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In footnotes or endnotes please cite AIP interviews like this:
Interview of Robert Fugate by Patrick McCray on 2000 November 27,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Fugate discusses his childhood; early interest in electronics and science; undergraduate education at Case Institute of Technology; Ph.D. in Physics from University of Iowa in 1970; employment at Wright Patterson AFB first as research physicist (1970-1972) and optics group leader (1972-1979); transfer to Kirtland AFB in 1979 as research physicist in optics and technical director of the Starfire Optical Range until 1995; since 1995, senior scientist for atmospheric compensation at Kirtland AFB; comments on graduate training and making transition to military research. Early research on lasers and laser detection; Involvement in adaptive optice (AO) research in early 1980s; AO research as part of Strategic Defense Initiative; role of JASON group; types of research done; effects of classification; competition in AO between Starfire and Lincoln Labs; acquisition of new facilities including 1.5 and 3.5 telescopes. Design features of the 3.5-meter telescope is discussed. Discussion of the declassification process of AO in the early 1990s. Current and future work in AO described by Fugate as well as future role of Starfire Optical Range.
Let's start with your personal background? Where were you born?
I was born in Jenkins, Kentucky, but my family moved to Dayton, Ohio, before I started school. I born was 1943 so it was right during World War II. My father was in the Army Air Corp and he actually spent some time in England and was involved in training fighter pilots. After the war we moved to Dayton, Ohio. I grew up in Dayton. I went to high school there, graduated there. I went to what was then Case Institute of Technology in Cleveland, Ohio. It's now part of Case Western Reserve University. From there I went to graduate school at Iowa State.
Were you interested in science as a young person?
Yes, I was. And, I really attribute my interest in all things technical to my father, because he got me interested in amateur radio when I was eight years old. I got my first license then.
Did you build some of your own equipment?
I did. I was especially interested in antennas and experimented with several types of multiple sloping dipoles. I also built several QRP (very low power) battery operated transmitters. I spent most of my time on the air as a CW operator (Morse code) I loved to send and receive code. When VHF and UHF repeaters became popular, I built several repeaters in the Dayton area including microprocessor controllers. I really liked the diverse technical aspects of amateur radio, but shortly after moving to Albuquerque, I could no longer find time for it and have been inactive for nearly 20 years. Maybe I'll get back to it if I ever retire. I also did several science projects. I was very successful doing science projects in high school. I won a Westinghouse science talent search award and the Navy flew me to Florida and I was able to spend a week on a minesweeper. It was quite inspiring and I got to see a lot of specialized equipment.
What was your project for the Westinghouse?
It was on electro luminescence. I built from scratch, electro luminescence panels. I was a senior in high school and that was the spring of 1961.
So picking a career in science and technology, broadly speaking, was something that was looked favorably upon by your family?
I think so, yes. I was strongly supported by my parents. I actually won a scholarship to the University of Cincinnati in engineering. Both my parents worked at the National Cash Register Company in Dayton, Ohio, and they had a program where they gave a scholarship to the son or daughter of an employee and it was a co-op scholarship. At the University of Cincinnati, engineering was a co-op program, and the on-the-job portion was to be spent working at NCR.
Summers or an extra year?
You spent every 3rd quarter working. The scholarship was a full ride and almost certain to result in a great job after school. It was a really great deal, but I didn't want to do that. I didn't want to be an engineer. I wanted to be a physicist.
I don't know. I was more interested in the basic nature of things rather than in how to build things. Well, I loved to build things too, but it was equipment and that sort of thing. I have a natural tendency to do that kind of stuff. My professor in graduate school said I was very good at it. But I was just more interested in the more basic nature of how the world works. I was more interested in physics than I was in engineering. The way I viewed it was, well, you'll be designing circuits, and I just wanted to get a little more basic than that. So that's why I was interested in physics.
Did you have particular teachers that stood out?
I had one in high school, Mr. Semmelman. He came around our freshman year in high school to all the general science classes to recruit sophomore lab aids. He was a junior chemistry and physics teacher. He came around to our science classes and he said, "For anybody interested in being a lab aid as a sophomore in my lab, come and see me at the end of your year." The end of your freshman year. So I did. In fact, I was the only freshman who took his class. I started working in his chemistry lab as a sophomore helping the junior and senior students with their lab experiments. So he became my mentor for these big science projects. I did one on chemiluminescence when I was a junior and electro-luminescence when I was a senior. I also had a little telescope when I was in high school. I saved my allowance and bought it at a flea market. It was a Unitron 2.4" refractor, complete with a wooden case, tripod and two eyepieces.
So you do have amateur astronomy interest?
Yes, I got interested in observing the sky early on and when I was at Case I went out and used the student telescope there at the Warner Swaysey Observatory, which was east of Cleveland about twenty-five miles. A friend of mine and I went on a regular basis. We lived across the hall from one another at the dorm, Jim Wyant do you know Jim Wyant?
In fact, it's interesting; one of my very good friends in Tucson was Jim Wyant's graduate student, and the two of them started WYCO together.
Well, Jim was in my wedding.
I just saw him not too long ago.
He's a great guy. He went off to Rochester and I went off to Iowa State after our undergraduate careers. But we, together, worked on that nine and a half inch telescope. We had to rebuild the worm gear drive. The telescope was built in the 1880s, and the worm gear in the clock drive was worn so it wobbled. When you looked at the sky, it created little sinusoids on the film. So we got in the student machine shop and we took the gear out, of the drive, and measured it. There were no blueprints or anything so we just kind of did it by cut and try. The interesting thing was Robert Shankland's suggestion. He was in the History of Science department at Case, did a lot of work on Einstein and also on Michelson, because Michelson was at Case when he did those famous experiments, the Michelson and Morley experiment. He told us to go up and look in the attic of the physics building because there just may be by accident some spare parts up there. So we went up and rooted around and we didn't find any spare parts for the telescope, but we found a box of lenses with a note in it that said, "Please see me before taking these lenses. A. Michelson." So we took that down to Robert Shankland, who was overjoyed with our find.
That's pretty amazing.
So, I used to have some pictures around from that 9-1/2" refractor. It turned out that the moon would just exactly fit at prime focus on 35 mm film. So we had 35 mm cameras. Well, we had one camera. And we made a little adapter that we could attach to the back of the focusing tube. So we took some great pictures of the moon.
It's a really interesting parallel to imagine you and Jim Wyant at that stage and your similar career paths. That's a really interesting parallel. Undergraduate and graduate work you were in physics. Were there particular types of physics that you were drawn towards? Solid state?
Yes, I was drawn toward solid state, actually, because I did a senior thesis and what I did was make elastic constant measurements of sodium chloride at liquid nitrogen temperature. My advisor on that project was Professor Don Schele. I was actually able to publish an article in a refereed journal, The Journal of Physics and Chemistry of Solids and he was another great inspiration for me. I think it was on my senior thesis. I won the best senior thesis prize at Case, the Dayton C. Miller Prize. He contacted Clayton Swenson at Iowa State University and said he had a really good potential graduate student that was very good in the lab, talking about me, and gave me a very strong recommendation. I won a NASA fellowship at Iowa State and I moved there the summer that I graduated.
It was a NASA fellowship that you could take anywhere or was it specifically —
I'm not sure about that. It may have just been one for Iowa State. I didn't compete for it on a national basis. I competed at Iowa State, I believe.
I think of Iowa State as being a really solid engineering school. How was it for physics when you went?
It was great. We had a super physics department.
Who was your advisor there?
Clayton Swenson. His field is the physics of solids at low temperatures. Of all my teachers, I must say that Professor Swenson had the most profound effect on me. I learned what I know today about doing and directing research from him. I correspond with him every year at Christmas and he visited us in Albuquerque a few years ago to tour the SOR. He has been a major influence on my career. His specialty was thermodynamic properties. So what I did as a thesis was I measured the constant volume heat capacity of solid neon and isotopes. There was a lot of interest at that time in the rare gas solids, solids made from neon and helium and argon, because the forces of the atoms are weak — the solids are weakly bound and they have very large thermal expansions and so there was a lot of theory about how these solids worked, but there weren't very many measurements. And all their calculations were done with constant volume, constant lattice spacing.
