in Astronomy, p. 261. 34. Interview with Benedict, 28 October 2003; interview with Fugate, 16 December 2002; interview with William Thompson, 9 October, 2002; Roddier, Adaptive Optics in Astronomy, p. 261; Glenn A. Tyler et al., “Adaptive Optics: Theory and Applications” (Technical Report AFRL-DEPS-TR-1998–1054, Pt. 1, the Optical Sciences Company, December 1999), pp. 10–11; Collins, “Making Stars to See Stars,” p. 18. 35. Interview with Benedict, 28 October 2003; interviews with Fugate, 16 December 2002 and 20 May 2003; interviews with William Thompson, 9 October, 2002 and 11 February 2003; interview with Fried, 2 April 2003; interview with William Happer, Princeton University, Department of Physics, 29 September 2005; Roddier, Adaptive Optics in Astronomy, p. 261; Tyler et al., “Adaptive Optics,” pp. 10–11; Collins, “Making Stars to See Stars,” p. 18. 36. Interview with Fried, 2 April 2003; interview with Fugate, 20 May 2003; Fugate and Wild, “Untwinkling the Stars: Part I,” p. 27. 37. Interview with Fried, 2 April 2003; interview with Fugate, 20 May 2003; interview with Glenn A. Tyler, CEO, the Optical Sciences Company, 10 July 2007; Fugate et al., “Measurement of Atmospheric Wavefront Distortion,” p. 144; Fugate and Wild, “Untwinkling the Stars: Part I” pp. 26–27. 38. Interview with Benedict, 28 October 2003; interview with Fugate, 16 December 2002; Deborah Shapley, “Jason Division: Defense Consultants Who Are Also Professors Attacked,” Science, 2 February 1973, pp. 459–462, 505. For a history of the Jasons, see Ann K. Finkbeiner, The Jasons: The Secret History of Science’s Postwar Elite (New York: Viking Press, 2006). 39. Others facetiously claimed Jason stood for Junior Achievers, Somewhat Older Now. Interview with Benedict, 28 October 2003; interview with Fugate, 16 December 2002; interview with Tether, 19 May 2005; Shapley, “Jason Division,” pp. 459–462, 505; Finkbeiner, The Jasons; Institute for Defense Analyses, http://www.ida.org (accessed 21 July 2004).

Notes to pages 77–81

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40. Interview with Happer, 29 September 2005. 41. Interview with Happer, 29 September 2005; Amy Cohen, Institute for Defense Analyses, e-mail message to author, 21 July 2004. 42. The “S” or SPAC method was first tested at Starfire Optical Range in 1987 and ended in 1988. Interview with Benedict, 28 October 2003; interview with Fugate, 16 December 2002; interview with William Thompson, 11 February 2003; interviews with Hutchin, 17 April 2003 and 16 June 2004; Benedict, Breckinridge, and Fried, “Atmospheric-Compensation Technology,” pp. 255–260; Hutchin and Vyce, letter to the editor, Physics Today. 43. Interview with Happer, 29 September 2005; Irwin Goodwin, “Happer Leaves DOE Under Ozone Cloud For Violating Political Correctness,” Physics Today, June 1993, pp. 89–91. 44. Interview with Happer, 29 September 2005; Goodwin, “Happer Leaves DOE,” pp. 89–91; Ronald Bailey, “Political Science,” Reason Magazine, December 1993, p. 61; Holman Jenkins Jr., “Al Gore Leads a Purge,” The Wall Street Journal, 25 May 1993. 45. Interview with Happer, 29 September 2005; interview with Tether, 18 May 2005; interview with Benedict, 28 October 2002; interview with Fugate, 21 April 2003; William Happer, Gordon J. MacDonald, Claire E. Max, and Frieman J. Dyson, “Atmospheric-Turbulence Compensation by Resonant Optical Backscattering from the Sodium Layer in the Upper Atmosphere,” Journal of the Optical Society of America, January 1994, pp. 263–76; notes to the author from Fugate, 7 November 2005; Hutchin, “History and Physical Principles of Lodestar Technology.” 46. Resonant scattering in sodium is much more efficient—returns more photons to the ground per watt of laser power—than Rayleigh scattering. In other words, it takes many more atoms of scattered Rayleigh light to equal the same amount of sodium scattered light. Interview with Happer, 29 September 2005; interview with Tether, 18 May 2005; interview with Benedict, 28 October 2002; interview with Fugate, 21 April 2003; Happer et al., “Atmospheric-Turbulence Compensation,” pp. 263–276; notes to the author from Fugate, 7 November 2005; Hutchin, “History and Physical Principles of Lodestar Technology”; Collins, “Making Stars to See Stars,” p. 18. 47. Interview with Happer, 29 September 2005. 48. Interview with Happer, 29 September 2005.

378

|   Notes to pages 81–84

49. Interview with Happer, 29 September 2005. 50. Interview with Happer, 29 September 2005; “Alfred Kastler—Biography,” Nobelprize, http:nobelprize.org/physics/laureates/1966/kastler-bio.html (accessed 18 September 2005). 51. Interview with Happer, 29 September 2005.

Chapter Five 1. Interview with Hutchin, 17 April 2003; interview with Fugate, 16 December 2002; interview with Benedict, 28 October 2003. 2. As it turned out, DARPA and the Air Force jointly funded the first Rayleigh experiment. Interview with Hutchin, 17 April 2003; interview with Fugate, 16 December 2002; interview with Benedict, 28 October 2003; interview with Hanson, 19 November 2002; interview with William Thompson, 11 February 2003; Graham P. Collins, “Making Stars to See Stars: DOD Adaptive Optics Work Is Declassified,” Physics Today, February 1992, p. 18. 3. Congress was sensitive about any kind of antisatellite capability, especially the program in the 1980s to launch a miniature kill vehicle from an F-15 aircraft. Some felt this weapon system would intensify Cold War tensions. Shifting attention to research on the Rayleigh backscattering option seemed to be less offensive, although antisatellite weapons remained the goal. Interview with Benedict, 28 October 2003; interview with Fugate, 16 December 2002. 4. Interview with Fugate, 16 December 2002; interview with Benedict, 28 October 2002; Robert Q. Fugate, David L. Fried, George A. Ameer, Bruce R. Boeke, Steven L. Browne, Phillip H. Roberts, Raymond E. Ruane, Glenn A. Tyler, and Lawrence M. Wopat, “Measurement of Atmospheric Wavefront Distortion Using Scattered Light from a Laser Guide-Star,” Nature, 12 September 1991, pp. 144–146; Francois Roddier, ed., Adaptive Optics in Astronomy (Cambridge, UK: Cambridge University Press, 1999), p. 299. 5. Interview with Fugate, 16 December 2002; interview with Benedict, 28 October 2002; Fugate et al., “Measurement of Atmospheric Wavefront Distortion,” pp. 144–146; Robert Q. Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation with Adaptive Optics Employing Laser Guide Stars,” paper presented at a meeting of the American Astronomical Society, Seattle, 27 May 1991.

Notes to pages 84–90

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6. Interviews with Fugate, 16 December 2002 and 14 May 2003; interview with Benedict, 28 October 2002; Fugate et al., “Measurement of Atmospheric Wavefront Distortion,” pp. 144–146; Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation”; David L. Fried, “Adaptive Optics Development: A 30-Year Personal Perspective” (Proceedings of SPIE: Laser Weapons Technology II, 16–17 April 2001), p. 11. 7. Interview with Benedict, 28 October 2002; interviews with Fugate, 16 December 2002 and 20 May 2003; Fugate et al., “Measurement of Atmospheric Wavefront Distortion,” pp. 144–146; Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation.” 8. Interview with Fugate, 16 December 2002; Fugate et al., “Measurement of Atmospheric Wavefront Distortion,” p. 146. 9. Interview with Fugate, 16 December 2002. 10. Interview with Fugate, 16 December 2002. 11. Interviews with Fugate, 16 December 2002 and 27 February 2004; Fugate et al., “Measurement of Atmospheric Wavefront Distortion,” p. 144; Robert Q. Fugate, “Laser Guide Star Adaptive Optics For Compensated Imaging,” in The Infrared and Electro-Optical Systems Handbook: Emerging Systems and Technologies, Vol. 8, ed. Stanley R. Robinson (Bellingham, WA: SPIE Optical Engineering Press, 1993), p. 136; “Astronomy Breakthrough,” U.S. Air Force news release 91-36, 27 May 1991; Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation.” 12. Fugate reported the success of the Rayleigh guide star experiments to a classified DoD conference in February 1984. Interview with Fugate, 21 April 2003; interview with William Thompson, 11 February 2003; interview with Brett Ellerbroek, California Institute of Technology, 11 July 2007. 13. Interview with Fugate, 21 April 2003; interview with William Thompson, 11 February 2003; interview with Ellerbroek, 11 July 2007; interview with Hutchin, 17 April 2003; notes to author from Fugate, 10 June 2004; Robert Q. Fugate, “Ground-Based Laser Energy Projection,” Technology Horizons, September 2001, pp. 12–14. 14. Notes to author from Fugate, 10 June 2004. 15. Ibid.; interview with Fugate, 21 April 2003; interview with William Thompson, 11 February 2003; interview with Hutchin, 17 April 2003; Fugate, “Ground-Based Laser Energy Projection,” pp. 12–14. 16. Ronald A. Humphreys, Lee C. Bradley, and Jan Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” Lincoln Laboratory Journal, Spring 1992, pp. 45–66.

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|   Notes to pages 90–95

17. Ibid. 18. Ibid. 19. Nomination for Giller Award, Robert Q. Fugate, n.d., ca. 1984; Air Force Weapons Laboratory, Citation of Giller Award for Technical Achievement presented to Dr. Robert Q. Fugate, n.d., ca. 1984. 20. Interviews with Fugate, 16 December 2002 and 21 April 2003; Robert K. Tyson, Introduction to Adaptive Optics (Bellingham, WA: SPIE Press, 2000), p. 14. 21. Interview with Fugate, 21 April 2003. 22. Interview with Fugate, 21 April 2003. 23. Interview with Fugate, 21 April 2003; Daniel V. Murphy, “AtmosphericTurbulence Compensation Experiments Using Cooperative Beacons,” Lincoln Laboratory Journal, Spring 1992, pp. 25–44. 24. Interview with Fugate, 21 April 2003. 25. Interview with Fugate, 21 April 2003; interview with Marquet, 9 November 2005; notes to author from Marquet, 4 November 2005. 26. Interview with Fugate, 21 April 2003. 27. Interview with Fugate, 3 May 2003. 28. Interview with Fugate, 3 May 2003; notes to author from Jim Mayo, 26 January 2007. 29. Interview with Fugate, 3 May 2003; notes to author from Mayo, 26 January 2007. 30. Interview with Fugate, 3 May 2003; notes to author from Mayo, 26 January 2007; Ash Dome, Product of the Ash Manufacturing Company, http://www. ashdome.com (accessed 25 October 2008). 31. Interview with Fugate, 3 May 2003. 32. Notes to author from Mayo, 25 January 2007. 33. Interview with James W. Mayo III, Northrop Grumman Corp., 25 January 2007. 34. Interview with Mayo, 25 January 2007; Jim Mayo and Gregg Crockett, “An Assessment of the Current Performance Level and Limitations of the DEER 1.5-Meter Contraves Telescope,” report for Logicon RDA, March 1998. 35. Interviews with Fugate, 21 April 2003 and 27 February 2004. 36. Interviews with Fugate, 2 April 2004 and 5 April 2004.

Notes to pages 95–104

381

37. Interviews with Fugate, 2 April 2004 and 5 April 2004. 38. Interview with Fugate, 5 April 2004. 39. Interviews with Fugate, 2 April 2004 and 5 April 2004; Fugate, entry in lab notebook, 13 February 1989; Fugate, “Laser Guide Star Adaptive Optics For Compensated Imaging,” p. 137. 40. Interview with Fugate, 5 April 2004; Fugate et al., “Measurements of Atmospheric Wavefront Distortion,” pp. 144–146. 41. The Gen I adaptive optics system differed from the earlier CIS, which was mounted on the side of the 1.6-meter telescope at Maui. The complex and bulky Gen I system was placed in a coudé room beneath the 1.5-meter telescope to give scientists easy access for making optical alignments and other adjustments. The Gen I adaptive optics system was too big to be mounted on the telescope. Fugate et al., “Measurements of Atmospheric Wavefront Distortion,” pp. 144–146; Robert Q. Fugate, Brent L. Ellerbroek, Charles H. Higgins, and Mark P. Jelonek, “Two Generations of Laser-GuideStar Adaptive-Optics Experiments at the Starfire Optical Range,” Journal of the Optical Society of America, 1 January 1994, pp. 310–312. 42. The Gen I adaptive optics system was too big to be mounted on the telescope. Fugate et al., “Measurements of Atmospheric Wavefront Distortion,” pp. 144–146; Fugate et. al., “Two Generations of Laser-Guide-Star AdaptiveOptics Experiments,” pp. 310–312. 43. Roland Shack at the University of Arizona modified the original Hartman sensor, hence the name Shack-Hartman sensor. Interview with Fugate, 14 May 2003; interview with Charles Hogge, 10 October 2002; Barry Hogge, “Beam Control: A Critical Part of a High Energy Laser System,” briefing, 21 March 2001. 44. Interview with Fugate, 14 May 2003; interview with Hogge, 10 October 2002; interview with Mark Ealey, 23 January 2004; Hogge, “Beam Control.” 45. Interview with Fugate, 27 February 2004; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 312–313. 46. Interview with Fugate, 27 February 2004; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 312–313. 47. Interview with Fugate, 16 December 2002; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 313–315. 48. Interview with Fugate, 16 December 2002; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 313–315; Arthur H. Guenther, ed., International Trends in Adaptive Optics (Bellingham, WA: SPIE Press, 2002), pp. 546–552.

382

|   Notes to pages 104–8

49. Interviews with Fugate, 16 December 2002, 21 April 2003, and 5 April 2004; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 313–315. 50. Colonel Leonard J. Otten III (Commander, Air Force Weapons Laboratory), Nomination of the Air Force Weapons Laboratory for Air Force Association Aerospace Unit of the Year, 31 May 1990. 51. Interview with Fugate, 27 February 2004; interview with Ellerbroek, 11 July 2007; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 315–323; Robert Q. Fugate, “A Quarter Century of Adaptive Optics at the Starfire Optical Range,” paper presented to the Optical Society of America, Rochester, NY, 11 October 2006. 52. Interview with Fugate, 27 February 2004; interview with Ellerbroek, 11 July 2007; Fugate et al., “Two Generations of Laser-Guide-Star AdaptiveOptics Experiments,” pp. 315–323; Fugate, “A Quarter Century of Adaptive Optics”; notes to author from Fugate, 10 June 2004; Fugate, “Laser Guide Star Adaptive Optics for Compensated Imaging,” p. 137. 53. Interview with Fugate, 27 February 2004; interview with Ellerbroek, 11 July 2007; Fugate et al., “Two Generations of Laser-Guide-Star AdaptiveOptics Experiments,” pp. 315–323; Fugate, “A Quarter Century of Adaptive Optics”; notes to author from Fugate, 10 June 2004; Fugate, “Laser Guide Star Adaptive Optics for Compensated Imaging,” p. 137; interview with Ealey, 23 January 2004. 54. Interview with Fugate, 27 February 2004; interview with Ellerbroek, 11 July 2007; interview with Ealey, 23 January 2004; Fugate et al., “Two Generations of Laser-Guide-Star Adaptive-Optics Experiments,” pp. 315–323; Fugate, “A Quarter Century of Adaptive Optics”; notes to author from Fugate, 10 June 2004; Fugate, “Laser Guide Star Adaptive Optics For Compensated Imaging,” p. 137; Robert Q. Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation,” paper presented to the 178th meeting of the American Astronomical Society, Seattle, WA, 27 May 1991; Colonel Peter J. Marchiando, Commander, Phillips Laboratory, “Recommendation for Award of the Air Force Outstanding Unit Award— Starfire Optical Range,” letter to Headquarters Air Force Space and Missile Center/Commander, n.d.s. 55. Major General Robert R. Rankine, Jr., Deputy Chief of Staff/Technology, Air Force Systems Command, “Laser Guide Star Adaptive Optics,” letter to Phillips Laboratory/Commander, 19 June 1992. 56. Rankine, “Laser Guide Star Adaptive Optics”; R. Earl Good, “Nomination for Harold Brown Award,” memorandum to USAF/ST, 30 March 1999.

Notes to pages 108–10

383

57. Rankine, “Laser Guide Star Adaptive Optics”; Good, “Nomination for Harold Brown Award”; Leonard J. Otten and Barry B. Hogge, “State of the Laser and Imaging Directorate: A Year To Remember,” report, February 1992; Peter J. Marchiando, “Recommendation for Award,” letter to Air Materiel Command/Commander, 6 January 1993. 58. “Air Force Improves Image of Orion Nebula,” U.S. Air Force news release 94-2, 12 January 1994; Lawrence Spohn, “Earth’s Fastest ’Scope,” The Albuquerque Journal, 3 May 1994. 59. USAF Phillips Laboratory, “High-Resolution Imagery of Satellites,” in Phillips Laboratory Success Stories, 1993–1994 (Albuquerque, NM: Phillips Laboratory History Office, 1995), pp. 76–77; USAF Phillips Laboratory, “Satellite Tracking at Starfire Optical Range,” in Phillips Laboratory Success Stories, 1996 (Albuquerque, NM: Phillips Laboratory History Office, 1996), pp. 52–53; USAF Phillips Laboratory, “Dr. Robert Q. Fugate Awarded Distinguished Achievement Citation,” in Phillips Laboratory Success Stories, 1996 (Albuquerque, NM: Phillips Laboratory History Office, 1996), pp. 126–127. 60. Dustin Johnston, “Collaborative Research in Adaptive Optics Between the Phillips Lab and Italian Astrophysicists,” The Alliance For Photonic Technology, Summer 1994, pp. 1, 4. 61. Ibid., p. 4. 62. Ibid, p. 4; “National Science Foundation (NSF) Astronomical Observations at Starfire Optical Range (SOR)” in Major FY 94 and FY 95 Phillips Laboratory Technical Achievements, n.d., p. 58; USAF Phillips Laboratory, “World’s Most Advanced Adaptive Optics System,” in Phillips Laboratory Success Stories, 1993–1994 (Albuquerque, NM: Phillips Laboratory History Office, 1995), p. 25. 63. Dynalectron Corporation, “Sandia Optical Range Facilities Description,” report A026, DE-5038, 30 October 1978, pp. 7–12; Air Force Research Laboratory, “Starfire Optical Range,” fact sheet, January 2001. 64. Robert W. Duffner, Airborne Laser: Bullets of Light (New York: Plenum Press, 1997), pp. 39–42. 65. Richard V. Feaster, John G. Duffey, James E. Negro, and Darrell E. Spreen, “Project DELTA,” report AFWL-TR-74–250, October 1974, pp. 3–4, 9–10; John G. Duffey and Darrell E. Spreen, “Project DELTA,” in Journal of Defense Research, Series A: Strategic Warfare—High Energy Lasers, May 1975, pp. 41–47. 66. Interview with William Thompson, 11 February 2003. 67. Interview with Otten, 9 June 2004.

384

|   Notes to pages 110–15

68. Interview with Otten, 9 June 2004; interview with Fugate, 16 December 2002. 69. Interview with Otten, 9 June 2004; interview with Fugate, 16 December 2002. 70. “The Silver Anniversary: 25 Years of Excellence,” report, Air Force Weapons Laboratory/History Office, 1 May 1988, pp. 36, 44; Robert W. Duffner and Daniel F. Harrington, History of the Air Force Weapons Laboratory, 1 October 1983–30 September 1984 (Kirtland Air Force Base, NM: Air Force Weapons Laboratory, 1985), p. 39; Robert W. Duffner, Daniel F. Harrington, and Barron K. Oder, Terminal History of the Weapons Laboratory, 1 October 1988–13 December 1990, (Kirtland Air Force Base, NM: Air Force Weapons Laboratory, 1985), p. 200. 71. Interview with Fugate, 14 May 2003; interview with Otten, 1 June 2004. 72. Interviews with Fugate, 14 May 2003 and 5 April 2004; interview with Otten, 1 June 2004; Colonel Leonard John Otten III, “Starfire Optical Range,” letter to Distribution A, 7 December 1988. 73. Larry L. Craig (manager, Air Traffic Division, FAA), “Operation of the Starfire Research Facility,” memorandum to Department of the Air Force, 17 August 1989; Captain Michael J. Mercer, “FAA vs. Air Force on Laser Propagation,” staff summary sheet to AFWL/ARCA/ARC/AR, 16 August 1989. 74. Lieutenant Colonel William H. Wilhelm (Air Force representative, FAA Southwest Region), “Minutes from Meeting at Starfire Optical Research Facility, 1 September 1989” and “Minutes Starfire Optical Research [Range], September 1, 1989,” memorandum and attachment to WL/AR, 28 September 1989. 75. Interview with Otten, 9 June 2004, Wilhelm, “Minutes from Meeting at Starfire Optical Research Facility” and “Minutes Starfire Optical Research [Range].” 76. Interview with Otten, 9 June 2004, Wilhelm, “Minutes from Meeting at Starfire Optical Research Facility” and “Minutes Starfire Optical Research [Range].” 77. Larry L. Craig, “Laser Firing, Kirtland AFB Controlled Firing Area,” memorandum to Department of the Air Force Regional Representatives, 2 May 1990.

Chapter Six 1. Interview with Darryl P. Greenwood, MIT/Lincoln Laboratory, 21 January 2004; Eva C. Freeman, ed., MIT Lincoln Laboratory: Technology in the National Interest (Boston: Nimrod Press, 1995), pp. vii–xvii, 1; William Z. Lemnios and Alan A. Grometstein, “Overview of the Lincoln Laboratory Ballistic Missile Defense Program,” Lincoln Laboratory Journal, 2002, Notes to pages 116–20

385

pp. 9–32; Eric Pace, “James Killian, 83, Science Adviser, Dies,” The New York Times, 31 January 1988. 2. SAGE’s radar system located targets and rapidly transmitted that data by telephone to combat control centers, where large computers processed the data and relayed it to interceptor aircraft. Interview with Darryl Greenwood, 21 January 2004; interview with Marquet, 18 February 2004. 3. Johns Hopkins Applied Research Laboratory, managed by Johns Hopkins University, was an FFRDC, but phased out in 1969. Federally Funded Research and Development Centers, http://www.ll.mit.edu/about/ffrdcs. html (accessed October 28, 2008); Paul G. Kaminski (undersecretary of state for acquisition and technology), “DoD-Sponsored R&D Centers Still Critical, Worth Keeping,” statement before the Research and Development Subcommittee, House National Security Committee, 5 March 1996. 4. Interview with Greenwood, 21 January 2004; interview with Charles A. Primmerman, MIT/Lincoln Laboratory, 22 January 2004; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Jack D. Drummond, and Andrea L. Tuffli, “20-Watt CW 589-nm Sodium Beacon Excitation Source for Adaptive Optical Telescope Applications,” paper presented at the AMOS 2003 Technical Conference, Wailea, Maui, Hawaii, 8–12 September 2003. 5. Interview with Greenwood, 21 January 2004; interview with Primmerman, 22 January 2004; Denman et al., “20-Watt CW 589-nm Sodium Beacon Excitation Source”; Darryl P. Greenwood and Charles A. Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” Lincoln Laboratory Journal, Spring 1992, p. 16; Ronald A. Humphreys, Charles A. Primmerman, Lee C. Bradley, and Jan Herrmann, “Atmospheric-Turbulence Measurements Using a Synthetic Beacon in the Mesospheric Sodium Layer,” Optical Letters, 15 September 1991, pp. 1367–1369. 6. Interview with Greenwood, 21 January 2004; interview with Primmerman, 22 January 2004; Denman et al., “20-Watt CW 589-nm Sodium Beacon Excitation Source”; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” p.16; Humphreys et al., “AtmosphericTurbulence Measurements,” pp. 1367-1369. 7. Interview with Benedict, 28 October 2002; Ronald A. Humphreys, Lee C. Bradley, and Jan Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” Lincoln Laboratory Journal, Spring 1992, pp. 45–47. 8. Interview with Benedict, 28 October 2002; interview with Marquet, 18 February 2004; Humphreys, Bradley, and Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” pp. 45–47.

