CHAPTER 8

The American Cyberskippers

DECADES AGO I CAME TO KNOW and respect my Russian nuclear colleagues, from their radiochemical signatures if not their names, so when the Cold War was over it was rewarding to meet them in person, to dine together and heave a sigh of collective relief. My familiarity with American nuclear weapons covers those same years, as I worked at the University of California’s Livermore Radiation Laboratory during the time of the Cold War’s last atmospheric tests.

The Livermore Lab was the brainchild of Edward Teller, its birth one consequence of the Teller-Oppenheimer struggle over the merits and feasibility of an H-bomb. For a decade Teller felt that an H-bomb, replicating the sun’s fire on earth, could be built, but until the winter of 1950-51 the details escaped him. Then, in March 1951, he and Stan Ulam published a paper through classified channels that articulated the solution.

Within fourteen months the U.S. Atomic Energy Commission asked the university to open a new weapons laboratory. It was to compete intellectually with Los Alamos, for in the eyes of many in Washington, that older institution had been infected with Oppenheimer’s 1949 view of H-bombs—that in all probability they wouldn’t work, and even if they could be made to work, they would cost too much in terms of money, talent, and tritium. Besides, they would be too heavy to deliver, and our efforts to build them would only spur the Soviets on to a similar H-bomb program, so we should not work on them in the first place.

The U.S. government, including the President of the United States, thought otherwise. This new laboratory was to be an offshoot of E. O. Lawrence’s Berkeley Radiation Laboratory. It would be located on a World War II naval air station just outside Livermore, thirty miles east of Berkeley. On July 1, 1952, the university accepted its new responsibility, adding Livermore to its portfolio of preeminent physics institutes. In September 1952 the Livermore Lab opened its doors. Herbert York became its first director; Edward Teller was its éminence grise.

HIS EMINENCE

Edward, as he has always been known at Livermore, saw things differently from most of us. During World War II, Edward Teller fled his native Hungary to become a bright young theoretical physicist at Los Alamos. From the summer of 1943, almost immediately upon his arrival at that wartime scientific nerve center, he left his stamp of genius on America’s nuclear weapons program. He arrived in hopes of pursuing thermonuclear technology in parallel with the difficult enough challenge of uranium fission weapons. He was disappointed. The wartime focus at Los Alamos was on immediately achievable, practical results: an A-bomb that could be fielded within a year or two.

At the time of Teller’s arrival, the favored solution to A-bomb design was the rapid assembly of two pieces of fissionable material, fast enough that they would go critical before the nuclear energy released could blow them apart. Enclosed guns firing uranium projectiles at each other was the envisioned solution. It was this approach that was used in Little Boy, the bomb dropped on Hiroshima on August 6, 1945, and it was the approach taken by the Soviets at their Moscow Laboratory Number 2 until they gained access to the secrets of Los Alamos. This gun-type assembly was a terribly inefficient use of U-235, and it would not work at all with the new reactor-bred metal, plutonium.

Teller’s earliest contribution to this program was his reflection on the compressibility of all matter, in particular, metals. One does not ordinarily think of iron as being compressible, like a gas, but in June 1943, Teller discussed this question with the great mathematician and fellow Hungarian refugee at Los Alamos, John von Neumann. They noted that at the center of the earth, where pressures are about five million atmospheres (75 million psi) there are indications that the earth’s iron core is compressed by something like 20 to 30 percent. The same effect might be achieved in a weapon by the convergence of shock waves driven by high explosives. Von Neumann had been studying this convergence of shock waves as a possible means of destroying German submarine pens, and one of his contributions to the A-bomb project was the development of high explosive lenses that would better focus these shock waves at the core of the weapon. Might the metals at the core be compressible?

Another scientist at Los Alamos, Seth Neddermeyer, had suggested the use of spherical implosions as a means of rapidly assembling a critical mass. Could these effects be combined? The scientific team at Los Alamos soon came to understand that with reasonable spherical convergence, explosive-driven shock waves would create pressures on the order of ten million atmospheres at the center of a metal ball. They further calculated that such pressures would significantly increase the density of the heavy metals known as “actinides.” The most prominent actinide is plutonium. Since critical mass depends on density, and since the rate of increase of criticality runs much faster with spherical convergence, the scientific team at Los Alamos had just hit upon the secret of the modern A-bomb: spherical implosion of a fissionable pit using carefully designed high explosive lenses. With that discovery, the bomb program was reoriented into two parts. The use of U-235 in Little Boy was continued, but spherically imploded balls of plutonium became the basis of the Trinity device, the Nagasaki bomb, the U.S. postwar nuclear inventory—and the Soviet A-bomb as well.

