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In footnotes or endnotes please cite AIP interviews like this:
Interview of William Baum by David DeVorkin on 1983 January 12,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
This interview surveys Baum's career as a physicist at the Naval Research Laboratory (NRL) and astronomer at Mt. Wilson and Palomar Observatories. After sketching Baum's early life, the discussion concentrates on Baum's role in the development of spectroscopy research at NRL, specifically his work on the UV spectrum of the sun - including the first successful UV spectra of the sun. Aspects of his experience in experimentation with V-2s and Aerobees, and his thesis research on rockets at CALTECH (PhD, 1950, physics) are also explored. Additional topics discussed include: Optics Division, NRL; White Sands Proving Ground (NM); relationships with, and costs and descriptions of Baird Atomic; V-2 missile experiments, development and launch; meetings with Werner Von Braun; and contacts with R.W. Wood, J. Strong, Lyman, Stockbarger, and Tousey.
I am interested to know about your training. First of all where you were born; where were your father and mother from; and that sort of thing.
I was born in Ohio. My parents were Earle Baum and Mabel Baum. He was a school teacher. I grew up in the Toledo area. We lived on a small f arm in my teen years. I went to the University of Rochester, went through in physics., and took a course or two at the Institute of Optics. I had sort of an interest in optics and optical things. That was in the time period from 1940 to 1943. I was there actually only three years, and managed somehow to get the necessary number of credits for graduation in three years.
Was that partly an acceleration due to the war?
It didn't start out that way. I just was very keen on everything that was going on, and I was taking courses right and left. I was one of those workoholic students that existed even in those times. Halfway through the third year, my advisor suggested to me, "Why don‘t you finish this year.” The idea was new to me; I mean, I hadn‘t even thought about it. So I did plan to f inish; and planned at the same time toward seeing whether I could get into graduate school. People were going off to the war at that time. It wasn't quite clear whether one could continue to be in school. I applied to Caltech graduate school and was accepted. I remember letters from Millikan and various others out there.
Who was your undergraduate advisor at Rochester?
Oh, I remember a man named Dick Long, but I don't remember him well. I didn't have that much contact with advisors. I do remember that it was through discussions with an advisor; and it may have been him, that this whole issue of graduating early came up, as sort of a last-minute afterthought. I’m not sure that I remember the particulars well. I do remember applying to Caltech and going out to California in the fall of 1943 to be a graduate student in physics. I had scarcely more than arrived before the selective service was after me, putting the pressure on. Millikan got kind of interested in it as a test case. He was trying to hang onto his teaching assistants; and he was dealing, in this instance, with a Draft Board in Ohio. Looking back on it, it was a most interesting time period because it brought me into firsthand contact — almost daily for some weeks — with a man of great stature and with his modus operandi.
Did you come specifically to work with Millikan?
No. I came there as a graduate student, but because he had put together his staff of teaching assistants.. (mainly because of the existence of a controlled teaching program: V-12 was the Navy teaching program at Caltech) and he was depending on his graduate students to look after student labs, and to be teaching assistants. He was trying to tell the Draft Board that this was essential war work. He was saying that these kids had the training to be able to do this job and that it was important to keep them. He was trying to pull strings to do it. And he was trying to work through his political ties, which were considerable. He failed. It became clear that, not only I, but some of the others, would soon be lost, and so I volunteered for service in the Navy.
So you had no contact with the rocket project that was developing then?
I did only casually, a little bit. I did a little work on the side, a little bit of small paid work under Conway Snyder at the rocket project at Caltech at that time.
What was your participation? Do you recall?
It was trivial. I was dealing with some data that had been obtained out at Goldstone, or wherever it was that work was being done; and they simply needed a kid to do some data reductions. It was trivial.
Since the connection now is going to be important, can you see any connection with your contact or slight brush with rockets at this time and your actual work on them?
No, that was incidental. I can't. I'd like to be able to say yes, but, the answer is no. I cannot claim that there is any connection. Then, I volunteered for service in the Navy as one of those 90-day wonders. Naval officers were taken in on that basis. I was followed soon after by three of my fellow graduate students, who within weeks or months after I went in, did essentially the same thing.
Who were they?
Dave Judd, David Lockhart Judd, and Frank Behle Esterbrook. Esterbrook is now at JPL. Judd, the last I heard, was up in the Northwest somewhere. Sorry, I don't really know. And William Walton Carter.
None of these were astronomers ?
They were all physics graduate students. And they all continued graduate study, as I did, after we came back to Caltech. We all went on together to finish our degrees. Now, it happened that my contacts with the Naval Research Laboratory, and with Richard Tousey, (which was the era which prompted this interview we are now having) took place as a consequence of my going into the Navy. And it took place in the time interval 1944 - 1949 before I finished my graduate work. At the time of finishing my graduate work in 1950, I went to Mt. Wilson Observatory in Pasadena, and took a permanent post on the staff as an astronomer at Mt. Wilson Observatory, beginning January 1, 1950. So the time period we are talking about was the time during which I was still, either in the Navy or a graduate student, or some combination of the two. Let's go back a little bit. I went through the usual basic training. I then spent one year at Caltech. I was reassigned back to Caltech while in Navy uniform; I was not allowed to teach, which was a disappointment to Millikan, who thought he had maneuvered me back there for that reason. He wasn’t above pulling strings, if he could. I was assigned to a local Naval office, to which I reported at regular intervals and I was sort of given free reign to do some kind of research project. I fiddled around a little bit with radio direction finding, which I somehow perceived to be of some possible use to the Navy. I never achieved anything of any consequence during that time. I certainly learned a lot. It was useful I suppose, to me, learning a little practical electronics and all that, and even the designing and building of instruments. But I cannot say that I accomplished anything for the Navy. I was then reassigned to the Naval Research Laboratory in Washington.