386

|   Notes to pages 120–22

9. Interview with Benedict, 28 October 2002; interview with Meyer, 6 December 2004. 10. Interview with Benedict, 28 October 2002; interview with Meyer, 6 December 2004; interview with Primmerman, 26 October 2004; Humphreys, Bradley, and Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” p. 52; Humphreys et al., “Atmospheric-Turbulence Measurements,” p. 1367. 11. Humphreys, Bradley, and Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” pp. 52–53; notes to author from Greenwood, 22 May 2006. 12. Avco was located in Everett, Massachusetts. Humphreys, Bradley, and Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” pp. 55–56; notes to author from Greenwood, 22 May 2006. 13. Because of the relatively low number of photons in the sodium layer, bigger diameter telescopes that could collect more light worked better with sodium guide stars. Humphreys, Bradley, and Herrmann, “Sodium-Layer Synthetic Beacons for Adaptive Optics,” pp. 55–56; notes to author from Greenwood, 22 May 2006. 14. Interview with Benedict, 28 October 2002; Darryl P. Greenwood and Charles A. Primmerman, “The History of Adaptive-Optics Development at the MIT Lincoln Laboratory,” in Active and Adaptive Optical Components and Systems II, ed. Mark A. Ealey (Bellingham, WA: SPIE Press, 1993), pp. 226–228; Robert Q. Fugate, “Laser Guide Star Adaptive Optics for Compensated Imaging,” in The Infrared and Electro-Optical Systems Handbook, Vol. 8, ed. Stanley R. Robinson (Bellingham, WA: SPIE Optical Engineering Press, 1993), p. 136. 15. Robert Q. Fugate, “Laser Beacon Adaptive Optics,” Optics & Photonics News, June 1993, pp. 14–19. 16. MIT News Office, “Awards and Honors,” Tech Talk, 6 October 1993. 17. SPIE Technology Achievement Award Listing, at http://www.spie.org (accessed 7 November 2007). 18. Interview with Primmerman, 22 January 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 16–17. 19. Charles A. Primmerman, Daniel V. Murphy, Daniel A. Page, Byron G. Zollars, and Herbert T. Barclay, “Compensation of Atmospheric Optical Distortion Using a Synthetic Beacon,” Nature, 12 September 1991, pp. 141–143; Strategic Defense Initiative Organization, “Short Wavelength Adaptive Techniques (SWAT),” fact sheet, May 1991. 20. Primmerman et al., “Compensation of Atmospheric Optical Distortion Using a Synthetic Beacon,” pp. 141–143; Strategic Defense Initiative Organization, “Short Wavelength Adaptive Techniques”; Byron G. Zollars, “Atmospheric-Turbulence Compensation Experiments Using Synthetic Beacons,” Lincoln Laboratory Journal, Spring 1992, pp. 67–77. Notes to pages 123–26

387

21. Interview with Primmerman, 22 January 2004; Primmerman et al., “Compensation of Atmospheric Optical Distortion Using a Synthetic Beacon,” pp. 141–143. 22. Interview with Primmerman, 22 January 2004; interview with William Thompson, 9 October 2002; interview with Fugate, 21 April 2003; Primmerman et al., “Compensation of Atmospheric Optical Distortion Using a Synthetic Beacon,” pp. 141–143; notes to author from Greenwood, 22 May 2006. 23. Interviews with Fugate, 21 April 2003 and 27 February 2004. 24. Interview with Greenwood, 21 January 2004; Zollars, “AtmosphericTurbulence Compensation Experiments,” pp. 82–83; Strategic Defense Initiative Organization, “Short Wavelength Adaptive Techniques (SWAT)”; Fugate, “Laser Guide Star Adaptive Optics for Compensated Imaging,” pp. 136–137; Graham P. Collins, “Making Stars to See Stars: DOD Adaptive Optics Work Is Declassified,” Physics Today, February 1992, p. 19. 25. Zollars, “Atmospheric-Turbulence Compensation Experiments,” pp. 85–86; notes to author from Greenwood, 22 May 2006. 26. Interview with Greenwood, 10 February 2005. 27. Theodore von Kármán, Toward New Horizons: A Report to General of the Army H. H. Arnold (submitted on behalf of the Army Air Forces Scientific Advisory Group, 15 December 1945). 28. Interview with Marquet, 18 February 2004; interview with Charles J. Infosino, Missile Defense Agency, 15 April 2004; interview with James E. Pearson, formerly of Hughes Research Laboratory and United Technologies Optical Systems, 17 February 2004; interview with James G. Roche, former secretary of the Air Force, 18 December 2007. 29. Interview with Benedict, 28 October 2002; interview with William Thompson, 9 October 2002; interview with Greenwood, 22 May 2006; Eva C. Freeman, ed., MIT Lincoln Laboratory: Technology in the National Interest (Boston: Nimrod Press, 1995), p. 137. 30. Interview with Benedict, 28 October 2002; interview with Greenwood, 22 May 2006. 31. Interview with Marquet, 18 February 2004. 32. Interview with Marquet, 18 February 2004. 33. Interview with Cooper, 18 May 2005; interview with Marquet, 18 February 2004.

388

|   Notes to pages 128–34

34. A completely satisfactory way to distinguish a real vehicle from a decoy has still not been found. Interview with Marquet, 18 February 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” p. 22. 35. Interview with Marquet, 18 February 2004. 36. Interview with Marquet, 18 February 2004. 37. Other potential applications included putting a high-power laser on an airplane to use against missiles and aircraft, on a ship for defense against sea-skimming missiles, and on a vehicle for a number of ground defense missions. Interview with Marquet, 18 February 2004; interview with Meyer, 6 December 2004. 38. Interview with Marquet, 18 February 2004; interview with Major General Donald L. Lamberson (USAF, Retired), 1 December 2002. 39. Interview with Marquet, 18 February 2004; interview with Benedict, 28 October 2002; interview with Charles Higgs, 21 January 2004. 40. Interview with Marquet, 18 February 2004; interview with John R. Albertine, former program manager for the Navy’s Mid-Infrared Advanced Chemical Laser program, 30 November 2004. 41. Interview with Marquet, 18 February 2004; interview with Albertine, 30 November 2004; interview with Meyer, 6 December 2004. 42. Interview with Higgs, 21 January 2004; interview with Marquet, 18 February 2004; interview with Albertine, 30 November 2004; Lee C. Bradley and Jan Herrmann, “Phase Compensation for Thermal Blooming,” Applied Optics, February 1974, pp. 331–334. 43. Charles A. Primmerman and Daniel G. Fouche, “Thermal-Blooming Compensation: Experimental Observations Using a Deformable Mirror System,” Applied Optics, April 1976, pp. 990–995. 44. Ibid.; interview with Primmerman, 10 December 2004. 45. Interview with Pearson, 17 February 2004; interview with Marquet, 18 February 2004; interview with Infosino, 15 April 2002; Greenwood and Primmerman, “Adaptive Optics at Lincoln Laboratory,” p. 7. 46. Interview with Infosino, 15 April 2002. 47. Interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004; Louis C. Marquet, Harold A. Pike, Daniel G. Fouche, Jan Herrmann, Ernest E. Huber, Peter Kafalas, Charles W. Kilcline, Robert Kramer, Jacob R. Lifsitz, David A. Mudgett, and Charles A. Primmerman, “Adaptive Optics Field Tests with a High-Energy Laser” (Project Report LTP-33, Massachusetts Institute of Technology/Lincoln Laboratory, 2 August 1977), p. 32.

Notes to pages 134–38

389

48. Interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004. 49. Interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004; Greenwood and Primmerman, “The History of AdaptiveOptics Development at the MIT Lincoln Laboratory,” pp. 220–223. 50. Interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004; Marquet et al., “Adaptive Optics Field Tests with a HighEnergy Laser,” pp. 75–77. 51. Interview with Marquet, 18 February 2004; interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004. 52. Interview with Marquet, 18 February 2004. 53. Marquet et al., “Adaptive Optics Field Tests with a High-Energy Laser,” p. 33. 54. Ibid., pp. 1–4; interview with Higgs, 21 January 2004. 55. Interview with Marquet, 18 February 2004; interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004; Marquet et al., “Adaptive Optics Field Tests with a High-Energy Laser,” pp. 49, 80–90. 56. Interview with Albertine, 3 December 2004; interview with Primmerman, 10 December 2004; interview with Marquet, 18 February 2004; Marquet et al., “Adaptive Optics Field Tests with a High-Energy Laser,” pp. 3, 32, 76, 80–90. 57. Interview with Marquet, 18 February 2004; interview with Edward A. Duff, Air Force Research Laboratory/Directed Energy Directorate, 5 April 2004; Marquet et al., “Adaptive Optics Field Tests with a High-Energy Laser,” pp. 1–2, 14, 32, 45. 58. Interview with Primmerman, 21 December 2004; Charles A. Primmerman, F. Bruce Johnson, and Irving Wigdor, “Thermal-Blooming Compensation Using the CLASP System,” Applied Optics, 15 September 1978, pp. 2909–2912. 59. Interviews with Primmerman, 10 and 21 December 2004; Primmerman, Johnson, and Wigdor, “Thermal-Blooming Compensation Using the CLASP System,” pp. 2909–2912; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” p. 13. 60. Interview with Primmerman, 21 December 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” p. 13; Freeman, MIT Lincoln Laboratory, p. 138. 61. Interview with Marquet, 18 February 2004. 62. Interview with Marquet, 18 February 2004; interview with William Thompson, 9 October 2002; D. G. Kocher, “Overview of Lincoln Laboratory

390

|   Notes to pages 138–43

High-Power Laser Local-Loop Adaptive Optics Experiments,” briefing, MIT Lincoln Laboratory, 13 July 1999. 63. Interview with Marquet, 18 February 2004; interview with William Thompson, 9 October 2002; Kocher, “Overview of Lincoln Laboratory High-Power Laser Local-Loop Adaptive Optics Experiments,” 13 July 1999. For a discussion of the multidither operation, see Thomas R. O’Meara, “The Multidither Principle in Adaptive Optics,” Journal of the Optical Society of America, March 1997, pp. 306–315. 64. Interview with Primmerman, 21 December 2004; Freeman, MIT Lincoln Laboratory, p. 138; Ronald R. Parenti, Robert H. Kingston, and Charles Higgs, “High-Energy Lasers and Laser Propagation,” Lincoln Laboratory Journal, 2002, p. 235; notes to author from Greenwood, 22 May 2006. 65. Interview with Marquet, 18 February 2004; interview with Higgs, 21 January 2004; interview with Primmerman, 22 January 2004. 66. Interview with Marquet, 18 February 2004; interview with Higgs, 21 January 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 11–12.

Chapter Seven 1. Interview with Meyer, 6 December 2004; interview with Cooper, 18 May 2005; William Thompson, e-mail message to author, 17 February 2006. 2. Interviews with William Thompson, 25 and 28 June 2004; interview with Benedict, 28 October 2002. 3. Interviews with William Thompson, 25 and 28 June 2004; interview with Benedict, 28 October 2002; interview with Meyer, 6 December 2004; William E. Thompson, “Assessment and Recommendations: Desirability of Modifications to Current Classification and Public Release Policies for Adaptive Optics and Artificial Beacon Technologies,” report, Phillips Laboratory/Lasers and Imaging, 11 March 1991. 4. Interviews with William Thompson, 9 October 2002 and 28 June 2004; interview with Benedict, 28 October 2002. 5. Interview with Marquet, 18 February 2004; Missile Defense Agency website, http://www.acq.osd.mil/bmdo/bmdolink/html/history, 28 June 2004. 6. Interviews with William Thompson, 25 and 28 June 2004; interview with Cooper, 18 May 2005; Thompson, e-mail message to author, 17 February 2006; Herbert P. Carlin, Building A New Foundation: Plans and Preparations For Establishing the Air Materiel Command, AFMC Historical Study No. 01, December 1992, pp. 1–4.

Notes to pages 144–47

391

7. Interviews with William Thompson, 25 and 28 June 2004. 8. Interviews with William Thompson, 25 and 28 June 2004; interview with Meyer, 30 August 2005; interview with Fugate, 29 August 2005. 9. Interviews with William Thompson, 25 and 28 June 2004; interview with Russell, 7 July 2004. 10. Interview with William Thompson, 9 October 2002; Thompson, “Assessment and Recommendations”; Renaud Foy and Antoine Labeyrie, “Feasibility of Adaptive Telescope with Laser Probe,” Astronomy and Astrophysics, 1985, pp. 29–31; Laird A. Thompson and Chester S. Gardner, “Experiments on Laser Guide Stars at Mauna Kea Observatory for Adaptive Imaging in Astronomy,” Nature, 16 July 1987, pp. 229–231; Laird A. Thompson, “Adaptive Optics in Astronomy,” Physics Today, December 1994, pp. 24–31. 11. Interview with Charles Primmerman, 22 January 2004; interview with Darryl Greenwood, 21 January 2004. 12. Interview with William Thompson, 9 October 2002; interview with Benedict, 28 October 2002; interview with Russell, 7 July 2004; interview with Cooper, 18 May 2005; William Thompson, “Assessment and Recommendations.” 13. Interview with William Thompson, 9 October 2002; interview with Benedict, 28 October 2002; interview with Russell, 7 July 2004; interview with Cooper, 18 May 2005; Thompson, “Assessment and Recommendations.” 14. Interview with Russell, 7 July 2004; interviews with William Thompson, 9 October 2002 and 25 and 28 June 2004; interview with Otten, 9 June 2004. 15. Interview with Russell, 7 July 2004; interviews with William Thompson, 9 October 2002 and 25 and 28 June 2004; interview with Otten, 9 June 2004; Thompson, “Assessment and Recommendations.” 16. Interview with William Thompson, 9 October 2002; Thompson, “Assessment and Recommendations.” 17. Interview with William Thompson, 9 October 2002; interview with Russell, 7 July 2004; Thompson, “Assessment and Recommendations”; Colonel John J. Russell (director, Advanced Radiation Technology Directorate, Weapons Laboratory), “Classification/Public Release Policy for the HAVE REACH Program,” letter to Dr. James Van Kuren, Foreign Technology Division/ Technical Director, 7 June 1990. 18. Interview with William Thompson, 9 October 2002; Thompson, “Assessment and Recommendations”; interview with Russell, 7 July 2004; Russell, “Classification/Public Release Policy for the HAVE REACH Program.” 19. Interview with Benedict, 28 October 2002; interview with William Thompson, 9 October 2002; Thompson, “Assessment and

392

|   Notes to pages 148–52

Recommendations”; James T. Van Kuren (technical director, Foreign Technology Division), “Classification/Public Release Policy for the HAVE REACH Program,” letter to Colonel John J. Russell, 18 July 1990; Graham P. Collins, “Making Stars to See Stars: DOD Adaptive Optics Work Is Declassified,” Physics Today, February 1992, pp. 17–21. 20. William E. Thompson, “HAVE REACH Program: Classification and Public Release Policies,” briefing, 9 October 1990. 21. Interview with Russell, 7 July 2004; interview with Cooper, 18 May 2005; Russell, “Classification/Public Release Policy for the HAVE REACH Program,” 7 June 1990. 22. Interview with Russell, 7 July 2004; interview with G. Wayne Van Citters Jr., program director, National Science Foundation, 14 April 2004; Thompson, “Assessment and Recommendations.” 23. G. Wayne Van Citters, “Declassification,” letter to Colonel John J. Russell, 27 August 1990; Jacques M. Beckers, “Adaptive Optics,” letter to Dr. Wayne Van Citters, n.d. 24. Interview with Van Citters, 14 April 2004; Van Citters, “Declassification”; Beckers, “Adaptive Optics”; Thompson, “HAVE REACH Program”; Claire Max, William Happer, Freeman Dyson, Patrick Diamond, and Marshall Rosenbluth, “Declassification,” letter to William E. Thompson, 1 August 1990. 25. Interview with Van Citters, 14 April 2004; Van Citters, “Declassification.” 26. Interview with Russell, 7 July 2004; Frederick M. Bernthal (acting director, National Science Foundation), “Adaptive Optics,” draft letter to Honorable Henry F. Cooper, director, Strategic Defense Initiative Organization, n.d., ca. July 1991; notes to author from Greenwood, 22 May 2006; Charles A. Primmerman, “Lincoln System Upgrades Mt. Wilson Telescope,” Tech Talk, 27 May 1992. 27. Interviews with Van Citters, 14 April 2004 and 2 July 2004; interviews with William Thompson, 9 October 2002 and 25 and 28 June 2004; Collins, “Making Stars to See Stars,” pp. 17–21. 28. Interview with Van Citters, 2 July 2004; interviews with William Thompson, 9 October 2002 and 25 and 28 June 2004; Thompson, “Assessment and Recommendations.” 29. Thompson, “Assessment and Recommendations.” 30. Interview with William Thompson, 9 October 2002; Colonel Leonard J. Otten III, “Classification/Public Release Policy for the Adaptive Optics and Artificial Beacon Technologies,” letter, 11 March 1991. 31. Thompson, “Assessment and Recommendations.”

Notes to pages 152–56

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32. Ibid.; interview with Van Citters, 14 April 2004; interview with Benedict, 28 October 2002. 33. Interview with Van Citters, 14 April 2004; interview with Benedict, 28 October 2002; Thompson, “Assessment and Recommendations.” 34. Otten, “Classification/Public Release Policy.” 35. Darryl P. Greenwood, “Declassification,” letter to William E. Thompson, 2 April 1991; Lieutenant Colonel John M. Rabins (Headquarters Air Force Space Command), “Classification/Public Release Policy for the Adaptive Optics and Artificial Beacon Technologies,” letter to Colonel Leonard J. Otten, n.d.; Dr. Joe Golden (Office of the Director of Defense Research and Engineering, Washington, DC), “Memorandum for the Director, Laser and Imaging Directorate, Phillips Laboratory, Kirtland AFB,” 25 April 1991. 36. G. Wayne Van Citters, “Declassification Proposal,” letter to Colonel Leonard J. Otten, 3 April 1991. 37. William E. Thompson, “HAVE REACH Security Classification Guide,” letter, 30 June 1991. 38. Ibid.; Graham P. Collins, “Making Stars to See Stars,” p. 17. 39. Interviews with William Thompson, 25 and 28 June 2004; notes to author from Fugate, 29 August 2005. 40. Interviews with William Thompson, 25 and 28 June 2004; interview with Fugate, 29 August 2005; Charles H. Townes, “AAS Session,” letter to Manfred Bester et al., 26 February 1991; notes to author from Fugate, 29 August 2005. 41. Phillips Laboratory’s Public Affairs Office, “Fugate Paper on Laser Guide Stars,” statement of clearance PL 91–0084, 1 March 1991. 42. Notes to author from Fugate, 29 August 2005. 43. Ibid.; Phillips Laboratory’s Public Affairs Office, “Fugate Paper on Laser Guide Stars,” statement of clearance PL 91–0217, 21 May 2004; Mark Sincell, “Making the Stars Stand Still,” Astronomy, June 2000, p. 46. 44. Interviews with Fugate, 21 April and 14 May 2003; interview with William Thompson, 9 October 2002. 45. Interview with William Thompson, 9 October 2002; Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation,” paper presented to the 178th meeting of the AAS, Seattle, WA, 27 May 1991; Phillips Laboratory, “Astronomy Breakthrough,” News Release 91-36, 27 May 1991. 46. Fugate, “Experimental Demonstration of Real Time Atmospheric Compensation.”

394

|   Notes to pages 156–61

47. Interview with William Thompson, 9 October 2002; interview with Van Citters, 14 April 2004; notes to author from Fugate, 13 July 2004. 48. Interview with William Thompson, 9 October 2002; interview with Van Citters, 14 April 2004; notes to author from Fugate, 13 July 2004. 49. Interview with William Thompson, 9 October 2002; W. Patrick McCray, University of California, Santa Barbara, transcript of interview with Robert Fugate, 27 November 2000; notes to author from Fugate, 29 August 2005. 50. Robert Q. Fugate, ed., Laser Guide Star Adaptive Optics Workshop: Proceedings, Vols. I and II, 10–12 March 1992; Rettig Benedict, Jr., James B. Breckinridge, and David L. Fried, eds., “Atmospheric-Compensation Technology,” special issue, Journal of the Optical Society of America A 11, no. 1 and 2 (January 1994). 51. Interview with Fugate, 21 April 2003. 52. Babcock died at 90 in September 2003; interview with Fugate, 21 April 2003; H. W. Babcock, “Astronomical Background For Adaptive Optics,” paper presented at Laser Guide Star Adaptive Optics Workshop, 10–12 March 1992, Albuquerque, New Mexico; Anahad O’Connor, “Horace W. Babock, 90, Planner and Developer of Telescopes,” The New York Times, 5 September 2003. 53. Fugate, Laser Guide Star Adaptive Optics Workshop: Proceedings, 10–12 March 1992. 54. Ibid. 55. Interview with Fugate, 21 April 2003. 56. Interviews with Thompson, 25 and 28 June 2004; Rex Graham, “Laser Beam Will Take Twinkle Out of Stars,” The Albuquerque Journal, 16 March 1992; Malcolm W. Browne, “Anti-Missile Technology Delights Astronomers,” The New York Times, 6 August 1991. 57. Interview with Fugate, 14 May 2003. 58. Interview with Otten, 9 June 2004; “Adaptive Optics for Large Telescopes: First Topical Meeting,” program sponsored by the Optical Society of America, Lahaina, Maui, Hawaii, 17–21 August, 1992. 59. Interview with Benedict, 28 October 2002. 60. Benedict, Breckinridge, and Fried, “Atmospheric-Compensation Technology,” pp. 255–260. 61. W. Happer, Gordon J. MacDonald, Claire E. Max, and Freeman J. Dyson, “Atmospheric-Turbulence Compensation by Resonant Backscattering from the Sodium Layer in the Upper Atmosphere,” Journal of the Optical Society of America A 11, no. 1 (January 1994), pp. 263–276; David L. Fried and John F. Belsher, “Analysis of Fundamental Limits to Artificial-Guide Star

Notes to pages 161–66

395

Adaptive-Optics System Performance for Astronomical Imaging,” Journal of the Optical Society of America A 11, no. 1 (January 1994), pp. 277–287; Ronald R. Parenti and Richard J. Sasiela, “Laser-Guide-Star Systems for Astronomical Applications,” Journal of the Optical Society of America A 11, no. 1 (January 1994), pp. 288–309; R. Q. Fugate, B. L. Ellerbroek, C. H. Higgins, and M. P. Jelonek, “Two Generations of Laser-Guide-Star Adaptive Optics,” Journal of the Optical Society of America A 11, no. 1 (January 1994), pp. 310–324. 62. Benedict, Breckinridge, and Fried, “Atmospheric-Compensation Technology,” pp. 779–782. 63. Interview with Benedict, 28 October 2002; interview with Claire E. Max, University of California at Santa Cruz, Center for Adaptive Optics, 18 August 2005. 64. Interview with Benedict, 28 October 2002. 65. Interview with Benedict, 28 October 2002; interview with Max, 18 August 2005; notes to author from Fugate, 29 August 2005. 66. Leonard J. Otten and Barry B. Hogge, “State of the Laser and Imaging Directorate: A Year to Remember,” report, Phillips Laboratory, February 1992; Graham, “Laser Beam Will Take Twinkle Out of Stars.”

Chapter Eight 1. Interview with Marquet, 18 February 2004; interview with Primmerman, 22 January 2004; Darryl P. Greenwood and Charles A. Primmerman, “The History of Adaptive-Optics Development at the MIT Lincoln Laboratory,” in Active and Adaptive Optical Components and Systems II, ed. Mark A. Ealey (Bellingham, WA: SPIE Press, 1993), p. 224. 2. Interview with Marquet, 18 February 2004; interview with Primmerman, 22 January 2004; interview with Meyer, 6 December 2004; Greenwood and Primmerman, “The History of Adaptive-Optics Development at the MIT Lincoln Laboratory,” p. 224. 3. Interview with Edward A. Frieman, University of California at San Diego, Scripps Institute of Oceanography, La Jolla, California, 8 February 2006; Lieutenant Colonel Donald R. Baucom (USAF), transcript of interview with Dr. George A. Keyworth, 28 September 1987, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 4. Interview with Frieman, 8 February 2006. 5. Interview with Frieman, 8 February 2006; Baucom, transcript of interview with Keyworth, 28 September 1987; Gregg Herkin, Cardinal Choices:

396

|   Notes to pages 166–71

Presidential Science Advising from the Atomic Bomb to SDI (New York; Oxford University Press, 1992), p. 212. 6. Interview with Frieman, 8 February 2006; interview transcript, Baucom, transcript of interview with Keyworth, 28 September 1987; William J. Broad, “‘Star Wars’ Research Forges Ahead,” The New York Times, 5 February 1985. 7. Interview with Frieman, 8 February 2006; interview transcript, Baucom, transcript of interview with Keyworth, 28 September 1987. 8. President Reagan dedicated most of his 23 March speech to explaining why the United States needed to build up its conventional military forces to be able to counter any aggression initiated by the Soviet Union. It was only near the end of his speech that he introduced his concept of a new strategic defense system. Interview with Marquet, 18 February 2004; interview with Frieman, 8 February 2006; President Ronald Reagan, “Address to the Nation on Defense and National Security,” 23 March 1983; William D. Marbach, “Realistic Defense or Leap of Faith?” Newsweek, 17 June 1985, pp. 41–42, 45; Gregg Herken, “The Earthly Origins of Star Wars,” Bulletin of the Atomic Scientists, October 1987, pp. 24, 26–27. See also Donald R. Baucom, The Origins of SDI (Lawrence: University Press of Kansas, 1992). 9. Interview with Marquet, 18 February 2004; interview with Frieman, 8 February 2006; Reagan, “Address to the Nation”; Marbach, “Realistic Defense or Leap of Faith?” pp. 41–42, 45; Herken, “The Earthly Origins of Star Wars,” pp. 24, 26–27; Major General Robert Rankine, “Know the Facts About SDI,” Astro News, 4 March 1988. 10. Interview with Frieman, 8 February 2006. 11. National Security Decision Directive Number 85, “Eliminating the Threat from Ballistic Missiles,” 25 March 1983. 12. Interview with Marquet, 18 February 2004; Richard H. Buenneke, Jr., ed., Guide to the Strategic Defense Initiative (Arlington, VA: Pasha Publications, Inc., 1986), pp. 13–14, 35, 103–107, 179, 219, 263; James C. Fletcher, “Report of the Study on Eliminating the Threat Posed by Nuclear Ballistic Missiles: Volume I, The Defense Technology Plan,” October 1983, pp. E1–E4. 13. Interview with Marquet, 18 February 2004; Fletcher, “Report of the Study on Eliminating the Threat,” pp. E1–E4; “Directed Energy Program,” SDI Fact Sheet, Strategic Defense Initiative Organization, February 1990. 14. Fifty distinguished scientists and engineers from industry, government, and universities served on the Fletcher panel. Interview with James A. Abrahamson (Lieutenant General, USAF, Retired), former director, Strategic Defense Initiative Organization, 15 June 2005; Fred S. Hoffman, “Ballistic

