DR. LOUIS RIDENOUR’S RESEARCHERS AT LOCKHEED MISSILE Systems were determined to hire Dudley Buck. Their repeated letters made clear that they remained of the view that cryotrons would form the basis of the guidance system for America’s nuclear deterrent.
Lockheed was already developing the Polaris submarine-launched missiles, and the X-7 test rockets. It had just developed the Agena upper-stage rocket—the first multipurpose spacecraft, which would go on to be used in the Gemini space missions and which continued to be used by NASA until the mid-1980s. It had been built, at this point, as part of Project Corona—an offshoot of the WS117L program, of which Buck was a part.
The satellite and missile programs were more or less part of the same work stream. Lockheed was working on both. The same rockets that were being developed to carry a nuclear payload would be used to launch satellites.
After his refusal of a full-time position, Lockheed tried to hire Buck as a consultant. There was a problem, however. When his contract with the NSA had been renewed in 1956, a new clause had been added. The NSA had started to get worried about conflicts of interest emerging between work done by its various advisers on behalf of the government and similar work done by contractors.
Buck’s consulting work had been a source of confusion in the past. The MIT patent department had been concerned to learn how much work Buck had been doing on the cryotron during his time on Arthur D. Little’s premises. To maintain full patent control, the university sought assurances that the key work been completed in Building 10 at MIT, rather than the Arthur D. Little labs.
Buck had been forced to fill in a form for the NSA detailing his various consultancy agreements. Where he had once gathered consultancy contracts here, there, and everywhere, he now started to think a little more carefully about how he divided his time. Arthur D. Little also got a little more possessive.
When Lockheed sent Buck a contract, offering him a consultancy role on its missile project, he sent the paperwork back. His contract with Arthur D. Little “precludes the possibility of my signing your agreement,” he wrote. He did come up with an elegant solution, however. “If your firm would like to explore the possibility of using cryotrons in missile systems, it would be perfectly proper for me to participate in such an exploration if arranged through Arthur D. Little Inc.,” he wrote to Lockheed in February 1957. “That is, your firm should contact Arthur D. Little with the request that they send me as a consultant if they feel that is advisable.… They are, as you know, a firm of consultants and I am sure that an agreement satisfactory to the interests of Lockheed could be worked out.”
Buck sent another, less formal, letter to Sam Batdorf, his main correspondent at Lockheed on such matters. He explained what he had just proposed. “Work is proceeding on the cryotron,” he noted. “We are still engaged in fabricating equipment to measure automatically a number of superconductor properties. In my personal opinion, I feel that it will be some time before cryotrons will be suitable for portable use in a missile system.”
Lockheed was undeterred by Buck’s pessimism, and Batdorf fired off a letter to Arthur D. Little requesting Buck’s services at the company’s missile research center in Sunnyvale, California:
The Missile Systems Division of Lockheed is interested in light and reliable airborne computing equipment for certain potential future applications. It is possible that the cryotron or some modification of it might be advantageous as compared with other proposed systems.
In an effort to ascertain whether or not this is the case, I called Dudley Buck on the telephone recently. However, because our applications are highly classified, we were not able to get very far in considering the question over the telephone. It also does not seem too feasible to process the question by exchanging letters. I, therefore, propose that Dudley come out and visit us.
Batdorf suggested that Buck spend one day with the firm, just to see if there really was any potential for the cryotron to become the guidance system he needed. Lockheed would expect Arthur D. Little to offer Buck for free initially, Batdorf said, but he would pay the firm $125 for every day subsequent to that if there was something worth pursuing.
The following month Buck flew to California. The trip was clearly a success. Three weeks after he returned, Arthur D. Little bumped Buck’s consulting fee up to two hundred dollars a day. Within a few months, Lockheed scientists were sending Buck letters with questions about how to set up their helium freezers and looking for tips on where they could buy cut-price tantalum and niobium. The cryotron was now a Lockheed research project.
Cryotron research labs were popping up all over America. In December 1956, while trying to recruit Cornell University academic George Yntema to his staff, Buck bragged about the extent to which his work was being followed. “I now know of 12 engineers outside of MIT whose full-time job is to exploit cryotrons for computer circuitry,” he wrote.
The research was all focusing on the idea Buck had hinted at in his award-winning paper for the Institute of Radio Engineers. Rather than using wires wrapped around one another, Buck and his acolytes across America were trying to create cryotrons by using thin films of superconducting metals. As Buck had predicted, the smaller the cryotron could be made, the quicker it would flick between zero and one.
IT WOULD BE misleading to give the impression that Buck was entirely on top of his multiple briefs. The conflicting demands on his time had left him spread extremely thin over too many projects.
Buck’s father, Allen Buck, died in February 1957—he was stabbed in an alley in an attack by a jealous lover. Dudley did not even go back to California for the funeral; they had barely spoken for years.
In the lab, he was starting to get distracted. He would become so immersed in his work that he would lose track of time. Simple domestic tasks would slip his mind.
“I would have perhaps a dollar left in my jeans at the end of the week,” remembers Allan Pacela, who started working in the lab in Building 10 as an undergraduate in 1956. “On the way home, Dudley would need to buy a carton of milk, but he would never remember to bring money. I would loan him a dollar, my last dollar, so he could buy milk for his kids.”
Carolyn and Douglas were growing up fast. As soon as they could talk, they were both introduced to the world of science. Carolyn would get a spoon of coffee in her milk as a breakfast treat if she could correctly recall the distance from Earth to the moon or the sun. Buck would take Douglas with him to the hardware store on Saturday mornings, so that he could “learn how a cash register worked.”