You were reassigned by whom?
By the Navy.
It was not identifiable?
By the Navy. It was an anomalous situation. Here I was, stationed out in California with, from the Navy's point of view, no well-justified reason, while the war was still on. I had been sent there at Millikan's behest, but he was not allowed to apply me to what he brought me there for. And so that was the time period I was at Caltech, roughly from early 1944 to early ‘45. Then I went to the Naval Research Lab in Washington, where I was first assigned to the Fire Control Division. The Fire Control Division does not deal with putting out fires, but with controlling the aiming of guns aboard ship. That was my first contact with computers. Computers in those days were boxes of gears and they were marvelous machines. They were just marvelous. They could do all kinds of things. They could integrate and differentiate, and they could add and subtract, and so on.
What kind did you have, something as sophisticated as Bush’s differentiating engine? This was before the Norc wasn't it?
For example, an integrater was a rotating disc, a rotating cylinder and a ball-bearing in between, that could be moved to different distances from the center of the disc. And a differentiater was, of course, a gear differential. Anyways I was involved with that, but only for a few months before learning that there was an opening in the Optics Division there.
This was closer to your interests?
Very much so. And I asked to be transferred to the Optics Division. I thought it would not only be more interesting work, but far more interesting people. The people in the Fire Control Division were perfectly okay people, but they just didn't have the same purpose in life that people in scientific endeavors do, and particularly in the field that I knew. So I became interested in transferring. I asked for a transfer. Tousey apparently needed somebody, and I went over to his group. Right away, the interest there was in going after the ultraviolet spectrum of the sun with the captured V-2 rockets.
Had you known that before you went into the Optics Division?
No, I did not know what they were into. I did not really know in any detail. But the possibility of utilizing the rockets developed rather early after I went there. I don't have any clear recollection of being involved there with anything else very much. My rocket participation must have gotten underway almost right away. There may have been a gap of some weeks in which there were some other activities, perhaps having to do with visibility ranging. E.0. Hulburt, who headed the division, was interested in visibility ranging, visibility at sea, and that kind of thing; and had developed some theoretical and experimental methods for testing that. I do know that a number of people in the division were tied up in some portion of that activity, and it seems to me I was in that a little bit. But I do remember that, at a fairly early stage, the idea of going after the ultraviolet spectrum of the sun came up. And because of having had a little hardware experience from working with machine tools, lathes, milling machines, and that sort of thing, I could do engineering drafting fairly competently; and having at the same time some concept of how to build an instrument with optics in it, I became involved in the rocket spectrograph project.
Let me back up just a few inches here. First of all, had you ever taken any courses in spectroscopy at Caltech, and were you aware of problems in the solar spectrum from the Mt. Wilson attachment to Caltech? Had you taken any courses from Ira S. Bowen, for example.
I had taken the general optics course from Bowen while at Caltech, starting in 1943. I did take his spectroscopy course, but I took it later. So things like the Grotrian Diagram were not part of what I had been exposed to at that point.
Well, then the question arises: Can you recall your impressions, your feelings about first hearing about the possibility of flying a spectrograph on a V-2 rocket?
Well, I suppose it was the adventure of exploring the unknown, because the ultraviolet spectrum of the sun had not been obtained; and one didn't have to be an expert spectroscopist to guess that this would be a very desirable thing to do. If you were a budding young scientist and wanted to do something exciting, you would want to go after just such a project.
Can you recall the mechanics? Were you called into Tousey's office? Did he meet you in the hall? Can you recall the instant that you were told to dedicate yourself, your talents to this project?
No. I don't really know just exactly how it came about. I do remember that once the idea of developing an instrument was planned, I got very much interested. The time scale in which it had to be done was very short. This was not a time when things went through careful engineering scrutiny with designs being carefully reviewed, discussed, and flight qualified. There wasn't anything like that at all. The modus operandi was simpler: if we could get something ready in a matter of weeks, we could take it out to White Sands, install it in a rocket, and off it would go. So I can remember coming in and working all kinds of odd hours down in the basement, literally drawing bolts and parts that could be screwed together to make certain prototype parts for this instrument; and rushing over to the machine shop with the drawings. Somehow the administrative channels have been cleared to make it possible, and the machinists over there turned the parts out for us. We packed them in a box, and took some of the stuff in our suitcases; and we went off to install them in the instrument.
Well, let me ask this, then. From what Dr. Tousey has told me, you and he were very much involved in the design of what was the first ultraviolet instrument?
But the actual machining and construction of the devices were done by Baird Atomic in Cambridge, Mass.?
That's true, but there were some parts that were made in the shops at the Naval Research laboratory. In a way, I'm getting a little bit ahead of my story. For example we had the idea that the space that would be available in the rocket, in the V-2, to put our instrument, would be in the nose, and that this would be the logical place to put it. But since we were going to work photographically, the survival of the film at the time of impact was our main concern. We didn't care about preserving the instrument. We would expect that to be smashed to bits but we wanted to get the film back intact. And the idea that we had was that we should protect the film in some kind of armour-piercing steel. I can remember that we went to our own machine shop with the drawings, and made a prototype of critical parts. We may even have made them for the later installation in the Baird-made instruments. I can't quite remember. I do remember myself down in the basement drawing plans. And I can remember the shop making parts; and it seems to me that it had to do at least with the cassettes, and possibly with some laboratory lash-ups, because we did not go to Baird immediately. By the time we went to Baird, we had pretty well drawn up and worked out what we were going to build.
So you knew the overall design parameters, including that it was going to use two little lithium fluoride beads?
Yes. That was Tousey's idea, by the way. He has full credit for the notion of using a spherical bead to form a little image of the sun, providing an effective entrance slit that was insensitive to the direction to the sun.