Notes to pages 171–74

397

Missile Defenses and U.S. National Security: Summary Report,” Strategic Defense Initiative Organization, October 1983. 15. Interview with Marquet, 18 February 2004; interview with Abrahamson, 15 June 2005; Caspar W. Weinberger, “Strategic Defense Initiative Priority,” Memo for Secretaries of the Military Departments and Directors of Defense Agencies, 4 September 1985; Charles Mohr, “General to Head Missile Program,” The New York Times, 28 March 1984. 16. Interview with Abrahamson, 15 June 2005. 17. Interview with Abrahamson, 15 June 2005. 18. Interview with Abrahamson, 15 June 2005; Biography: Lieutenant General James A. Abrahamson, USAF, Office of External Affairs, Strategic Defense Initiative Organization, January 1989; “The Road to Ballistic Missile Defense, 1983–2007,” Federation of American Scientists Space Policy Project, http:// www.fas.org/spp/starwars/road.pdf (accessed 27 June 2005). 19. Through 1990, Congress authorized approximately $23 billion for SDI. Buenneke, Guide to the Strategic Defense Initiative, pp. 118–119. See also Robert W. Duffner, Airborne Laser: Bullets of Light (New York: Plenum Press, 1997). 20. Interview with Marquet, 18 February 2004. 21. Interview with Marquet, 18 February 2004; interview with Meyer, 6 December 2004; interview with Cooper, 18 May 2005. 22. Interview with Cooper, 18 May 2005. 23. Interview with Tether, 19 May 2005; interview with Cooper, 18 May 2005. 24. Interview with Tether, 19 May 2005; interview with Marquet, 18 February 2004; interview with Abrahamson, 15 June 2005. 25. Interview with Tether, 19 May 2005; interview with Marquet, 18 February 2004; interview with Abrahamson, 15 June 2005. 26. Interview with Benedict, 28 October 2002; interview with Meyer, 6 December 2004; Lincoln Laboratory, “Submarine Laser Communication Program,” briefing slide, n.d., from Darryl Greenwood’s files. 27. Interview with Greenwood, 10 February 2005. 28. Interview with Benedict, 26 January 2005; interview with Meyer, 28 January 2005; interview with Hogge, 11 February 2005. 29. Interview with Meyer, 28 January 2005. 30. Interview with Benedict, 28 October 2002; interviews with Meyer, 6 December 2004 and 28 January 2005; interview with Greenwood,

398

|   Notes to pages 174–80

10 February 2005; “Ecological Studies of Navy Antennas Should Be Reanalyzed,” News: The National Academies, at http://www4. nationalacademies.org/news.nsf/isbn (accessed 20 December 2005); phone conversation with James Reisa, director, Environmental Studies and Toxicology, National Research Council, 22 December 2005. 31. Greenwood would return to Rome Laboratory to serve as its chief scientist from March 1994 through February 1996 while on sabbatical from Lincoln Lab. Interview with Greenwood, 21 January 2004; interview with Benedict, 28 October 2002; résumé, Darryl P. Greenwood, February 2004. 32. Interview with Marquet, 18 February 2004; résumé, Greenwood, February 2004. 33. Interview with Greenwood, 21 January 2004; interview with Daniel V. Murphy, Lincoln Laboratory, 22 January 2004; interview with Benedict, 28 October 2002. 34. Interviews with Greenwood, 21 January 2004 and 10 February 2005; interview with Murphy, 22 January 2004; interviews with Benedict, 28 October 2002 and 26 January 2005; Darryl P. Greenwood and Charles A. Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” Lincoln Laboratory Journal, Spring 1992, pp. 10, 14. 35. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004. 36. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 11, 14–15. 37. Interview with Murphy, 22 January 2004; Daniel V. Murphy, “AtmosphericTurbulence Compensation Experiments Using Cooperative Beacons,” Lincoln Laboratory Journal, Spring 1992, pp. 35–37. 38. Interview with Murphy, 22 January 2004; Daniel V. Murphy, “AtmosphericTurbulence Compensation Experiments,” pp. 35–37; notes to author from Greenwood, 22 May 2006. 39. Interview with Murphy, 22 January 2004; Murphy, “Atmospheric-Turbulence Compensation,” pp. 35–37. 40. Interview with Murphy, 22 January 2004; Murphy, “Atmospheric-Turbulence Compensation,” pp. 35–37; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 12, 15; Phillip M. Boffey, “Research Success Marks Recent Days For ‘Star Wars,’” The New York Times, 18 June 1985.

Notes to pages 181–85

399

41. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 12, 15. 42. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; interview with Benedict, 26 January 2005; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” p. 15. 43. Interview with Abrahamson, 15 June 2005; interview with Meyer, 28 January 2005; interview with Greenwood, 10 February 2005. 44. Interview with Abrahamson, 15 June 2005; interview with Meyer, 28 January 2005; interview with Greenwood, 10 February 2005. 45. Interview with Primmerman, 22 January 2004; interview with Meyer, 28 January 2005; interview with Greenwood, 10 February 2005; “Lieutenant General James A. Abrahamson,” U.S. Air Force Biographies, October 1988, http://www.af.mil/bios/bio.asp?bioID=4464 (accessed October 30, 2008). 46. Notes to author from Greenwood, 22 May 2006. 47. Navy Captain Daniel C. Brandenstein commanded the seven-person Discovery crew that included Prince Sultan Salman al-Saud, the first Arab astronaut. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 13, 16; NASA, “Space Shuttle Mission 51-G,” press kit, June 1985. 48. Interview with Greenwood, 21 January 2004; interview with Meyer, 6 December 2004; Lieutenant Colonel Gotthard Janson III (Lyndon B. Johnson Space Center), “HPTE Post Mission Operations Report,” letter and report to CC, 26 August 1985, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; Edward H. Kolcum, “Discovery Crew Tests Laser Tracker, Surpasses Mission Goals,” Aviation and Space Technology, 1 July 1985, pp. 20–21. 49. Interview with Meyer, 28 January 2005. 50. Interview with Greenwood, 21 January 2004; interview with Meyer, 6 December 2004; Kolcum, “Discovery Crew Tests Laser Tracker,” pp. 20–21. 51. Interview with Greenwood, 21 January 2004; interview with Meyer, 6 December 2004; Kolcum, “Discovery Crew Tests Laser Tracker,” pp. 20–21; Lincoln Laboratory, “SDIO Experiment: Precision Tracking of Space Shuttle Mission 51 G,” report, 21 June 1985, pp. 1–4; William J. Broad, “Laser Beam Hits 8-Inch Target in Space,” The New York Times, 22 June 1985. 52. Interview with Greenwood, 21 January 2004. 53. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; Lieutenant Colonel Tom Meyer, “SDI Maui Rocket

400

|   Notes to pages 185–90

Experiment,” background paper for General Abrahamson, 27 September 1985; “Further Space Laser Test Set,” The New York Times, 11 July 1985. 54. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; Lieutenant General James A. Abrahamson, “Quick Response Shuttle Mission for SDI,” memorandum for the associate administrator for manned space flight, 29 January 1985; Meyer, “SDI Maui Rocket Experiment.” 55. Interview with Greenwood, 21 January 2004; interview with Murphy, 22 January 2004; interview with Benedict, 28 October 2002; Abrahamson, “Quick Response Shuttle Mission for SDI”; Meyer, “SDI Maui Rocket Experiment.” 56. Interview with Greenwood, 21 January 2004; Memorandum for Correspondents, released by SDIO, 17 October 1985. 57. Interview with Greenwood, 21 January 2004; interview with Benedict, 28 October 2002; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 15–16; David L. Fried, “Adaptive Optics Development: A 30-Year Personal Perspective,” Proceedings of SPIE: Laser Weapons Technology II, 16–17 April 2001, p. 9; Memorandum for Correspondents, released by SDIO, 17 October 1985; Strategic Defense Initiative Organization, “Short Wavelength Adaptive Techniques (SWAT),” fact sheet, May 1991; “Further Space Laser Test Set,” The New York Times, 11 July 1985. 58. Interview with Greenwood, 21 January 2004; interview with Benedict, 28 October 2002; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 15–16; Fried, “Adaptive Optics Development: A 30-Year Personal Perspective,” p. 9; Memorandum for Correspondents, released by SDIO, 17 October 1985; “Short Wavelength Adaptive Techniques (SWAT),” May 1991; “Further Space Laser Test Set,” 11 July 1985; Secretary of Defense, Washington, DC, “Congratulations for Successful Experiment,” message to Lincoln Laboratory, 9 October 1985; Meyer, “SDI Maui Rocket Experiment.” 59. Interview with Greenwood, 21 January 2004; interview with Primmerman, 21 January 2004; notes to author from Greenwood, 22 May 2006; Charles A. Primmerman, “Lincoln System Upgrades Mt. Wilson Telescope,” Tech Talk, 27 May 1992. 60. Richard L. Garwin, Kurt Gottfried, and Henry W. Kendall were three leading members of the Union of Concerned Scientists who took the position that SDI would not work. See John Tirman, ed., The Fallacy of Star Wars (New York: Vintage Books, 1984). Interview with Marquet, 18 February 2004; Phillip M. Boffey, “Physicists Express ‘Star Wars’ Doubts,” The New

Notes to pages 190–93

401

York Times, 23 April 1987; John A. Adam, “Star Wars in Transition,” IEEE Spectrum, March 1989, pp. 32–38. 61. Interview with Marquet, 18 February 2004; Boffey, “Physicists Express ‘Star Wars’ Doubts.” 62. Opening remarks by Dr. Alexander H. Levis, Chief Scientist of the Air Force, at the Air Force Centennial of Flight Symposium, Washington, DC, 17 September 2003; Alexander H. Levis, ed., The Limitless Sky: Air Force Science and Technology Contributions to the Nation (Washington, DC: Air Force History and Museums Program, 2004), p. 1. 63. After retiring as chairman of Oracle Corporation, where he served from 1992–1995, Abrahamson made a business trip to Russia, where he dined with a group of retired generals from the Soviet Rocket Forces who had worked on a Russian program similar to SDI. After several toasts, one Russian general said to Abrahamson, “Your name was always associated with those newspaper articles, but we were told it was really okay because SDI was nothing but a big scam—an imaginary program—and I thought you were imaginary too! It is interesting now to meet you.” Abrahamson smiled and responded, “I’m real and the program is still real!” Interview with Marquet, 18 February 2004; interview with Abrahamson, 15 June 2005. 64. Irwin Goodwin, “Aspin Shoots Down ‘Star Wars’ for Down-to-Earth Defenses,” Physics Today, Volume 46, June 1993, p. 91; Associated Press, “In Russia, Reagan Remembered for Helping to Bring Down Soviet Union,” 21 March 2005, http://www.msnbc.msn.com/id/5145921 (accessed October 30, 2008). 65. James A. Abrahamson, “Progress and Policy Paradigms,” Theodore von Kármán Lecture, presented at the 31st Aerospace Sciences Meeting, American Institute of Aeronautics and Astronautics, 13 January 1993, pp. 17–18, 25; Frances Fitzgerald, Way Out There in the Blue: Reagan, Star Wars, and the End of the Cold War (New York: Simon and Shuster, 2000), pp. 473–475. 66. Department of Defense, “Strategic Defense Initiative: Progress and Promise,” n.d., pp. 27–28. 67. LDEF remained in orbit until the shuttle Columbia retrieved it on 12 January 1990. Interviews with David P. Dimiduk, former LACE project officer, 10 February 2005 and 7 March 2005; Donald M. Horan, “Low-Power Atmospheric Compensation Experiment (LACE),” October 1991, http:// www.nrl.navy/HomePage/LACE (accessed 5 November 2004). 68. Interview with Dimiduk, 10 February 2005; interview with Primmerman, 22 January 2004; Strategic Defense Initiative Organization, “Low-Power Atmospheric Compensation Experiment (LACE),” fact sheet, May 1991;

402

|   Notes to pages 193–95

Naval Research Laboratory, “NRL-Developed SDIO Satellite To Be Launched,” news release, 29 December 1989; William J. Broad, “The Star Wars Program Prepares for a Year of Reckoning,” The New York Times, 29 November 1988. 69. Interview with Dimiduk, 10 February 2005; interview with Primmerman, 22 January 2004; Strategic Defense Initiative Organization, “Low-Power Atmospheric Compensation Experiment (LACE)”; Naval Research Laboratory, “NRL-Developed SDIO Satellite To Be Launched”; Broad, “The Star Wars Program”; Strategic Defense Initiative Organization, “SWAT Atmospheric Compensation Experiments,” briefing chart, 6 May 1991; Office of the Assistant Secretary of Defense, “SDIO Launches LACE/RME Space Experiments,” news release, 14 February 1990; Vincent Kiernan, “SDIO Ready to Launch Two Laser Research Satellites,” Space News, 15–21 January 1990, p. 32. 70. Lieutenant Colonel Roger D. Hartman (Air Force Research Laboratory), “RME,” memo for record to Air Force Research Laboratory/AR, 8 February 1990; Robert W. Duffner, Daniel F. Harrington, and Barron K. Oder, Terminal History of the Weapons Laboratory, 1 October 1988–13 December 1990 (Kirtland Air Force Base, NM: Phillips Laboratory, 1991), pp. 208–209; “SDIO Directed Energy Experiment Set for Launch on Commercial Delta 2,” Aviation Week & Space Technology, 12 February 1990, p. 30. 71. The Delta II booster also carried a second satellite into space, used by the Air Force Weapons Laboratory to conduct its Relay Mirror Experiment or RME. This experiment involved sending a low-power laser beam from the Maui Optical Station ground site to bounce off a mirror on the RME satellite as it passed overhead. The beam was reflected to a ground station scoring board located at Kihei on Maui. RME measured jitter of the beam when it hit the satellite mirror, and jitter and pointing accuracy of the beam when it reached the scoring board on the ground. All these data helped to advance the Air Force’s pointing and tracking technology for propagating laser beams into space. RME was one of the most successful laser beam demonstrations in the history of the Air Force Weapons Lab. McDonnell Douglas built the Delta launch vehicles. The Delta II that carried LACE into space was the company’s 192nd launch of a Delta booster. Interview with Dimiduk, 10 February 2005; Murphy, “Atmospheric-Turbulence Compensation,” pp. 38–39; “LACE/ RME Overview,” SDI Fact Sheet, Strategic Defense Initiative Organization, February 1990; Edward H. Kolcum, “SDI Laser Test Satellites Placed in Precise Orbits,” Aviation Week & Space Technology, 19 February 1990, pp. 24–25; Air Force Research Laboratory, “Relay Mirror Experiment,” undated fact sheet; Phillips Laboratory, “Relay Mirror Experiment Ends,” news release, 23 April 1991.

Notes to pages 196–97

403

72. Interview with Dimiduk, 10 February 2005; Murphy, “AtmosphericTurbulence Compensation,” pp. 38–39. 73. Interview with Dimiduk, 10 February 2005; Murphy, “AtmosphericTurbulence Compensation,” pp. 39–41; Lieutenant Colonel David Dimiduk, “Precision Space Tracking Using the SDIO LACE Satellite at SOR,” memorandum, 21 February 1995; Phillips Laboratory, “Low-Power Atmospheric Compensation Experiment (LACE),” fact sheet, May 1991. 74. By the mid-1990s, communications with LACE had terminated and the spacecraft became an abandoned satellite. Interview with Dimiduk, 10 February 2005; Donald M. Horan (chief scientist, NRL LACE Program), “LACE,” letter to Captain Matthew P. Le Vasseur, USMC, 15 September 1997; Murphy, “Atmospheric-Turbulence Compensation,” pp. 41–43; SDIO, “Major SWAT Accomplishments,” briefing chart, 2 May 1991. 75. James M. Romero (deputy director, Phillips Laboratory), “Recommendation for Award of the Air Force Organizational Excellence Award to Phillips Laboratory,” letter to Space and Missile Center/Commander, 26 October 1992. 76. Interview with Primmerman, 22 January 2004; notes to author from Greenwood, 22 May 2006; SDIO, “Major SWAT Accomplishments”; Strategic Defense Initiative Organization, “Short Wavelength Adaptive Optics Techniques (SWAT).” 77. Interview with Dimiduk, 10 February 2005; Murphy, “AtmosphericTurbulence Compensation,” pp. 42–43; Greenwood and Primmerman, “Adaptive Optics Research at Lincoln Laboratory,” pp. 18–19; “SDI Results,” undated press briefing from the files of Dr. Tom Meyer; Strategic Defense Initiative Organization, “LACE Achievements,” briefing chart, 13 May 1991. 78. “Two Satellites Lofted in a Laser System Test,” The New York Times, 15 February 1990. 79. A large share of the SDIO directed-energy budget was invested in the Ground Based Free Electron Laser Technology Integration Experiment, an Army program that sought to build a high-power free electron laser and beam control system at White Sands Missile Range, intended to shoot down enemy missiles in their boost phase. Technical setbacks and high costs canceled the program in the early 1990s. Interview with Meyer, 16 February 2005; Eva C. Freeman, ed., MIT Lincoln Laboratory: Technology in the National Interest (Boston: Nimrod Press, 1995), p. 143; Strategic Defense Initiative Organization, “LACE Achievements”; Department of Defense, “History of the Missile Defense Organization,” fact sheet, http:// www.defenselink.mil/specials/missiledefense/history.html.

404

|   Notes to pages 197–202

80. Interview with Meyer, 16 February 2005; Director, Operational Test & Evaluation, “FY 1998 Report,” February 1999, http/www.fas.org/spp/ starwars/program/dote98/98thaad.htm; House Armed Services Committee, “Aspin Proposes New Priorities For SDI, Dims Brilliant Pebbles,” news release, 24 April 1991; speech delivered by Les Aspin, chairman, House Committee on Armed Services, to the Washington Chapter, National Security Industrial Association, Arlington, VA, 24 April 1991.

Chapter Nine 1. United States Air Force, “A Brief History of the Airborne Laser,” fact sheet, 27 February 2003; United States Air Force, “The Airborne Laser (YAL-1A),” fact sheet, September 2004; Missile Defense Agency, “Cool Facts About the Airborne Laser,” information sheet 04-MDA-633, n.d.; Raytheon, Strategic Business Areas, “Missile Trajectory Phases,” information sheet, http:// www.raytheonmissiledefense.com/static/node3866.html (accessed 6 April 2005); Boeing, “The Airborne Laser (YAL-1A),” news release, http://www. boeing.com/defense-space/military/abl/news/2003/11003.html (accessed16 March 2005). See also “MDA Director Lt. Gen. Trey Obering Call with Media Regarding Ground-Based Midcourse Defense Flight Test Status,” news conference transcript, 12 January 2005, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 2. In most cases, the laser would cause the missile to collapse or rupture. Predictions were that only about 20 percent of the time would the laser cause the missile to explode. United States Air Force, “A Brief History of the Airborne Laser”; United States Air Force, “The Airborne Laser (YAL-1A)”; Missile Defense Agency, “Cool Facts About the Airborne Laser”; Raytheon, “Missile Trajectory Phases”; Boeing, “The Airborne Laser (YAL-1A).” See also “MDA Director Lt. Gen. Trey Obering Call with Media Regarding Ground-Based Midcourse Defense Flight Test Status.” 3. Hans Mark, “The Airborne Laser from Theory to Reality: An Insider’s Account,” Defense Horizons, August 2002, p. 3. 4. Ibid. 5. Airborne Laser System Program Office, “Frequently Asked Questions,” news release, 28 April 2004; United States Air Force, “The Airborne Laser (YAL-1A)”; Sharon Weinberger, “Everett Warns of ABL Cost Overruns,” Defense Daily, 4 August 2004; Barry Hogge, “Beam Control: A Critical Part of a High Energy Laser,” briefing, 21 March 2001. 6. George Cahlink, “Shield of Dreams,” Government Executive, 1 March 2005, p. 52.

Notes to pages 202–5

405

7. Lieutenant General Henry A. Obering III, USAF, Director, Missile Defense Agency, transcript of testimony before the Strategic Forces Subcommittee, House Armed Services Committee, 15 March 2005; Boeing, “Airborne Laser Overview,” http://www.boeing.com/defense-space/military/abl/overview. html (accessed 16 March 2005). 8. The Ballistic Missile Defense Organization became the Missile Defense Agency on 2 January 2002. Obering, transcript of testimony before the Strategic Forces Subcommittee; Boeing, “Airborne Laser Overview”; Boeing, “Airborne Laser Mission,” http://www.boeing.com/defense-space/military/ abl/mission.html (accessed 16 March 2005); Department of the Air Force, “‘Mis’ Perceptions,” briefing, n.d. 9. Initially the Air Force managed ABL, but in 2002 management and funding authority for the program transferred to MDA. United States Air Force, “A Brief History of the Airborne Laser”; Missile Defense Agency, “The Airborne Laser,” fact sheet, November 2004; Boeing, “Airborne Laser Mission”; United States, Missile Defense: Actions Are Needed to Enhance Testing and Accountability: Report to Congressional Committees (Washington, DC: U.S. General Accounting Office, April 2004), p. 63; Boeing, “Missile Defense Agency Opens Kirtland Facility,” news release, 26 January 2004, http://www. boeing.com/defense-space/military/abl/news/2004/012604.html (accessed 15 March 2005); USAF Phillips Laboratory, “Airborne Laser Extended Atmospheric Characterization Experiment,” in Phillips Laboratory Success Stories (Albuquerque, NM: Phillips Laboratory History Office, 1995), p. 55. 10. Lt. Gen. Trey Obering, director, Missile Defense Agency, and Rear Adm. Kathleen Paige, Program Manager for Aegis Missile Defense, transcript of media call, 9 March 2005; Missile Defense Agency, “The Airborne Laser,” fact sheet, August 2004 (updated November 2004); United States Air Force, “The Airborne Laser (YAL-1A)”; Airborne Laser Program Office, “Frequently Asked Questions”; Adam J. Hebert, “Laser Gets Tagged,” Air Force Magazine, September 2005, pp. 20–21. 11. Colonel Ellen Pawlikowski, Director, ABL System Program Office, transcript of news media teleconference on ABL issues, 19 November 2004; United States, “Defense Acquisitions: Status of Ballistic Missile Defense Program in 2004: Report to Congressional Committees” (Washington, DC: U.S. Government Accountability Office, March 2005), p. 55. 12. United States Air Force, “Where the Computers Yell ‘Fire,’” fact sheet, January 2004; Boeing, “Airborne Laser: Battle Management (BMC4I),” information sheet, 1999. 13. United States Air Force, “Where the Computers Yell ‘Fire’”; Boeing, “Airborne Laser: Battle Management.”

406

|   Notes to pages 206–8

14. United States Air Force, “Much More Than Just Another 747,” fact sheet, January 2004. 15. Ibid.; Boeing, “Boeing Airborne Laser Team Achieves First Flight,” news release, 3 December 2004, http://www.boeing.com/news/releases/2004q4/ nr_041203n.html (accessed 16 March 2005). 16. Robert W. Duffner, Robert R. Butts, J. Douglas Beason, and Ronald R. Fogleman, “Directed Energy: The Wave of the Future,” in The Limitless Sky: Air Force Science and Technology Contributions to the Nation, ed. Alexander H. Levis (Washington, DC: United States Air Force, 2004), pp. 228–234. 17. Ibid., pp. 230–234. 18. United States Air Force, “Contact at the Speed of Light: The Lasers That Make up the Airborne Laser System,” fact sheet, January 2004. 19. Ibid.; United States Air Force, “Much More Than Just Another 747.” 20. Missile Defense Agency, “Airborne Laser Achieves ‘First Light,’” news release 04-FYI-0035, 12 November 2004; Pawlikowski, transcript of news media conference; Boeing, “Boeing Airborne Laser Lights Up Test Facility,” news release, 12 November 2004, http://www.boeing.com/news/releases/2004/ q4/nr_0411125.html (accessed 16 March 2005); Hassaun A. Jones-Bey, “High Power Lasers: Airborne Laser Achieves Lethal Antimissile Power Levels,” Laser Focus World, February 2006, p. 1. 21. Missile Defense Agency, “ABL Testing Boosts Confidence in Ability to Shoot Down Ballistic Missiles,” news release 05-FYI-0070, 6 December 2005; Marc Selinger, “Airborne Laser Achieves Full Power in Ground Test,” Aerospace Daily, 12 December 2005, http://aimpoints.hq.af.mil/display. cfm?id=8307&printer=yes (accessed 12 December 2005). 22. Interview with Cooper, 18 May 2005; interview with Otten, 9 June 2004; interview with Ealey, 23 January 2004; Harrison Donnelly, “Interceptor Deployer: Quality Control and Mission Assurance for Multi-Layer Defense,” Military Aerospace & BMDS Technology, March 2005, pp. 17, 19–20. 23. United States Air Force, “Lots of Mirrors, Lots of Lenses—The Airborne Laser Beam Control/Fire Control System,” fact sheet, September 2004; Boeing, “Team ABL Continues Making Progress with Delivery of Two Airborne Laser Steering Mirrors,” news release, 1 June 2000, http://www. boeing.com/defense-space/military/abl/news/2000//060100.html (accessed 16 March 2005). 24. Interview with Kenneth W. Billman, Lockheed Martin, 7 April 2005; United States Air Force, “Lots of Mirrors; Lots of Lenses”; “Lasers To Take On the Missiles,” Space Daily, 10 August 1999, http://www.spacer.com/news/laser99b.html (accessed 19 April 2005); D. N. Gritz, R. R. Mazzuca, M. J. Edwards,

Notes to pages 208–14

407

J. G. Fagan, G. Peters, W. M. Decker, B. L. Kelchner, J. W. Mayo, and T. McCarthy-Brow, “Conformal Window for the Airborne Laser Aircraft,” Proceedings of SPIE, August 1999, pp. 227–238. 25. United States Air Force, “The Airborne Laser (YAL-1A)”; Boeing, “Team Airborne Laser Delivers Infrared Sensors for Lab Testing and Aircraft Integration,” 10 July 2001, http://www.boeing.com/defense-space/military/ abl/news/2001/071101.html (accessed 3 March 2005). 26. Missile Defense Agency, “The Airborne Laser.” 27. Ibid.; United States Air Force, “Contact at the Speed of Light”; Lockheed Martin, “New Solid-State Laser Developed for Airborne Laser Program,” news release, 30 March 2001, http://www.lockheedmartin.com/wms/ findPage.do?dsp, 16 March 2005. 28. United States, “Missile Defense: Actions Are Needed to Enhance Testing and Accountability,” p. 60; Raytheon, “Raytheon Delivers Key Component for Missile Defense: First ABL Track Illuminator Laser Provided to Lockheed Martin,” news release, 18 November 2002, http://www.prnewswire.com/ cgi-bin/micro_stories.pl (accessed 11 March 2005). 29. United States Air Force, “Contact at the Speed of Light”; Duffner et al., “Directed Energy: The Wave of the Future,” pp. 227–228; Missile Defense Agency, “The Airborne Laser”; Brent D. Johnson, “Airborne Laser Illuminator Delivered,” Photonics, May 2003, http://www.phonics.com/ spectra/applications/XQ/ASP/aoaid.308/QX/read.htm (accessed 27 January 2005); “Northrop Grumman Delivers Key Component for Airborne Laser,” Aerospace Daily, 27 February 2003, p. 4; Lockheed Martin, “Lockheed Martin Completes Integrated Testing of Major ABL Sub-System,” news release, 21 April 2004, http://www.lockheedmartin.com/wms/findPage. do?dsp (accessed 16 March 2005). 30. Interview with Billman, 22 April 2005; United States Air Force, “Contact at the Speed of Light”; Duffner et al., “Directed Energy: The Wave of the Future,” pp. 227–228; Missile Defense Agency Fact Sheet, “The Airborne Laser,” November 2004. 31. Interviews with Billman, 7 April and 22 April 2005; Charles Higgs, Herbert T. Barclay, Daniel V. Murphy, and Charles A. Primmerman, “Atmospheric Compensation and Tracking Using Active Illumination,” Lincoln Laboratory Journal, 1998, pp. 5–7. 32. Interview with Billman, 22 April 2005. 33. Interview with Ealey, 23 January 2004. 34. Interview with Billman, 22 April 2005. 35. Interview with Billman, 22 April 2005.