This is Cv?
Yes, Cv. So the theorists at the time couldn't handle changing atom spacing in order to calculate some of the thermodynamic properties. So it was important to make the measurement at constant volume, which meant high pressure experiments because as the temperature goes up the solid wants to expand. If you want to maintain the solid at constant volume, you have to contain it in a high-pressure vessel.
Was there a lot of equipment building involved?
I had to build all the equipment. That was Professor Swenson's policy with all his students, and I think it is a very good one. I had a high-pressure apparatus. I could make argon a solid at room temperature.
So how many atmospheres of pressure was there?
Two hundred thousand pounds per square inch or over 13 kilobars. I made a beryllium copper calorimeter. It was connected to room temperature through a stainless steel capillary high pressure tubing. I had to do some interesting things because I first tried to silver solder the beryllium copper together and I actually tried to do this in a hydrogen atmosphere. We had a minor explosion in the lab. So then I went to putting this thing together with indium o-rings, an unsupported area Bridgeman seal.
A lot of interesting materials and
Oh, it was unbelievable. One of the hardest things, actually, was I had this long capillary tube that had a ten thousandths ID [inner diameter] hole in it and I was trying to minimize the heat leak because when you make the calorimeter you want to isolate it thermally. It turns out that my biggest heat leak was not from the heater and thermometer wires but from the thermal conductivity in this ten-thousandths ID column of solid neon. So I put a nine and a half thousandths OD [outer diameter] stainless steel wire in this tube, in this capillary. And of course it was about four feet long. I used a lathe up in the student shop to do this. I grabbed it in the chuck and I moved it in a thousandth of an inch at a time until I got it the full length of the tubing.
How long did that take?
It took like a month. A trial of many tries to get that right.
At this point you were doing work in low temperature solid state. Where were you thinking your career was headed?
When I graduated in 1970 there was a huge glut of PhDs on the market. It was a very bad time to get a job as a PhD physicist. There weren't even any companies recruiting on campus.
Sure, after Sputnik and the greater amount of funding put into the sciences, you're going to have some sort of glut.
Right, sure. There weren't any academic positions. So I was without a job, basically, and then this fluke of a deal came up where my mother in law talked with one of her customers about a fellow at Wright Patterson Air Force Base who realized this and was trying to hire PhDs in physics and engineering because he knew that people were more desperate and they were more likely to go to work for the government. So I got in touch with him, Elmond E. Decker, and he invited me out. I went out and gave a talk and interviewed around and then a week or so later they made me an offer.
Was it personally a difficult decision to make? I understand that there weren't many jobs, but to have your hopes set or your mind set, perhaps, on an academic career and then find yourself working for the government?
At first, but once I got there and kind of looked at what the opportunities might be I really wasn't disappointed. And I have to say now that I'd do it again because I've had a great career in the government. I think I'm able to do things in the government that I probably wouldn't be able to do anywhere else. Also, facilities like this are rare outside the government and even though it's difficult and funding is roller coaster at times, it has been worth it. Of course, I think that's true most anywhere, especially in the sciences. We get to see across the board. Being a government employee you're not restricted, often times, from seeing what companies are doing and if people in universities are willing to share their work you certainly get to see that. So I think that's part of working for company XYZ, there's a lot of proprietary stuff you wouldn't be able to share across the board. And I think also, the government, especially in the military R & D, is willing to take more risks. I mean some of these first experiments we did were sponsored by DARPA, and back at that time DARPA was really in the business of high risk, high pay off. And if you failed, you weren't condemned, necessarily. If you did a good experiment and there was the right kind of analysis and thinking behind what you were doing and there was some science behind what you were doing and it failed and you could explain why, that was considered a success. You learned that it's probably not a good idea to go down this road, whereas it's much more difficult, I think, in private industry to do high risk, high payoff research. Well, for instance, in the adaptive optics area, the National Science Foundation was reluctant to fund proposals for doing adaptive optics because most reviewers thought it was impossible. We briefed Wayne Van Citters a couple of years before our work was made public. So he knew what was going on. We just felt it was our duty to let him know that some of this was possible so that he could make more informed decisions about funding various kinds of research in astronomy.
So in 1970 you're at Wright Patterson Air Force Base.
The information, I believe, from the material that you sent me was you were working in laser detection.
I'm a little unclear what that is.
This was for threat warning. If you are piloting a military aircraft and your enemy is pointing a laser at your aircraft to guide a missile that will shoot you down, you want to be aware of it. That is threat warning. I worked on sensors that could discriminate laser light from other non-coherent sources (like sun-glint). Another area I worked on was remote detection and potential characterization of high energy lasers the type suitable for weapons like the Airborne Laser. The concept is to detect Mie and Rayleigh scattered photons from a high power beam that is being propagated through the atmosphere between two points (the laser and the target) on the ground. This was being done at U.S. test sites in Florida, New Mexico and California and the question was, was it also being done in the Soviet Union? If you have a sensitive optical receiver in a highflying aircraft or satellite, for instance, you might be able to detect a few scattered photons, and if you understood the physics, you could make an estimate of how powerful the laser was. I built several ground-based and aircraft-based radiometers to study the physics of this problem at U.S. test sites. It was my real first involvement with atmospheric laser propagation physics. And then from a tactical sense people are always worried about laser designators for guided missiles.
What is a laser designator?
You've heard about laser-guided bombs?
So you shine a laser on a target. The seeker in the weapon looks at the reflected light and guides itself to the target. So people were worried about that sort of thing for shoulder-launched missiles against aircraft. As I mentioned earlier, if you're a pilot you need to have some kind of warning that you're being lased by a ground-based laser, for instance. Or, maybe another airplane has a laser that's designating you in order to guide a weapon.
Did this work that you were doing on laser detection build at all on what you had done as a graduate student or was this an entirely new —
Well, it did in some sense in that some of the detectors were solid-state devices and some were cryogenically cooled and that sort of thing. But I think the biggest benefit of graduate school was I learned how to conduct research. That's what I really learned from Clayton Swenson. He did not allow us to buy any commercial instruments. The students up on the floors above us, however, would use an existing apparatus built by a student years earlier and just plug in a new sample or different solid state compound, a different three-five compound, or whatever, and put it in the apparatus and measure its physical properties and write a thesis.
So basically just take something and see what it's properties were?
Yes, take something that already existed, collect some new data. And that's not the way Clayton Swenson worked. The way he worked was you need to start with an empty room and build your equipment up from the ground. Now, it took an extra year or maybe more sometimes. I was there five years, but it's paid enormous dividends for me because even today when we have stuff made in the machine shop, I can better direct what needs to be done. I mean when I first started working for the government, actually, I went across the street to a different organization where they had laboratories. The place where I was first employed had no laboratories, so I went to another organization and started doing experiments in a lab. In order to direct research I think you have to have done it yourself to the extent that you understand what the steps are, what the processes are, and how to make the right choices on separating the good stuff from the bad stuff and being efficient. You have to have a knack for what is important and what to do next, especially when things are going wrong.
Did you have people working for you shortly after you began at Wright Patterson?
Not very many. I had one helper for a year or so and I was mostly sort of horning in on other people's resources and sort of borrowing from them and stealing equipment to set up my own things. So I didn't really have a team, so to speak. Before I left there in 1979 I did have four or five people working for me and I had set up a couple of interesting laboratories and we were doing also some field experiments on aerosol scattering of laser beams.
So you were there for nine years doing laser detection work the whole time?
It was mostly laser detection work.
You mentioned you left in '79?