Were there any alternative ideas at the time?
We explored different onces. I can remember trying to draw up little reflective slit-jaw schemes. When you use the bead, you are optically utilizing a tiny fraction of the bead to direct light into the collimator of the spectrograph, and the apparent location of the "slit" (the sun's image) depends on the direction to the sun. If, instead, you try the slit scheme, some kind of slit with sloping and internally reflective jaws, you're in effect up against the same problem. There is no way that you can make the jaws reflective, and at the same time, define the position of the slit uniquely. You're trying to do the impossible, like overcoming the second law of thermodynamics. You can't get the light from any arbitrary direction through a defined position, and make the light go into the direction you want it to go, without some kind of sacrifice. The bead turned out to be the best solution.
In retrospect, was it the best?
I think so. I don't see what else we could have done better. Yes, I think it was the best way to go. It's incredible how small a 2-millimeter diameter bead is, especially lithium fluoride, which is a delicate crystal to begin with. Those were made at the Naval gun factory for us. I remember, there was a man named Mr. Devlin, who headed an optical shop in the Naval gun factory; and it was he who cooperated with us in seeing that the lithium-f luoride beads got made. I don't know that he made them personally, but I do remember that the whole idea of making something this odd was no small problem. It is true that we made a deal with Baird Atomic to make the spectrographs. They made them, as I recall, for the grand sum of $7,000 per instrument.
And how many were made initially?
I don't know for sure. It seems to me that they were made sequentially in some manner; and some were certainly made after I left to go back to be a graduate student; so I don't think I could answer that question.
Did you actually, at NRL, make a mock-up, or basic test instrument with the grating and the lithium fluoride beads, and the film on a jig before you took it to Baird?
My memory is rusty, but I do remember our working on the film cassette at NRL; and I think this had to do with satisfying ourselves that we could machine armour-piercing steel, We needed to do that. A solid cylindrical piece of armour-piercing steel had to be not only bored out, but a slender slit had to be broached in the side of it. Then that slit had to be filled with velvet in some way to make it light tight, and yet permit film to be passed through. Then a plug was screwed into the cylindrical hole in the armour-piercing cylinder. A little shaft came out the other end. It was terribly simple conceptually, but it wasn't the easiest thing to make. Well, these were made, but I can't now remember whether later on they were made at Baird. Perhaps they were. Maybe Tousey would remember.
He told me that you actually spent a considerable amount of time in Cambridge monitoring some of the first instruments. What was your interaction with Baird? What was your role up there? Can you give me some sort of a feeling for what you did?
I suppose I was sort of a pest (laughs). I'm sure that Dr. Baird would have been glad if I were not there. I don't mean that there was any bad relationship; but this fresh kid, you know, came up from the Naval Research laboratory, and was there sort of hanging over them. They were trying their best to get this project out in a short time. They had a number-one draftsman who developed the detailed plans for the instrument in the form that they would make it. It seems to me that his name was Robins, or Robinson, or something like that. It seems to me he was physically handicapped, but he was very good as a design draftsman. I worked with him. My time was spent, to a large degree, in the basement of their operation there. They were in an old industrial building.
How big was the operation? How many employees?
I couldn't say, because I wasn't that much aware of the whole of Baird at that time. It couldn't have been big. It must have been a small outfit. I mean, one could walk into the offices there; and there was Dr. Baird, and there were a few other people upstairs; and then there were a handful of people that were designing, drafting, and machining things downstairs. It was a small company. Well, these instruments were designed and built, and in 1946 — I hope I have it right — I think we went to White Sands with the first one. Does that tally with what Tousey says?
Sure. The very first flight that would have had one of your spectrographs was in June ‘46.
I have photographs from June of ‘46.
You do? Oh, marvelous.
Taken at White Sands, showing the rockets going off, and showing various things. I remember digging them out not long ago and just looking for nostalga at them.
We are up to the June 1 launching of the V-2 with the UV spectrometer in the V-2. You took the entire package out to White Sands yourself?
Yes, that's correct.
I should ask one thing. When you received it all back from Baird, when you brought it back yourself, I guess, from Baird to NRL, did you test it at NRL in a way before you took it out to White Sands?
I'm sure we did. I'm sure we took some films and tried it out. I remember that the spectra were recorded on 25-foot lengths of film. And we had to set up a scheme for developing 25-foot lengths of film in a way that would be photometrically uniform. I'm not sure we did the right thing, actually; but what we did do was to set up some 25-foot long tanks so that one could stretch the film out flat. Several people were involved during film processing. One person was the timer. Two or three people walked along the side of the tank with camel's hair paint brushes, —Tousey believed in brush development — to smoothly brush lengthwise down the long piece of film. We just walked slowly beside the tank, one person after another. And then as soon as one person got to the end, he ran back to the beginning, and so on. And we had to do this in a dark room, of course.
Was this pretty unique?
Indeed, it was unique. I'm not sure whether this procedure accomplished the best photometric processing possible, but that was the method that we used.
How many people manned the brushes?
I would guess, maybe three were brushing. I remember being the timekeeper during some of this work. It was a curious process. Then there was a separate tank for plunging the film into the hypo. We strung the roll of film out on some kind of lifting frame, and then we brushed it for the necessary four or five minutes. Then we transferred the whole frame quickly, plunging it into the hypo. What I can't tell you is how much of that procedure had matured before we went to White Sands for the first time, and how much was dealt with later after we got back. I suspect that it was not all done ahead of time, because the whole time scale of the project was very fast. Things were thrown together, taken to White Sands, and flown on a time scale that nobody would think of today. You couldn't get anything done today in that kind of time.
So you drove out to White Sands?