408

|   Notes to pages 214–18

36. Interview with Billman, 22 April 2005. 37. When the Ground-Based Free Electron Laser Technology Integration Experiment was terminated in 1990, William Thompson and Jim Mayo worked with Phillips Laboratory and Strategic Defense Initiative Organization personnel to have the project’s primary mirror transferred to Phillips Laboratory. A few years later, it became the primary mirror for the Advanced Electro-Optical System (AEOS). The 3.67-meter diameter blank determined the AEOS telescope’s ultimate aperture size. Interview with Billman, 22 April 2005. 38. Missile Defense Agency, “ABL Testing Boosts Confidence in Ability to Shoot Down Ballistic Missiles,” news release 05-FYI-0070, 6 December 2005; Marc Selinger, “Airborne Laser Achieves Full Power in Ground Test,” Aerospace Daily, 12 December 2005. 39. Lynn Farrow and Marc Selinger, “ABL: Teammates Working Toward ’08 Intercept Test,” Boeing Frontiers, July 2006, pp. 26–27. 40. “ABLEX Project,” Phillips Laboratory/Airborne Laser Technology Division White Paper, n.d.; “ABLE-X Summary,” Phillips Laboratory/Airborne Laser Technology Division Talking Paper, n.d. 41. Lenore McMackin, John Gonglewski, Boris Venet, Mark Jelonek, James Spinherne, Raymond Dymale, and Ken Bishop, “Horizontal Propagation Experiment: Final Report” (Kirtland Air Force Base, NM: Phillips Laboratory, 1 June 1993), pp. i–v. 42. Ibid.; John C. Brownlee, Robert W. Duffner, and Ruth P. Liebowitz, History of the Phillips Laboratory: 1 October 1992–30 September 1993 (Kirtland Air Force Base, NM: Phillips Laboratory, May 1994), pp. 87–89. 43. Lanny J. Larson and Richard D. Tebay, “Program Plan: Airborne Laser Technology Insertion Program” (Kirtland Air Force Base, NM: Phillips Laboratory, Airborne Laser Division, 7 January 1994), p. 5; Paul Merritt, Salvatore Cusumano, Mark Kramer, Shawn O’Keefe, and Charles Higgs, “Active Tracking of a Ballistic Missile in Boost Phase,” paper presented at the SPIE AeroSense Conference, Orlando, Florida, 10 April 1996. 44. Duffner et al., “Directed Energy: The Wave of the Future,” p. 226. 45. Phillips Laboratory/Airborne Laser Division, “ABLEX Project,” Technology Division White Paper, n.d.; Russell Butts and Lawrence D. Weaver, “ABLEX: High Altitude Laser Propagation Experiment,” The Proceedings of the NASAUCLA Workshop on Laser Propagation in Atmospheric Turbulence, February 1994, pp. 49. 46. Lawrence D. Weaver and Russell R. Butts, “Airborne Laser ExperimentABLEX,” Phillips Laboratory Technical Report 94–1076, vol. I, October 1994,

Notes to pages 218–21

409

pp. I.1:1–I.1:4, VI.1:1, VI.2:1; Lawrence D. Weaver and R. R. Butts, “ABLEX: High Altitude Laser Propagation Experiment,” Laser Digest, PL-TR-93–1097, vol. II, August 1994, pp. 141–165. 47. Weaver and Butts, “Airborne Laser Experiment-ABLEX,” pp. I.3:1, VI.1:1, VI.2:1; USAF Phillips Laboratory, “ABLEX—Airborne Laser Experiment,” in Phillips Laboratory Success Stories 1993–1994 (Albuquerque, NM: Phillips Laboratory History Office, 1995), pp. 54–55. 48. Interview with Glenn Tyler, 10 July 2007; Weaver and Butts, “Airborne Laser Experiment-ABLEX,” pp. I.1:1–I.1:4; Barry Hogge, “ABL Technology Program,” briefing, 28 November 2005. 49. Duffner et al., “Directed Energy: The Wave of the Future,” pp. 226–227; Weaver and Butts, “Airborne Laser Experiment-ABLEX,” pp. I.1:1–I.1:4, I.3:1–I.3:5, VI.1:1, VI.2:1; Donald C. Washburn, D. W. Banton, T. T. Brennan, W. P. Brown, R. R. Butts, S. C. Coy, R. H. Dueck, K. W. Koenig, B. S. Masson, P. H. Merritt, S. D. O’Keefe, D. H. Peterson, R. W. Praus, G. A. Taylor, B. P. Venet, and L. D. Weaver, “Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE),” Phillips Laboratory Technical Report 96-1084, Pt. 1, May 1996, pp. 1:1–1:2. 50. Weaver and Butts, “Airborne Laser Experiment-ABLEX,” pp. I.1:1–I.1:4, VI.3:5–VI.3:6; Weaver and Butts, “ABLEX: High Altitude Laser Propagation Experiment,” pp. 141–165. 51. Interview with Donald Lamberson, 1 December 2002. 52. Washburn, et al., “Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE),” p. 1:1; Duffner et al., “Directed Energy: The Wave of the Future,” p. 227. 53. Washburn, et al., “Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE),” pp. 1–2; Larson and Tebay, “Program Plan: Airborne Laser Technology Insertion Program,” pp. 23–26; USAF Phillips Laboratory, “Airborne Laser Extended Atmospheric Characterization Experiment,” p. 55. 54. Washburn, et al., “Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE),” pp. 1:14–1:15; USAF Phillips Laboratory, “Airborne Laser Extended Atmospheric Characterization Experiment,” p. 55. 55. Washburn, et al., “Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE),” pp. 1:14–1:15. 56. Ibid., pp. 1:10–1:12; Larson and Tebay, “Program Plan,” 7 January 1994, pp. 8–9. 57. Washburn, et al., “Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE),” pp. 1:24–1:25. See also Michael W. Oppenheimer,

410

|   Notes to pages 222–26

“Algorithm Development for On-Line Control of the Airborne Laser: Dissertation,” Air Force Institute of Technology, 2000–2002. 58. Interview with Mark A. Kramer, Air Force Research Laboratory/DE, 30 October 2000; interview with William Thompson, 27 October 2000; phone conversation with Steve Lamberson, ABL/SPO, 1 December 2000; Catherine Shuck, e-mail message to Air Force Research Laboratory/Directed Energy Human Resources Branch DistE, 3 November 2000. 59. Interview with Kramer, 30 October 2000; interview with William Thompson, 27 October 2000; phone conversation with Steve Lamberson, 1 December 2000; Shuck, “Congratulations to Fourth Quarter Winners.” 60. The Air Force contracted with the Optical Sciences Company, headed by Glenn A. Tyler in Anaheim, California, to support the adaptive optics experiments at NOP. Interview with Kramer, 30 October 2000; Barron K. Oder, Air Force Research Laboratory/Corporate Information Office/ History Office, transcript of interview with Lieutenant Colonel Richard J. Bagnell, Air Force Research Laboratory/Directed Energy Airborne Laser Technologies Branch, 12 November 1999; “Airborne Laser Advanced Concepts Testbed,” Directed Energy Weekly Activity Report, 13–19 May 2000. 61. Interview with Kramer, 30 October 2000; Oder, transcript of interview with Bagnell, 12 November 1999; “Airborne Laser Advanced Concepts Testbed.” 62. Interview with Kramer, 30 October 2000; Oder, transcript of interview with Bagnell, 12 November 1999; “Airborne Laser Advanced Concepts Testbed”; R. Jensen, “North Oscura Peak Beam Control Facility,” videocassette VP-433A, 6 April 2000; Kramer, “NOP Lasers,” notes, 18 December 2000, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 63. For some experiments, a laser beam was propagated from NOP to Salinas Peak, a diagnostic site 52 kilometers southwest of NOP. Interview with Kramer, 30 October 2000; Russ Butts, Steve Ford, and Matt Whiteley, “Preliminary Report on the ABLE ACT Non-Cooperative Dynamic Compensation Experiment,” briefing, 6 November 2000. 64. Interview with Kramer, 30 October 2000; Bill Thompson, “Airborne Lasers for Theater Missile Defense,” Technical Area Review and Assessment Briefing, Air Force Research Laboratory/Directed Energy Program Integration Division, 1 March 2000. 65. Interview with Kramer, 30 October 2000; Thompson, “Airborne Lasers for Theater Missile Defense”; Anne Marie Squeo, “A Light Dawns: Laser Weapons Get Lift from New R&D in Targeting Missiles,” The Wall Street Journal, 5 September 2000.

Notes to pages 226–30

411

66. Interview with Kramer, 30 October 2000; Kramer, “NOP Lasers”; Robert R. Butts, “The Non-Cooperative Dynamic Compensation Experiment,” Technology Horizons, September 2001, pp. 10–12. 67. Interviews with Kramer, 30 October and 18 December 2000. 68. Interview with Kramer, 30 October 2000; Butts et al., “Preliminary Report on the ABL ACT”; Shuck, e-mail message to Air Force Research Laboratory, 3 November 2003; “ABL Advanced Concepts,” Directed Energy Weekly Activities Reports, 30 August, 4 September, and 11 September 2000; Squeo, “Light Dawns.” 69. Interview with Lawrence D. Weaver, Air Force Research Laboratory/ Directed Energy Airborne Laser Technologies Branch, 6 November 2000; “ABL STAR III Pre-Deployment Briefing,” AFRL Briefing, 21 April 2000. 70. Interview with Weaver, 6 November 2000; “Argus,” Directed Energy Weekly Activity Report, 14–18 February 2000; Lawrence D. Weaver, Wilbur Brown, Pat Kelly, Liz Boll, and Mike Keltos, “ABLSTAR,” Technical Report AFRLDE-TR-2002–1024, April 2002, pp. 1–2. 71. Interview with Weaver, 6 November 2002; “ABLE STAR,” Directed Energy Weekly Activity Report, 6–12 May 2000. 72. Interview with Weaver, 6 November 2002; “ABLE STAR.” 73. Interview with Weaver, 6 November 2000; Larry Weaver, “Atmospheric Characterization: The ABL Star Experiment,” briefing to the Air Force Scientific Advisory Board, Kirtland Air Force Base, 13 December 2000; “Test Aircraft Returns,” Directed Energy news release 2000–46, 20 June 2000; Karen Wickwire, “Crew Gathers Critical Data for Airborne Laser Program,” Air Force News, 18 February 2000. 74. Interview with Weaver, 6 November 2000; Larry Weaver, “Atmospheric Compensation,” briefing to the Air Force Scientific Advisory Board, 13 December 2000; Cindy York, “ABL Program Tests Atmospheric Turbulence During World Tour,” Air Force News, 22 February 2000. 75. “Team Wins Special Achievement Award,” ABL news release 2000–61, 25 August 2000. 76. Mark, “The Airborne Laser,” p. 6; Hogge, “ABL Technology Program.” 77. Interview with Roche, 18 December 2007.

412

|   Notes to pages 231–35

Chapter Ten 1. Interview with Fugate, 23 September 2005. 2. Interview with Fugate, 23 September 2005; Ray Wick, Al Hopkins, Walter Wilde, Janet Fender, Bill Thompson, Terry McCarthy-Brow, Dick Frosch, and Jim Mayo, Air Force Weapons Laboratory/ARTO, “Report of the 3.5 Meter Telescope Primary Mirror Assessment Committee,” 30 September 1988, pp. 1–6; Phillips Laboratory, “Phillips Laboratory Dedicates 3.5-Meter Telescope,” news release no. 94–45, 17 May 1994; Phillips Laboratory, “Phillips Laboratory Awards $17 Million Contract,” news release no. 95–3, 19 January 1995; Phillips Laboratory: FY 92 Tech Achievements, 5 May 1993; “Starfire Optical Range Mission,” http://www. de.afrl.mil/sor/sormission.htm (accessed 6 March 2006); “AF Unveils Largest Telescope,” BMD Monitor, 20 May 1994, pp. 180–181. 3. Interview with Fugate, 23 September 2005. 4. Interview with Fugate, 23 September 2005. 5. Notes to author from Jim Mayo, 27 October 2006. 6. Ibid.; Jim Mayo, “Four Meter Telescope Considerations—A Preliminary Assessment,” unpublished manuscript, n.d., ca. December 1987, pp. 1–13. 7. Interview with Fugate, 23 September 2005. 8. Interview with Fugate, 23 September 2005. 9. As time went on, Air Force leadership became even more supportive of the 3.5-meter telescope. There was enormous interest in the scientific community for the type of research that could be conducted with a 3.5-meter telescope. Declassification of the laser guide star technology in May 1991 (see chapter 7) strengthened the conviction of the Air Force and Congress that research with the 3.5-meter telescope was a great example of technology transfer that offered the additional benefit of spending taxpayer money only once to help both military and civilian scientists. Interview with Fugate, 23 September 2005. 10. Interview with Fugate, 23 September 2005; Wick et al., “Report of the 3.5 Meter Telescope,” p. 6; Air Force Space Technology Center, “World Class Research at the Weapons Laboratory,” activity report, 9 July 1990. 11. Fugate and Hogge set up a small telescope in the Manzano Mountains to determine if seeing was better there than at SOR. Interview with Fugate, 23 September 2005. 12. Interview with Fugate, 23 September 2005. 13. Interview with Fugate, 23 September 2005.

Notes to pages 237–41

413

14. Interview with Fugate, 23 September 2005; Corey S. Powell, “Mirroring The Cosmos,” Scientific American, November 1991, p. 115. 15. In 1983, five years before Fugate’s first visit to Angel’s operation, the Weapons Lab’s chief scientist, Art Guenther, and Lieutenant Colonel Jim Mayo, chief of the Advanced Resonator Optics Branch, met with Angel in Tucson to learn more about his early mirror casting experiments. Guenther and Mayo believed Angel’s mirror work might have useful applications for the lab’s laser and optics programs. Although impressed with Angel’s progress, the lab did not have the budget at the time to pursue such a project. Interview with Fugate, 23 September 2005; notes to author from Mayo, 27 October 2006; author’s notes on meeting with Roger Angel, 14 September 2004. 16. Interview with Fugate, 23 September 2005; notes to author from Mayo, 27 October 2006; author’s notes on meeting with Angel, 14 September 2004. 17. Interview with Fugate, 23 September 2005; notes to author from Mayo, 27 October 2006; author’s notes on meeting with Angel, 14 September 2004. 18. Interview with Fugate, 23 September 2005; notes to author from Mayo, 27 October 2006; author’s notes on meeting with Angel, 14 September 2004; “Apache Point Observatory: Astrophysical Research Consortium,” brochure, n.d. 19. Interview with Fugate, 23 September 2005; interview with J. Roger P. Angel, University of Arizona, 14 September 2004. 20. Interview with Angel, 14 September 2004. 21. Interview with Mayo, 9 January 2006. 22. Other members of the committee besides Wick and Mayo included Al Hopkins, Walter Wild, Janet Fender, Bill Thompson, Terry McCarthy-Brow, and Dick Frosch, all from the Air Force Weapons Laboratory. Petras V. Avizonis (Technical Director, AFRL/AR), “3.5 Meter Telescope Primary—Assessment,” letter to RDA (Mayo), 11 August 1988; Wick et al., “Report of the 3.5 Meter Telescope,” pp. 1–3; Jim Mayo, “Planning Meeting—3.5-Meter Telescope Primary Mirror Assessment,” meeting minutes transmitted to Dr. R. Wick, 12 August 1988; Robert W. Duffner, Daniel F. Harrington, and Barron K. Oder, Terminal History of the Weapons Laboratory, 1 October 1988–13 December 1990 (Kirtland Air Force Base, NM: Phillips Laboratory, 1991), pp. 224–225; Air Force Research Laboratory, “3.5-Meter Telescope,” fact sheet, January 1998. 23. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; R. V. Wick, “Mirror Review Committee Assessments, Conclusions and Recommendations,” memorandum to Avizonis, 14 September 1988. 24. Notes to author from Mayo, 27 October 2006. 25. Ibid.

414

|   Notes to pages 241–44

26. Interviews with Mayo, 9 and 10 January 2005; interview with Angel, 14 September 2004. 27. Interviews with Mayo, 9 and 10 January 2005; interview with Angel, 14 September 2004; Wick et al., “Report of the 3.5 Meter Telescope,” p. 2; sketches of 3.5-meter mirror prepared by Fugate, 9 January 2006. 28. Interview with Fugate, 9 January 2006; interview with Mayo, 9 January 2006; Buddy Martin, John M. Hill, and Roger Angel, “The New Ground-Based Optical Telescopes,” Physics Today, March 1991, p. 29. 29. Interview with Fugate, 9 January 2006; interview with Mayo, 9 January 2006; Martin, Hill, and Angel, “The New Ground-Based Optical Telescopes,” p. 29. 30. Interview with Fugate, 9 January 2006; interview with Mayo, 9 January 2006; Martin, Hill, and Angel, “The New Ground-Based Optical Telescopes,” p. 29; Air Force Research Laboratory, “3.5-Meter Telescope.” 31. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; Duffner, Harrington, and Oder, Terminal History of the Weapons Laboratory, FY 89–90, pp. 226–227; Martin, Hill, and Angel, “The New Ground-Based Optical Telescopes,” p. 29; Air Force Weapons Laboratory, “Laboratory Advances Telescope Technology,” news release, 28 June 1989. 32. Interview with Angel, 14 September 2004. 33. Interview with Angel, 14 September 2004; interview with Fugate, 23 September 2005; Phillips Laboratory, “Phillips Laboratory Dedicates 3.5-Meter Telescope.” 34. Air Force Weapons Laboratory, “Laboratory Advances Telescope Technology,” news release no. 89–29, 28 June 1989; Donna D. Broome (3.5m Mirror Associate Project Officer, AFWL/AROB), “Weekly Activities in 3.5m Mirror Procurement Contracts,” memorandum for the record, 16 June 1989; Duffner, Harrington, and Oder, Terminal History of the Weapons Laboratory, FY 89–90, p. 229. 35. Interview with Mayo, 9 January 2006. 36. Barron K. Oder, Phillips Laboratory/History Office, transcript of interview with Captain Charles H. Villamarin, Phillips Laboratory/Lasers and Imaging Directorate/Starfire Optical Range Branch, 28 January 1992; Air Force Weapons Laboratory, “Construction Begins For DOD’s Largest Telescope,” news release no. 90–60, 23 October 1990. 37. Interview with Fugate, 23 September 2005; Jim Erickson, “The Vatican Observatory is One of the Oldest Astronomical Institutes in the World,” http://www.space.com/scienceastronomy/astronomy/vatican_ observe_000716.html (accessed 24 January 2006). 38. Interview with Angel, 14 September 2004; interviews with Fugate, 23 September 2005 and 9 January 2006; Air Force Weapons Laboratory, Notes to pages 245–52

415

“Laboratory Advances Telescope Technology,” news release no. 89–29, 28 June 1989. 39. Interview with Fugate, 23 September 2005; Burke E. Nelson (RDA), “Review of U of A OS Fabrication Capabilities in Connection with the 3.5M Optic,” letter to Dr. R. Wick (Air Force Weapons Laboratory/ARO), 6 September 1988; Corey S. Powell, “Mirroring The Cosmos,” Scientific American, November 1991, p.115. 40. SOML’s first two 3.5-meter mirrors were not polished at that location. They were sent to two different private contractors, but neither was able to polish the mirrors to the desired precision. Both mirrors ended up back at SOML, where their polishing was completed after the successful polishing of the SOR mirror—more testimony to the efficacy of Angel’s stressed-lap polishing technique. SOR’s 3.5-meter mirror was the third mirror to be built, but the first one polished to specifications. Interview with Mayo, 9 January 2006; interview with Fugate, 23 September 2005; Air Force Research Laboratory, “3.5-Meter Telescope.” 41. Interview with Mayo, 10 January 2006; Martin, Hill, and Angel, “The New Ground-Based Optical Telescopes,” p. 25; John Strong, “Evaporation Technique for Aluminum,” Physical Review, March 1933, p. 498. 42. Interview with Mayo, 10 January 2006. 43. Interview with Fugate, 23 September 2005; Air Force Research Laboratory, “3.5-Meter Telescope.” 44. Interview with Fugate, 23 September 2005. 45. Interview with Fugate, 23 September 2005; interview with Mayo, 10 January 2006. 46. Interview with Mayo, 3 December 2006; notes to author from Mayo, 27 October 2006. 47. Interview with Mayo, 3 December 2006; notes to author from Mayo, 27 October 2006. 48. Interview with Fugate, 23 September 2005; notes to author from Mayo, 27 October 2006. 49. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; notes to author from Mayo, 27 October 2006. 50. Interview with Fugate, 23 September 2005; notes to author from Mayo, 27 October 2006. 51. Notes to author from Mayo, 27 October 2006; Mayo, personal calendar entry for 19 January 1993; airline itinerary/invoice for James Mayo, prepared by Classic Travel Inc., 19 January 1993.

416

|   Notes to pages 253–56

52. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; notes to author from Mayo, 27 October 2006. 53. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; Phillips Laboratory, “Gimbal and Mount for DOD’s Largest Telescope Are Installed,” 30 November 1992; Major Anderson, “Tracking of Satellite by 3.5-Meter Telescope,” Phillips Laboratory Significant Events (Kirtland Air Force Base, NM: Phillips Laboratory, 22 June 1993); SOR Inputs for GBL Quarterly Report, “Telescope,” May 1993; “Phillips Laboratory Most Significant Accomplishments (1 Jul 92–19 Apr 93),” n.d., Kirtland Air Force Base, NM; Contraves Goerz Corporation, “Product Description for the Mobile Optical Measurement System (PD-3976),” report, May 1981. 54. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; Phillips Laboratory, “Gimbal and Mount for DOD’s Largest Telescope Are Installed”; “Phillips Laboratory Significant Events”; SOR Inputs for GBL Quarterly Report, “Telescope”; “Phillips Laboratory Most Significant Accomplishments”; Contraves Goerz Corporation, “Product Description for the Mobile Optical Measurement System.” 55. Interview with Fugate, 23 September 2005; Air Force Weapons Laboratory, “Construction Begins for DOD’s Largest Telescope.” 56. Interview with Fugate, 23 September 2005; Air Force Research Laboratory, “3.5-Meter Telescope.” 57. Interview with Fugate, 23 September 2005; Air Force Research Laboratory, “3.5-Meter Telescope.” 58. Interview with Fugate, 23 September 2005; interview with Mayo, 9 January 2006; Air Force Research Laboratory, “3.5-Meter Telescope.” 59. Interview with Fugate, 14 May 2003; Phillips Laboratory, “Concrete Poured For DOD’s Largest Telescope,” news release, 17 September 1991; Air Force Research Laboratory, “3.5-Meter Telescope.” 60. Michael H. Brady, “The 3.5-Meter Telescope Enclosure,” Phillips Laboratory Technical Report 93-1028, April 1994, pp. iii, 1. 61. Ibid., pp. i–iii, 1; “AF Unveils Largest Telescope.” 62. Interview with Mayo, 27 January 2006; Brady, “The 3.5-Meter Telescope Enclosure,” pp. i–iii, 1. 63. Brady, “The 3.5-Meter Telescope Enclosure,” p. 2. 64. Ibid., pp. 2–9. 65. Ibid., pp. 10–15. 66. Ibid., p. 10.