With the end of the war Edward Teller’s mind turned to other new challenges. In later years Eugene Wigner, another prominent Hungarian physicist, would describe Teller as “the most imaginative person I have ever met.” This gift of unclouded vision regularly led Teller to urge U.S. pursuit of technology that did not yet exist. His mind looked carefully into the physics of any given challenge. Once satisfied that a proposed scheme or plan was not contrary to the laws of physics, Teller would put his name and prestige on the line most forcefully, assuring all who would listen (and some who did not wish to listen) that this thing could be done. The time, practical engineering, and resources required to bring these insights to fruition seldom concerned Teller. He became bored with the details that could be worked out by other, lesser minds. To his dying day he probably did not have a clear idea of how the intricate components of U.S. H-bombs really work. Such things were engineering details to him, although most of us designers think of them as mind-boggling physics and materials challenges. I worked for Teller in the 1960s, and I thought he was a man of vision; others thought he was nuts.

As World War II ended, Teller refocused his vision onto the thermonuclear challenge. In 1946, Los Alamos convened a conference on the super. It was a gathering of distinguished physicists, including Teller and Klaus Fuchs, to consider whether thermonuclear reactions could be achieved on earth. They sketched out some ideas, but the war was over; most of those present wanted to turn their attention to other things. Then, on August 29, 1949, with the first Soviet A-bomb test, priorities changed. Teller urged a full-scale U.S. H-bomb program on any who would listen, and on January 31, 1950, President Truman authorized the development of such weapons.

It is one thing to implode a ball of plutonium to get a critical mass and thus a few kilotons of explosive yield. It is quite another to achieve the temperatures, pressures, and densities found at the center of the sun in order to start fusing hydrogen nuclei into helium. Teller’s initial scheme for achieving these conditions was simply to light a tube of thermonuclear fuel at one end, using an adjacent A-bomb as the “match” or igniter. The name “super” became attached to this particular geometry, and Teller promoted it heavily in early 1950. But life turned out not to be so simple. Within a few months of Truman’s approval to proceed with the program, cooler heads—John von Neumann and his associates—undertook some serious machine calculations of the super configuration, using the new digital computers available at Princeton. They concluded that the Teller approach would not work. Later calculations show otherwise, but at the time, the von Neumann findings caused a serious political setback.

The results of these calculations troubled Teller deeply. He had been instrumental in pushing the U.S. government into an H-bomb program, but it was not until the winter of 1950-51, a full year after President Truman’s go-ahead, that Teller finally hit upon the idea of using the radiation field from an adjacent primary to implode, compress, and light the thermonuclear fuel. In March 1951 he and Stanislaus Ulam published their paper. Twenty months later a device based on their concept, and yielding ten megatons, blew away much of Elugelab Island at the Eniwetok atoll.

Teller’s next intellectual leap occurred in the summer of 1956, when the U.S. Navy was thinking about pulling together the technology of nuclear-powered submarines and ballistic missiles to create a new, invulnerable deterrent. The Navy called a conference at the Nobska light-house facility at Woods Hole, Massachusetts, to discuss all sorts of nuclear and missile technologies. At that time, U.S. intercontinental missiles were undergoing their first flight tests. The Atlas ICBM was a monster. The Soviet R-7, booster for Sputnik, was even bigger. The thought of putting a useful ballistic missile into a submarine seemed ludicrous, but the game was worth the candle. Missiles on submarines would be invulnerable to surprise attack; the nuclear deterrent would be stable in times of crisis.

The size of a missile would be determined by the size of its warhead. On August 12, 1953, the Soviets fired their first H-bomb, known as RDS-6s. As they reported at Dubna, in 1996, that device weighed five tons and gave a yield of 400 kilotons, only 15 to 20 percent of which came from thermonuclear fusion. American technology was a little better, but the first Atlas was designed to deliver a similar five-ton payload. Then, at Nobska, Teller asked the rhetorical question: Why use 1958 technology in a 1965 warhead? He promised that his new Livermore Laboratory could produce a megaton-yield device in a package suitable for delivery by a 30,000 pound rocket. (The Soviet R-7 rocket weighed over 600,000 pounds, twenty times the Teller goal.)

The other weapons experts in attendance were astonished. His companion from Livermore, Johnny Foster, was appalled. No one had a clear idea of how to accomplish such a thing, but Teller had that feel for physics that his peers lacked. The inventive minds at Livermore made good on his promise. Four years later the first Polaris submarine went on combat patrol, armed with a Livermore-designed warhead with a yield substantially greater than the Soviet RDS-6s but weighing very much less. Edward Teller was vindicated; thermonuclear technology had miniaturized warheads.