By the summer of 1958, Jackie was pregnant for a third time. Buck was trying to arrange his affairs so that he could see more of his children. He would try to get home to Wilmington before bedtime, then catch up on paperwork later at night.
The house on Birchwood Road was starting to feel small, especially when Buck was trying to work from home. He decided to convert the basement, which had been more or less useless up to this point; anything more than a passing rain shower caused it to flood. “Dudley used to jest that the Ipswich River originated in his basement,” remembers Jackie.
Buck asked Allan Pacela, who was always in need of some extra cash, to come out to Wilmington to help him dig a new drainage trench to take the water away from the house. It didn’t really work, but Pacela got a few dollars in his pocket, a hot meal, and spent the night on the Buck family sofa.
Buck then came up with a devious plan to create a false floor that could sit above the water. He set a layer of concrete blocks tipped on their sides, with gaps between them for the water to run out. He then rigged a pump that would pull away the water when required.
Once it had dried out, Buck walled off the heating furnace and hot water tank. He then tiled the whole thing to create a playroom for the kids where they would run around on wet winter days. In the other corner of the basement, Buck set up a desk and some shelves to create a home office.
It was from here that Buck finally typed up his doctorate thesis on superconductive electronic components. Although Gordon Brown, his head of department, had instructed him to complete this task by June 1957, it was some eleven months later, in May 1958, that the paper was delivered.
Buck liked the quiet, subterranean office in the family home. Over time, more and more of his files made their way into the basement. Often the curious little puzzles that would be sent his way by the NSA would be resolved at home.
His troubleshooting work for the NSA continued to be varied. He had been pulled back into air defense projects, including the Semi-Automatic Ground Environment (SAGE) system that was taking over from the Whirlwind machine in watching the skies for Soviet bombers. Diary entries also suggest he had been involved on the fringes of US Air Force Project 438L—the code name for a plan to develop a supercomputer that would be able to target incoming missiles.
Buck was also developing a deeper interest in what was then referred to as either self-organizing or self-learning systems—forms of artificial intelligence.
Self-organizing systems adapt to changing environments, in response to new information. Such a system could, for example, push a missile back on course toward its target if it got caught up in the jet stream.
Buck started to correspond with Frank Rosenblatt, at Cornell University, who was pioneering the field. Rosenblatt was another of the scientists who was also developing something that looked a bit like a microchip. Together they started to share ideas on circuits that could react to rewards and punishments, aping the basic tests to define intelligence that had been performed on rats and pigeons for years.
When it came to Buck’s cryotron, there were still a great many skeptics who were either unwilling to believe in the quasi-magical powers of super-conductors or failed to comprehend how the design could ever be made to work.
After one of his conference appearances, Buck received a pointed letter from E. Mendoza, who worked at the University of Padua in Italy but had also worked with the world-renowned British computer scientists at the University of Manchester, where Alan Turing had worked post-war.
Mendoza could not comprehend how Buck proposed to dissipate heat from his device. If he could make something that switched so quickly from one to zero, surely it would generate heat. If it generated heat, then it would interfere with the temperature inside his helium flask. Given that the whole concept relied on controlling temperatures at the exact point at which a metal would switch from a superconducting to a resistive state, it all sounded a bit far-fetched.
“Your question is most to the point,” said Buck in his reply of July 24, 1958. “Aside from the problem of building a tiny component in the first place, the problem of getting rid of the heat which results from its operation is of prime importance. We have not yet dreamed of operating superconductive switches at as high a repetition frequency as you mention in your letter, but have extrapolated measured values of energy dissipation for the present wirewound cryotrons to values for much smaller cryotrons which would operate at high speed.”
Buck explained the math behind his research, which showed in basic terms that as it got smaller the cryotron would use exponentially less power and so create significantly less heat; “If, for example, we are successful in our present effort to reduce the size by a factor of 100, the speed will increase by a factor of 10,000. The operating current will decrease by a factor of 100 … and therefore the energy dissipated per flip of one unit will have decreased by a factor of 10 to the power of 6.”
Buck had already addressed many of the possible issues. For one, he had devised a way to capture and recycle the helium in his experiments, answering the complaints of those who thought he would use up too much of America’s supplies of the gas with his experiments. He envisaged that the cryotron could become, over time, a stand-alone device with a captive helium supply built in.
When it came to controlling the temperature, Buck explained to Mendoza that one of their bigger problems was stopping heat from being conducted down the cables that connected the cryotrons in their vat of helium with the components outside the flask: “We have, for example, a student-designed cryotron computer under construction which requires 32 fine copper wires plus 16 shielded copper wires for its connection to the peripheral equipment. The heat loss due to thermal conduction evaporates one liter of liquid helium in about ten hours.”
Buck said that there were countless ways around these problems and the heat problems “will probably not be objectionable in a finished system.” He added, “Our present work is aimed at the problem of constructing cryotrons on a very small scale. We plan to use electron beams to replace light in an etched-wiring process which promises to allow evaporated thin films to be cut up into the desired conducting paths. A multilayer technique, then, would allow large groups of cryotrons to be made simultaneously. This work is in its infancy, however, and no progress can be reported at this time.”
Many of these issues had already been addressed by the time Buck gave his well-received presentation to the Eastern Computer Conference in December 1958. Other issues were being chalked off the list day by day, week by week and month by month. Buck would make the cryotron work, if only he could find the time.