Notes to pages 256–63

417

67. Air Force Research Laboratory, “3.5-Meter Telescope”; Robert Q. Fugate, “A Quarter Century of Adaptive Optics at the Starfire Optical Range,” paper presented to the Optical Society of America, Rochester, NY, 11 October 2006. 68. Notes to author from Fugate, 27 March 2006; SOR Inputs for GBL Quarterly Report, “Telescope.” 69. Interview with Fugate, 23 September 2006; Anderson, “Tracking of Satellite by 3.5 Meter Telescope.” 70. Interview with Fugate, 23 September 2005. 71. United States Air Force, “Phillips Laboratory Dedicates 3.5-Meter Telescope”; “First Light at the Starfire Optical Range (SOR) 3.5-Meter Telescope,” in Major FY 94 and FY 95 Phillips Laboratory Technical Achievements, n.d., p. 15; Robert Q. Fugate, Brent Ellerbroek, Eric Stewart, D’nardo Colluci, Raymond E. Ruane, James M. Spinhirne, Richard A. Cleis, and Robert Eager, “First Observations with the Starfire Optical Range 3.5-Meter Telescope,” in SPIE Proceedings: Advanced Technology Optical Telescope, ed. Larry M. Stepp (Bellingham, WA: SPIE Press, 1994), pp. 481–493. 72. United States Air Force, “Phillips Laboratory Dedicates 3.5-Meter Telescope”; “First Light at the Starfire Optical Range (SOR) 3.5-Meter Telescope,” p. 15; Fugate et al., “First Observations with the Starfire Optical Range 3.5-Meter Telescope,” pp. 481–493. 73. Interview with Fugate, 9 January 2006. 74. Interviews with Fugate, 23 September 2005 and 9 January 2006; Phillips Laboratory, “Dedication of the 3.5 Meter Telescope,” program, 18 May 1994; USAF Phillips Laboratory, “3.5-Meter Telescope Activated,” in Phillips Laboratory Success Stories, 1993–1994, (Albuquerque, NM: Phillips Laboratory History Office, 1995), pp. 28–29; Phillips Laboratory, “Phillips Laboratory Dedicates 3.5-Meter Telescope”; Phillips Laboratory, “Phillips Laboratory Dedicates 3.5-Meter Telescope,” news release, 23 May 1994. 75. U.S. Senator Jeff Bingaman, “A Message from Senator Jeff Bingaman,” letter, 18 May 1994. 76. USAF Phillips Laboratory, “High Resolution Satellite Images from the New Starfire Optical Range (SOR) 3.5-Meter Telescope,” in Phillips Laboratory Success Stories, 1995 (Albuquerque, NM: Phillips Laboratory History Office, 1996), pp. 42–43; John Gonglewski (Phillips Laboratory/Lasers and Imaging Directorate/Imaging Technology Branch), “First High Resolution Satellite Images from SOR 3.5 Meter Telescope,” memorandum, 9 January 1995. 77. USAF Phillips Laboratory, “High Resolution Satellite Images from the New Starfire Optical Range (SOR) 3.5-Meter Telescope,” pp. 42–43; Gonglewski, “First High Resolution Satellite Images from SOR 3.5 Meter Telescope”;

418

|   Notes to pages 264–69

“High Resolution Satellite Images from the Starfire Optical Range (SOR) 3.5-Meter Telescope,” in Major FY 94 and FY 95 Phillips Laboratory Technical Achievements, n.d., p. 17. 78. Interview with Fugate, 23 September 2005; notes to author from Fugate, 9 January 2006. 79. Hughes Danbury Optical Systems (HDOS) was formerly Perkin-Elmer Electro-Optics. HDOS became Raytheon Optical Systems Incorporated (ROSI) in the late 1990s. In November 2000, BF Goodrich bought ROSI. Interviews with Fugate, 23 September 2005 and 20 March 2006; Air Force Research Laboratory, “Advanced Electro-Optical System,” fact sheet, July 2002; “Goodrich Electro-Optical Works on Government Contracts,” at http://www.diversitycareers.com/articles/pro/03-decjan04/dia_goodrich. htm, 10 March 2006; “BFGoodrich Completes Acquisition of Raytheon Optical Systems,” at http://www.ir.goodrich.com/phoenix, 10 March 2006; SOR Inputs for GBL Quarterly Report, “Adaptive Optics,” May 1993. 80. Interviews with Fugate, 23 September 2005 and 9 January 2006; interview with Ealey, 23 January 2004. 81. Eventually, the 3.5-meter telescope adaptive optics system was disassociated from the development of the AEOS adaptive optics system. Interviews with Fugate, 23 September 2005 and 9 January 2006; interview with Mark Ealey, 23 January 2004; interview with John R. Kenemuth, Air Force Research Laboratory/VS, former AEOS technical director, 22 September 2006; interview with Colonel Janet C. Augustine, Commander, and Lieutenant Colonel Scott Hunt, Deputy Commander, Detachment 15, Maui, 30 August 2006; J. M. Spinhirne, J. G. Allen, J. M. Brown II, J. C. Christou, T. S. Duncan, R. J. Eager, M. A. Ealey, et al., “The Starfire Optical Range 3.5m Telescope Adaptive Optical System,” in Proceedings of SPIE: Adaptive Optical System Technologies, ed. Domenico Bonaccini and Robert K. Tyson (Bellingham, WA: SPIE Press, 1998), pp. 22–33. 82. Barron K. Oder, Phillips Laboratory/HO, transcript of interview with Lieutenant Colonel John M. Anderson, PL/LIG, 29 October 1997; James M. Spinhirne and George A. Ameer, “Adaptive Optics Using the 3.5m Starfire Optical Range,” Proceedings of SPIE: Adaptive Optics and Applications, ed. Robert K. Tyson and Robert Q. Fugate (Bellingham, WA: SPIE Press, 1997), pp. 257–268. For a detailed technical description of the operational workings of the SOR adaptive optics system, see Robert Q. Fugate, David J. Lee, and James M. Spinhirne, “Lessons Learned at the SOR 3.5-M Adaptive Optical System,” in 1999 AMOS Technical Conference, 30 August–3 September 1999, pp. 297–305.

Notes to pages 270–71

419

83. Oder, transcript of interview with Anderson, 29 October 1997; Spinhirne and Ameer, “Adaptive Optics Using the 3.5m Starfire Optical Range,” pp. 257–268. 84. Oder, transcript of interview with Anderson, 29 October 1997; Spinhirne and Ameer, “Adaptive Optics Using the 3.5m Starfire Optical Range,” pp. 257–268. 85. Interview with Fugate, 20 March 2006; Oder, transcript of interview with Anderson, 29 October 1997; Spinhirne and Ameer, “Adaptive Optics Using the 3.5m Starfire Optical Range,” pp. 257–268; Robert Q. Fugate, “GroundBased Laser Energy Projection: Development and Operation of a Stateof-the-Art Test Bed for Ground-Based Laser Beam Control Technology Is Highly Successful,” Technology Horizons, September 2001, pp. 12–14. 86. Interview with Fugate, 20 March 2006; Oder, transcript of interview with Anderson, 29 October 1997; Spinhirne and Ameer, “Adaptive Optics Using the 3.5m Starfire Optical Range,” pp. 257–268; interview with Fugate, 20 March 2006; Fugate, “Ground-Based Laser Energy Projection,” pp. 12–14. 87. Interview with Fugate, 23 September 2005; Dave Lee, Brent Ellerbrook, and Julian Christou, “First Results for the Starfire Optical Range 3.5m Telescope Adaptive Optics System: Point-Spread Functions and Tracking Performance,” in Proceedings of SPIE: Adaptive Optical System Technologies, ed. Bonaccini and Tyson, 23–26 March 1998, pp. 1080–1091; Fugate, “GroundBased Laser Energy Projection,” p. 12; R. Earl Good, “Nomination for Harold Brown Award,” memorandum and attachments to USAF/ST, 30 March 1999. 88. Interview with Fugate, 20 March 2006; Fugate, “JTO Sponsored Target Beacon Demonstration,” briefing chart, n.d.; Fugate, “Ground-Based Laser Energy Projection,” pp. 12–14; Tim W. Parker, “SOR Operations” (Technical Report AFRL-DE-PS-TR-2004-1031, Kirtland Air Force Base, NM, 31 January 2004), p. 5. 89. SOR’s sending of a compensated beam from the ground to a satellite in 2002 duplicated and validated the earlier SWAT beam compensation experiments conducted by Lincoln Laboratory. Interview with Fugate, 20 March 2006; Fugate, “JTO Sponsored Target Beacon Demonstration”; Fugate, “GroundBased Laser Energy Projection,” pp. 12–14; Parker, “SOR Operations.” 90. Robert Q. Fugate, remarks at the Air Force Presidential Rank Award Ceremony, 21 April 2004; United States Air Force, “Research Scientist Receives Presidential Rank Award,” news release, 19 May 2004; J. Allen Gannaway, “PSA’s Progress Medal Honoree Dr. Robert Q. Fugate,” Photographic Society of America Journal, October 2000, p. 10. 91. Interview with Lyles, 25 September 2007. 92. Interview with Lyles, 25 September 2007; interview with Roche, 18 December 2007.

420

|   Notes to pages 272–75

93. Interview with Ronald M. Sega, physics department, Colorado State University, former director of Defense Research & Engineering, and former undersecretary of the Air Force, 7 November 2007. 94. Fugate, remarks at the Air Force Presidential Rank Award Ceremony. 95. Fugate, remarks at the Air Force Presidential Rank Award Ceremony.

Chapter Eleven 1. Phone interviews with Rick W. Sturdevant, deputy director, Air Force Space Command History Office, 12 February 2008 and 14 January 2009; interview with James L. McNally, former AEOS program manager, 23 August 2006; interview with Kenemuth, 22 September 2006; interview with Joseph F. Janni, former chief scientist, Phillips Laboratory, 29 August 2006; interview with Major J. Raley Marek, Air Force Research Laboratory/Directed Energy Space Surveillance Systems Branch, commander, Detachment 15, 28 February 2002; interview with Augustine and Hunt, 30 August 2006; Major Raley Marek, “Maui Space Surveillance System Overview,” briefing, 23 February 2001; Air Force Research Laboratory, “AEOS Telescope Facility,” fact sheet, December 1998; U.S. Strategic Command, “U.S. Strategic Command,” fact sheet, March 2004; United States Air Force, “Air Force Space Command,” fact sheet, October 2005. 2. Phone interview with Sturdevant, 12 February 2008 and 14 January 2009; interview with McNally, 23 August 2006; interview with Kenemuth, 22 September 2006; interview with Janni, 29 August 2006; interview with Marek, 28 February 2002; interview with Augustine and Hunt, 30 August 2006; Marek, “Maui Space Surveillance System Overview”; Air Force Research Laboratory, “AEOS Telescope Facility”; U.S. Strategic Command, “U.S. Strategic Command”; United States Air Force, “Air Force Space Command.” 3. Phone interview with Sturdevant, 12 February 2008 and 14 January 2009; interview with McNally, 23 August 2006; interview with Kenemuth, 22 September 2006; interview with Janni, 29 August 2006; interview with Marek, 28 February 2002; interview with Technical Sergeant Robert S. Medrano, Air Force Research Laboratory/Directed Energy Advanced Optics and Imaging Division, Det 15, 28 February 2002; interview with Augustine and Hunt, 30 August 2006; Marek, “Maui Space Surveillance System Overview”; Air Force Research Laboratory, “AEOS Telescope Facility”; U.S. Strategic Command, “U.S. Strategic Command”; United States Air Force, “Air Force Space Command.”; meeting with Lisa Thompson, Air Force Research Laboratory/ Directed Energy Space Surveillance Systems Branch, 30 August 2006.

Notes to pages 276–78

421

4. Interview with Marek, 28 February 2002; interview with Medrano, 28 February 2002; Air Force Space Command, “Historical Perspective of MSSS,” briefing chart, n.d., archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; “Facility on Maui May Help to Destroy Enemy Missile,” Honolulu Advertiser, 15 June 1966; U.S Strategic Command, “U.S. Strategic Command.” 5. Interview with McNally, 23 August 2006; interview with Janni, 29 August 2006; Joseph Bishop, Gary Puhek, David Covey, Robert Medrano, Steven Baker, Irma Aragon, John Kenemuth, Valerie Skarupa, Michael Vigil, Donald Forrester, and Melvin Bentz, “The Advanced Electro-Optical System: A Program Overview,” briefing, 23 December 1999. 6. Interview with McNally, 23 August 2006; interview with Janni, 29 August 2006; interview with Fugate, 29 January 2007; Bishop et al., “The Advanced Electro-Optical System: A Program Overview.” 7. On 28 July 2006, the Air Force decided to close down Cheyenne Mountain operations, but to keep the facility in a standby status so it could be quickly reactivated during a national emergency. Initially, AEOS images went to AFSPC’s 1st Command and Control Squadron (CACS)—redesignated as the 1st Space Control Squadron (1st SPCS) on 1 October 2001—at Cheyenne Mountain near Colorado Springs. Later on 9 June 2008, SPCS inactivated and its resources and functions shifted to the 614th Air and Space Operations Center/Joint Space Operations Center at Vandenberg Air Force Base, California. Phone interviews with Sturdevant, 30 March 2007 and 14 January 2009; interview with Marek, 28 February 2002; interview with Medrano, 28 February 2002; interview with Captain Joshua D. Snodgrass, Air Force Research Laboratory/Directed Energy Space Surveillance Systems Branch, Det 15, 1 March 2002; J. Raley Marek, “FY 2001 Accomplishments,” briefing charts, n.d., archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; Boeing Maui-Rocketdyne Technical Services, “AMOS User’s Manual: Maui Space Surveillance Site,” January 1999, pp. 2–8; “Cheyenne Mountain Directorate,” http://www.norad.mil/about_us/cmoc.htm (accessed 29 March 2007); Rich W. Sturdevant, e-mail message to author, 14 January 2009. 8. The System includes all the Air Force telescopes and facilities on top of the mountain; the Complex includes telescopes and facilities owned and operated by the Air Force and non–Air Force organizations. AMOS (Air Force Maui Optical Supercomputing Site) includes the Air Force telescopes and facilities on top of the mountain and the Air Force–operated Maui High Performance Computing Center at the base station in Kihei.

422

|   Notes to pages 279–80

Interview with Marek, 28 February 2002; interview with Medrano, 28 February 2002; interview with Major Samuel L. McNiel, Detachment 3, 18th Space Surveillance Squadron, 28 February 2002; Boeing MauiRocketdyne Technical Services, “AMOS User’s Manual: Maui Space Surveillance Site,” pp. 3, 9–27. 9. Interview with Marek, 28 February 2002; Boeing Maui-Rocketdyne Technical Services, “AMOS User’s Manual: Maui Space Surveillance Site,” pp. 4–5. 10. Interview with Augustine and Hunt, 30 August 2006; interview with Mayo, 29 January 2007; notes to author from Fugate, 29 January 2007. 11. Interview with Augustine, 30 August 2006; USAF Phillips Laboratory, “Maui High Performance Computing Center,” in Phillips Laboratory Success Stories: 1993–1994 (Albuquerque, NM: Phillips Laboratory History Office, 1995), pp. 38–39; United States Air Force, “Maui High-Performance Computing Center,” fact sheet, May 2002. 12. Interview with Captain Dale R. White, Air Force Research Laboratory/ Directed Energy Space Surveillance Systems Branch, Det 15, MHPCC Program Manager, 1 March 2002; interview with Snodgrass, 1 March 2002; interview with Janni, 29 August 2006; interview with Kenemuth, 5 March 2002; Captain Dale White, “MHPCC Overview,” briefing prepared for MCC QPR, February 2002; Andrew J. Glass, “Computer Sharpens Focus On Space Objects,” Atlanta Journal and Constitution, 22 November 2000. 13. Interview with Marek, 28 February 2002; interview with Good, 27 November 2001; Bishop et al., “The Advanced Electro-Optical System”; Lewis C. Roberts, Jr., “Characterization of the AEOS Adaptive Optics System,” Publication of the Astronomical Society of the Pacific, November 2002, pp. 1260–1266. 14. Jim Mayo and Don Killpatrick, Logicon RDA, “3.67-m AEOS Telescope Test and Verification Status,” briefing, 16 April 1996. 15. Maui’s 1.6 and twin 1.2-meter telescopes, introduced in the mid-1960s, were able to detect much fainter satellites and obtain higher resolution images with better detail than the Baker-Nunn cameras (manufactured by PerkinElmer) used earlier for satellite tracking. Air Force Research Laboratory, “Advanced Electro-Optical System,” fact sheet, July 2002; Jim Mayo, “AEOS Telescope: The Road to First Light,” paper presented at AMOS 2002 Technical Conference, Wailea, Maui, HI, 13 September 2001.

Notes to pages 280–81

423

16. Jim Mayo, Northrop Grumman, “MSSS Program Review,” briefing, 21 February 2003. 17. Interview with Mayo, 30 May 2006. 18. Mayo, “AEOS Telescope.” 19. Interview with Mayo, 30 May 2006; Major Patrick Dougherty, Air Force Systems Command, “Response to Staffer Questions on New 4-Meter Telescope,” briefing, June 1990; Mayo, “MSSS Program Review”; “Background Paper on the Advanced Electro-Optical System (AEOS),” n.d., archives of Air Force Research Laboratory, Kirtland Air Force Base, NM; Air Force Research Laboratory, “Advanced Electro-Optical System”; Phillips Laboratory, “Maui Telescope Is Nearly Complete,” news release, 13 January 1997. 20. Interview with Mayo, 30 May 2006; interview with McNally, 23 August 2006. 21. Rocketdyne Power Systems replaced Avco as the site support contractor in August 1990. Interview with Mayo, 30 May 2006; interview with McNally, 23 August 2006; “Background Paper on the Advanced Electro-Optical System (AEOS)”; Jim Mayo, “Telescopes: Historical Perspectives for Scientists and Engineers,” paper presented at AMOS Technical Conference, 10 September 2003. 22. Some perceived congressionally mandated or add-on monies as “pork barrel” funding that tended to favor representatives working together to support one another’s special interests by directing handpicked projects and federal dollars to states they represented. Interview with McNally, 23 August 2006; interview with Janni, 29 August 2006. 23. Air Force Weapons Laboratory members of the initial AEOS review team included Major Paul Idell, Captain Heidi Beason, Lieutenant Rich Elder, Lieutenant Mark Jelonek, John Gonglewski, Sal Cusamano, and Paul Pitts. Mayo and David Fried, from the Optical Sciences Company, served as the two contractor technical advisors. Interview with Mayo, 30 May 2006; Mayo, “MSSS Program Review.” 24. “Dual-use” was a politically correct 1990s buzz word that helped to justify expensive government research and development programs. Interview with McNally, 23 August 2006; interview with Janni, 29 August 2006; interview with Kenemuth, 5 March 2002. Bishop et al., “The Advanced Electro-Optical System,” 23 December 1999. 25. Interview with Janni, 29 August 2006; “Background Paper on the Advanced Electro-Optical System (AEOS),” n.d.; Daniel K. Inouye, chairman, Senate Appropriations Subcommittee on Defense, “AEOS,” letter to the Honorable Donald B. Rice, secretary of the Air Force, 3 April 1992.

424

|   Notes to pages 282–85

26. Interview with Mayo, 30 May 2006. 27. Interview with Mayo, 30 May 2006; notes to author from Fugate, 29 January 2007. 28. Interview with Mayo, 30 May 2006; Mayo, “MSSS Program Review.” 29. There was no coudé room for the only other telescope with adaptive optics on Maui, the 1.6-meter telescope on which the Air Force’s first Compensated Imaging System had been installed in the early 1980s (see chapter 3). Interview with Mayo, 30 May 2006; interview with Kenemuth, 22 September 2006. 30. Interview with Mayo, 30 May 2006; interview with Kenemuth, 22 September 2006. 31. Interview with Mayo, 30 May 2006; interview with Kenemuth, 22 September 2006; Mayo, “MSSS Program Review.” 32. Mayo, “MSSS Program Review.” 33. “Background Paper on the Advanced Electro-Optical System (AEOS),” n.d.; Inouye, “AEOS.” 34. Interview with McNally, 23 August 2006; “Background Paper on the Advanced Electro-Optical System (AEOS),” n.d.; Inouye, “AEOS.” 35. “Background Paper on the Advanced Electro-Optical System (AEOS).” 36. Phone conversation with Paul Erickson, AEOS Construction Manager, 29 March 2007; phone conversation with Ray Richmond, Boeing, 30 March 2007; interview with Mayo, 30 March 2007; notes to author from Kenemuth, 29 March 2007; Jim Mayo, sketch of 3.67-meter telescope, 30 March 2007, archives of Air Force Research Laboratory, Kirtland Air Force Base, NM. 37. Phone conversation with Erickson, 29 March 2007; phone conversation with Richmond, 30 March 2007; interview with Mayo, 30 March 2007; notes to author from Kenemuth, 29 March 2007; Mayo, sketch of 3.67-meter telescope; Mayo, “MSSS Program Review.” 38. Interview with Mayo, 30 May 2006; Mayo, “AEOS Telescope.” 39. Interview with McNally, 23 August 2006; interview with Kenemuth, 22 September 2006; interview with Mayo, 28 September 2006; Mayo, “MSSS Program Review.” 40. Interview with McNally, 23 August 2006; interview with Kenemuth, 22 September 2006; interview with Ealey, 23 January 2004; résumé, John R. Kenemuth, 2006. 41. Interview with McNally, 23 August 2006; interview with Kenemuth, 22 September 2006; interview with Ealey, 23 January 2004; résumé, Kenemuth, 2006.

Notes to pages 285–92

425

42. Mayo, “MSSS Program Review”; Air Force Research Laboratory, “Advanced Electro-Optical System”; résumé, Kenemuth. 43. Lieutenant Colonel Jim McNally, “Advanced Electro-Optical System (AEOS) Program Overview Briefing to HQ AFSPC,” briefing, Air Force Space Command, November 1994. 44. Ibid.; Phillips Laboratory, “Senator Participates In Ground-Breaking Ceremony,” news release, 10 April 1995; Phillips Laboratory, “New Telescope For Phillips Laboratory,” news release, 19 April 1995. 45. Mayo, “AEOS Telescope.” 46. Ibid. 47. Ibid.; interview with Mayo, 30 May 2006; USAF Phillips Laboratory, “Construction of DOD’s Largest Telescope Begins,” in Phillips Laboratory Success Stories, 1995 (Albuquerque, NM: Phillips Laboratory History Office, 1996), p. 35. 48. The warehouse also came complete with a copious supply of ants, spiders, and other six- and eight-legged vermin. On one memorable occasion, workers removed a large tarp from the warehouse floor, sending a frenzied scattering of hundreds of spiders, bugs, and roaches in all directions. Mayo often described this unsavory incident in papers he delivered on AEOS, wryly explaining that the Puunene warehouse was no place for arachnophobics; interview with Mayo, 30 May 2006; . Mayo, “AEOS Telescope”; USAF Phillips Laboratory, “Construction of DOD’s Largest Telescope Begins,” p. 35. 49. Interview with Mayo, 30 May 2006. 50. Interview with Mayo, 30 May 2006. 51. Mayo, “AEOS Telescope.” 52. “Background Paper on the Advanced Electro-Optical System (AEOS)”; Air Force Materiel Command, “Phillips Laboratory Builds Largest Telescope,” news release, 15 April 1994. 53. Daniel K. Akaka, Hawaii’s other senator, was unable to attend the AEOS dedication ceremony. Phillips Laboratory, “Air Force Unveils Maui Telescope,” news release, 7 July 1997. 54. Phillips Laboratory, “Air Force Unveils Maui Telescope.” 55. Interview with Mayo, 30 May 2006; Bishop et al., “The Advanced ElectroOptical System”; résumé, Kenemuth; Mayo, “AEOS Telescope.” 56. Interview with Mayo, 30 May 2006; Mayo, “AEOS Telescope.” 57. Interview with Mayo, 30 May 2006; Mayo, “AEOS Telescope”; Bishop et al., “The Advanced Electro-Optical System.”

426

|   Notes to pages 292–99

58. Mayo, “AEOS Telescope.” 59. Interview with Kenemuth, 22 September 2006; résumé, Kenemuth. 60. Interview with Rusty Hughes, manager, Trex Enterprises, 30 August 2006. 61. Interview with Kenemuth, 22 September 2006; interview with Hughes, 30 August 2006. 62. Interview with Rene Abreu, Goodrich Corporation, 2 November 2006. 63. Interview with Abreu, 2 November 2006. 64. There was speculation that damage to the five actuators—caused by high noise levels created when operating the system—occurred during initial testing at the Hughes facility in Danbury. Interview with Hughes, 30 August 2006; interview with Kenemuth, 22 September 2006; interview with Janni, 29 August 2006; interview with Lewis C. Roberts, Jr., Boeing, 29 August 2006; Rene Abreu, David Chadwick, Rick D’Amico, Charles Delp, Sarma Gullapalli, David Hansen, Michael Marchilnna, et al., “The SAAO Adaptive Optics System,” paper presented at the SPIE Conference in San Jose, California, January 2000. 65. Interview with Hughes, 30 August 2006; interview with Kenemuth, 22 September 2006; interview with Janni, 29 August 2006; interview with Roberts, 29 August 2006; Interview with Abreu, 2 November 2006; Abreu et al., “The SAAO Adaptive Optics System.” 66. Interview with Abreu, 2 November 2006. 67. Abreu et al., “The SAAO Adaptive Optics System.” 68. Interview with Abreu, 2 November 2006; interview with Kenemuth, 22 September 2006; interview with Hughes, 30 August 2006. 69. Notes to author from Kenemuth, 29 March 2007. 70. Interview with Hughes, 30 August 2006; interview with Kenemuth, 22 September 2006; interview with Abreu, 2 November 2006. 71. Interview with Hughes, 30 August 2006; interview with Kenemuth, 22 September 2006; interview with Abreu, 2 November 2006; interview with Roberts, 29 August 2006; interview with Christopher R. Neyman, W. M. Keck Observatory, 31 August 2006; Lewis C. Roberts, Jr., and Christopher R. Neyman, “Characterization of the AEOS Adaptive Optics System,” The Astronomical Society of the Pacific, November 2002, pp. 1260–1266; J. Raley Marek (Major, USAF), Air Force Research Laboratory/Directed Energy Space Surveillance Systems Branch (Det 15, AFRL), “Letter of Appreciation,” letter to Raytheon Electronic Systems, 16 January 2001; Lieutenant Colonel David L. Richards (Chief, AFRL Maui Operating Location), “Certificate of Commendation Awarded to the Raytheon SAAO Team,” n.d.