A quarter century later came Teller’s third leap. He had been thinking about intercepting incoming missile warheads since the late 1950s. By 1982 he shared President Reagan’s desire for some sort of defensive system. Teller’s solution was the X-ray laser, and early experiments had shown some limited success. The idea was to identify attacking missiles as they lifted off, to then fire a specially designed nuclear device in space, focusing the X-ray energy coming out of that device onto the attacking missile half a world away. These ideas were destined to play a significant role in President Reagan’s Strategic Defense Initiative, the trump card in that President’s end game versus the Soviet Union, even though he chose not to pursue Teller’s specific solution.

New ideas were the Teller trademark, and from its inception his new laboratory at Livermore was to work on such potential breakthroughs. In practice, however, it nearly choked on these new ideas. Livermore’s first A-bomb prototype, certainly an unconventional design, was tested, as the Ruth event, in Nevada on March 31, 1953. It was a total disaster, with the shot tower left standing. Livermore’s first thermonuclear, fired as the Koon event at Bikini on April 6, 1954, was similarly unsuccessful. The university leadership understood that in good science some experiments must fail, but the Ruth and Koon shots did inject a note of reality into the new institute’s life. To rescue the laboratory from this wilderness, and to guide its recovery to the sunny uplit highlands of success, the university turned to two very young men: Harold Brown, still in his twenties, and John Foster, then thirty-two.

THE AMERICAN WITH SAFETY ON HIS MIND

Johnny Foster was a teenage radar technician during World War II. He came home from the war, got his B.S. at McGill, then joined the growing firmament of physics stars at the University of California at Berkeley, working in Nobel Prize–winner E. O. Lawrence’s Radiation Laboratory. Foster was awarded his Ph.D. in 1952 and immediately thereafter joined in the formation of the new Livermore Laboratory. During that summer, in the wake of the early Soviet nuclear tests and the ongoing Korean War, American thermonuclear leadership was the nation’s top priority. It was akin to the moon-landing program of the sixties. The country needed a success, and Foster appreciated the opportunity. His technical contributions were substantial from the very beginning, but the force of his personality put Livermore on the map.

In 1956, Foster accompanied Teller to the Navy’s future technology conference at Woods Hole, described above. On July 20, Teller spoke at length. His words astounded all who heard him in that pre-Sputnik era of 1956. Teller foresaw a Navy “which essentially consists of nuclear submarines.” He described Soviet progress in nuclear weapons as “really disquieting.” He saw little military usefulness in multimegaton H-bombs, but he did see an urgent need for a solid-fueled, intermediate-range ballistic missile that could be carried on and fired from a submerged nuclear-powered submarine. As a payload for such a missile, Teller foresaw (or promised) a megaton-class H-bomb, no larger than a small trunk. That was an enormous leap of faith, since the megaton weapons first tested in the Pacific only two years before were the size and weight of railroad cars.

The “customers” in Teller’s audience—that is, the Navy officers— were ecstatic. The “competitors”—the scientists from Los Alamos— were dubious. Johnny Foster from Livermore was startled. Neither he, nor Harold Brown, nor anyone else at Livermore had any clear idea of how to fulfill Teller’s pledge, but they went to work. Five months later, as a result of that meeting and its follow-up studies, Secretary of Defense Charles Wilson initiated the Polaris Submarine Launched Ballistic Missile program. Within a year Foster and his associates created a new approach to the design of primaries, the A-bombs that start the thermonuclear explosions. A version we will call Birdie was fired successfully in the late 1950s as the primary for the Teller-promised warhead. The product of an insightful mind, a dedicated organization, and a sophisticated high-explosive test facility, Birdie was a great breakthrough in many ways. High yield, low weight, and materials efficiency were important, but Foster had another objective in mind.

On an early trip to the Armed Forces Special Weapons Center in Albuquerque, Foster saw a military technician testing the detonators of an early Mark-7 A-bomb with live electrical probes. Mindful of his wartime experiences with the troops, he began to worry. The United States had some very rigid rules and regulations for the care of nuclear weapons, but what if one of those probes had too much voltage? What if somebody dropped one of these things? What if the aircraft carrying one crashed, or burned on the ground? What if a U.S. nuclear storage site in Europe was overrun by bad guys? What if an American officer just lost it and tried to fire his weapon?

There was little interest in these “what ifs” right after World War II. Back then, it was tough enough just getting A-bombs to go off when you wanted them to. In 1950, however, the Korean War broke out and the United States began to change its custodial procedures. A-bombs were released from secure AEC bunkers in New Mexico, to be dispersed and forward deployed with Air Force units around the world. Soon thereafter the accidents started, five of them in 1950 alone. By “accident” I mean a nuclear weapon leaving its aircraft unintentionally, the high explosive inside going off, or a weapon splitting open with radioactive material being dispersed. In fact, there has never been an accidental nuclear detonation of a U.S. weapon, nor has there ever been any nuclear yield as a result of an accident involving a U.S. weapon.