Yes, actually what had happened was a captain in the Air Force from here and throughout Kirtland, Ron Grotebeck, moved to Wright Patterson for an assignment for about three years and while he was there we worked on a couple of projects together. So we got to know one another. Then he moved back to Kirtland to work on the high-energy laser program and he started calling me about coming here to work with him, to move, to change positions. One of the things I was doing, of course, was making these aerosol measurements on high-energy laser beams.
So you're looking at scattering of lasers?
I was looking at aerosol scattering out of the laser beam. They had the old Airborne Laser Laboratory (ALL) here, which was about a five hundred thousand watt CO2 laser. Whereas the one they had here at the SOR was about a hundred kilowatts. And they were propagating it from a hanger at the east end of the runway at the airport over there to a down range target site a few kilometers to the south. So I set up an infrared radiometer along that path midway and was actually out here on temporary duty making measurements on that laser beam. That was in 1978.
This might be a naive question. What were the purposes of these high-energy lasers?
Well, they were trying to make a weapon, basically, to shoot down missiles. In fact, later on they did. The Airborne Laser Laboratory shot down five air-to-air missiles that were fired at the aircraft. Now, of course we have the Airborne Laser HEL, which is a much higher power, much shorter wavelength, much more sophisticated device and its intent is to shoot down things like scud missiles at hundreds of kilometers range.
So this would be an orbiting platform?
Yes, it's in a Boeing 747. When you say orbiting I mean it's an aircraft. It flies in friendly territory, basically. The idea is to shoot the missile during it's boost phase as it's rising. They like to say it's a speed of light weapon. So you have to acquire the missile, direct the laser, and focus the laser on the missile body and cause it to break up. You thermally damage the structural properties of the missile. In order to do that, one of the key elements, of course, is adaptive optics because if you did this without adaptive optics the beam just spreads out. The atmospheric turbulence destroys the coherence of the beam and you can't keep it focused.
So in a sense it's almost the reverse of what astronomers are looking for in adaptive optics.
Again, this may just be going off on a tangent, but this airborne laser system, does it have any similarity at all to what's being planned for now soon building SOFIA and some of the telescopes that are in aircraft?
I think there are a lot of common problems. The boundary layer, the turbulent boundary layer around the aircraft will be important. And the vibrations in the airplane and how you manage that and how you isolate the telescope in the optical system.
How do you do the pointing and tracking?
Yes, the pointing and tracking for the airborne laser, they actually have some smaller lasers that are used to illuminate the target and the reflected light from the target illuminator is used to track the target. They do passive acquisition from the plume of the rocket, but then in order to designate the area to focus the HEL it's sort of like the laser designator thing we talked about how they use a low power laser to illuminate the nose cone of the missile. We're not directly associated with that project, only through some of the technology. But they do have certain aim point areas that they think are more vulnerable than others so their intent is to direct the focused part of the energy laser at those aim points.
So when did you officially make your transition out to New Mexico?
October of 1979.
You were married at this point?
I got married the summer after I graduated from undergraduate school, 1970.
Okay, so you'd been married for about nine years.
I get all this mixed up. 1965. My wife would kill me if she heard me say 1970. 1970 was when I graduated from Iowa State. So in 1965 I graduated from Case. We got married that June and we moved to Iowa and we set up a house in married student housing at Iowa State. I was there five years and then we moved to Dayton to work at Wright Patterson. And then in 1979 we moved here.
Was it difficult making the transition just from having been more of a Midwestern type of environment to moving out west?
It was quite a big change because of the environment, the climate. We really love it here. It would be really hard to get me to go back, but it was somewhat of a change because of the work and it quickly became much more interesting than what I had been doing at Wright Patterson.
So when you first arrived in New Mexico, what types of projects were you associated with?
The first project I was associated with was actually out here at the SOR. Now, at the time when I got here the SOR was almost closed. There was no activity here. In the mid '70s, they had that one hundred thousand watt CO2 laser. It was one of three lasers built by Pratt and Whitney in Florida called the tri-service laser. The Army had one, the Navy had one, and the Air Force had one. It was put together right up here on the side of the hill. If we go around I'll show you. Somewhere here, if you want, I may have some pictures.
Sure, that would be interesting to see.
They shot a drone airplane down with that laser in 1974, Project Delta. If you're interested I'm going to put you in contact with the person in the history office and he actually has some other materials.
Is that Bob Duffner?
That's Bob Duffner.
I'm actually meeting with him this afternoon.
Great, outstanding. I was going to get you two hooked up. He's written a couple of books on some of the history of the high-energy laser program. And there's a new one, actually, on the creation of the Air Force Research Lab that was put together for Maj. Gen. Paul. I haven't seen the book yet. I'm trying to get a copy of it; I think it's just been published. So after that project there was a half-meter beam director, a high speed telescope that was built by Hughes that was mated with this Pratt and Whitney CO2 laser and it had an IR tracker and so forth. And they actually used it as the first laser weapon they had an old propeller driven drone that they launched in the field out there and it flew circles in a race pattern around and they shot it down with this laser.
So in these cases the telescope is being used — the mirror of the telescope is being used to aim or direct?
Aim and focus the laser.
I have to keep reversing my aim.
Your astronomy perspective.
Right. Everything's going in the opposite direction. So the laser is fired at the telescope mirror and then that focuses it at a particular target.
Exactly. And sometimes in this business we call that a beam director as opposed to a telescope, but same thing. So the place had kind of been mothballed out here after that. When I got here in 1979 there was interest in how to point pulsed lasers. What if you had a high-powered pulsed laser instead of a CW laser? How would you point and track with a pulsed laser, which is only on occasionally?
CW is a?
Continuous wave, always on. Well, it's the 10.6-micron, hundred-kilowatt laser at the SOR and the airborne laboratory lasers were both CW. In fact, the Airborne Laser, the 1.3-micron iodine laser, is also CW. But there was interest in pulsed CO, carbon monoxide, which lasers around five microns instead of ten. There's always a desire to go to shorter wavelengths because there is less diffraction and more energy on the target. You can make the spot smaller. But of course the problem you run into eventually is the atmosphere. At long wavelengths the atmospheric turbulence is not a problem, but as you get to really short wavelengths then you have to correct for the turbulence or you can't focus the beam. So I started an experiment out here in 1979 and 1980 in which we co-bore sighted a CW laser, a continuous wave laser, with a pulse laser.
Okay, so these are aimed at the same target?
Right. The idea was so now can I use a CW laser, a lower power one as a designator to keep the high-energy laser on track, so to speak, to properly point it. So we actually did some propagations from what eventually became the meter and a half telescope location down range to the one mile site. There's a site down range here just a mile away. So that's kind of how things got started. And then about late 1981 and early 1982 the business of laser guide stars came up. There was some discussion and I don't know what you've gleaned so far from what's been published, but there was already some work going on up at Rome Air Development Center by Don Hanson. He had some contracts with Itek (here and elsewhere). They had actually tried to do some experiments with lasers and putting out multiple beams and that sort of thing. But about the same time —another fellow became involved and that was Rich Hutchin. Now at the time, believe it or not, Rich changed his name. It was Hutchinson originally.
I noticed that. One of his things said —
Right, Rich, for some reason beyond me — I've talked to him about this, but he said,"Well, people would never get it right and kept calling him Hutchin," so he finally changed it. That was kind of weird. So he and Don Hanson were sort of working together and then some people at Itek, Julius Feinleib, notably, spun off a little company called Adaptive Optics Associates in Cambridge. Julius was out at Maui.
He was out of the Haleakala.
He was out at Haleakala one night to witness operation of the Compensated Imaging System (the system built by John Hardy at Itek) installed on the 1.6 m telescope. Julius was outside observing the sky when he was attracted to a pulsed visible LIDAR beam being propagated from the site to measure atmospheric transparency. That is the moment he got the idea of using Rayleigh scattered light to create an artificial beacon for an adaptive optical system. The 1.6 meter telescope was used for imaging satellites. Of course, it all worked passively using sunlight reflected from satellites to make a beacon, basically, for measuring wave front distortion. The satellite would serve as the source of light outside the atmosphere that you need in order to do wave front correction, to make a wave front measurement, a wave front distortion measurement. So that is what they normally did there and do even now. The LIDAR is a laser radar.