Notes to pages 299–306

427

72. Besides the adaptive optics hardware, other deliverables from the contractor included drawings, software, reports, test plans and procedures, and operational and maintenance manuals for the system. Interview with Hughes, 30 August 2006; interview with Kenemuth, 22 September 2006; interview with Abreu, 2 November 2006; interview with Roberts, 29 August 2006; interview with Neyman, 31 August 2006; Roberts and Neyman, “Characterization of the AEOS Adaptive Optics System,” pp. 1260–1266; Marek, “Letter of Appreciation”; Richards, “Certificate of Commendation.” 73. Interview with Kenemuth, 22 September 2006; interview with Abreu, 2 November 2006; Roberts and Neyman, “Characterization of the AEOS Adaptive Optics System,” pp. 1260–1266; notes to author from Kenemuth, 29 March 2007. 74. Interview with Kenemuth, 22 September 2006; interview with Abreu, 2 November 2006; B. F. Goodrich, “AEOS AO: Site Acceptance Test Report” (Technical Report TET17–0321, CDRL A-023, 16 February 2001). 75. Kenemuth commented that Maui’s turnkey adaptive optics system was routinely operated by nonscientific personnel. If the system was run by scientists, he believed, it could be fine-tuned in the same way as the SOR adaptive optics system. Interviews with Kenemuth, 22 September 2006 and 29 March 2007; interview with Abreu, 2 November 2006; interview with Janni, 1 September 2006; interview with Neyman, 31 August 2006; interview with Hughes, 30 August 2006; Goodrich, “AEOS AO: Site Acceptance Test Report.” 76. Interview with Charles L. Matson, Air Force Research Laboratory/Directed Energy Directorate, 17 November 2006; interview with Janni, 1 September 2006; Jim Riker, Air Force Research Laboratory/Directed Energy Optics Division/Space Surveillance Systems Branch Chief, Maui, “Post-Processing For AMOS Ground-Based Imagery,” briefing, 13 December 2004. 77. Interview with Matson, 17 November 2006; interview with Janni, 1 September 2006. 78. It is difficult to image space objects during daylight hours because of sky brightness and sun-driven atmospheric turbulence. However, special filters on the 1.6-meter telescope removed much of the sunlight. By pointing the telescope slightly away from the satellite, an image of the background could be taken and then subtracted from the total picture, leaving just the image of the satellite remaining. Interview with Matson, 17 November 2006; interview with Janni, 1 September 2006; Mark Lundgren, Jeff Houchard, Victor Wang, Fesseha Marmiam, and Andrew Suzuki, “ADONIS, Daytime Speckle Camera, for Air Force Maui Optical Station, Overview,” SPIE, vol. 2540, pp. 78–85, 1995; USAF Phillips Laboratory, “Daytime Optical Near-Infrared

428

|   Notes to pages 306–8

Imaging System (ADONIS) For Ground-Based Telescopes,” in Phillips Laboratory Success Stories, 1993–1994 (Albuquerque, NM: Phillips Laboratory History Office, 1995), p. 35; John Gonglewski, Air Force Research Laboratory/ Directed Energy Directorate, “Daytime Imaging,” notes to author, 10 October 2008. 79. Interview with Matson, 17 November 2006; Charles Matson, e-mail message to author with GEMINI attachment, 17 November 2006; notes to author from Matson, 4 June 2007. 80. Interview with Matson, 17 November 2006; interview with Janni, 1 September 2006; notes to author from Matson, 4 June 2007; USAF Phillips Laboratory, “Maui High Performance Computing Center,” pp. 38–39. 81. Interview with Matson, 17 November 2006; interview with Janni, 1 September 2006; notes to author from Matson, 4 June 2007; Joseph Janni, e-mail message to author, 8 September 2006; Riker, “Post-Processing For AMOS Ground-Based Imagery.”

Chapter Twelve 1. Interview with Happer, 29 September 2005; W. Happer, G. J. MacDonald, C. E. Max, and F. J. Dyson, “Atmospheric-Turbulence Compensation by Resonant Optical Backscattering from the Sodium Layer in the Upper Atmosphere,” Journal of the Optical Society of America, January 1994, pp. 263–276; John M. Telle, Peter W. Milonni, and Paul D. Hillman, “Comparison of Pump-Laser Characteristics from Producing a Mesospheric Sodium Guidestar for Adaptive Optical Systems on Large Aperture Telescopes,” paper presented to the SPIE Conference on High-Power Lasers, San Jose, California, January 1998; John Telle, Jack Drummond, Craig Denman, Paul Hillman, Gerald Moore, Steven Novotny, and Robert Fugate, “Studies of a Mesospheric Sodium Guidestar Pumped by Continuous-Wave Sum Frequency Mixing of Two Nd:YAG Laser Lines in Lithium Triborate,” paper presented to the SPIE Defense and Security Symposium, Orlando, Florida, 17–21 April 2006; notes to author from Craig Denman, 17 July 2007. 2. The term sodium laser is technically not correct, because sodium atoms are not directly excited to produce a sodium laser. Craig Denman, who led the sodium guide star laser program at SOR, offered an alternate term. “What we have done to avoid its use is to define a new term to describe the sodiumwavelength guide star excitation source: we call it a FASOR. This acronym stands for Frequency Addition Source of Coherent Optical Radiation. So now we can discuss: the sodium fasor, fasor beam, fasor system, sodium

Notes to pages 309–14

429

guide star fasor, etc.” Interview with Fugate, 13 December 2006; notes to author from Denman, 10 May and 17 July 2007. 3. Interview with Thomas H. Jeys, Lincoln Laboratory, 26 February 2007; interview with Craig A. Denman, Air Force Research Laboratory, Directed Energy Directorate, Laser Division, 19 December 2006; notes to author from Denman, 17 July 2007; Thomas H. Jeys, A. A. Brailove, and Aram Mooradian, “Sum Frequency Generation of Sodium Resonance Radiation,” Applied Optics, 1 July 1989, pp. 2588–2591; Thomas H. Jeys, R. M. Heinrichs, Kevin F. Wall, Jeffrey Korn, and T. C. Hotaling, “Observation of Optical Pumping of Mesospheric Sodium,” Journal of the Optical Society of America, 15 August 1992, pp. 1143–1145. 4. Herb Frieman at Lawrence Livermore National Laboratory also used tuned dye lasers for isotope separation. Interview with Fugate, 13 December 2006; Thomas H. Jeys, Kevin F. Wall, and Jeffrey Korn, “840-Hz Nd:YAG Laser Source of Sodium Resonance Radiation: Final Report to the U.S. Air Force Phillips Laboratory, January 1989–March 1991,” 11 May 1992, pp. iii, 1–29; Thomas H. Jeys, “Development of a Mesospheric Sodium Laser Beacon for Atmospheric Adaptive Optics,” The Lincoln Laboratory Journal, 2 November 1991, pp. 133–150. 5. The Chinese invented and patented lithium triborate in the early 1990s. Interview with Jeys, 26 February 2007; interview with Fugate, 13 December 2006; Jeys et al., “840-Hz Nd:YAG Laser Source,” pp. iii, 1–29; notes to author from Denman, 10 May 2007. 6. In the 1980s and 1990s, others were experimenting with dye lasers to test the sodium guide star concept. Interview with Jeys, 26 February 2007; interview with Fugate, 13 December 2006; notes to author from Denman, 10 May 2007. 7. Jeys was also engaged in a number of theoretical studies at Lincoln Laboratory exploring ways to optimize sodium light emitted from the mesosphere to a ground-based telescope. Interview with Fugate, 13 December 2006; notes to author from Denman, 10 May 2007. 8. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; notes to author from Denman, 10 May 2007. 9. Interview with Fugate, 13 December 2006; résumé, Craig A. Denman, November 2006; Air Force Research Laboratory/Directed Energy Laser Division, “Summary of Candidate [Craig A. Denman] Contributions,” award nomination, n.d.; notes to author from Denman, 10 May 2007; Russell F. Teehan, Joshua C. Bienfang, and Craig A. Denman, “Power Scaling and Frequency Stabilization of an Injection-Locked Nd:YAG Rod Laser,” Applied Optics, 20 June 2000, pp. 3076–3084. 10. Interview with Fugate, 13 December 2006.

430

|   Notes to pages 314–16

11. Interview with Fugate, 13 December 2006; résumé, Craig A. Denman; Craig Denman, “Sodium Beacon Laser Project: Beacon Laser Design Blueprints,” briefing, December 2000. 12. Interview with Fugate, 13 December 2006; notes to author from Denman, 10 May 2007. 13. Notes to author from Denman, 10 May 2007; interview with Denman, 19 December 2006; William L. Baker (Chief Scientist, Directed Energy Directorate), “Impact Statement Supporting the Nomination of Dr. Craig A. Denman for AFRL Fellow,” memorandum for Air Force Research Laboratory/CT, 7 May 2004; Air Force Research Laboratory/Directed Energy Laser Division, “Summary of Candidate [Craig A. Denman] Contributions.” 14. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; Craig A. Denman, “Sodium Guide Star Laser: Progress, Plans, Recommendations,” briefing, 21 June 2002. 15. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; Craig Denman, Paul Hillman, Gerald Moore, and John Telle, “Sodium Guidestar Project,” briefing to Air Force Scientific Advisory Board, 5 December 2002; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Joseph E. Preston, Jack D. Drummond, and Robert Q. Fugate, “Update on the AFRL 50-Watt Facility-Class Sodium Guidestar Pump FASOR,” 2005; notes to author from Denman, 10 May 2007. 16. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; notes to author from Denman, 10 May 2007. 17. Lawrence Livermore National Laboratory had developed pulsed dye lasers that produced at best about 18 watts of power. Large chillers are required to cool the large pump lasers needed to pump the dye. The dye is usually soluble in methanol or some other alcohol—that is why the lasing medium is flammable. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; notes to author from Denman, 10 May 2007; Valerie Coffey, “Powerful CW Laser Produces Bright Guidestar,” Laser Focus World, March 2003, pp. 11, 14. 18. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; Craig Denman and Paul Hillman, “Sodium Guidestar Project,” briefing presented at the Directed Energy Technology Council Review, 19–21 November 2003. 19. Another important member of Denman’s team, Captain Brent Grimes, was reassigned in the summer of 2002 to the Air Force Institute of Technology at Wright-Patterson Air Force Base in Dayton, Ohio. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006;

Notes to pages 317–20

431

Air Force Research Laboratory/Directed Energy Laser Division, “Summary of Candidate [Craig A. Denman] Contributions.” 20. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Joseph E. Preston, Jack D. Drummond, and Robert Q. Fugate, “High-Power Continuous-Wave Solid-State Sodium Guidestar Laser Systems,” IEEE Newsletter, http://www.ieee/organizations/pubs/newsletters/ leos/dec04/hottopic.html (accessed 1 March 2006); Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Jack D. Drummond, and Andrea L. Tuffli, “20 Watt CW 589 nm Sodium Beacon Excitation Source for Adaptive Optical Telescope Applications,” Optical Materials, September 2004, pp. 507–513; notes to author from Denman, 10 May 2007. 21. Interview with Jeys, 26 February 2007; notes to author from Denman, 10 May 2007. 22. Lawrence Livermore National Laboratory had demonstrated 1,100 watts of average power from a pulsed dye laser in 1992. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Jack D. Drummond, and Andrea Tuffli, “20-Watt CW 589-nm Sodium Beacon Excitation Source for Adaptive Optical Telescope Applications,” paper presented at the AMOS 2003 Technical Conference, Wailea, Maui, Hawaii, 8–12 September 2003; Joshua C. Bienfang, Craig A. Denman, Brent W. Grimes, Paul D. Hillman, Gerald T. Moore, and John M. Telle, “20 W Continuous-Wave Sodium D2 Resonance Radiation from Sum-Frequency Generation with Injection-Locked Lasers,” Optics Letters, 15 November 2003, pp. 2219–2221; Denman and Hillman, “Sodium Guidestar Project”; Coffey, “Powerful CW Laser Produces Bright Guidestar,” pp. 11, 14; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Brent W. Grimes, and Joshua C. Bienfang, Continuous Wave Sodium Beacon Excitation Source, US Patent 7,035,297 B1, filed 25 April 2006; notes to author from Denman, 10 May 2007. 23. The beam director is technically called a coelostat, an optical device capable of tracking a celestial body with a beam of light. The coelostat directs light from the ground to hit an object in space. Light reflected off that object is then collected and analyzed by a telescope on the ground. Interview with Fugate, 13 December 2006; interview with Happer, 29 September 2005; Craig Denman, Paul Hillman, Gerald Moore, John Telle, Jack Drummond, Steven Novotny, Mark Eickhoff, and Robert Fugate, “Single Frequency Sodium Guidestar Excitation at the Starfire Optical Range,” paper presented at the 90th annual meeting of the Optical Society of America, Frontiers in Optics

432

|   Notes to pages 321–22

2006, Rochester, New York, 11 October 2006; Craig Denman, e-mail message to author, 9 February 2007; notes to author from Denman, 10 May 2007. 24. Interview with Fugate, 13 December 2006; interview with Happer, 29 September 2005; Denman et al., “Single Frequency Sodium Guidestar Excitation”; Denman, e-mail message to author, 9 February 2007; notes to author from Denman, 10 May 2007. 25. Denman et al., Continuous Wave Sodium Beacon Excitation Source, US Patent 7,035,297 B1, files 25 April 2006. 26. Interview with Fugate, 13 December 2006; John Albertine (Review Panel Chair), “SAB 2003 S&T Review: Feedback to AFRL/DE,” briefing, 6 December 2002. 27. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; Craig Denman, Paul Hillman, Gerald Moore, Joseph Preston, Jack Drummond, and John Telle, “Continuous Wave Sodium Guidestar Laser Systems: Solid State and Diode Laser Technology Review,” briefing, Albuquerque, NM, 8–10 June 2004. 28. Interview with Denman, 19 December 2006; Jack Drummond, John Telle, Craig Denman, Paul Hillman, Jim Spinheirne, and Julian Christou, “Sky Tests of a Laser-Pumped Sodium Guidestar With and Without Beam Compensation,” Proceedings of SPIE, ed. Domenico Bonaccini and Brent Ellerbroek (Billingham, WA: SPIE Press, 2004), pp. 12–22; notes to author from Denman, 10 May 2007. 29. Interview with Denman, 19 December 2006; interview with Jack D. Drummond, Air Force Research Laboratory/Directed Energy Directorate, 9 March 2007; Drummond et al., “Sky Tests of a Laser-Pumped Sodium Guidestar With and Without Beam Compensation,” pp. 12–22; notes to author from Denman, 10 May 2007; notes to author from Jim Mayo, 26 January 2007; Jack Drummond, John Telle, Craig Denman, Paul Hillman, and Andrea Tuffli, “Photometry of a Sodium Laser Guide Star at the Starfire Optical Range,” Publications of the Astronomical Society of the Pacific, March 2004, pp. 278–289; Craig Denman, Paul Hillman, Gerald Moore, Jack Drummond, and John Telle, “Continuous-Wave Sodium Guidestar Laser Systems,” presented at CLEO/IQEC Conference, San Francisco, California, 16–21 May 2004. 30. Keck and Lawrence Livermore National Laboratory completed the Keck laser guide star system in January 2001. That was integrated with the Keck II adaptive optics system in September 2003. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; interview with Jeys, 26 February 2007. “Laser Guide Star Available For Adaptive Optics,” http://www.keckobservatory.org (accessed 24 July 2006).

Notes to pages 323–26

433

31. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; interview with Jeys, 26 February 2007; interview with Drummond, 9 March 2007; Drummond et al., “Photometry of a Sodium Laser Guide Star,” pp. 952–964; Denman et al., “20-Watt CW 589-nm Sodium Beacon”; Denman et al., “Continuous-Wave Sodium Guidestar Laser Systems”; notes to author from Denman, 10 May 2007. 32. Interview with Denman, 19 December 2006. 33. Interview with Denman, 19 December 2006; Denman et al., “Single Frequency Sodium Guidestar Excitation”; notes to author from Denman, 10 May 2007. 34. Interview with Denman, 19 December 2006; interview with Fugate, 13 December 2006; notes to author from Denman, 10 May 2007. 35. Interview with Denman, 19 December 2006; interview with Fugate, 13 December 2006; notes to author from Denman, 10 May 2007. 36. Interview with Denman, 19 December 2006; interview with Fugate, 13 December 2006; interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007. 37. The Association of Universities for Research in Astronomy (AURA) played a major role in assuring that Denman received funding for his 50-watt program. When enough funding from the Air Force Office of Scientific Research and the National Science Foundation did not materialize, AURA lobbied Congress aggressively to secure $3 million of add-on funding so Denman could proceed. Interview with Denman, 19 December 2006; interview with Fugate, 13 December 2006; notes to author from Denman, 10 May 2007; Craig Denman, Paul Hillman, Gerald Moore, John Telle, Jack Drummond, Joseph Preston, and Robert Fugate, “50 Watt Mesospheric Sodium Guidestar Laser,” briefing to the Air Force Scientific Advisory Board, 26 October 2004. 38. Interview with Denman, 19 December 2006; Eva Blaylock, “Research Lab’s Laser Brings Space Clearly into View,” Nucleus, 21 July 2006, p. 7; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Joseph E. Preston, Jack D. Drummond, and Robert Q. Fugate, “50-W CW Single-Frequency 589-nm FASOR,” paper presented at Advanced Solid-State Photonic Conference, Vienna, Austria, 6–9 February 2005, pp. 698–702; notes to author from Denman, 10 May 2007. 39. More precisely, the goals of the 50-watt sky testing were “to demonstrate the reliability of the system, check bore sight of the launch optics at various elevations, image the beacon to obtain its size, scan the wavelength across the D2 lines to obtain the wavelength for the highest photon return, and measure return flux at various fasor powers to check for saturation and to determine

434

|   Notes to pages 327–29

the sodium column density.” Denman et al., “50 Watt Mesospheric Sodium Guidestar Laser”; Denman et al., “50-W CW Single-Frequency 589-nm FASOR,” pp. 698–702. 40. Interview with Denman, 19 December 2006; Barbara Wilson and Bob Selden, “Air Force Science & Technology 2004 Quality Review,” briefing to Air Force Research Laboratory and others, December 2004. 41. Air Force Scientific Advisory Board, “Air Force Science & Technology 2004 Quality Review.” 42. Interview with Denman, 19 December 2006; Jack Drummond, Steve Novotny, Craig Denman, Paul Hillman, John Telle, and Gerald Moore, “Sodium Guidestar Radiometry Results from the SOR’s 50W Fasor,” paper presented at AMOS Advanced Maui Optical and Space Surveillance Technologies Conference, Wailea, Maui, Hawaii, 10–14 September 2006, pp. 340–349. 43. Interview with Denman, 19 December 2006; interview with Drummond, 9 March 2007; interview with Happer, 29 September 2005; notes to author from Denman, 10 May 2007. 44. Interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007. 45. Interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007. 46. Interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007; Craig Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Joseph E. Preston, Jack D. Drummond, and Robert Q. Fugate, “Realization of a 50-Watt Facility-Class Sodium Guidestar Pump Laser,” paper presented to SPIE—Photonics West—LASE 2005 Conference, San Jose, California, 22–27 January 2005; Craig A. Denman, Paul D. Hillman, Gerald T. Moore, John M. Telle, Jack D. Drummond, Steven J. Novotny, Robert Q. Fugate, James M. Spinhirne, Joseph E. Preston, and Mark L. Eickhoff, “Recent Results Using the 50 Watt Sodium Guidestar Pump Source at the Starfire Optical Range,” paper presented at AMOS Technical Conference, 5–9 September 2005, pp. 646–655. 47. Interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007; Denman et al., “Realization of a 50-Watt Facility-Class Sodium Guidestar Pump Laser”; Denman et al., “Recent Results Using the 50 Watt Sodium Guidestar Pump Source at the Starfire Optical Range,” pp. 646–655; John Telle, Jack Drummond, Craig Denman, Paul Hillman, Gerald Moore, Steven Novotny, and Robert Fugate, “Studies of a Mesospheric Sodium Guidestar Pumped by Continuous-Wave Sum-Frequency Mixing of Two Nd:YAG Laser Lines in Lithium Triborate,” paper presented at Atmospheric Notes to pages 329–32

435

Propagation III, Kissimmee, Florida, 20 April 2006; Drummond et al., “Sodium Guidestar Radiometry Results”; Denman et al., “Single Frequency Sodium Guidestar”; notes to author from Denman, 10 May 2007. 48. Notes to author from Denman, 10 May 2007. 49. Ibid.; Drummond et al., “Sodium Guidestar Radiometry Results,” pp. 340– 349; Denman et al., “Single Frequency Sodium Guidestar.” 50. Interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006; interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007. 51. Interview with Denman, 19 December 2006; interview with Drummond, 9 March 2007; notes to author from Denman, 10 March 2007. 52. Notes to author from Denman, 10 May 2007. 53. Ibid. 54. Interview with Denman, 19 December 2006; notes to author from Denman, 10 May 2007. 55. Interview with Drummond, 9 March 2007. 56. Interview with Drummond, 9 March 2007; interview with Fugate, 13 December 2006. 57. Interview with Drummond, 9 March 2007. 58. Interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007. 59. Interview with Drummond, 9 March 2007; notes to author from Denman, 10 May 2007; interview with Fugate, 13 December 2006; interview with Denman, 19 December 2006.

Conclusion 1. Over the last three decades, Air Force leadership from the laboratory level up through the chief of staff and the secretary of the Air Force has consistently been a strong advocate for adaptive optics. Among the most vocal and influential proponents were Colonel Leonard J. Otten III, commander of the Air Force Weapons Laboratory; Colonel Richard W. Davis, commander of Phillips Laboratory, and his chief scientist, Joseph F. Janni; R. Earl Good and Bruce L. Simpson, directors of the Directed Energy Directorate at the Air Force Research Laboratory; General Richard R. Paul and General Paul D. Nielsen, the first two commanders of the Air Force Research Laboratory; and Donald C. Daniel, the lab’s executive director. Secretaries of the Air Force Sheila E. Widnall and James G. Roche, Chiefs of Staff of

436

|   Notes to pages 332–41

the Air Force General Ronald R. Fogleman, General John P. Jumper, and General Lester L. Lyles, commander of Air Force Materiel Command, and Lieutenant James A. Abrahamson, director of SDIO, along with his top civilian advisor, Lou Marquet, all were strong supporters of adaptive optics research and ensured that sufficient political support and funding sustained the program. DARPA directors, especially in the 1970s and 1980s, recognized the importance of funding adaptive optics experiments. Bob Cooper was one of the many forward-looking DARPA directors who saw adaptive optics as a revolutionary technology that would offer high payoffs. Rett Benedict at ARPA (the same agency under an earlier name) recognized and promoted early adaptive optics research. At the Department of Defense, Hans Mark, a former secretary of the Air Force who also served as the Pentagon’s director of defense research and engineering during the Clinton administration, fervently promoted adaptive optics research, as did Ron Sega, who served as director of defense research and engineering during the second Bush Administration. 2. Alex Roland, Strategic Computing (Cambridge, MA: The MIT Press, 2002), pp. 3, 330–331. 3. Ann Finkbeiner, The Jasons: The Secret History of Science’s Postwar Elite (New York: Viking Penguin, 2006). 4. Because DoD granted clearances to selected Jason members, a limited number of academics, including Claire Max, Will Happer, and Freeman Dyson, were privy to classified adaptive optics research prior to the Air Force’s declassification meeting in 1991, but of course could not share the information with colleagues. For the most part, the Jasons supported Air Force research in adaptive optics. Will Happer, a Princeton professor, originated the idea for a sodium laser guide star in 1982, and Claire Max would lead the way in the astronomy community using sodium laser guide stars with the 3-meter Shane telescope at Lick Observatory in California. 5. One early example of civilian-military cooperation was the Sacramento Peak Observatory, a solar research center funded by the Air Force in the mountains near Cloudcroft, New Mexico. Astronomer Donald Menzel, who ran the Harvard College Observatory, helped to design and build “Sac Peak,” as it was commonly called, where civilian and military scientists worked together to measure conditions in the upper atmosphere and their effect on communications, missiles, aircraft, and other military systems. Ruth Liebowitz gives an excellent description of the project in “Donald Menzel and the Creation of the Sacramento Peak Observatory” (Journal for the History of Astronomy 33, part 2 [May 2002], pp. 193–211). Civilian-military cooperation continues today at Air Force telescope and optical tracking sites.

Notes to pages 342–46

437

6. David H. DeVorkin, Science with a Vengeance: How the Military Created the US Space Sciences After World War II (New York: Springer-Verlag, 1992), pp. 1–6. 7. Frank Morring Jr., “Hubble Endgame: Ground-Based Adaptive Optics Seen as Overtaking Last Upgrade,” Aviation Week & Space Technology, 14 January 2008, p. 26.