As a result of the accidents of 1950, people began to think about the unique challenges of nuclear safety. On one hand, a nuclear weapon must be absolutely reliable. When the President decides that our nation’s security is so imperiled that nukes must be used, there can be no doubt that they will in fact work as designed. On the other hand, an occasional accidental nuclear explosion is simply out of the question. There can be nothing less than absolute safety (protection against accidental detonation) and security (protection against unauthorized detonation). Yet these design objectives of reliability and safety conflict. At the heart of the problem is the high explosive.

A-bombs work when a charge of high explosive implodes pieces of plutonium or uranium into a supercritical mass, doing so quickly before the multiplying chain reactions can blow the assembly apart. Designers want to use the most powerful explosives, delivering the most energy per unit weight, to minimize the payload the military must carry to target. Such “racehorse” high explosives tend to be temperamental. If dropped or set on fire, they can go off, and such assemblies may not be “one point safe”; that is, if ignition occurs at any one point due to ground impact or a flying fragment, a nuclear yield might result.

As a young physicist reflecting on the accidents of the 1950s, and after seeing the soldier testing the Mark-7 detonators, Foster got serious about safety, feeling it should be designed into weapons, not left to the guards. He started to discuss this problem with the Armed Forces Special Weapons Project, the military agency responsible for nuclear custody. No interest: “Our rules and procedures work just fine.” He thought of some internal design solutions, but they were not of interest to the then-director of Livermore: “Not good physics. It’s a Sandia problem.” The Sandia Laboratories are the part of the weapons complex that makes the fusing and firing sets. Foster started conversations there but soon ran up against the reliability wall. Sandia was managed by Western Electric, at the time the nation’s principal supplier of telephone equipment. Sandia knew all about the reliability of switches. Their engineers were appalled at the thought of putting switches, intended to work without fail for decades, inside metal cans to be welded shut.

But time was working in Foster’s favor. In 1956 he was appointed to run B Division, the part of Livermore that designs atomic bombs and primaries for thermonuclear bombs. By 1958 he had designed safety into his Birdie device. He thought it would be one point safe, but with his increased stature, Foster now began to cajole his physics and electronics associates into other safety measures.

Some were smart electronics, like putting an electronic map inside the bomb case, thus precluding an arming sequence unless the weapon is outside U.S. boundaries. Another solution was the introduction of insensitive high explosive, a material with less bang per pound, but immune to detonation by flying fragments or fires. A third approach became known as “permissive action links,” or PALs. These are a family of devices and circuits that preclude a nuclear weapon from arming itself unless some outside information is inserted, information held only by the President and his designated successors.

In 1961, after earlier directors Herb York and Harold Brown had departed Livermore to serve in the Pentagon, Foster became director of the Lawrence Livermore Laboratory. He pursued all of these approaches to safety. They came to fruition in early 1962.

On September 1, 1961, the Soviet Union unilaterally and with a big bang breached the nuclear testing moratorium in effect since 1958. President Kennedy immediately authorized the resumption of underground testing, and in early 1962 approved an atmospheric test series in the Pacific, to be known as Operation Dominic. On March 23, 1962, Kennedy came to visit the Berkeley lab, to tell the physicists of his decisions and to deliver a pep talk. Kennedy would stand behind the weaponeers and take the political heat, but he expected a lot of hard and productive work in exchange. At that meeting, Foster got to show Kennedy one of his prototype PAL devices. The President liked the concept and soon afterward directed its orderly introduction into all U.S. nuclear weapon systems.

Since 1980 there have been no nuclear accidents of any sort in the U.S. inventory. Birdie technology is the basis for all Livermore-designed weapons and most Los Alamos weapons in the stockpile.

THE WEST POINTER

Carl Haussmann was a graduate of the U.S. Military Academy at West Point. He entered the Academy during World War II, mindful of the slaughter of innocents that can occur when their governments do not tend to their basic responsibilities. He graduated from West Point in 1946, now mindful of and comfortable with his commitment to duty, honor, and country. The Army recognized young Haussmann’s talents, sending him on to earn a graduate degree in physics from Penn State and earmarking him for responsibilities in the new atomic Army. He was sent to a six-month nuclear weapons course at the Special Weapons Center in Albuquerque, spent a few weeks at Los Alamos, then was sent off to babysit nuclear weapons in the U.S. stockpile. In the early 1950s the United States had only a few hundred atomic bombs. Their assembly was complicated, and they were stored in the disassembled mode for reasons of safety. But Lieutenant Haussmann’s quiet life did not last long. A West Point classmate already was involved in the very secret Project Matterhorn at Princeton.