Okay, so instead of using radio waves you're using laser.
It sends out a pulse of light and the light that's back scattered either from Rayleigh or aerosol scattering is used to measure layers of constituents like sub visual cirrus clouds, is a good example. There are often clouds or nearly clouds that you don't see visually, but which effect the attenuation of visible light, for instance. So if you want to know whether the sky is photometric or not, this is one way. You probe as you slew across the sky looking at a satellite; you can fire a laser into the vicinity of where the satellite is along that path and measure the atmospheric transmittance.
When was the Haleakaka sight put into operation?
I'd say in the early to mid '70s.
Was it designed as a satellite tracking facility?
Right, exactly. It's where they first put a passive adaptive optic system. Do you have that 1977 issue of JOSA that was dedicated to adaptive optics?
No, I don't. This was 1977 you say?
1977. And I have that at home.
I can get it at work. We have back issues of those there.
There's quite a few articles in there by John Hardy. And also, I tried to put together at once, articles — well, we can go into that later. Some articles on some of the first AO (Adaptive optics) systems.
So the one at Haleakala in the '70s then, they're not using laser guide stars?
They're using the satellites themselves as the reference point?
Right, exactly. But Julius Feinleib was there because he was interested in the adaptive optics, obviously. He had been involved in this atmospheric compensation system that had been built with — it had an analog reconstructor, network of resistors. John Hardy describes it in several places in some of his articles. It was kind of the first operational system on a reasonable sized telescope.
Were any astronomers getting access to Haleakala?
I don't think so.
I've always been curious.
They used stars as engineering targets, but I don't think they were really doing any astronomy. You need to talk to John Hardy, or there's actually probably the people that were actually there most of the time. I'm trying to think of a name who you might still have access to. No one comes to mind immediately, but if I do I'll let you know. You might want to talk to some people at Haleakala. At any rate, Julius Feinleib was there one night and they were using the visible LIDAR as they were slewing across the sky out of a different mount. They have twin 1.2-meter telescopes, which I think you can see in the photograph here. And one of those had a LIDAR on it. So it had a, I don't know whether it was a ruby laser at the time. I think it might have been. They'd fire the laser and they'd use the telescope to look at the return light and measure with a photo multiplier what the time history of the return pulse looked like. From that they could see thin layers of clouds and what not. So, that's where Julius got the idea of using a laser beacon.
From what I see here I guess there were two different points in the atmosphere that this could be fired at. One was to use the Rayleigh scattering and the other was to use —
Sodium resonance. We didn't learn about the sodium until the JASON committee and that was Will Happer's idea.
What was JASON?
JASON is a group that — I don't know for sure, but some people say that since they meet in the summer, it's July, August, September, October, November. It's an acronym for the months during which they meet. It's a group that works for the Department of Defense to look at new and promising technologies and physics in order to evaluate their worth and whether or not the Department of Defense should continue to fund these efforts or whether or not they should initiate funding for these efforts in proposals and so forth. They're a very high-powered group from academia who are very critical about what you are doing we used to say when we had to go out for a JASON interview that the best you could hope to do is break even because they are probably the toughest peer review group that you could ever run into.
Who would be people be who would be a member of —
Well, they're people like Charles Townes, Richard Garwin, Will Happer, Freeman Dyson, and Claire Max from Livermore. I'm just speaking of the people that I briefed over the years. There are several Nobel laureates for instance, in the group.
They're drawn from universities, but they're doing work on defense related projects.
No, not necessarily. They're just being asked to advise the Defense Department.
So they don't need security clearances?
They do need security clearances, yes. So at the time of these discussions this was still all classified. And what happened was in the fall of 1981 there were a couple of meetings back in Boston. I was at these meetings with Don Hanson, David Fried, who was under contract to Don Hanson at the time, Julius Feinleib and Rett Benedict at DARPA. There were half a dozen or so people that met. Julius proposed this idea of using a focused laser beam to measure atmospheric distortion. David Fried said this will never work. It's not high enough. It's not sampling enough of the atmosphere. Next topic. So we actually kept pounding on David that afternoon, and he went off that night to his hotel room and wrote down all the equations that needed to be evaluated in order to mathematically describe this effect and it turned out they weren't analytically solvable. We got together the next morning. He said he would go off and do some numerical calculations. So he and John Belsher, a person who worked for his company called the Optical Sciences Company in California went off and did the calculations. About a month later he called up and he said, "You know, this may not be such a bad idea." Well, what we did then was we talked to Rett Benedict and suggested an experiment at the SOR to test this new theory, but he was still skeptical or didn't have the budget.
So, in the summer of 1982, this came up as a JASON topic. We all went out to La Jolla where they met and Will Happer was chairman of the committee. David Fried gave a talk on his theory and talked about this thing that — at the time we didn't really have a term for it, but actually Tom O'Meara at Hughes Research Laboratories later on called it focus anisoplainatism some people now call focal anisoplainatism which is more grammatically correct. But people who are interested in the history of things still use and I still use the term focus anisoplainatism, which is what it was first called. So he described this at that JASON meeting and Will Happer said, "Well, why don't use resonant excited sodium?", which allows you to make a beacon at higher altitude since there's not enough atmosphere for Rayleigh scattering see, the problem is Rayleigh scattering runs out of steam when you get above fifteen or twenty kilometers because there aren't enough air molecules.
But you want to be able to sample —
But you want to be able to sample the correct atmospheric path. Let me just draw you a quick diagram. The problem is you have a big telescope and you have a beacon that's at low altitude. This is all way out of scale here. You have rays coming from infinity along these lines. The problem is out here at the edge the ray coming from the laser beacon here is sampling the wrong atmosphere. It needs to be sampling this one. So you need a beacon at infinity. Well, what if you had a beacon at ninety kilometers rather than fifteen? Well, this makes a much smaller angle.
So that angle there is what you want to try to minimize as much as possible?
You want to minimize that. In fact, this angle — you know, there's an angle that's characterized by the turbulence, the anisotropy of the turbulence called the isoplanatic angle. It's the angle over which the turbulence is essentially the same. If this angle (on the diagram) gets to be larger than the isoplanatic angle, then you start to make significant errors in your measurement using a laser beacon. So the idea was can we get the beacon higher to reduce this effect and make it more like a natural beacon.
So looking at this picture you've drawn here, if you want to have your point of reference on infinity, having a natural guide star is a particularly good thing because its essentially at infinity?
That's the best. And in fact, having — see, there's another form of anisoplainatism caused by the fact that the beacon's not at the same location laterally in position, in angular position as the object. So if you had a galaxy you want to look at, but there's no bright stars around, but there is one over here, then the problem now is if this angular separation of these two objects is bigger than the isoplanatic angle then the correction you get by using this as your source isn't very good over here.
So you needed a natural guide star then that is very close to the object of interest?
And that's of course the problem for astronomy because there aren't enough of these.
You can't make those.
And you can't make those. Not readily, anyway. And we sometimes call this ordinary anisoplainatism. This we call focus anisoplainatism. There's all kinds of anisoplainatism. There's chromatic anisoplainatism when you're measuring the distortions at one wavelength but using those measurements to make a correction at a different wavelength. If there's not a lot of dispersion, in other words, if you're not looking near the horizon, that's not a problem because the optical path difference without dispersion is the same at both wavelengths.
So at some point — I'm trying to get a sense then of how these developments fit into the larger picture of, say, the Strategic Defense Initiative. Is there a direct linkage between that?
Yes, let me tell you what happened. So after this JASON meeting —
Which is in?