I think we went on the train. I seem to remember having a crate on the train. Some of us just took it down to the railroad station, and we put it in the end of the passenger car in which we were riding. I remember that the train people fussed at us "Oh, you can't have the baggage there. No, you've got to check this baggage." I don't know, but somehow, we ended up keeping it at the end of our car.
It wasn't that large, was it?
There was a relatively large crate. The instrument by itself was not so terribly big, but you always have a certain amount of associated stuff.
Yes. Who was with you?
I think I was there for more than one launch. And I think that Dewitt Purcell was along once, and it seems to me that Kenichi Watanabe was along another time. He's someone I did not remain in touch with, but I understand that he died.
Yes, he did.
I remember that he was from Hawaii. I think that Watanabe, Purcell and I were out there together. I can't say whether we were all three there on the first launch.
Okay. Well, it's your impressions of the first launch that are important. Did you actually place the instrument in the nose cone, or was that done for you by the General Electric people?
Our instrument included, not only the operating guts, but it also included the nose portion of the nose cone, because it had to be machined out to leave the necessary little apertures for the lithium fluoride beads to see through. So, what we presented to other people for attachment to the rocket was pretty much an integral instrument, including its own skin. Installation was a matter of fastening it on mechanically, and attaching it to battery power. I don't remember the particulars of that. I remember being around the hangar at White Sands where the work was being done, largely by German orews. I remember the V-2s themselves, which were astonishing because they looked as though they had been put together out of the scrap heap. They were not made in a sophisticated way. The sheetmetal looked as if it had been odd scrap pieces that had been riveted together to make up whatever shapes were needed. And there were even plywood parts in the V-2s. However, the fuel tanks, the plumbing, and control system looked as though they bad been built for the purpose, but then installed into whatever least costly shell of scrap they could throw together.
Did this make you worry about the whole operation?
It boggled me a bit, I guess.
Here you had made this spectrograph in a hurry.
I do remember one thing that really turned me off, — that really bothered me: there wasn't any very clear idea as to what the weight limits were. We had gone to some trouble not to get too heavy, to keep our instrument size down and to make it compact, despite required parts like the heavy armour-piercing steel film cassette, and the somewhat heavy nose shell that was in front. We had been given some guide lines, based, I guess, on the original rockets. But what they did in practice was to get a rocket all assembled, and then put it up on some kind of balancing device that enabled them to find out whether or not the weight was properly distributed. And I remember, to my horror, that the weight was found not to be properly distributed; and what they had to do was to add a big hunk of concrete to the front end to balance it. So our care in holding the weight down had been all for naught. (laugh).
Obviously they were not concerned with weight yet.
They were not concerned with total weight. It was not a sophisticated business. Go to the Air and Space Museum and look at the V-2, which is propped up there. Look at it closely and I think you will quickly convince yourself that the thing is probably noncircular by an amount you can see with the naked eye, and that the shapes that make up the tail and so on are sort of warped. It looks like an automobile that had been in a number of accidents and had been straightened out again. All the V-2s looked like that.
Yes. So, was your confidence shaken? Did you think your whole experiment, and your many months of effort were not going to work, or were you even concerned about such things at the time?
We knew that the launch experience with the V-2s was not particularly good. I can remember that we met together with Graf Von Braun, as he was then known to us facetiously.
He was known as Graf?
Graf Von Braun, Yes.
He responded to that?
Well, I think he wished to be known as Dr. Von Braun, upon coming to this country, but anyway, Von Braun met with us. I think we merely knew him amongst ourselves as Graf Von Braun, with tongue-in-cheek. He was by no means alone. There was a crew of other people. I have since met and talked with Ernst Stuhlinger a little bit; and I think that Stuhlinger may have been one of the people that we talked with in 1946. But I didn't specifically remember him from the 1946 trips.
Did Stuhlinger or Von Braun talk to you at all, or reminisce about their efforts during World War II to fly an ultra-violet spectrograph?
No, I know nothing of that. But they did give us some idea based on their experience as to what fraction of rockets were likely to be successfully launched. It wasn't terribly high. I can't remember the fraction, but let's suppose it was a half that might very well just never make it, so that we shouldn't think that every flight was going to carry us up to 100 kilometers.
Did they express any interest in what you were doing?
I think so. I remember, at a very early stage they were telling us that we shouldn't put our instruments in the nose. We should put them in the tail. I don't think it had ever dawned on us that there would be room in the tail; but the tails were somewhat thick, and you could reconfigure an instrument and put it in there. And that is precisely what we did later on.
But you do recall that it was the German team, someone on the German team telling you to do that?
You don't remember which one?
It may have been Von Braun himself; he was the one who had the best command of English. I can remember that there were some others sitting around sort of nodding, yes, yes, yes, but they didn't say a lot. What he pointed out was that on return into the lower atmosphere, the rocket plunged into the denser air with quite high velocity, and it was not stable enough aerodynamically; it would normally shake itself apart. What they counted on as a wartime weapon was the impact of the warhead. Whether the rocket came apart in flight on the way down was immaterial. In fact, they would come apart, and you could count on it. When a warhead came down it would make quite a crater; and we were told that we shouldn't count on finding usable parts afterward. The heat dissipation would be enough to melt our film.
So you had been forewarned, even before the launch?
Yes. I think we described how it was we were going to try to recover the film. I don't think it was ruled out by any means, but Von Braun told us we were taking a big chance on trying to find anything, and we certainly learned soon afterward that he was right.
There was no communication between these guys and Tousey's team before your discussions with them?
No direct discussions, that I am aware of; but Tousey may know something I don't remember.
Nothing has been revealed.
What I recall is this discussion at White Sands, and we were given the advice that we should consider mounting the instrument in the tail. I also remember that when we actually did launch an instrument, it took off, landed out in the desert, and made a big crater. We went out and looked at the crater with dismay, and we couldn't find a damned thing.