With President Truman’s 1950 decision to proceed with the H-bomb, John Wheeler, a preeminent physicist in the wartime A-bomb project, was asked to oversee the thermonuclear burn calculations for the new weapons. He accepted, but he would not return to Los Alamos to do that work, so the AEC set up a laboratory around him at his then-current academic home, Princeton University. Thus the Matterhorn complex was born, and by the fall of 1951, Wheeler had attracted some bright young stars to its galaxy. Carl Haussmann was one of them. A secondary reason for locating the new lab at Princeton was the proximity of the Sperry Rand Univac facility in nearby Philadelphia. Calculating the conditions for successful thermonuclear ignition are quite complex, and unlike Johnny Foster’s Birdie, H-bombs cannot be designed by small-scale experiment. Only gedanken, or thought-experiments, are possible, and they require extensive computational support.

In 1951 it became possible to do these calculations on the new computers under development in Philadelphia. In Moscow it was being done by acres of ladies punching desk calculators. America’s brand-new Univac computers used vacuum tubes rather that mechanical relays. As they were being assembled, Carl Haussmann and the Matterhorn staff were writing the computational codes to make them run. There was no time even to move the machines off the factory floor for shipment to Princeton. The Univac machines that helped design the first H-bomb could remember only a few kilobits of information, and they could process it with clock speeds of only a few hundred instructions per second. It would have taken ten thousand Univacs to compete with a single Cray I machine twenty years later, but they did the job. The Mike device worked; the thermonuclear era began.

After that, Matterhorn’s bomb work began to close down. Much of it was taken over by the new lab at Livermore. Those remaining at Princeton turned their attention to the possibilities of controlled thermonuclear reactions as a source of commercial energy. In 1953, Haussmann resigned from the Army and moved to the new laboratory at Livermore. He brought with him the Matterhorn computer codes and a sense of urgency. All around the world challenges to democracy were growing more worrisome. In March 1953 he began work on Harold Brown’s thermonuclear team. He ran calculations for Brown on Livermore’s new IBM 701 computer, the first fully electronic machine. It ran twelve times faster than Univac. In the summer of 1954, Haussmann spent time in the Pacific during the nuclear tests there. At home he pushed for the development and acquisition of still bigger and faster computers. He started to do design work on the new machines, and within a few years became Brown’s deputy leader of A Division. At the time, both men were still in their twenties. By the spring of 1958, Haussmann was working on his end of Teller’s bargain with the Navy, preparing several alternative devices for test during the summer.

At the same time, the wise men in Washington came up with another in a long chain of “good ideas.” This one was to be the “gentlemen’s agreement” described in earlier chapters. The Soviet Union promised to discontinue all nuclear testing, without verification or enforcement. To most of us, the phrase “trusting the Russians” was an oxymoron; to the wise men it seemed like a good idea, a “step toward peace.” This moratorium was to start at midnight on October 31, 1958.

Haussmann thought about the devices planned for test before then. He felt the lab could do better, that it must do better in the face of the coming moratorium. During April 1958 a new approach took shape, and during the first week of May, Haussmann, Brown, and a handful of others started work on a new approach to thermonuclears. Working feverishly with the new all-transistorized IBM 709 computers, the Haussmann group, their supporting engineers, and their machinists conceived, gestated, and delivered a brand-new device in only twelve weeks.

When their device was tested in the Pacific it gave twice the expected yield. When Harold Brown moved on to management of the whole laboratory in 1959, Haussmann became the leader of A Division. His major challenge was to exploit the new technology, but without the benefit of nuclear tests. His role in my life was to be at the right place, at the right time, to invite me to join A Division.

THE FARM BOY FROM ILLINOIS

John Nuckolls’s love of explosives may have been hereditary. His father was an explosives expert who worked for the Underwriter’s Laboratory. He had attended nuclear physics courses at the University of Chicago and built a library on that subject that would entrance his son. On the Illinois farm where the Nuckolls family lived, young John entertained himself with those books in the evening. In 1948, as a high school junior, he entered the Westinghouse Science Talent Search. Having read the 1945 Smyth Report, Atomic Energy for Military Purposes, his entry in the contest was an H-bomb design. It wasn’t very good and would not have worked, but even then that put him on a par with Edward Teller; in 1948, Teller had not figured out how to build an H-bomb either.