The summer of 1982. In the fall of 1982 at the beginning of the new fiscal year, Rett Benedict at DARPA was able to secure enough funding to perform two experiments. One, using sodium and one using Rayleigh scattering. Now, they selected Lincoln Laboratory to do the sodium experiment and they selected us here at the SOR (Starfire Optical Range) to do the Rayleigh experiment.
Did you have a preference either way or did it not matter to you which one you ended up doing?
I kind of think we made a proposal for the Rayleigh because we could see a way forward to get it done and since we had already proposed the experiment to Rett in the spring of 1982. The problem with the sodium approach was the laser and building a big dye laser. It sort of fell into place because AVCO up in Boston was building big dye lasers and Lincoln Laboratory was right next-door and so they could work with them and have AVCO provide them the laser. The actually did the experiment at White Sands Missile Range. So both the experiments were done in New Mexico. That's kind of an interesting side note. So they worked on that experiment and we worked on the Rayleigh experiment. They actually only measured the tilt difference in two sub-apertures that were separated up to a meter. I think, actually, three quarters of a meter. And we actually built an eighteen sub-aperture wave front sensor and compared the higher order of wave front error from the laser backscatter to that from Polaris. In our view it was a healthy competition because we were sort of racing to see who could get there first. We got the first result in December of 1983.
How much funding was required to get these two experiments going?
We had about a hundred thousand dollars.
So in the scheme of things these are pretty small?
I don't know quite what the funding was that went to Lincoln Laboratory, but they had a lot of problems. In their defense, they had a lot of problems with this laser. Even today, building sodium lasers is not a turnkey thing it's not a done deal. We are today still working on that technology. In the spring of 1984 there was a meeting here. By the way, at this time all of this work was covered under a special access required security program.
Meaning DARPA decided since they were going to pay for this they set the security and they decided since we don't really know the ramifications of all of this we're going to keep it classified until we know more about it and they limited the access. So special access meant that it was a very strict need to know. You actually had to sign up a statement agreeing to certain terms and your name was kept on a list. So it was a very small group of people. When we were doing these experiments here there were probably ten or twelve people here at the base that knew about them.
Was this the first time you had been involved with a project hat had this level of classification?
How did you feel about that?
I don't know. I figured it was like something I had to do. It has its disadvantages in the sense that you can't talk to people about it. You can't bounce ideas off of people. You can't get other people's thinking on the subject. We saw benefits in spades when we declassified all of this and got the astronomers involved because they have a lot of really great ideas. And being able to exchange information with people just makes things go better. Although I have to say there were a lot of people that were involved in this project, and nationwide there were about one hundred and fifty or two hundred people, they were really, really good people. I mean they were guys like David Fried who are just top notch. Every time I'm around David I come away feeling like a mental midget. He's just got so many great ideas. But on the other hand, you've got guys like Roger Angel (astronomer at the University of Arizona) who has an idea a minute.
Yes, he does.
I have an enormous amount of respect for him as well. And there's been really, really great benefit in declassifying this and I pushed really hard for two years to get it declassified. So we started out working on these two experiments — and about a year into the experiments, SDIO (Strategic Defense Initiative) kind of got created. Well, I guess Reagan's speech was in March of 1983 and SDIO was created shortly thereafter and they went around and just scooped up everything that was going on in DOD that they thought had any relevance at all to their problem, to their charter. So what happened was the work that had been sponsored by DARPA was taken over by SDIO and they didn't really know that they had a need for it or not, but the other big application for this, not just satellite imaging, is projecting lasers, as we've talked. And in particular, when you're projecting a laser to a satellite, you have to lead the satellite.
Lead it meaning to be just a little bit ahead?
Yes, you need to point the laser ahead of where it appears to be in the sky. Just like shooting a duck. I'm not a duck hunter, but that's what I understand. Even for a duck if you aim at the duck you're going to miss because the duck won't be there when your shot gets there. So the problem is that means you can't use the satellite as a beacon because of "ordinary" anisoplainatism. So you need a beacon in the direction you're pointing. In the so-called point ahead direction. And so a laser beacon would help solve that problem. In SDIO they had relay mirrors in their architecture, but these were all cooperative targets. They all had cooperative beacons. What that means is if you have a relay mirror that's flying along and you want to point a laser to it, you still need to point ahead of where you're tracking the relay mirror. You can put a boom out in front of it and put a light source on it so now it becomes a cooperative target as opposed to an uncooperative target, which is one you want to destroy, for instance. So there really wasn't a need for this laser beacon technology in SDIO because if they were going to use relay mirrors, they would have a beacon of their own. So you didn't need a laser beacon, a laser guide star. Laser beacon technology became an application for primarily imaging satellites that were too faint to observe as a beacon or for projecting lasers for other reasons. What's now called space control. If you want to deny some enemy or potential enemy the use of space resources, one way to do that is to use a laser from the ground.
So basically if those were satellites or something that you wish to knock out.
You wish to blind or whatever. You might want to do that with a ground based laser.
Did having this go from DARPA control to SDI make things confusing?
Oh, very confusing. And then it eventually came back to the Air Force. Even before SDIO was changed over to BMDO (Ballistic Missile Defense Organization) or I don't remember exactly when this happened, but the good thing that came out of the SDIO connection was we got the meter and a half telescope.
Was this called Starfire Optical Range at that point?
No, it was called Sandia Optical Range. There's another interesting story behind that, which I'll digress to quickly. It was called Sandia Optical Range since way before I got here. It became known as SOR. It really belonged to the Air Force, not to Sandia Laboratories. And so one of the commanders decided this is ridiculous. We need to change the name of this place. And they called it the Directed Energy Experimental Range, DEER. And he decreed that it would henceforth be called the DEER. Well, guess what? Nobody in the world ever called it that. They kept calling it the SOR and it just kept coming back to haunt him and the people in the management chain. A new commander came along and one afternoon, I got a call from him. He said, "You have until four o'clock today to come up with a new name for your place, but it has to have the initials SOR."
This was after we had the meter and a half and it was actually after we had demonstrated that you could do laser beacon adaptive optics. We have this semi famous picture of the meter and a half. It's probably in that magazine there, an article somewhere. Not that one. That's a Roger Ressmeyer's picture, but keep going. The next one maybe, no. I thought it was in there, but maybe it's not. Here it is. That picture there.
This was on the cover of Physics Today.
Yes, it was. And in looking at that picture I said, "Well, we've got lasers and we've got stars. Let's try Starfire." So I called back at 3:30 to the commander and said, "How about Starfire Optical Range?" "That's great." That's what happened.
Who built the meter and half telescope?
It was built by Contraves, they're not a typical aerospace company. They're sort of an old world company that's very customer oriented and they often win based on their bid, low bid. In fact, all three mounts that we have here one way or another were built by Contraves. The three and a half was also built by them. We have a coelostat here that was originally at White Sands and it was also built by them.
That's up here?
Yes, it's up here at the top of the hill. Another interesting note is that coelostat is the mount used by MIT/LL in the first sodium guide star experiment back in 1984 when the mount was at WSMR. We'll have to take a look at that when we walk around.
So having this fall under SDIO, did that complicate things?
It complicated things management wise and it added considerable more bureaucracy to things, but that's where the action was at the time. There was a lot of attention, a lot of interest. When we went forth to propose the meter and a half telescope, we did that to SDIO, and we actually proposed it as a jointly funded project about fifty-fifty between the Air Force and SDIO. We demonstrated the concept of using laser beacons using Polaris. We had a twenty-four inch flat that could move only one degree. It was in a mount that could move one degree. So the only star we could track was Polaris. Behind that flat on the output side of it, so to speak, we had a sixteen-inch off axis parabola. We used that to make a telescope. And that's the way we did that first experiment the one we called SOR-1. I have some pictures of some of that stuff, too, which by the way I don't think have ever been published. So the idea was if we could get a real telescope mounted on a gimbal we could look around in the sky and we could point to other stars and we could do a lot more interesting experiments. So I went up to SDIO and proposed that we build this meter and a half telescope for like seven hundred and eighty thousand dollars. Then the Lincoln Laboratory folks came back and said, "Well, we've been doing adaptive optics longer than those guys and we ought to be the ones to build this telescope." So there was a bit of a fracas over this and I was kind of surprised that we ended up winning that battle and it kept the work going here. But for several years after that the SOR and MIT Lincoln Laboratory worked in parallel on various projects involving laser beacons. It was a very good, very productive time. We had extensive meetings twice a year. One on theory and one on experiment and we'd get together with them.