438

|   Notes to pages 346–47

Inde x

AAS. See American Astronomical Society Abercrombie, Neil, 295 ABL. See Airborne Laser ABLE ACE. See Airborne Laser Extended Atmospheric Characterization Experiment ABLEX. See Airborne Laser Experiment ABL Star. See Airborne Laser Star Abrahamson, George, 260, 268, 402n63 Abrahamson, James A., 174–79, 186, 189, 436n1 Abreu, Rene, 302–3, 307; on AEOS, 304 ACT. See Advanced Concepts Testbed (ACT) Active Ranging System (ARS), 214 actuators, 36–37, 42–44, 49, 53, 58, 106–7, 109, 126, 138, 144, 183, 247, 252, 267, 270–71, 290–92, 303 Adaptive Optics Associates, 75, 105, 159, 216 adaptive optics feasibility model, 32 ADONIS. See Air Force Maui Optical Site Daytime Optical NearInfrared Imaging System Advanced Concepts Testbed (ACT), 228 Advanced Electro-Optical System (AEOS), 62, 277, 298, 373n55,

409n37; Abreu on, 304; acceptance of, official, 307; advantages of, 283; construction of, authorization for, 292; cost of, 283, 297, 304; dedication ceremony for, 295–97, 297; dome, 300; dual buy plan for, 302; dual-use concept of, 284; environmentalist objections to, 288; factory acceptance testing, 303–4; first light, 299–300, 301; first picture of, 294; foundation, 287, 289; funding for, 282–83, 286; goal of, 299; groundbreaking of, 292; image quality of, 307; inspection of, 306; maintaining, 306–7; as national treasure, 297; operation of, 306; praise for, 296; precontractual work for, 284; problems with, 304–5; reasons for building, 281; religious leaders objections to, 288; responsibility of, 278, 279, 285; schematic of, 288; software package for, 302–3; specifications for, 284; specifications for, preliminary, 285; technical issues of, 302–3; testing of, 306; turnkey adaptive optics system for, 302, 306, 428n75 Advanced Radiation Technology Office (ARTO), 238 Advanced Reconnaissance System, 9

439

Advanced Research Projects Agency (ARPA), 1, 15–17, 22, 26, 32, 49, 57; creation of, 11; establishment of, 1; funding for, 14; future needs and, 13; goals of, 12; imaging at, 16; nontraditional research and, 13; responsibilities of, 12. See also Defense Advanced Research Projects Agency Advanced Solar Telescope, 280 Advanced Tag Team Phase 1 Experiment, 73 AEOS. See Advanced Electro-Optical System Aerospace Defense Command, 15, 58 Aerospace Federally Funded Research and Development Center, 120 AFRL. See Air Force Research Laboratory AFSPC. See Air Force Space Command AFWL. See Air Force Weapons Laboratory AIM-9B Sidewinder air-to-air missiles, 115, 175 Airborne Laser (ABL), xvii, 72, 193, 202, 207–35, 373n55; in attack scenario, 214; battle-management system, 207–8; beam control/fire control system for, 208, 212, 218; checks/ balances on, 228; conformal mirror of, 212; contractors, 206–7; critics of, 232; delays in, 207; development of, 204; final engineering integration phase of, 207; lasers making up, 215; management of, 406n9; as primary boost phase defense element, 206; primary mirror of, 213; “revolutionary potential” of, 206; safety and, 210; schematic of, 208; scintillation limit on, 221; second generation, 205–19; skeptics of, 226; test

440

|   Index

flight of, 208–9; tests aboard, 218; validation of, 231 Airborne Laser Experiment (ABLEX), 220–25, 228, 232, 234; Clear1 model, 221; flight experiments, 221; funding of, 221; scaled experimentation of, 223; success of, 226 Airborne Laser Extended Atmospheric Characterization Experiment (ABLE ACE), 224–28; conclusions of, 226, 234; critics of, 232; goal of, 225; predictions, 225; success of, 226 Airborne Laser Laboratory (ALL), 21, 91, 114–15, 175, 193, 203; flight-testing, 72–73; shortcomings of, 224; watercooled mirrors of, 212 Airborne Laser Star (ABL Star), 232–35; success of, 234 air density refractive index, 17 Air Force, 343; Avionics Laboratory’s Reconnaissance Division, 63; CIA and, relationship between, 10; CORONA role of, 29; Defense Support System, 279; Materiel Command, 147–48; Project, 120; reputation of, 167; scientific reputation of, 110; space object identification mission of, 340; space situational awareness mission of, 318; Systems Command, 59, 62, 110, 147–48, 150, 174, 283–84 Air Force Maui Optical and Supercomputing Site (AMOS), 280–81, 306, 341, 345 Air Force Maui Optical Site (AMOS), 126, 130, 370n21; Large Optical Facility Testbed, 282; managing, 280; opening of, 278–79; operating, 280; telescope upgrades at, 281–82 Air Force Maui Optical Site Daytime Optical Near-Infrared Imaging System (ADONIS), 308–9

Air Force Research Laboratory (AFRL), xvii, 23, 42, 148, 228, 280–81, 319, 339 Air Force Scientific Advisory Board (SAB), 110, 224, 319–20, 324, 329 Air Force Space Command (AFSPC), 58, 150, 278, 280, 282, 412n1; 1st Space Control Squadron, 279, 422n7; operational needs of, 307–8, 311; Space Object Identification Statement of Need, 14-89, 278, 421n1 Air Force Weapons Laboratory (AFWL), xv, 58, 64–65, 71–73, 89–90, 94, 96–97, 103, 114–17, 131, 145, 147, 149–50, 169, 181, 209, 237–40, 243, 247, 251, 255, 283, 285, 318, 339, 342; consolidation of, 148 Airy diffraction pattern, 46 Airy, George Biddell, 46 ALL. See Airborne Laser Laboratory Alpaugh, Harold, 2 Ameer, George, 91 American Astronomical Society (AAS), 158; bulletin, 159 American Physical Society, 192–93 Amor, J. P., 238 AMOS. See Air Force Maui Optical Site, Air Force Maui Optical and Supercomputing Site Anderson, John, 117, 264–65, 272 Angel, Roger, 241, 253, 414n15; Fugate and, partnership between, 242–43 Anti-Ballistic Missile Treaty, 1972, 179 antisatellite, 21, 65–66, 75–76, 89, 97, 108, 133, 135, 141, 146, 151–52, 179, 183, 238, 295, 281–82, 285, 315, 340, 379n3 APAC. See astral point ahead compensation Apache Point Observatory, 242 Arcetri Astrophysical Observatory, 112 Arcturus, 109

Index

Aristotle, xx Army Ballistic Missile Agency, 5, 6 Arnold, Hap, 131, 276, 346 ARPA. See Advanced Research Projects Agency Arroyo Center, 120 ARS. See Active Ranging System ARTO. See Advanced Radiation Technology Office Aspin, Les, 147 Association of Universities for Research in Astronomy (AURA), 434n37 astral point ahead compensation (APAC), 75 Atlas missile, 6, 29, 364n30 Atmospheric Compensation Experiment (ACE), 98–99, 154, 182, 191; beam quality of, 185–86; characteristics of, 183–84; cooperative targets of, 184; diagnostic aircraft for, 186; evolution of, 183; field tests, 184; phase 1 of, 184–85; phase 2 of, 185– 86; phase 3 of, 190; research phases of, 183; sounding rocket tests, 192; wavefront sensor, 184 “Atmospheric Fluctuations: Their Nature and Techniques for Compensation,” 158–59 atmospheric turbulence, xxi, xxiii, 15–26, 30, 34–35, 38, 43, 46–47, 51, 53, 55, 57, 59, 62–64, 72–80, 84–85, 87, 89–90, 94–97, 99, 102–9, 121–23, 125–29, 133, 135–36, 140, 144, 146, 149, 154–55, 166, 170–71, 181, 183–85, 187, 189, 190, 195, 197–98, 200–2, 204, 208–9, 214–17, 219–26, 229–30, 232–34, 240–41, 249, 257, 261, 272–74, 280, 307, 313, 315, 323, 326, 330, 340, 346; absence of, 33; causes of, 17; data, 23; database on, 25; defining effects of, 20, 24, 25; height of, 24; intensity of, 18, 24; Justice

441

on, 369n15; literature search on, 31; properties of, 33; simulating, 368n6; structure of, 33; understanding, 20; Urtz on, 369n15 atomic bomb, 28 Attaya, Bill, 2 Augustine, Jim, 289, 291 AURA. See Association of Universities for Research in Astronomy Automatic Telephone and Electric Company, 31 Avco Everett Research Laboratory, 55, 58, 89, 123, 283; location, 387n12; replacement of, 424n21 Aviation Week & Space Technology, 347 Avizonis, Petras, 89, 97, 102, 238–40, 243, 253, 268; record of, 244 Babcock, Horace W., x, 33; presentation by, 163; real-time sensing/ correction paper by, 34 Babcock, Ray, 2 Bagnell, Richard, 234 Baker, Bill, 316 Baker-Nunn cameras, 423n15 Ballistic Missile Defense Organization (BMDO), 146, 147, 202 Ballistic Missile Division, 29 Bandermann, Lothar, 218 battleground, future, 240 beacon stitching, 129 Bell, Alexander Graham, 104 Belsher, John, 79 Bendix aircraft detection radar system, 118 Benedict, Rettig, 13, 15, 47, 131, 165–66, 436n1 Berggren, Ralph, 35 Bernthal, Frederick M., 154 Bessmertnykh, Alexander, 194

442

|   Index

Betelgeuse, 105, 108, 109 Bienfang, Joshua C., 319–20, 323, 327 BILL. See lasers, beacon illumination Billman, Ken, xvii, 218 binary star, 109; discovery of, 272, 274, 306; 53 Ursa Major, 160 Bingaman, Jeff, 269 bismuth silicon oxide crystal, 366n46 Bissell, Richard M., Jr., 10 Blankinship, Ross, 218 BMDO. See Ballistic Missile Defense Organization Boeing, 206–8, 219, 280, 301, 306, 327–28 Boeke, Bruce, 90 bomber gap, 9 Bonaccini, Domenico, 112 Boston University Physical Research Laboratory (BUPRL), 2, 29 Bradbury and Stamm Construction, 259 Bradley, Lee, 125, 137 Brandenstein, Daniel C., 400n47 Breckinridge, James R., 165 Brewster-cut Nd:YAG rods, 321 British Telecommunications Research, 31 Britton, Bill, 2 Browne, S. L., 91 Brown, Harold, 59, 60 Browning, William F., 201 Buchsbaum, Saul, 170 BUPRL. See Boston University Physical Research Laboratory Bush, George H. W., 82, 159, 202 Butts, Russ, 223, 228 C3I Federally Funded Research and Development Center, 120 C-119 Flying Boxcar, 11 C-130 Hercules, 11

camera: Baker-Nunn, 423n15; Compensated Imaging System, 58; CORONA, 16; cryogenically cooled near-infrared, 113 Campbell Demag TC 1200 crane, 295 Campbell Generator, 251 Cape Canaveral Air Force Station, 197 Capella, 109 carbon-based life, ix Carr, James, 323 Casey, Harold C., 29 Cayetano, Benjamin J., 296 CCD. See charge-coupled device Center for Adaptive Optics, 319 Center for Naval Analyses, 120 Central Intelligence Agency (CIA), 8–9, 11, 29, 58; Air Force and, relationship between, 10 Chadderdon, Jim, 2 Challenger shuttle disaster, 195 charge-coupled device (CCD), 109, 269 Charyk, Joseph, 10 Cheney, Dick, 159 Ching, Mike, 227 CIA. See Central Intelligence Agency CIS. See Compensated Imaging System Clark, William, 173 CLASP. See Closed-Loop Adaptive Single Parameter Cleis, Richard A., 90, 159 Clifford, Mark, 291 Closed-Loop Adaptive Single Parameter (CLASP), 141; conclusions of, 142; first experiment, 142; success of, 142–43 closed-loop system, 35, 94, 126, 128, 141, 185, 368n8; building real-time, 97 Cloudcroft Electro-Optical Observatory, 63 Coast Steel Fabricators, 261

Index

coelostat, 432n23; at SOR, 112 COIL. See lasers, chemical oxygen iodine Cold War, 2, 12, 14, 16, 39, 119, 146–47, 193, 202, 205; end of, 373n54; intensifying, 379n3; space situational awareness in, x–xi; Strategic Defense Initiative and, 172 Columbia shuttle, 402n67 Compensated Imaging System (CIS), x, 32, 43, 49–50, 56, 63, 65, 68, 74, 171, 183, 300–1, 307, 312; Acceptance Test, 54; authorization to ship, 54; cameras, 58; customers, 58–59; delays of, 54, 55; final review of, 54; first image from, 55; Hardy on, 53; installing, 55; investment in, 52; Itek winning contract for, 51; logistical plan for, 53; performance of, 61–62; phase 1 of, 50; phase 2 of, 51; praise for, 59; price of, 54; problems with, 54, 59; refining, 58; reputation of, 62; retirement of, 62; shearing interferometer, 57; team photo, 52; testing, 55; theory of, 57–58; viewing time, 58–59 Comsat RSI, 293 Cone, Peter, 35 Continuous Wave Sodium Beacon Excitation Source, 324 Continuum Inc., 315 control servo requirements, 41 Cooper, Bob, xvii, 147, 169, 177–78, 211– 12, 436n1 Cooper, Henry F., 154 Copernicus, Nicholas, xx CORONA, 11; Air Force’s role in, 29; approval of, 9; cameras, 16; control struggle over, 10; goals of, 9; shutdown of, 10; start of, 29–30; stories about naming, 358n21 Covey, Stephen, 42 Cusack, Jim, 42

443

Daigneault, Steve, 218 Daniel, Donald C., 436n1 DARPA. See Defense Advanced Research Projects Agency Davies, Merton E., 27 Davis, Richard W., 436n1 Daytime Optical Near-Infrared System, 269, 308 DEER. See Directed Energy Experiment Range Defense Advanced Research Projects Agency (DARPA), x–xi, xvi, 11, 13, 26, 30–34, 42, 48–49, 52–53, 62, 71, 73–76, 79, 81–82, 87, 89, 120–21, 131–32, 135, 143, 145–46, 150, 169–72, 175, 178–81, 183, 191, 201, 203, 339, 341, 343, 359n28, 379n2, 437n1; budget of, 178; failure of, 342; Order 26, 46, 51; risks of, 342; Strategic Defense Initiative Organization and, relationship between, 177. See also Advanced Research Projects Agency De La Rue, Imelda, 328 DeLaurer, Richard D., 173, 177 Delta II booster, 403n71 Denman, Craig, xv, 318–29, 331–32, 336–37, 343; definition of sodium laser, 429n2; praise for, 324, 334; reputation of, 316–17; strengths of, 317; two-frequency experiments proposed by, 333–34 Department of Defense Appropriations Act of 1991, 284 DeVorkin, David H., 346 diffraction-limited image, 49 directed energy, xvi, 13; definition of, 62; goal of, 173, 175, 177, 243; Itek and, 373n54 Directed Energy Directorate (DE), xiii, xv, 148, 219, 228, 234, 277, 316, 319

444

|   Index

Directed Energy Experiment Range (DEER), 116–17 Discoverer 1, 30 Discoverer 14, 30 Discovery shuttle, 20, 186; crew of, 400n47; operation error, 187–88; schematic, 188 “distorting the distortion,” 37 “Donald Menzel and the Creation of the Sacramento Peak Observatory” (Liebowitz), 437n5 doubly resonant optical cavity, 321 Douglas Aircraft Company, 364n26 Drone Experiment Laser Test and Assessment (Project DELTA), 114–15 Drummond, Jack, 328 Duncan, Alan, 218 Dyson, Freeman, 345, 437n4 Ealey, Mark, 63, 217, 270, 373n55 education reforms, 4 Eisenhower, Dwight D., 1, 8–14, 30; Christmas message of, 6; promoting science and technology, 356n9 Elder, Rich, 286, 291 electromagnetic reconnaissance data, 358n22 electro-optics, 39; complexities of, 129 Ellerbroek, Brent, 109, 164 Eno, Richard, 190 evening neutral event, 47 Everglaser, 138, 142 Excalibur, 171 Experimental Laser Device (XLD), 135–36, 142–44; accomplishments of, 141; beam diagnosis tests, 140; compensation tests on, 138–39; experiments, 138; optics room, 140 Explorer I satellite, 6, 7

F-14 Tomcat fighter aircraft, 214 F-15 Miniature Homing Vehicle, 66 FAA. See Federal Aviation Administration FASOR. See Frequency Addition Source of Coherent Optical Radiation Federal Aviation Administration (FAA), 117–18 Federally Funded Research and Development Centers (FFRDC), 120, 386n3 Feinleib, Julius, 35–36, 75, 76 FFRDC. See Federally Funded Research and Development Centers Finkbeiner, Ann, 344 Firepond Optical Research, 220 first wave optics propagation code, 137 Fletcher Commission, 173, 397n14; findings of, 174 Fletcher, James C., 173 fluorescence. See light focal, 377n33 focal anisoplanatism, 77, 79, 80–82, 84–85, 90, 95, 122, 125, 129, 164, 166, 313–14; Fried’s theory on, 94 Fogleman, Ronald R., 206, 295–97, 436n1 Ford, Steve, 231 Foreign Technology Division, 152 Foster, John S. “Johnny,” 174 Fouche, Dan, 137 Fox, Marsha, 308 Foy, Renaud, 148, 155 fratricide, 204 freedom, 341 Frequency Addition Source of Coherent Optical Radiation (FASOR), 429n2 Fried, David L., xvii, 48, 51–54, 76–79, 81–82, 91, 95–96, 125, 131, 164, 166, 343; paper by, 166; theory on focal anisoplanatism, 94

Index

Frieman, Edward, 170 Frieman, Herb, 430n4 FSSS. See Future Security Strategy Study Fugate, Robert Q., xii, xiv–xv, 38, 66–73, 76, 81, 84, 89–99, 101–10, 112–13, 115, 117–19, 125, 129, 131, 145, 148, 152, 155–56, 158–64, 166–67, 237–44, 256, 263–64, 266–71, 275–76, 315–18, 327, 343, 375n17, 380n12; Angel and, partnership between, 242–43; biography of, 67–71; “Experimental Discussion of Real Time Atmospheric Compensation with Adaptive Optics Employing Laser Guide Stars” by, 158–59; national/ international attention on, 110; parents of, 67; presentation by, 159– 60; Presidential Rank award for, 276; press brief by, 162; principles of, 67; sales pitch for telescope by, 238–40; senior thesis of, 68; team, 70–71; workshop by, 163 future, military blueprint for, 131 Future Security Strategy Study (FSSS), 173–74 Galilei, Galileo, xix–xxi, 12, 343; first telescope, 14; Roman Catholic Church condemnation of, xx Galileo National Telescope, 112 GBFELTIE. See Ground-Based Free Electron Laser Technology Integration Experiment GEMINI, 309 General Operational Requirement No. 892, 9 GEODSS. See Ground-Based ElectroOptical Deep Surveillance System Gerasimov, Gennady, 194 German V-2 rocket, 356n10, 357n12

445

Goldberger, Marvin L., 81 Goldberger, Mildred, 81 Golet, Marcel, 366n47 Gonglewski, John, 308 Good, Earl, 316, 436n1 Gorbachev, Mikkhail, 193–94; perestroika introduced by, 194 Greenwood, Darryl, xvi, 41–42, 51–53, 122, 129, 131–32, 134, 144, 149, 155–56, 179, 181–83, 185, 187, 190–92, 343, 399n31 Greenwood frequency, 41, 181 Greenwood, Lee, 299 Grimes, Brent W., 319, 323, 431n19 Grotbeck, Ron, 72 Ground-Based Electro-Optical Deep Surveillance System (GEODSS), 279 Ground-Based Free Electron Laser Technology Integration Experiment (GBFELTIE), 218, 286; cancellation of, 404n79, 409n37 ground-based laser technology antisatellite program, 66 Guenther, Art, 414n15 guide stars, high mark for brightness of, 334; hybrid system, 327. See also laser(s) guide stars, 20-watt sodiumwavelength, 320, 323–24, 328; photon return of, 326–27, 330–32; problems with, 336; sky testing, 325; at SOR, 324–27; success of, 327, 336 guide stars, 50-watt sodiumwavelength, 331; automation of, 329; demonstration of, 328–29; at full power, 331, 334; funding for, 434n37; hardware purchasing for, 328; modeling for, 327; mounting, 328, 329; operator of, 332; peak sodium flux return, 332; photon return on, 328–29, 330, 333; power scaling

446

|   Index

for, 327; praise for, 329; problems with, 336; sky tests, 329–30, 333–34, 434n39; success of, 336 guide stars, declassification of, 118, 132, 145–50, 155–62, 164, 193, 344–45, 413n9; benefit of, 156, 167; concerns over, 151; consumers and, 152; rationales for, 157; risk involved in, 152; support for, 156 guide stars, laser, x–xi, xiv, xxi, 58, 64, 66, 73–74, 77–79, 81–82, 85–86, 89–90, 96, 103–5, 107–10, 115, 125, 129, 132, 166–67, 216–17, 318, 330; as artificial beacon, 95; control algorithm for, 74; early concepts, 74–75; foundation of, 71–72; security, 145–46; single-pulsed, 75; sketch of, 91; solid-state, 336; space control applications improved through, 146 guide stars, multifrequency sodium, 336–37; expectations for, 337 guide stars, Rayleigh, 75, 80, 84, 87, 90, 119, 121, 149, 200, 313–14, 316, 342; creating, 92; first experiment of, 93; funding for, 379n2; information leaked about, 149; maintaining, 92; performance of, 96; results of, 94; setting up, 92; success of, 380n12; testing of, 90 guide stars, sodium, 79, 83–87, 89, 95–96, 121–25, 314–20, 322–23, 330–31, 333, 336–37, 342, 387n13; concept of, 119; drawback to, 84; funding for, 315; future of, 334, 336; generating bright enough, 314; goal of, 121; information leaked about, 149; space situational awareness mission and, 318 Hafnagel, Bob, 363n20 Hanson, Don, xvi, 41–42, 45–46, 48–49, 51–52, 54–55, 62, 74, 76, 131, 343

Happer, Will, xvi, 82–84, 86–87, 166, 313, 437n4 Hardy, John W., xvi, 27, 30–34, 36, 39, 44–45, 47–48, 52–53, 55, 59, 368n7; on Compensated Imaging System, 53; scientific revolutionary acclaim for, 62 Harold Brown Award, 59, 60 HARP. See High Altitude Reconnaissance Platform HAVE REACH, 147–48, 150, 153, 157; classification guide, 157–58 Heilmeier, George H., 51 heliocentric theory, xx Herrmann, Jan, 125, 137 Herschel, William, xxi High Altitude Large Optics program, 370n26 High Altitude Reconnaissance Platform (HARP), 221 High-Energy Laser Propagation and Beam Control Group, 182 Hilliker, Henry, 26 Hill, John M., 244–45 Hillman, Paul D., 319–21, 323, 327, 333 Hoffman, Fred S., 174 Hogge, Barry, xv, 131, 240 Holmes, Rich, 218 HoPE. See Horizontal Path Experiment Horizontal Path Experiment (HoPE), 219–20, 234 Horwitz, Bruce, 218 Hubble Space Telescope, xxiv, 20, 59, 109–10, 112, 273–74, 310, 318, 347; justification for, ix; launch of, xxiii Hufnagel, Bob, 370n23 Hughes Danbury Optical Systems, xvii, 64, 254, 270, 292, 300–2, 305; disappointment in, 271; reorganized, 373n55, 419n79 Hughes Research Laboratory, xvii, 50, 64

Index

Hughes, Rusty, xvii, 301–4, 307 Humphreys, Ronald A., 89, 95, 122, 125 Hunter, Duncan, 180 Hunter, Robert, 74 Hutchin, Richard A., xvii, 50–53, 55, 74–75, 81, 125; name change, 370n24 hydrogen bomb, 28 ICBM. See intercontinental ballistic missile Idell, Paul, 54 Ikle, Fred C., 173–74 image post-processing techniques, 281, 308 Infrared Search and Track sensors (IRST), 214 Inouye, Daniel K., 283–84, 287, 292, 295, 297 Institute for Defense Analyses Studies and Analyses, 120 intercontinental ballistic missile (ICBM), 3–4, 8–9, 14, 28, 171, 279, 364n30 interference fringes, 24 intermediate-range ballistic missile (IRBM), 364n30 International Geophysical Year, 5 International Test and Evaluation Association, 234 interviews, list of, 349–53 IRBM. See intermediate-range ballistic missile IRST. See infrared Search and Track sensors isotope separation, 430n4 Itek Optical Systems, xvi, 10, 16, 26–36, 38–39, 41–55, 57–59, 61, 63–64, 74–75, 109, 126, 137, 143, 164, 183–84, 192, 217, 270, 291, 366n46, 366n47, 368n7; buying out of, 373n55; contracts of, 29; directed energy

447

and, 373n54, 373n55; employees of, 29; first public notice of, 27; objectives of, 32; setting up, 29; winner of CIS contract, 51 James Webb Space Telescope, xxiii Janni, Joseph, xvi, 285, 310, 436n1 Jason, 79–82, 345, 377n39, 437n4; meetings, 81, 82, 313 The Jasons: The Secret History of Science’s Postwar Elite (Finkbeiner), 344 Jet Propulsion Laboratory, 6 Jeys, Tom, xvi, 314–15, 321, 325–27, 430n7 Johns Hopkins Applied Research Laboratory, 386n3 Johnson, F. B., 141 Johnson, Kelly, 10 Johnson, Roy, 12 Joint Space Operations Center, 421n1 The Journal of Physics and Chemistry of Solids, 68 Journal of the Optical Society of America, 47, 157; special edition, 158, 163, 165–66 Jumper, John P., 235, 275–76 Jupiter C rocket, 5, 6, 357n12 Justice, Jim, 49; on atmospheric turbulence, 369n15 Kappa-Pegasus, 272 Kastler, Alfred, 86 Keck II telescope, 433n30 Keck I telescope, 20, 113, 261, 326, 355n1; completion of, 433n30 Kelly, Quentin, 66 Kenemuth, John R., xv, 289–92, 428n75; responsibilities of, 300–1, 305–7 Keyworth, George, 170 Khrushchev, Nikita, 8; on Vanguard I, 357n11