At Wheaton College, in Illinois, Nuckolls majored in physics. He became known as “Atom Bomb Nuckolls.” He built rockets too, not all of which worked. One launch failure caused shrapnel to hit his shoulder. The faculty was proud of him, although they considered him “unusual.” In 1953, Nuckolls graduated from Wheaton and entered graduate school in the physics department of Columbia University. It was a prestigious department, with some of the brightest minds of nuclear physics on the faculty, such as I. I. Rabi, who was awarded the Nobel Prize for physics in 1944 for his prewar work on magnetic resonance. Rabi had spent the early war years at MIT developing radar, then moved to Los Alamos. After the war, he came to Columbia to build a world-class physics department. During that time, he was appointed to the General Advisory Committee of the Atomic Energy Commission, with service as its chairman starting in 1953. He opposed development of the H-bomb in 1949. Robert Serber was another of the Columbia stars. He was a wartime veteran of Los Alamos, author of The Los Alamos Primer,a then-secret booklet printed in April 1943 to supplement his orientation lectures on nuclear matters to the new arrivals. When the war was over, Serber joined the exodus to Columbia. In time he served as president of the American Physical Society. He also had opposed development of the H-bomb.

These men may have been famous, but they were too rigid for Nuckolls. Within a year of entering Columbia, he was locked in serious battles with his elders over the matter of quantum mechanics, a theory he found insufficient to explain the results of some of the classic physics experiments. He agreed with Einstein: “God does not play dice.” As a boy, Nuckolls had read of Hitler’s atrocities. Now, in the 1950s, he was hearing about similar horrors in Stalin’s Gulags and Mao’s communes. He was alarmed by the first Soviet nuclear test but took comfort in the American responses. In the distance he heard (figuratively) the rumble of H-bombs going off in the Pacific. He felt it was time to take action, not to argue further with the Columbia faculty.

In February 1955, Nuckolls saw a recruiting advertisement for the University of California’s new Livermore Laboratory. Following its early exploits with great interest, he applied, hoping to find a home more tolerant (and appreciative) of his creative talents. At his interview with the Livermore recruiter, Nuckolls was asked if he “liked to calculate.” The implication was mechanical adding machines with shift registers. Livermore offered Nuckolls a job. In June 1955 he called it quits at Columbia, accepted a master’s degree, and headed west, joining the enormous technoimmigration into California that was remaking that state. The result was a boom that no one then understood, but it was enormously good fun. Those bright young men and women of the fifties left behind what they felt to be the intellectual dust bowl of postwar America to head for the promised land. When he got there, Nuckolls was on the first team, finally designing real H-bombs.

He went to work for another genius and another recent Columbia graduate. Harold Brown had received his Ph.D. in physics there in 1950, at the age of twenty-one, and started work at Livermore shortly thereafter. Now, at the ripe old age of twenty-eight, Brown was running the thermonuclear design division. He became the director of Livermore in 1960, then went on to an illustrious career in Washington. He became President Kennedy’s Director of Defense Research and Engineering, President Johnson’s Secretary of the Air Force, and President Carter’s Secretary of Defense. But in the summer of 1955, Brown needed a helper to run design calculations.

As real computers began to appear, Nuckolls began to develop codes to run on them. He developed an early one-dimensional hydrodynamic code and, in response to Sputnik, an early code to calculate satellite orbits and to predict their decay. Harold Brown was drawn to those with imagination and intellectual curiosity. He asked Nuckolls to critique the Van Dorn cannon. In response to the Soviet launch of Sputnik, a University of California professor named Van Dorn had come up with a bizarre scheme: a nuclear detonation that might drive a thousand-ton payload up a one mile tunnel and out into orbit. It never got off the ground.

Three years after Nuckolls’s arrival at Livermore, the U.S. entered into the ill-considered nuclear testing moratorium. Haussmann and others were caught up in the intricate physics of weapons design and their associated engineering problems—how to meet Teller’s full commitment to the Navy without further tests—but Nuckolls was thinking about the fundamentals. To him the basic question was how to compress thermonuclear fuel to high densities. When the Soviet Union unilaterally, and by total surprise, broke the moratorium on September 1, 1961, Nuckolls’s mind was a fertile source of new ideas.

WHAT SORT OF PERSON IS A BOMB DESIGNER?

At Arzamas-16, in the Soviet Union, and at Los Alamos in the United States, the design of nuclear weapons started out as a top-down process. The leaders were serious, senior people with world-class reputations as physicists. They spent their lives measuring nuclear cross sections or developing equations of state. ³⁰ Under their guidance, mathematicians use such equations of state to calculate implosions or use cross sections to calculate the burn efficiency of thermonuclear fuel. Only at the bottom of this pyramid would one find the designers, often designated “engineers,” who actually laid out the designs of things to be built based on these scholarly calculations.