Would the meetings be here and then there?
They would be here and there. They did some experiments at Haleakala. SWAT was a series of experiments called Short Wave Adaptive Techniques done by MIT/LL.
Yes, I've seen the acronym.
They had another dye laser out there they used, but they were using it for Rayleigh scattering at the time, not for sodium beacon.
You weren't going out to Haleakala yourself?
Not much, but I made several trips there to witness and watch their experiments. We even had a meeting there. Actually, we had two meetings there. I have a picture on my wall there is one that was taken at Haleakala. That's Rett Benedict, Darryl Greenwood. Somebody once called this the magnificent seven. This fellow here was not part of the normal group. He was also from DARPA but I don't remember his name, but he was there at the time. So this is Rett Benedict, this is me, this is Don Hanson, David Fried, Barry Hogge, Chuck Primmerman, and Darryl Greenwood. So these two fellows were from Lincoln. I was from SOR and of course Rett was sponsoring stuff from DARPA and Barry Hogge also worked for the Air Force, and was my boss.
Was funding fairly secure during this time?
Because the popular perception, I guess, is that when SDIO was created there was just this huge pot of money.
It wasn't that huge for us, but I think SDIO enabled us to get the meter and a half telescope and enabled a lot of really useful experiments and demonstrations to be done.
When did the three and a half meter telescope come along?
The three and a half came along in the early '90s. That was all Air Force. And we were interested then in demonstrating this technology at the scale that could be useful for doing very high resolution imaging of satellites as well as projecting lasers. It took about four years, I guess, to build the three and a half.
This is using a Roger Angel Mirror.
Yes. That was another interesting thing. When I went over there the first time I thought, boy, this is a big mistake. Because here we are, guys from the military, a bunch of war mongers. We're coming into a university environment and there will probably be guys carrying protest signs. But it wasn't like that at all. Roger was extremely interested in working with us. They had no qualms about whatever uses we were going to make of this. Of course, they were interested in obtaining funding to keep their mirror laboratory going. I think even now Roger will admit that if it hadn't been for the Air Force funding the mirror lab project may have died. They may have never been able to build big mirrors.
I know a lot of the Air Force funding went to help build the optical test facilities.
Exactly, right, to get the infrastructure together in order to develop the stress lap polishing and the metrology.
Was there any difficulty in your having the mirror — and I realize that's only one part of an elaborate system, but was there any difficulty there of keeping people at Arizona sort of in the dark about what this was being used for or was that not really a problem?
No, that wasn't really a problem. And of course when we started the 3.5-m telescope project was before the laser beacon results were publicly released, which was in the spring of '91. I think we actually started our discussions there in 1988–1989.
When was the three and a half meter mirror cast? I want to say '89.
I think that's a little early. We had first light in February of '94.
So the mirror was made there and it was also polished there?
It was also polished there, right.
What's the focal ratio of the mirror?
It's a pretty fast mirror.
It's a very fast mirror, right. The one that they had made previously, the one down at Apache Point is F1.75.
Then they also made the one for the WIYN telescope.
Yes, the WIYN telescope is also a 3.5 f/1.5 mirror. But ours was the first one of the three and a halves that was polished by using this stress lap technique. The Apache Point mirror, was being polished by Norm Cole, who has an optical shop there in Tucson and he hand polishes mirrors. He was working on the Apache point mirror and we actually finished the SOR three and a half meter mirror using the stress lab before he finished that one even though it was started like a year earlier.
Yes, I know this from talking to Roger and various people that the Air Force one was done — was it pretty much on time, on schedule?
It was pretty much on time and on schedule.
Because I know with the first three and a half meter they had some schedule problems with just getting it out the door.
So they moved from Norm's place over to the mirror lab in and three months they polished it. So after they'd sort of broken the code on our mirror in terms of what to do right and what not to do, they were quick to finish up the other one. Ever since we've had a really great relationship with Roger Angel. I mean this Science article, for instance, was a joint thing.
Has it been a good way for them to demonstrate the credibility of their mirror technology?
Yes, absolutely. They've been getting money from the Air Force Office of Scientific Research to develop deformable secondary mirrors, new methods for doing wave front sensing, detector technology, all kinds of critical components that are going to show a big benefit for the Air Force. I really enjoy Roger's far out thinking. So it's been a great relationship.
It's an ongoing one?
It's an ongoing one, right.
How does your three and a half meter telescope differ from a conventional telescope?
Mostly in it's ability to track fast targets.
So how fast does it slew?
It slews at about twelve degrees per second. And while it's slewing at twelve degrees a second it has only six hundred nano radians RMS jitter.
So it's moving fast and it's moving stable?
It's moving fast and it's very smooth. That's the principle. And in order to do that without exciting resonant vibration modes, it's a very stiff structure. So if you look at in terms of — well, like the Apache Point telescope, for instance, or the Keck telescope, the upper parts of the structure on those telescopes are much lighter weight because those telescopes don't have to slew at high speeds and they don't have to reject resonances that would cause problems.
So it has a lot of extra steel built into it that you wouldn't find in a normal, conventional —
That's right. It has bigger motors and more robust control systems and things like that.
The enclosure of it is fairly unconventional looking also. How did that come about?
Well, when you're tracking a satellite, it goes by in a couple of minutes. So the question is do you look through a slit and rotate the dome at high speed? The other thing, since this is an alt-az mount, there's a singularity at the zenith. So if something goes, say, within one degree of zenith the telescope has to go around a hundred and eighty degrees, very fast. And in fact, at twelve degrees a second, it means that a satellite that's within ten degrees of zenith and 250 kilometers high, which is a very low satellite, is the limit to which we can track. Now, if it's a thousand kilometers high, we can get within a few degrees of the zenith. Because the higher the satellite is the slower it's moving in angular speed and so you have more time to get around. But since this is an R & D facility not an operational facility, we decided that an alt-az mount was the most economical, space saving, and so forth. Especially in terms of dome sizes and what now. If you build a three-axis mount it requires a lot more room and it's much more difficult to build one that slews fast and so forth.
So the dome, though, is still a problem. If you turn a dome that weighs a lot at twelve degrees a second, it makes a lot of vibration and creates a lot of thermal problems and what not. So we were all sitting around at lunch one day and we said, "What we really need for this telescope is no dome at all." Somebody said, "Well, the telescope's going to get wet." So then, somebody said, "Well, how about those oil drums that expand and contract based on how much oil they have in them?" Have you ever seen these telescoping oil drums?
No, but I was driving up past it, it reminded me of a Boy Scout folding cup. Just a collapsible —
Exactly. And somebody said, "What about a Boy Scout cup?" So we got busy and did a little in-house engineering and made some concepts and then when the time came we put out a request for bids, and we got none. People thought we were totally bonkers. The request for bids only went out to U.S. companies. That's a government thing. We talked to Coast Steel up in Canada and said if we resubmitted this request for bids would you guys bid on this? They said they would. So we resubmitted the bid to all of Europe and Canada and Australia and Japan, the whole world, basically. And sure enough, they bid and they ended up getting the contract. It's great. It takes eight minutes to completely lower the dome.
That's it and we haven't had a bit of trouble with it. It's the only dome on the hill that doesn't leak. And now, there's one similar to it over at Haleakala.
My next question was whether these types of dome structures are being used other places?
I really like the Gemini dome.