Did you look personally?
You did. Well, let me try to recall your impressions on the day of flight, Did you know the time of launch; was there any setback?
I remember that there was an informality about it that wouldn't parallel what happens today at Cape Canaveral. (laugh). There was a block house, and everyone was supposed to be in the blockhouse or behind a boondook, one or the other.
Where were you? Where did you choose to go?
It seems to me I was behind a boondock, because I took pictures of the rocket going up and at different heights. I must have been out in the open.
So you have photographs of the original June launching?
Yes. There was a throbbing sound from those things when they went off that was impressive. It was a kind of a throbbing sound that you feel in your chest, as well as hearing with the ears, even though the rocket is by then fairly well up. You are very conscious of that, and then of the stillness that follows. Next you are trying to find out where the thing may have gone. There are tracking people who are looking after that. Then the impact is finally located. They had planes that looked around for the point of impact; and I remember we all got in a jeep. There was a fellow named Charlie Strain, who was a physicist. And Charlie, I remember, drove our jeep. A number of us went bouncing out across the desert in the jeep to try to locate the crater.
At your discretion, you certainly have the opportunity to read the transcript and to give the whole thing a second thought.
I understand. There are places where memory may serve me wrongly; so if you find me in conflict with Tousey or others, put a certain probability on all of us. It's one of those things where, if I could sit down with the others, and we could run through the story; somebody could say: "oh, no, no, no, you've got that wrong;" then I could retreat in the right places and step forward in the right places. I'm giving you my perceptions of it, and my perceptions could be faulty.
This is absolutely understood for the purposes of oral history. In fact, it would be marvelous if you could get a number of people together. If you are in Washington some time, you can.
Let's go on then. You don’t recall any peculiar delays or problems on the day of launch? It went off pretty much informally.
I don’t remember whether the first launch went off just as planned. Yes, there were delays. There are always delays. But as I say, the getting ready was very informal. Once they were fueled, of course, there was a great anxiety to get them off. I can't fill you in on that. I could remember with more vividness a launch that took place a little bit later, a year or so later, in which I had my own spectrograph which was my own thesis project. Those were Aerobee rockets. I can remember in intimate detail exactly how that went.
Great; we can do that later.
But this first V-2 launch, I cannot add to what I have said.
That's fine. but what were your duties during this day? Were you simply to sit back and wait, or did you have any telemetry to watch? Were there any sensors on the instrument that you had to monitor?
No, once we had delivered the instrument there and fully assembled it, it was our job to chew our nails until we could locate the crater and see if we could find anything (laugh). Maybe that's an oversimplification. I suppose we occupied ourselves somewhat usefully, but I can't remember that we had anything important to do on launch day until after the launch had occurred.
Okay. Were there other people there? I know that periodically other astronomers were there in other capacities. I know that Dorrit Hoffleit was interested in the ballistic path of the captured V-2s and was there at WSPG doing ballistics, off and on. Periodically, astronomers visited. Do you recall, during the first few launches that you were there, anyone else who later became an astronomer, identified as such?
I don't remember. I now know Dorrit Hoffleit slightly, but I don't remember her from then. One person I vaguely remember was — I'm sorry, the name slips me, but he belonged to the group from APL at Johns Hopkins. They, too, wanted to get the ultraviolet spectrum of the sun. They had a different instrument. If there was anybody that was sort of our competition, it was them.
Clearman or Hopfield?
Hopfield, that's the name that comes to mind. I can't tell you much about them. I just remember that there was such a project, and that they had a little different instrument concept than we did. I don't know whether it was merely because of our esprit de corps, or whether our perception was well based, but we had a notion that we had a better instrument than Johns Hopkins did. I don't remember what their instrument was like.
That's okay. I'm tracking that down.
I think you should, because that would have been the other attempt at the solar ultraviolet spectrum. I remember that first launch, The nose cone did dig a crater. As far as I remember, it must have been the first launch. We found nothing at all in or around the crater. If the front of the armour-piercing head, the cassette, and all the rest was down there somewhere, it was under tons of rock and rubble. Essentially, we gave up on the spot, and said Von Braun was right — we had to put our instrument in the tail next time.
Yes. Now, did you phone back to Dr. Tousey; or how did that communication go?
I don't remember phoning, but we might have. I think the result was mainly communicated afterward.
Then, I imagine your trip back to Washington was relatively uneventful.
I don't remember it.
Do you recall any feelings about the continuation of this project? Or did you know that, obviously, the next step was to put it in the tail?
By then, it seemed clear to me that our instrument should go in the tail. We not only had been advised for reasons that were very sensible, but we had had it very well demonstrated to us that we didn't have the instrument in the right place.
Now, after June, I mean, after the problem, I know that there also was a small group at NRL that began looking seriously into a way to telemeter spectroscopic data by using photocells, photomultipliers, and standard telemetry; and that this project over that summer, 1946, did develop a prototype. Were you involved in that at all?
No, we went on using film.
Were you aware of that?
At that time I might have been, but it doesn't ring a bell now. There weren't generally things going on in which the comminication was particularly bad. The rocket division, or rocket sonde section, or whatever it was, with Homer Nowell and Sirey, were involved in some other instruments, but our game, the solar ultraviolet spectrum, was pretty much Tousey's baby. That was in the optics division, and if there were other groups that were involved somehow in another aspect of it, I am unclear where they would have been.
Well, working somewhat with your group, is my impression. The question here, of course, is one of philosophy of technology.
I wonder if it didn't come in just a little later, because, you see, what happened is this:Beginning in the fall of ‘46, 1 went back to being a graduate student at Caltech; but that was not full time on a long time scale. That is to say, between ‘46 and ‘50, 1 retained a position at NRL, and I did so by taking leave from NRL for various time intervals. I was always building up a lot of compensatory time whenever I was on the job at NRL.