The Lawrence Livermore Laboratory was different. When it was founded in 1952, large-scale computers also were being born. These new machines would allow imaginative leaders like Brown and Haussmann to reallocate the skills of the scientific staff. The theoreticians and mathematicians were put to work building computer codes, not bombs. Their mathematical recipes would calculate and graphically display the inner workings of a thermonuclear device. These codes had names like Proteus, Egg, Coronet, and Ghoti. The latter was pronounced “fish,” taken from an observation by George Bernard Shaw that the English language can be mystical: Gh as in “enough,” o as in “women,” and ti as in “nation.” The targets of this joke were the computer operators. The codes were user-friendly, at least by the standards of the 1960s. A thermonuclear device designer needed only input geometry and some initial conditions. The codes and the computers would calculate the consequences, the flow of energy or matter over time. In that world, time is measured in nanoseconds, not minutes, since a thermonuclear capsule will complete its implosion and burn within a few hundred nanoseconds. There are a billion nanoseconds in a heartbeat.

Assigning the best physics and mathematics minds to the creation of computer codes led to the creation of a new class of “user” physicist at Livermore. Creative young men and women now could bring their talents to bear on new design concepts without going through all of the equations. Their elders had set them free. These young people with the energy to try new ideas—youngsters lacking the “experience” to “know” that certain things could not be done—set about doing them. They became known as “designers.” They had inquiring minds, a creative flair, a good feel for hydrodynamics, and an adequate understanding of the other physical phenomena that take place in a thermonuclear device. They had graduate degrees of some sort in physics, but they were not potential Nobel laureates. They were practical, focused, driven, and creative people.

Rather than calling them “designers,” John Nuckolls likes the word “explorers.” Like Columbus, these people boarded ships built by others to look for new worlds. The explorers of five centuries ago, Columbus and Magellan, needed to understand how the wind would fill their sails, how moving ballast could destabilize their ships, and how to read instruments like barometers, sextants, compasses, and clocks. But they did not need to know how the clocks and barometers worked. Their job was to find new worlds. To get there, they needed good boats plus vision, courage, and stamina. Those explorers of the sixteenth century boarded their ships (today we would say “entered their data”) and set sail across unknown waters (“uncharted cyberspace”) to seek new worlds.

In the mid-twentieth century the nuclear designers/explorers could cast their eyes to the far horizons of technology. They could sail wherever they wanted aboard their computational cyberships, asking “what if” in ways the old-time physicists could only dream about. How lucky I was, at the age of twenty-seven, to be given command of one of those cyberships.

COMING INTO SAN FRANCISCO

As 1959 began to unfold, I was still stationed at the Air Force Ballistic Missile Division in Los Angeles. I became an expert on missile reentry vehicles, but with my first trip to Albuquerque, I was becoming our expert on nuclear weapons as well. I was granted the clearances needed to understand the difficult choice that lay ahead for the Minuteman program office and ultimately the U.S. Air Force: Should we design our new systems with tested and known nuclear warheads, or should we gamble on a scale-up of the new technology for twice the yield? The payoff from a doubled yield could be significant. A better assurance that those early, less accurate missiles could destroy their intended targets could in turn cut the size of the needed missile force. That would have a significant impact on the defense budget. There also were tradeoffs in weight, diameter, and center of gravity—all important to the aerodynamicists. There were issues of maintainability, reliability, and cost. And then there was the ultimate bet-your-country issue. Will they work?

It became a fascinating niche. Once I understood the technology, once I had read the top secret files, I would spend much of early 1959 explaining these issues to the program managers, briefing the Office of the Secretary of Defense, and meeting with our British cousins to compare notes. Best of all, my charter as BMD’s warhead expert regularly took me to the heart of the American nuclear weapons complex, the laboratories at Livermore, Los Alamos, and Sandia.

My first trip to Livermore occurred on January 27, 1959. Four of us, military officers and our technical advisers, went there to talk about both Titan and Minuteman warheads. The visit lit up my life, for on that day the name “Livermore” took on substance. The easy informality of a university environment, the intellectual firepower seated around the table, the hearty disdain for any claims not based on provable fact, the evident power of the new transistor-driven computers—all combined to make me want more.

Or was it the Irish coffee at the Buena Vista? Nuclear weapons are serious things, but let’s be honest, one cannot write about a young lieutenant’s first exposure to San Francisco in the fifties and stay serious. Cheap food? The Spaghetti Factory. Nocturnal coffee? The Vesuvio in North Beach, with “beatnik costumes” (shaggy wigs) to help young officers fit in. Music? The Hungry i, the Purple Onion, and best of all, the Red Garter, where young officers en route to the Pacific could stop in, uniforms on, to sing their service hymns along with the banjo band. The night air of San Francisco and the daytime brilliance of Livermore captured my heart, like the song says.