Which is also made by Coast Steel.
Which has the slits on the side that open to allow air ventilation, which can also be closed when there's high winds.
Yeah, I was just there a couple of weeks ago and I remember they opened up for me. It was pretty amazing. It actually gave me a really good sense of a scale to see those louvers go up to see how tall they were.
I think that's a super kind of an arrangement there. That probably still wouldn't solve our problem because you'd still have to rotate the whole thing very fast.
So something like the MMT has where they actually have the building that rotates. That would just me too much
That would just be too much mass to be rotating at that speed.
So what do you do about the problem of the telescope getting wet?
Oh, well, it closes up, right?
I mean when somebody says we don't need any dome at all, everybody was envisioning no dome, period. Just nothing. A plastic tarpaulin or something. No, the dome closes completely like it is now. We can go up and take a look.
Would you like to do that? I have some questions about the declassification part, but maybe at this point it would actually be helpful to see some of the hardware.
Will we still have time when we come back?
I've kind of blocked out the whole morning here. [Break; Fugate takes McCray on two-hour tour of SOR]
Some of the questions may be redundant from things we talked about there, but having them on tape is important. A good question to start with was — I'm assuming you were aware of the civilian work that was being done with it with adaptive optics?
Yes, in fact, what drew our attention of course was the paper by Foy suggesting the use of a laser beacon or a laser guide star. So that was kind of the beginning of a push to try to get this declassified because we knew that eventually they would reach the same level that we had already reached and we could save some time and money by doing that.
Could you give me sort of a sketch of how the declassification process went?
Well, the basic part is you have to provide a study why it's been official to do so. Why it, A, won't harm national security and why it, B, will have some benefit to the scientific world or to the public world or whatever. And, C, that it may even have benefit to us. One of the main areas of my approach to this was the third item to show that by working with other people that have a very similar problem we could get some benefit. We could get some payback. We tell them what we know and open a dialogue so that we can interact with them. And that's been, in my opinion, the biggest benefit to us. I don't know how much we've benefited the astronomy community, but the thing I was most amazed about once this got started was there seems to be a lot of respect for this operation here at the SOR within the astronomy community, which kind of amazes me. Well, I don't know. I just always thought of what they do as much better than what we do.
You say better.
Well, I don't know, as a broader appeal in terms of the public interest. Clearly, people aren't interested in what satellites look like that much, but people are very much interested in knowing is there anybody else out there, where are we in this giant cosmos, and so forth. I like to show this picture here on the wall. Somebody comes in telling me that they have a problem with — the one of Orion is the one I was talking about. One of my guys comes in and says he has some kind of problem, some kind of administrative problem or whatever and I start pointing out to him things about that picture and pretty soon they begin to feel pretty insignificant.
It's a good management tool.
Exactly. A way to say, "Now, what was your problem?"
Tell me about the declassification process.
Let me give you an example. We had designed some lenses and it was based on some Schott glass from Germany. It was in stock so we proceeded with the design. Well, we got the design done and this was a pretty complicated design. It involved three elements over a large wavelength range and so forth. We called up to order the glass but their stock had been depleted. Sort of the way Schott works is they tell you they have some or they don't, not how much they have. They don't tell you whether they're going to run out soon or whether they're going to make more or whatever. It's just a binary answer. So a Friday afternoon I sent an e-mail to Steward Observatory to ask them if they had some of this glass in their shop that we could buy from them now or borrow and then replace or whatever. On Monday, this message had been propagated to Australia, to Chile, to Europe and we eventually found some glass. But I was just amazed at the response that the community put together to try to help us.
Was this after the declassification?
This was well after the declassification. In the meantime, we had a workshop here for a week in which we tried to explain what we had done, and had been doing for the past ten years. And basically, my philosophy was here's what we've done, if it's useful we'll make all of it available to you that we can. We've tried to help people by letting them borrow equipment, letting them use our algorithms when they want, helping giving them data or whatever.
When was this conference?
It was in the spring of 1992. I actually have a proceedings that I will give you.
Was it sort of like a coming out party for the adaptive optics?
Yes, that's exactly what it was.
This was held in March 1992?
What was the astronomy community's reaction?
Well, it was kind of interesting. I discussed this with Chuck Primmerman at MIT/LL, and he said, "You know, nobody's going to come to this. They're not going to be interested in this." But we sent out the notice and within three or four days there were two hundred and twenty people signed up. We had to move the location like three times in order to accommodate them.
Had word been circulating through the community about this?
Oh, yes. Well, it had been a year since we declassified it. And that's the other amazing thing. Charles Townes, who conducted the session at the American Astronomical Society Meeting in Seattle, where this was first publicly released, had been aware of this work for a couple of years. Actually, probably longer than that.
Because of his JASON —
Because of his JASON connection. So there was quite a lot of anticipation at that meeting and I was kind of overwhelmed because at that session it was like standing room only. There were like six hundred people in the room and I was like — I hadn't talked to a group bigger than like thirty people on this topic before because of the classification.
When was that?
That was May of 1991, I think.
What was that like? The session was announced and all these people attended and —
I had people calling me on the phone. The title was announced in the bulletin for the meeting and so people started calling me up wanting details but the actual official release was not until the Friday before the meeting, which started on Monday. So I couldn't say anything over the phone.
The official release being?
Officially approved for public release. Public Affairs has to officially release whatever you're going to present publicly, you have to get it released for public consumption. And so they had not been clear that it was released in Washington. Rumors have it that it went all the way to the White House to get publicly released. So for people that were calling up the week before, I couldn't tell them anything.
People would be calling saying what's your —
What are you going to talk about during this paper? Because the title is very intriguing.
What was the title?
I've actually got it here somewhere. I don't know. We can look for it in a minute.
What did you talk about, though? This was the first public presentation of this stuff.
I just talked about the results we had showing how we'd closed an adaptive optics loop with a meter and a half telescope with a laser beacon and gave some idea of what some of the results were.
You had images to show?
I had images to show and it was really funny because Laird Thompson from the University of Illinois was the next speaker and he was one of the people that caught onto this early on after the French published it. He had been trying to do some measurements at Mauna Kea trying to make a sodium beacon. Well, not really trying to make a sodium beacon. He was just trying to verify that you could excite sodium. So he got up after I talked and he said, "I've never been so scooped in my entire life," or something like that. He says, "I think I should just sit down," because there were a million questions.
What types of questions were you getting?
Well, it was just every variety you could imagine.
Like, "Where can I get one of these?"
How do you do this? Where can I get one of these? How does this really work? How much does it cost? Can I put this on my telescope? It was just pandemonium.
How did you feel, after years of having your work be classified, to be able to talk about it?
Well, I was very nervous to begin with. I'm normally not nervous when I go to speak at conferences and things, but I was just really nervous. I didn't know whether I was going to get eggs and tomatoes thrown at me or whether it was going to be well received.
Why did you think it might not be well received?
Well, I just didn't know the astronomy community that well and as it turns out it's a great group. I've never run into a more closely knit, well networked, everybody knows what everybody's doing kind of thing and everybody is willing to help everybody. It's a great group of people.
In terms of the declassification of adaptive optics what was the National Science Foundation's role in it?
They were strongly supporting it. Basically, what has to happen is it has to go up through the whole chain of command through the Air Force into the Pentagon, into the Department of Defense, and they evaluate it, apparently based on the criteria of how well you establish that it's not going to affect the national security. That it's going to benefit the scientific community and that it is in fact going to benefit the Department of Defense. So they look at the write-ups. And quite honestly, what happened is it would get up part way and it would come back and we'd have to change things. And we just kept sending it out. Of course, during this time, I guess, we had the demise of the Soviet Union.
And that helped a lot.
So the process for declassifying actually began before —
It began in '88.
How much did the fall of the Soviet Union matter?
I think it helped enormously, but I don't know that for sure. Also, we had the strong support of Charles Townes.
How important was that?