Was it because you were working literally day and night?
Something like that. And so, what would happen, would be that I would take compensatory time, and go to Caltech for a semester or so; then go back and be at NRL for awhile, and work a while to make some money and build up some more compensatory time; and then go back to school again. I was not unconnected with the project, but I wasn't there throughout some of the activity. I can remember very well I was not present for the flight when the first spectrum was obtained.
October of ‘46.
Yes, and I remember getting a letter from Tousey in which he told me the good news, that the spectrum had been successfully obtained.
Any chance that you would have that letter?
It's conceivable. I have a lot of old and somewhat interesting archival material, but I saved things mainly because of their Mt. Wilson context a little later. But I could have some of that NRL file from the 1945-1949 period.
Okay, so you weren't directly involved in the October, ‘46 flight. That was the first successful one.
I was not directly involved in the flight. It was the same basic instrument. I have to assume it was a tail launch, but you had better verify that. (It was a tail-launch.)
Do you recall, by any chance, who did take the instrument out to White Sands that time? Did you know?
No, I wouldn't be able to say; but what I do remember was that the letter from Tousey had a very curious sentence in it; very amusing, in a way. I can't remember the exact wording, but if I can paraphrase it, it was so amusing — the letter had been typed and it is a "typo" that I am referring to. It was a sentence put in the negative something like: "It would have been much worse if you had been present." Tousey had carefully crossed out "you" and corrected it to "yaw". (laugh together). That was it. "It would have been much worse if yaw had been present.” (laughs).
Now, when you were back at Caltech and you were a graduate student, were you planning on a particular package to launch at this point in ‘46; or was that later?
It must have been a little bit later, because I had some graduate student course requirements to complete. And I must have been mainly wrapped up in that. I didn't start a thesis project instantly, but when I did come to starting a thesis project, I was interested in going back to the solar spectrum problem, because I had some ideas of how to get more optical throughput, or at least, I thought I did. You see, Tousey had his heart set on Lyman alpha, and I thought that, if one were willing not to necessarily push for Lyman alpha so much, but simply get more signal onto the film, one might be able to do better at longer ultraviolet wavelengths. So I did design a different instrument. There is an item that we have passed over here that is kind of an interesting side story, so I would like to go back a little bit before we go further, if you do want to go further.
When we were first planning the V-2 instrument, and planning to undertake this project and thinking about how to do it, Tousey wanted to get some advice from some old friends and acquaintances. We got in a car and we drove up to Baltimore, and we visited R.W. Wood and John Strong, and some of their colleagues as well, to get some ideas about how to design our instrument. Today, there's a tremendous aura surrounding the names of R.W. Wood and John Strong. There was substantially less so in those days. They were well know , but it wasn't like meeting God, exactly, though R.W. Wood may have thought so. I remember that R.W. Wood had been in a motor-car accident; and Strong was asked, "Well, how is he? The answer was that his ego came through intact. (laugh). Anyway, we met briefly with Wood, and we met much more with John Strong. I can't remember his specific ideas. I just remenber coming away with the feeling that we had had a very useful visit.We also went up and talked with Theodore Lyman up at Harvard. I know Lyman was puzzled that we would be able to send that instrument up and get it back down, and that anything would survive. As he put it, he was sure that our melon would go, “squash” on impact. I remember that phrase. We talked with Stockbarger at MIT. I don't remember his first name, but he was a professor of physics. He was the sole source of good optical crystals like lithium fluoride and calcium fluoride. Harshaw Chemical was also making these things, but they were just starting to make them under Stockbarger’s guidance. It was Stockbarger who had pioneered the vacuum crystal growing technique, if I recall correctly. I don't know enough of the history of that to be a good spokesman for it. Anyway Stockbarger gave us a piece of his lithium fluoride. As I remember it was out of his piece that we made the lithium fluoride beads.
That certainly can be traced down, because in some of the NRL reports there are detailed acknowledgements.
And I can also trace down some of his own work.
It should be verified, but I think it is correct. I think that later on we got materials from Harshaw Chemical.
I would imagine your meeting with R.W. Wood and Strong would be basically on optical design matters. With Lyman did you discuss the spectrum that you would be looking for, and possible minimum exposure times, or anything technical like that?
Yes, I think so. But again, a better person on that aspect of it may be Tousey; but I do remember being present, or getting together very briefly. You know, casually dropping into the office, saying hello, and then a little chatting about the experiment, and what it was that we were proposing to do. I have to say that Tousey was the brains of the project. After all, a graduate student like myself could maybe have ideas at times, but the real planning was Tousey's, and I was just along.
That's an interesting recollection that you have of travelling and talking to these other people. Anyone else? No astronomers, I take it. Was there any contact with any astronomers?
There was very little contact with astronomers, that I was conscious of. I came to know the astronomers much later.
Well, where should we go from here, to your Caltech work?
Perhaps it's of interest to tell a little bit about some of that, because in undertaking a thesis project, it would seem natural to think along the same lines. There had been the success of the V-2 flight. There was a reconfiguring of the instrument, as I recall, at NRL. As I recall we were later on not using the original Baird configuration any more, but were using a different configuration.
What was the cause for the changeover?
I think it had something to do with fitting it into the tail; and it also had to do with using two entrance slits coming in opposite sides, together with a single film transport fitting the Rowland circle. I couldn't draw you a picture of the instrument today. I just remember that we did reconfigure the NRL instrument. However, I had the notion that one should build, or at least try to build, a refractive instrument, instead of a grating instrument.
Why is that?
Because lithium f luoride was by then available from Harshaw in relatively high purity with quite high transmission per centimeter even down to Lyman alpha. I had a notion that we could build a very compact instrument to go in small rockets. After all, the V-2s were going to run out. What America had next was the Aerobee, and we wanted somehow to use the Aerobee. We had to have a smaller and more compact instrument.