448

|   Index

Kibblewhite, Edward, 148, 164 Kiewit Pacific Inc., 292 Killian, James R., 5, 119; appointment of, 356n9 kinetic energy weapons, 173, 202, 206 kinetic-kill systems, 146, 183 King, Marvin, 51, 53 Kirtland Air Force Base, xiii–xiv, xvii– xviii, 65, 71–72, 89, 93, 100, 114, 117, 121, 124, 129, 145, 147, 150, 163, 165, 170, 200, 206, 219, 234, 241, 256, 277, 283–84, 287, 316, 318 Kitt Peak Observatories, 242 K. L. House Construction Company, 257 Knowlton, Robert, 122, 125 Kocher, Dave, 143 Kolmogorov, Andrei N., 33 Kramer, Mark, xv, 227–28, 230–31 LAAT. See Large Aperture Acquisition Telescope Labeyrie, Antoine, 148, 155 LACE. See Low-Power Atmospheric Compensation Experiment Laika, 2; death of, 356n2 Lamberson, Don, 175, 177, 224 Large Aperture Acquisition Telescope (LAAT), 299 Large Aperture Speckle Experiment, 269 Large Field Acquisition Telescope (LFAT), 299 Large Optics Generation machine, 251 Larson, Lanny, 290 laser(s), applications of, 170; beam control experiments, 72; bluegreen, 179; carbon dioxide, 72, 114, 361n5; “center of the tuning curve” of, 314–15; communications in submarines, 179–80; continuous wavelength argon-ion, 197;

continuous wavelength sodiumwavelength, 320; continuous-wave Nd:YAG solid-state infrared, 320–21; copper vapor, 73; diode, 321; directing, 24; discovery of, 20; dye, 123, 125, 320, 430n4, 430n6; field experiments, 21; flashlamppumped pulsed dye, 123; health hazards of, 117–18; high-energy, 132–44; high-power solid-state, 314–15; improving beam quality in, 132; injection-locked, 321–22; intensity of, 23; intercepting, 38; low-power, 24; low-repetitionrate dye, 126; making up Airborne Laser, 215; megawatt-class CO2 gas dynamic, 135–36; 3.5 micron wavelength range, 133; modelocked pulsed, 315; as precision weapon, 21; pulsed frequencydouble Nd:YAG short wavelength visible green, 92; quality of, 23; refraction index of, 133; research at SOR, 66; scoring green, 190; short wavelength, 18–19; shortwavelength oxygen-iodine, 361n5; slewing, 141; sodium, 429n2; 6-watt sodium wavelength, 319–20; solidstate Yb:YAG diode-pumped, 214; in space, 170; X-ray, 171. See also guide stars; light; specific lasers 405B Laser Communication Program, 63 laser guide stars. See guide stars, laser Laser Integration Technology program (LITE), 317 Lasers, Beacon Illumination (BILL), 208, 215, 221; preliminary testing of, 216; principle of, 217 lasers, chemical oxygen iodine (COIL), 169, 204, 208, 212–18, 223, 231; features of, 209; first light, 211; fuel interaction in, 210; knowledge point of, 211; modules of, 209–10

Index

lasers, prototype attack (YAL-1A), 207 Laser, Track Illumination (TILL), 214– 15, 217 Lawrence Livermore National Laboratory, 431n17, 432n22 Lawrence, Robert, 363n22 LDEF. See Long Duration Exposure Facility lead zirconate titanate (PZT), 36 Leghorn, Richard, 27, 29; surveillance conclusions of, 28 Lennon, Peter, 283 Leonid meteor showers, 330 LFAT. See Large Field Acquisition Telescope Lick Telescope, 326, 437n4 Liebowitz, Ruth, 437n5 Lifsitz, Jacob, 185 Light, maximizing available, 74; outof-phase, 18; source of, x; travel method of, 18; wrinkled, 18; year, 18. See also laser(s) Lincoln Laboratory, xvi, 15, 41, 51–53, 58, 64, 89, 98–99, 110, 119–32, 134–39, 141–45, 147, 149–50, 154, 156, 161, 163, 166–67, 169, 171, 179, 181–84, 186–87, 189–92, 195–97, 199–201, 203, 217, 220, 230, 268–70, 302, 309, 314, 320, 325, 339, 342–43; expansion of, 120; funding for, 120; mission of, 120; origins of, 119; reputation of, 167 Lippershey, Hans, xix Lipson, Steven, 35 LITE. See Laser Integration Technology program Lockheed Martin Space Systems Company, 10, 50, 206, 208, 214, 216, 218 Lockheed “Skunk Works,” 10 LODESTAR, 76; funding of, 146; “need to know” status of, 146; termination of, 147

449

Long Duration Exposure Facility (LDEF), 195; retrieval of, 402n67 Lorenzini, Dino, 131 lower-tier missile defense, 202 Low-Power Atmospheric Compensation Experiment (LACE), 195–202, 198, 219; communication terminated with, 404n74; cost of, 197; counterweight boom on, 199; delay of, 195, 196–97; diagnostic detector array on, 197; experiments in, 200; gravity gradient boom on, 199; under hostile conditions, 200; launches scheduled for, 196–97; launch of, 197, 201; preparation of, 196; retroreflector beacon on, 197; retroreflector boom on, 199; sensor array subsystem on, 197; success of, 201 Lukasik, Stephen J., 49 Lyles, Lester L., xvi, 275–76, 436n1 MacDonald, Duncan E., 29 Maiman, Theodore H., 20 Mangano, Joseph A., 175 Manzano Mountains, 103, 114, 240–41, 413n11 Marchiando, Peter J., 156–57, 284 Mark, Hans, 204, 436n1 Marquet, Lou, xvi, 98, 133–37, 139, 141, 169–70, 172, 175, 177–79, 181–82, 195, 343, 436n1; awards for, 179; retirement of, 179 Matson, Chuck, xv, 308–9 Maui High Performance Computing Center (MHPCC), 281, 309, 310 Maui Space Surveillance Complex (MSSC), 280 Maui Space Surveillance System (MSSS), 280, 309 Max, Claire, 154, 437n4 Max Planck Institute for Astronomy, 112

450

|   Index

Mayo, Jim, xv, 4–5, 54, 102–3, 212–13, 239, 243–44, 255–56, 282–91, 293–96, 299, 343, 409n37, 414n15, 414n22, 414n23, 426n48 McDonald, Gordon, 86, 87 McDonnell Douglas, 197, 403n71 McDougall, Walter A., 4 McElroy, Neil H., 5 McGlamery, Ben, 53 McNally, Jim, xvi, 289, 292 MDA. See Missile Defense Agency Medaris, John Bruce, 6, 356n10 Meyer, Tom, xvi, 71, 98, 102, 148, 177, 189, 343 micro thermal probes, 24 Military Critical Technologies List, 146 military mission, 341 Milky Way, 267 Miller, Franklin C., 174 Miller, Richard, 247, 256, 285 Miller, Steve, 289, 291 Milonni, Peter W., 318 Miniature Homing Vehicle, 59 miniature kill vehicle, 379n3 Mink, Patsy T., 295 mirror, x; acid etching, 250; after cooling, 248; Airborne Laser’s conformal, 212; Airborne Laser’s primary, 213; aluminum on, 254; casting experiments, 414n15; coating, 254, 291; continuoussurface deformable, 366n47; deformable, x, xi, xvii, xxi, 20, 32, 35–39, 43–50, 53–54, 58, 64, 74, 76, 94–95, 97, 106–7, 109, 113, 126–28, 137–44, 150, 152, 155, 160, 164, 183–85, 190, 196, 198–99, 204, 218–20, 230–31, 255, 259, 270–71, 274, 290–92, 302–4, 323, 340, 366n47, 377n55; dichroic, 321; fabrication of large lightweight, 370n26;

honeycomb-hexagon configuration on, 249; liquid-cooled, 373n54; manufacturing, changes in, 373n55; membrane, 366n47, 370n23; segmented, 366n47; solid-glass, 249; spin casting, 241, 242, 246–54; stressed-lap (computer driven) polishing procedure, 241, 242, 251–54, 252; tarnished silver on, 254; types of, 366n47; ventilation system, 250; water-cooled, 138; Zerodur blank, 286, 287, 290, 291 mirror, monolithic piezoelectric (MPM), 35–36, 38, 44, 50, 366n47; next generation, 54; schematic of, 36 Missile Defense Agency (MDA), 147, 206, 211, 406n9 missile race, 3, 5 missiles. See specific missiles Mitchell, Harold F., 11 Mobile Optical Measurement System (MOMS), 99, 257, 311 MOMS. See Mobile Optical Measurement System Mooradian, Aram, 314–15 Moore, Gerald, 319, 323, 327 Mount Wilson Observatory, x, 33–34, 113, 154, 192, 345 MPM. See mirror, monolithic piezoelectric MSSC. See Maui Space Surveillance Complex MSSS. See Maui Space Surveillance System multidither technique, 50, 143 Murphy, Dan, xvi, 191, 197, 201 NASA. See National Aeronautics and Space Administration National Aeronautics and Space Administration (NASA), xxiii, 12,

Index

59, 68, 99, 173, 175, 186–87, 195, 257, 311, 347 National Air and Space Intelligence Center, 278 National Cash Register Company, 67 National Defense Education Act, 356n6 National Defense Research Institute, 120 National Oceanic and Atmospheric Administration, 363n22 National Optical Astronomical Observatory (NOAO), 293 National Reconnaissance Office (NRO), 10; denial of existence, 358n20 National Science Foundation (NSF), 4, 113, 152–57 National Security Decision Directive: Number 85, 173; Number 119, 174 Navy Vanguard rocket disaster, 5–6 Nelson, Burke E., 252 Newsweek, 176 Newton, Isaac, xxi, 33 Neyman, Christopher R., 306 NGC3583, 267 NGC4147, 267 Nielsen, Paul D., 436n1 NKC-135 research aircraft, 203 NOAO. See National Optical Astronomical Observatory NoDyCE. See Non-cooperative Dynamic Compensation Experiment Non-cooperative Dynamic Compensation Experiment (NoDyCE), 230–34; end of, 231; success of, 231 nonlinear lithium triborate crystal, 321 NOP. See North Oscura Peak (NOP) North Oscura Peak (NOP), 228–33, 411n60, 411n63; equipment of, 230; goal of, 228–29

451

Northrop Grumman Space Technology, 206, 208, 210–11, 213, 216, 356n7 NRO. See National Reconnaissance Office NSF. See National Science Foundation nuclear effects data, 27 Nuclear Regulatory Commission, 178 Obering, Henry A., III, 205–6 OCULAR. See Optical Compensation of Uniphase Laser Radiation Ohara, 245, 246; E6 borosilicate, 245 O’Keefe, Shawn, 225 O’Meara, Tom, 144 open-loop system, 94, 110, 127, 137, 141 Operation Paperclip, 356n10 Optical Compensation of Uniphase Laser Radiation (OCULAR), 143; design of, 143–44; field testing of, 143–44; planning of, 143–44 optical maser, 20 optical phase distortion, 53 optical reciprocity, 76 Optical Sciences Company, xvii, 50, 52, 76, 125, 131, 159, 164, 166, 411n60 opto-mechanical control system, 127 Orion nebula, 112 Otten, John, xvi, 116–17, 148, 150, 152, 156–57, 164–65, 243–44, 283–84, 289, 436n1 ozone layer depletion, 82 Packard, David, 170 parabolic reflecting telescope, xxi, 355n1 parallel processor, 35 Parenti, Ronald, 166 passive illumination, 74 Paul, Richard R., 23, 295, 436n1 Pawlikowski, Ellen, 207, 211 Perkin-Elmer, 50

452

|   Index

phase correction, 137, 141, 366n46 phase shift, 24, 47 Phillips Laboratory (PL), 62, 103, 110, 115, 125, 145, 147–50, 154–59, 163–65, 169, 219, 221, 223, 227, 229, 269, 284–87, 289–90, 292, 308–10, 339, 409n37 Physical Science Study Committee (PSSC), 4; high school textbook, 356n7 Pickering, William H., 6 Pitts, Tom, 42 Polaris, 90 population inversion, 135 post-detection method, 32 Powers, Gary Francis, 8 Pratt & Whitney’s jet engine test facility, 135 predetection compensation, 47 Preston, Joe, 327 Primmerman, Charles A., xvi, 89, 119, 122, 125–26, 131–32, 134, 137, 141–42, 144–45, 149, 158–59, 161–63, 187, 191, 343; awards for, 125; presentation by, 161; workshop by, 163 Principles of Adaptive Optics (Tyson), 18 Pringle, Ralph, 303 Project Air Force, 120 Project DELTA. See Drone Experiment Laser Test and Assessment Project Feedback, 358n19 Project Orbiter, 6 PSSC. See Physical Science Study Committee Ptolemy, xx PZT. See lead zirconate titanate radar, 8, 15–16, 21–22, 24–25, 27, 41, 117, 120, 279, 370n21; Bendix aircraft detection, 118; SAGE, 386n2 RADC. See Rome Air Development Center

radio: amateur, 67; controlled aerial target, 114 RAND Corporation, 9, 27, 120; origins of, 364n26; Project Feed Back, 358n19 range profiling, 15 Rankine, Robert R., Jr., 110, 177 Rayleigh guide stars. See guide stars, Rayleigh Rayleigh scattering technique, 71–72, 76–77, 84, 89, 148, 166, 378n46, 379n3 ray point-ahead compensation (RPAC), 74 Reagan, Ronald, 97–98, 170–75, 177, 186, 193–94, 202, 238; death of, 194; “Star Wars” speech of, 172–73, 397n8 Real-Time Atmospheric Compensation system (RTAC), 27, 36, 43, 183; night and, 47; small-scale model, 42–43; success of, 45; testing, 43, 44, 46–47; themes from, 48 reconnaissance vehicles, 8 reconstructor, 37, 39, 45, 126, 302–4 reentry vehicle v. decoy, 134, 389n34 Relay Mirror Experiment (RME), 403n71 resolution formula, xxii–xxiv Reykjavik Summit, 193 Rhodamine 590 6G chloride, 123 Ring Nebula M57, 299–300, 301 Risley prism plate, 92 RME. See Relay Mirror Experiment Roberts, Lewis C., Jr., 306 Roberts, P. H., 91 Roche, James G., xvi, 235, 275–76, 436n1 Rockefeller, Laurance, 27 Roddier, Francois, 163–64 Roessler, Fred, 86 Rogers, Tim, 327 Roggemann, Mike, 308

Index

rogue nations, 205 Roland, Alex, 342 Rome Air Development Center (RADC), 16, 20–21, 24–26, 32, 39, 48–49, 51–52, 54–55, 62, 64, 109, 124, 131, 181, 281–83, 339, 343; location of, 22; mission of, 362n11 Ross, Grant, 2 RTAC. See Real-Time Atmospheric Compensation system Ruane, Ray, 90 Russell, John J., xvi, 148, 150–53, 156 SAB. See Air Force Scientific Advisory Board Sacramento Peak Observatory, 437n5 SAGE. See Semiautomatic Ground Environment Salinas Peak, 411n63 SAMOS. See Satellite and Missile Observation System Sandia National Laboratory, 117 Sandia Optical Range. See Starfire Optical Range Satellite and Missile Observation System (SAMOS), 358n22 Saturn, 111, 306 al-Saud, Salman (Prince Sultan), 400n47 Schawlow, Arthur L., 20 Schele, Don, 68 Schlossberg, Howard, 318 Schott Glass Works, 243, 287, 289–90 Schriever, Bernard A., 9–10, 28 Science with a Vengeance: How the Military Created the US Space Sciences After World War II (DeVorkin), 346 scintillation, 220, 223; high-bandwidth, 225; limit on ABL, 221

453

SCORE. See Signal Communications by Orbital Relay Equipment Scud missiles, 202, 204–6, 232 SDI. See Strategic Defense Initiative SDIO. See Strategic Defense Initiative Organization SEASAT, 273 Sega, Ron M., xvi, 276, 436n1 Semiautomatic Ground Environment (SAGE), 120; radar system, 386n2 Sepucha, Robert, 175 Shack, Roland, 382n43 shadow imaging, 25, 363n20 Shane telescope, 437n4 shearing interferometer, xvi, 24, 34–35, 47, 50, 57–58, 68, 75, 81, 183–84; Compensated Imaging System, 57; improvements to, 51 shearing point ahead compensation (SPAC), 75, 81; testing, 378n42 Short, Hames, xxi Short-Wave Adaptive Optics Techniques (SWAT), 98, 110, 122, 126–30, 163, 182, 195–96, 199, 201, 220; end of, 200; validation of, 420n89 shower door effect, ix, 360n39 Signal Communications by Orbital Relay Equipment (SCORE), 6 Simpson, Bruce L., xv, 436n1 Skantze, Lawrence, 174–75 Smith, Dow, 29 sodium resonant scattering, 121, 166, 378n46 Software Engineering Institute, 120 solar heating, 17 sound barrier, breaking of, 346 Soviet Rocket Forces, 402n63 Soviet Union, 1, 3–5, 8–9, 14, 27, 30, 119, 152, 179, 193–95, 239, 281, 344, 397n8; atomic bomb test, 28; demise of,

454

|   Index

344; failure of reforms in, 194; hydrogen bomb test, 28 SPAC. See shearing point ahead compensation space: age, 1, 3; based kinetic interceptors, 146; debris, 66; photographs, 30; race, 2; surveillance network, 278 Space and Missile Systems Organization, 15 Space-Based Laser, 373n55 “Space Object Imaging From The Earth’s Surface,” 32 space shuttle. See specific shuttles Spinhirne, James, 328 Sputnik, 1–8, 11–12, 28, 81, 355n1 Sputnik I, 1–2, 6; first U.S. photograph of, 3; psychological effect of, 4; public outcry over, 4; tracking, 2 Sputnik II, 2–3 Sputnik III, 3 Starfire Optical Range (SOR), xiv, 65–66, 72–73, 90–91, 93–100, 111–18, 123–25, 128, 148, 150, 154, 158–61, 164–66, 199–200, 202, 217, 219–20, 237–44, 247, 251–52, 254–57, 259–75, 277–81, 284–85, 289, 292–93, 302–4, 306–7, 311, 315–16, 318, 324–27, 341, 343, 345, 378n42, 413n11, 416n40, 420n89, 428n75, 429n2; 20-watt sodium-wavelength guide star system at, 324–27, 325; advantages of, 115; coelostat, 112; construction of, 114; cooperative research of, 113; credibility of, 239; dome at, 260–61, 262, 263; excavation of, 259; first light at, 267; funding for, 115–16; Generation I experiment at, 103–8, 161, 382n41; Generation II experiment at, 103, 108–10; historical record of, 240; human spotter at, 118; ice making at, 259; laser research at, 66; long-term

vision of, 238; official acceptance of, 259; propane-fired boiler at, 259; repairs at, 307; reputation of, 112; rivalries/jealousies over, 116; safety precautions at, 118; skeptics of, 275; support for, 275; telescope cost at, 269; telescope dedication ceremony at, 269–70; telescope installed at, 99–102, 101, 266; telescope model at, 258; telescope plans at, 238; telescope running at, 103; testing interrupted at, 93; tours at, 164–65; turning point of, 276; world-class status of, 274 starlight, xxii, 24, 55, 57, 90, 92–94, 108– 9, 223, 233 The Starry Messenger (Galilei), xx stars. See binary star; specific stars Steward Observatory Mirror Laboratory (SOML), 241, 243–45, 248, 250–51, 253–54, 416n40 strategic computing, 342 Strategic Computing (Roland), 342 Strategic Defense Initiative (SDI), 71, 94, 98, 154, 170, 173, 177–78, 186, 192–95, 201–2, 373n54, 402n63; as blackmail, 194; Cold War and, 172; cost of, 194–95; criticism of, 194–95; establishment of, 171; funding for, 398n19; implementation of, 174 Strategic Defense Initiative Organization (SDIO), xvi, 65, 96–99, 102, 116, 120, 152–54, 171, 173, 176, 178–79, 187, 192–96, 201–2, 218, 238, 282, 339, 343, 404n79, 409n37, 436n1; benefits of working for, 177; budget of, 177, 404n79; Cold War and, 146–47; critics of, 192; DARPA and, relationship between, 177; establishment of, 174; funding for, 175, 202; High Precision Tracking Test, 186; leadership at, 147; relocation of, 178; restructuring of, 202

Index

Strehl, Karl, 108 Strehl ratio, 108–110, 128, 223–24, 274, 303, 305, 307; improving, 229 Stribling, Bruce, 309 Strong, John, 254 Strutt, John William, 71, 77 Stubbs, David, 218 subapertures, 31–32, 37, 39, 58, 92, 101–6, 123, 271 sum-frequency generation cavity, 320– 22, 324 sum-frequency mixing, 320 SWAT. See Short-Wave Adaptive Optics Techniques Target Return Adaptive Pointing and Focus (TRAPAF), 143–44 Tatarskii, V. I., 33 Telescopes, 1.5-meter telescope, 94, 96, 100–1, 109, 111, 209, 213, 221, 237, 260, 268, 270–73, 289, 311, 316, 330; 3.5-meter telescope, 237-76; 3.67meter telescope, 277–312 Telle, John M., 318, 319, 323, 328 Teller, Edward, 170–71 Tempel-Tuttle comet, 330 terminator phase, 57, 308–9 Terrier-Malamute two-stage sounding rockets, 190 terrorist groups, 205 Thayer, Paul, 177 theater ballistic missile defense, 147 Theater Missile Defense, 21, 202 thermal blooming, 16, 21, 31, 64, 120, 132– 44, 166, 169, 184, 209, 290, 374n16; compensating for, 137; conditions for, 133; simulating, 142; solutions to, 133; understanding, 139, 144 thermal turbulence, 360n2 Thirty Meter Telescope, 355n1 Thomas, Tom, 293

455

Thompson, Bill, xv, 147–8, 150, 152, 155– 57, 161–62, 286–87 Thompson, Laird, 148, 161 Thor missile, 6, 29, 364n30 TILL. See Laser, Track Illumination Titan, 111 Toward New Horizons (Arnold & von Kármán), 131 Townes, Charles H., 20, 158–59, 162 transmissive hole diffraction grating technique, 136 TRAPAF. See Target Return Adaptive Pointing and Focus TRW. See Northrop Grumman Space Technology Tyler, Dave, 308 Tyler, Glenn, xvii, 91, 411n60 Tyson, Robert K., 18 U-2 reconnaissance aircraft, 8–10, 28, 30; legacy of, 9; shooting down of, 8 unidentified flying objects, 26 Union of Concerned Scientist, 192–93 United States Space Command (USSPACECOM), 278, 308 United States Strategic Command (USSTRATCOM), 278–79; operational needs of, 307, 311 United Technologies Optical Systems (UTOS), xvii, 64, 159, 373n55 Urtz, Raymond P., xvi, 22–27, 33–34, 41–42, 49, 51, 53, 57, 59–62, 343; on atmospheric turbulence, 369n15 USSPACECOM. See United States Space Command USSTRATCOM. See United States Strategic Command UTOS. See United Technologies Optical Systems

456

|   Index

Van Allen belts, 6 Van Allen, James A., 6 Van Citters, Wayne, 152–53, 157, 161 Vandenberg, Hoyt S., 119 Vanguard, 5–6, 357n11 Vasselli, John, 51 Vatican Advanced Technology Telescope, 251 velocity turbulence, 360n2 Villamarin, Chuck, 256 visual system, human, 38–39 voice, human, 6 Von Braun, Wernher, 6, 356n10 Von Kármán, Theodore, 131–32, 276, 346 Vo, Quoc, 332 Vravel, Joe, 2 Vyce, Richard, xvi, 30–34 Walkowicz, Theodore “Teddy,” 27–28 Wallner, Edward P., 53 Walters, Don, 240 Walton, James M., 116 wavefront, 31, 34–36, 38–39, 43, 45–46, 48, 53, 57–58, 74, 123, 126, 143, 150, 155, 184, 198, 204, 216, 220, 225, 230–31, 255, 270–71, 274, 291–92, 299, 302–4, 313, 336, 340; distortion, 18–19, 23; measuring, 89; shape of, 35 wavefront sensor, xi, xxi; Atmospheric Compensation Experiment, 184; Hartmann, 50; Shack-Hartmann, 105–6, 109 Wave Propagation in a Turbulent Medium, 33 WDD. See Western Development Division weapon system WS-117L, 9, 28, 358n22 Weaver, Larry, xv, 221, 232 Weinberger, Caspar W., 174

Western Development Division (WDD), 9, 29; mission of, 28 Westinghouse Electric Corporation, 31 Wick, Ray, 243, 253, 414n22 Widnall, Sheila E., 206, 436n1 Wigdor, I., 141 Wilson, Charles E., 6 WS-117L program. See weapons system WS-117L Wopat, Larry, 90 Wright, Bill, 180 Wright-Patterson Air Force Base, 9, 28, 42, 58, 63, 71–72, 178 Wyant, James, xvi, 35, 50–51, 68

YAL-1A. See lasers, prototype attack Yeager, Chuck, 346 Yerkes telescope, 355n1 Yonas, Gerold, 175 York, Herbert, 12 Young, Mark, 213 Zeta Orionis, 109 Zollars, Byron, 126

Xinetics, xvii, 63, 217, 270–71, 292, 303, 373n55; founding of, 270 XLD. See Experimental Laser Device

Index

457