I think it was very important. Being an astronomer and understanding the technology and the science and understanding the benefit it could have. And we had very strong support from Wayne Van Citters at the NSF because he needed as much evidence as he could get for the nay-sayers in the community that said this is too hard to do, too complicated a problem, it will never work, and so on.
Did you interact fairly closely?
We did. We kept him appraised of what we were doing and what progress we were making and what the prospects were.
Based on your experience with this declassification process, what are the biggest hurdles to making it happen?
First of all, I think it has to be something that's really worth declassifying. And secondly, I really do think it has to be something that's useful. If those two conditions exist I think then its just bureaucracy. You just have to keep hammering on people and convincing them. I think the hardest part of convincing them is that it's not going to effect national security. That's the hardest part.
That also seems like it would be a hard thing to convince people of.
Yeah, it is. It really is. Unless you have a really strong case for why it will benefit mankind, if you will, you're not going to get anywhere with it.
Did the NSF come in at that point with being able to say this would really help the astronomy community?
Yes, they did.
So since the declassification took place in —
'91. What are your thoughts about how the astronomy community has taken that technology and gone with it?
Well, I think they've embraced it full speed ahead. Today, every large astronomical telescope has an adaptive optics program or has adaptive optics on their telescope. Most of them are looking at using lasers to get better sky coverage and I think we're starting to see quite a bit of science come out of adaptive optics observing.
Anything in particular that's caught your attention?
Some of what might be gee whiz things, but if you look at Keck, for instance, I happened to be there the night that they observed a binary brown dwarf. As far as I know it's the only one seen since. It's like less than a tenth of an arc second separation, a faint companion. They've also been able to resolve most of the big volcanoes on Io. If you look at the resolution possible with an 8-meter telescope, it becomes a significant discovery and science-generating machine. We have seen spectacular results on photometry of individual stars in globular clusters and structure at the center of our galaxy. If we can make tomography work and have thirty- to hundred-meter telescopes, we'll be able to see much more.
Now, tomography is looking not just at the plane, but looking at a three dimensional volume?
Looking at a three dimensional volume and basically reconstructing what that volume of turbulence is at that instant.
So this would be the multi-conjugate adaptive optics?
It would be, yes. Using multiple laser beacons, and multiple deformable mirrors.
What is the big challenge then for doing that, again, other than funding?
I think its just doing it. There's a good theory that's been developed.
Who is this?
Mostly Brent Ellerbroek. Brent used to work here. He's now in charge of adaptive optics at the Gemini Observatory. Did you meet him when you were there? Brent is an absolutely brilliant guy.
How did he make the transition from here to there?
Well, one of the things is our funding is going down. Some of the things that I think he wanted to do here, there just was no hope of getting them done. He saw an opportunity there. He had been working with them through a cooperative research and development agreement and so they got to know him very well, to know his talents. It was a big loss for us, a big gain for them. That's the ultimate technology transition if you move a person. That's it. You can't do better than that. I think he should get credit for that somehow. I'm just so enthused about wanting everybody's adaptive optics program to succeed because I'm a believer in this technology and I think it's going to be the basis of a big revolution in ground based astronomy.
What groups do you see doing — I realize that's a loaded question, but which groups do you see as being out front?
On the leading edge?
Well, I think it's Gemini and Keck of course and I think Steward Observatories is a leader in new concepts Palomar is starting to come up. And I think ESO (European Southern Observatory) has some excellent work going on.
Was there a concern during the declassification process, because astronomy is so internationally oriented, that the technology wouldn't just stay in the United States?
Yes, there is. Part of the problem with adaptive optics technology is that it is on the military critical technology list, because it is an enabling technology for things like laser weapons, like airborne laser. However, if the technology is applicable to astronomical applications or whatever, but does not give away some sort of military advantage, there's no problem in releasing that technology to foreign countries.
The final set of questions I have just related more about what's being done now here. Again, if the questions are too sensitive just say. One question is how much astronomy work is done here at Starfire?
Almost none. That's kind of disappointing. We're so funding constrained that we really have to do what's required for the Air Force it's the golden rule problem. The person who has the gold makes the rules. Right now we're in a situation where we have to do what our customer wants to do and that unfortunately doesn't include any astronomy.
Out of a hundred percent of the time that's used here, what percent would you say, or is there any percent?
For astronomy? Three to five percent. We did some Leonid meteor trail observations. We have a sodium LIDAR that was brought here by the University of Illinois, Chet Gardner's group. And they've been using it study upper atmospheric dynamics, temperature, and winds. And we've been collaborating with them on it because it gives a measure of the column density of sodium throughout the night, and throughout the year. So they used that LIDAR to interrogate these long live meteor trails from the Leonid meteor shower, to try to understand some of the chemistry associated with what's going on there. In a sense, there is some benefit to the Air Force. The Air Force is interested in meteors and upper atmospheric space weather because of their satellites. So we were able to justify it on that basis. But in terms of just making observations of galaxies or stars or planets or whatever, there's very, very little of that going on.
Do you see that changing in the near future?
Well, if not astronomy then can you give me a sense of what is done?
Our goal right now is to try to keep things moving to the extent that we're doing things of interest to Air Force customers. In terms of imaging, making databases for satellites, helping out space command, diagnosing problems with military satellites that are in trouble of one kind or another. We're still trying to get the where-with-all to do laser beacon adaptive optics on the three and a half. We have no laser beacon at the three and a half. In fact, we have no operational laser beacon AO system at the moment. A bit ironic.
I wasn't aware of that.
We're moving the meter and a half telescope. That old copper vapor laser has been decommissioned. So it's kind of ironic. We did quite a bit of astronomy out of the meter and a half with that system. But at the moment we have none. So we're trying to keep our people. The people are our most valuable resource. We have literally hundreds of person years of experience in adaptive optics here, probably more than any other place. So we're desperately trying to save that.
Has the lab maintained close connections with other facilities? With Lincoln Labs or others?
Yes, we have a pretty close working relationship with Maui and the facilities on Haleakala. They have a similar AO system over there that's just coming on line.
This isn't the AEOS?
Yes, the AEOS.
I can't recall what that stands for.
AEOS is actually the 3.6-meter telescope over there. Advanced Electro Optical System. We still have a lot of interaction with Gemini, with Keck, with Steward Observatory, with some folks at ESO, and University of Chicago. What else? I've been asked to serve on various kinds of committees. The Institute for Adaptive Optics at Santa Cruz.
That's Jerry Nelson's group.
Is the day far away when push button adaptive optics will be available?
I don't think it's that far away.
What's required to get that?
I think most places now have things down to one person as an operator and I think eventually with sort of smart systems and artificial intelligence and what not — we have had on the books for a while the interest in proposals to do adaptive processors to actually change the reconstructor. That big matrix I showed you. Change that in real time based on a condition.
So the matrix might grow?
The matrix might grow or shrink and you'd construct more or less terms and use iterative algorithms to do quickly and you could do predictive things like if the wind is blowing or if you're slewing the telescope you know ahead of time based on a past measurement what's coming in a different part of the aperture, those kinds of things and that all predicts better performance. You saw some of the images how it's not rock solid al the time. It would fix those kind of problems. In a sense, some of it's maybe gold plating, but because there's lots that can be done with post processing of images. The adaptive optics is still only a partial correction. It's not a Strehl ratio of .99, but there's lots and lots of science that can be gotten out of these images.
I don't have any other formal questions. I actually have one more and that's I normally have a consent form that interviewees sign, but it's on my desk back in Washington. So I'd just like to get your oral permission if it's okay to use the interview that we conducted today for the purposes of writing the book that I described earlier?
Sure, yes. Yes, it is.
And the other aspect is I will send a consent form for this is I may have the American Institute of Physics do a formal transcription of this and add this to their collections because some of what we talked about today might be useful in the general history of physics community. So I just wanted to let you be aware of that there is a special form for that.
All right, okay.