Didn't you plan to fly something on a WAC Corporal?
The WAC Corporal was, as I remember, a still smaller rocket, a 12-inch rocket, wasn't it? The Aerobee was the 15-inch rocket, and it was an Aerobee that we got the go-ahead to use. Whether there was a little bit of history of thinking of alternatives, I can't recall. Somebody else may be able to fill you in on that.
You know that you never flew anything on a WAC Corporal. That's what I'm trying to ascertain.
I don't remember it. All I remember is trying to get an instrument ready for flying on an Aerobee.
All right. Now, you made this instrument at Caltech, or at NRL?
At JPL, the Jet Propulsion Laboratory was then in Quonset huts on a hill near a canyon at the outskirts of Pasadena.
Yes. My father worked there.
Is that right? I was a graduate student at Caltech, but it was set up to that so that the actual making of my instrument could be done in the machine shop at JPL. Mickey Shurburne was the head of the machine shop. He had formerly been at Mt. Wilson. I only learned that afterward. I didn't know that at the beginning,
Aside from the lithium fluoride prisms, was the design of this spectrograph a standard one or two-prism arrangement? Did you use lenses for collimating?
I designed a rather strange shaped prism. This prism was made of lithium fluoride, and it had a shape that accepted light from an angle to the axis of the instrument, bent it in the desired direction, and at the same time dispersed it, I don't now remember the particulars of that prism shape, but I do remember what it did. Because of the delicacy of the lithium fluoride, we had the idea of mounting it in quite a sturdy piece which was machined out of magnesium. The prism was virtually embedded in the magnesium. One of the features that I was trying to incorporate was a sun follower, so that the input aperture would track the sun in one-axis. It had a side-looking bead. It was side-looking from the nose of the Aerobee rocket. The block of magnesium I mentioned was fitted into a large-diameter bearing. It was the tip of the nose cone forward of that bearing which rotated, and which contained the imput window. Then the light went through the strange-shaped prism somehow, was turned to go down the axis of the rocket, and at the same time dispersed. The whole thing was very small and very compact.
Let me ask a few questions about procedural matters, as you were a graduate student. You must have had a thesis proposal; did you have an advisor?
Yes, my advisor was W.R. Smyth, professor of physics, whose specialty was electricity and magnetism. It wasn't Bowen. Bowen by then had gone to be director of Mt. Wilson Observatory. I can't remember how it was that I came to be working with Smyth, but anyway, I was. Smyth was very happy to see me pursue this project.
There was no question about the feasibility of such a project, what would happen if it crashed, for your thesis, at least?
It was strangely informal. I don't remember any pieces of paper by which this project was approved. I don't remember anything, except that it was set up informally. The things that I would need locally through the department, my ordinary expenditures, long distance phone calls, and that sort of thing, would be made through Smyth. JPL would build the instrument parts in the JPL instrument shop. Then I had some small amounts of money, the origin of which I don't remember, that had to do with getting the optics, acquiring the pieces of lithium fluoride from Harshaw and having them polished. They were polished by a firm called Penn Optical, by a man named, Penfold, vho ran Penn Optical.
Was this in California?
It was in Pasadena. I remember there was one disaster along the way. Things went slowly. The prisms weren't getting made. I would make periodic visits to Penn Optical to find out why not, and there was always one excuse after another. Then, they had some kind of an accident in which part of the polishing equipment fell down on these delicate prisms, and broke two of the blanks we had. We had several blanks. I remember that we somehow worked our way out of the disaster. Anyway, that was the way the prisms got made.
Were you in contact at all with Tousey during this period?
A little bit, but not a lot. I was doing this much more on my own. Well, let me think a minute. It seems to me that during some portion of that period, at least, that I was again employed at NRL. There certainly was some level of sponsorship from NRL in this. You asked me about the formality. Certainly, today the undertaking of a thesis project would be done more formally than it was then.
Certainly. Dr. Tousey made it quite clear that operations at NRL at that time were very informal.
Yes, I can remember that they were very much concerned, in fact, because there was a guy named John Riley, who was their administrative aide for that division, and Riley was an American Irishman with a great deal of blarney. He somehow managed to talk the administration into letting me accumulate vast amounts of compensatory time, and then go away for months at a time. There was a great deal of throwing up of hands as to when all of this would come to an end. Somehow, in my youth and innocence, I guess I just didn't appreciate how peculiar it was. This sun-follower prism instrument was then put into an Aerobee at White Sands for a launch.
Well, they had had thirteen successful Aerobee launches up to that point, and mine was the fourteenth, so I had high hopes. The instrument was operated by silver chloride batteries. Silver chloride batteries were, I think, a new development at that time. They contained dry silver chloride and magnesium; and to activate them, you simply put water on them. And a little one about the size of a flashlight battery, could put out enough current to start a car, but only for a few minutes. It would essentially cook itself to death within minutes. You could draw amperes from such a battery for a very short time. The idea was that these very lightweight little batteries could be used to provide a lot of power for a very short time.
The sun follower required motors?
That’s right. There were circuits, and a motor, my own concoction, a vacuum tube system. There were little thyratrons in some sort of an oscillator; when the thyratrons fired they drove the motors. They drove them one way or the other, according to the error signal coming in. It was my own self-invented crude servo for using a minimum number of components to drive a reversible electric motor. I remember that I literally went and bought a pound of coffee in order to got the coffee can, which was used to contain the batteries, and which was built into the instrument. The batteries were put inside the can, and a little water-filling tube was silver soldered onto the can.
Why a coffee can in particular?
It was the right shape and size, and it was a lot cheaper to buy one than to make one.
Was it any particular brand?
Do you remember the brand?
No. It was just a very ordinary one-pound coffee can because it was the right shape and size. And if you ever tried to do any sheetmetal work to make something like that, it would take many hours of work, and it wouldn't be as good (laughs). So, I remember that I mounted the little pack of batteries into the coffee can, and the resulting package with its filling tube was very lightweight. Before the launch, we had to have everything ready. Everything was in the tower and ready to go.
You put it in while the Aerobee was vertical in the tower?
Oh yes, then I climbed up in the tower and I poured some water down the funnel, and it ran down into the batteries. Then I went away. I had some pins, like big knitting needles, stuck into the Aerobee. There were two of them, and there were strings attaching them to some big solenoids on the tower. And when a button was pressed from a safe distance below, it would pull these two pins out. That action would connect the electrical circuitry that would start drawing power from the battery. The battery would last for an hour or two, if not electrically connected to a load, after you put the water in. Then, once you pulled the pins, and started drawing current, you then had a very short period of time, measured in minutes, during which the battery would last. Well, I remember that we got all ready to fire. The rocket was all set. I was all set. The water was in. We had pressed the button to pull the pins, and they didn't pull. I was watching through some sort of big binoculars, the big handle-bar type binoculars mounted on a post, to watch the pulling of the pins. We tied little ribbons around them so you could see from a distance whether they actually pulled out. They didn't pull.
Solenoids? No electricity?
I think they had been tested before. Some break in the line somewhere. The wire leading out there through the boondocks had broken somewhere. There was an open circuit somewhere, and indeed, the pins just didn't pull. So I rushed into the blockhouse and said: "Hold it, hold it, hold it, the pins didn't pull. Okay, what to do? " And then some guy volunteered to go out and pull them. So, some sailor or soldier went out and climbed up the tower, pulled the pins manually, and came back down. Then they went ahead with the rocket firing. The rocket started up the tower, got about halfway up the tower, and exploded. It beat the tower all out of shape, in addition to blowing itself up. The rocket then staggered barely out of the top of the tower. It came down and blew up again, blowing pieces all over the desert floor. So that was my thesis project. (laughs).
Now, where did it go from there?
I simply got back on the train to Pasadena, went home and started a new thesis project, a different one. (laughs).
Yes, literally. (laughs). We never launched the second instrument.
You had a second instrument?
We had the makings of one. It wasn't fully prepared.
Why didn't you continue with it?
I could have, I guess. I don't know. I don't remember feeling any strong emotions about it. I just remember thinking, "Well, this is not the best way to go; I’ll just do something else that's easier and more routine."
Did anyone talk to you about it? Did you seek out anyone's advice?
Not particularly. It's strange how little counseling and advice there was. I can't explain that. I don't remember feeling that something was missing. It was more of a do-it-yourself time, I guess.
The funding for the Aerobee, for the launch — did this go through the rocket panel at all?
I don’t remember, now.
Okay. That can be checked from the rocket panel records.
Yes. There probably were levels of approval, certainly at JPL for undertaking the project, that I don't really know about.
In the preparation stage, did you ever obtain any spectra in the lab, or of the sun from the ground with your instrument?
Oh, I would imagine so.
So you did test it that way?
Oh, I think so. I remember assembling things out at White Sands. I didn't take it there already assembled. I took the parts out there, made sure the optics were all clean, and did the final assembly of the instrument there just prior to launch. I can remember a test run. I can't remember how we provided the battery power for the test, maybe I had a spare battery can. I remember setting the instrument up and turning it on. It spun around and grabbed the sun. And I can remember manually rotating the base under it. We even tossed it from one person to another, and the instrument kept on trying to keep itself with the right side toward the sun.
So the sun follower really worked.
No one tried to encourage you to continue?
I don't remember that. I don't remember being under any pressure in the matter. I remember discussing alternatives, considering whether I might do some other kind of thesis project. The project I finally did was NRL related, and it had to do with ultraviolet transmission of the lower atmosphere. It was done at Caltech campus. There was a level of involvement with Larry Dunkleman of NRL. Larry had been doing a little bit in related work. It was, so to speak, a very safe project. It didn't depend on rocket flights. I didn't have any clear employment ideas. I was still, in effect, an NRL employee on leave. I must have been supposing I was still connected with NRL, and going back there; and thought I would get back in the rocket business in some way other than the thesis connection.
You were in uniform for awhile at NRL, weren't you?
Yes, I was. As I mentioned, I went into the service and went through some basic training. Actually, I was trained for radar school, which didn't materialize. I went, instead, to Caltech for one year, and then to NRL, and was in uniform up until 1946, when at some point I got out of uniform and put on civies again.
Now the Aerobee flight that you had tried for your thesis must have been during the time when they were still flying some V-2s, because they did overlap. So it seems that it's also slightly before the time that Jesse Greenstein flew his spectrograph. Do you know anything about that?
No, I don't, I came to know Greenstein around ‘49 or so, casually at least, and later on much more, but I don't know about his project.
So, during the time when the destruction of that Aerobee was still fresh in your mind, you had no contact with someone like Greenstein or people like that?
No, no. I guess, in retrospect, the thing that astonishes me is how little the Aerobee failure disturbed me emotionally. I don't know why. Maybe I just thought that, from the V-2 experience rocketry was a very chancey business anyhow; and if a rocket worked, fine, and if it didn’t, all right, we'll do something else. It was partly that point of view, and perhaps an element of youth. Youth is indestructible, you know; and somehow rebounds rather easily.
You did go back to NRL f or awhile?
Yes, but only intermittently. I never was back for any long stretch, and when offered a post at Mt, Wilson, I talked it over with Tousey, who indicated he would like me to stay at NRL, if I would; but he understood if I wanted to do otherwise.