In September the Secretary of Defense made the hard choices in selecting a warhead for Minuteman. These events set my mind to thinking about the future. During one fall visit to Livermore it all came together. I was seated next to Carl Haussmann, the new A Division leader. I mentioned the end of my obligated tour at BMD; two days later he was on the phone with a job offer. Not just any job, but a chance to come do design work with the big boys in Livermore’s A Division. I couldn’t have been happier. I finished my work at BMD; on November 15, 1959, I departed Los Angeles and headed north. Starting serious work at Livermore after the holidays, I was assigned to the group that had designed the wonder experiment of 1958, the shot that had given twice the calculated yield for no apparent reason. After a short course on thermonuclears, learned from written memoranda in the files, I was put to work.

I was to recalculate the performance of the device using the new two-dimensional codes and the all-transistorized IBM 709s. It would be an attempt to replicate that astonishing yield as well as all the other observables: transit time, radiochemistry, and electromagnetic signals. Calculating the two-dimensional transfer of energy, neutrons, and hydrodynamic forces from the primary had been barely feasible with the 1958 codes. Now things were different. We could develop a first-class computational model of what went on in that device during the few nanoseconds of its active life.

I spent January 1960 collecting data on exactly what was shot and what was observed. In February, I laid out the geometry in what is known as a LaGrangian grid, suitable for computation. The process was done by hand, onto input sheets, which were then transferred to punch cards. In March the Brits came to town to take a look at my calculations to offer some advice. The two-dimensional radiation and hydrodynamic calculations were to be run on the new IBM 709 machines. Each run would take a day and a half of computer time, so they were scheduled for weekends, when shorter production runs were out of the way. In April the first runs started and I was exposed to the twenty-four-hour life of a weapons lab. The designers knew they should drop in every few hours to see if their calculations were running smoothly or to make repairs if they were not, and so I did. During May we calculated the flow of neutrons out of an exploding primary using a Monte Carlo type code and megadoses of computer time. I then inserted those results back into the basic model for another 2-D calculation. It ran for thirty-eight hours on a 709 available over the weekend at Newport Beach. By late May we had good solid calculations on how matter and energy emerged from the primary and impacted the secondary. Now it was time for two-dimensional implosion calculations.

June was dedicated to writing the input for the 2-D hydrodynamic code. More hours on the 709, but while it was running I also was becoming a serious player in the warhead design world. In mid-June there was a review of possible new Minuteman warheads. Livermore, Los Alamos, and the British Atomic Weapons Research Establishment people were there. So were the careful thinkers from RAND and a knowledgeable chairman, Mike May, later to become lab director. This review put me on the same podium as my earlier hero, Jack Rosengren. He talked about the Minuteman program; I reported on the efforts to understand the surprise test of 1958. It was a serious, major-league oral exam. I seem to have survived, in the process earning accreditation among my peers.

By the end of June the hydro implosion calculations were complete. It was time to calculate the burn of the thermonuclear fuel. There was a wonderful new machine for this work, IBM’s 7090, still another order of magnitude faster than the 709s they replaced. The 7090 would only run for ten to fifteen minutes before crashing, but those were impressive minutes. A month was consumed in getting the burn code to run on the 7090 and then in doing my calculations, but by the end of the month they were done. The calculated results were beginning to match the observed values.

In the fall of 1960, I was a speaker at A Division seminars, at the Naval Ordnance Lab, and at other nuclear weapons forums, explaining my findings. An assistant, Dobree Adams, helped with final computations and wrote up the results. Another assistant helped in the design of spin-offs for other military systems. The calculations were essentially complete; they had taken almost a year of manual inputs, computer time, laborious hand-plotting of results, and recycling to recover from mistakes. Today those calculations would take only a few minutes on the lab’s mainframe computer, less than an hour on a stand-alone PC anywhere in the world.

In March 1961, I signed off on a final report. The bottom line: with the correct initial conditions, opacities, cross sections, and mixing, one could correctly reproduce the observables if one used the new, two-dimensional codes to calculate events during those nanoseconds of the device’s active life. I gave a full seminar to the laboratory, and a week later my bosses reported a flood of compliments from our peers.

My mind was no longer on 1958, however. In January 1961, as I was assembling a final report on that device, it came to me. Certain things had happened that made it work surprisingly well; they could be used on a whole new family of devices. Those insights led to a flurry of calculations, a few papers, some conversations with John Nuckolls, and a new device name. Let’s call it Oso. During April the verbs in my memoranda on this concept shifted from “should” to “will” work.

On May 4, 1961, A Division held a seminar on prospects for the high compression of thermonuclear fuel. There were two speakers. One was future director John Nuckolls; his topic was “Wild Ideas.” I was the other speaker; my topic was Oso. The problem was that any such new design would require nuclear testing. No such testing was allowed in the spring of 1961, nor was there any prospect of tests in the future. Thus there was no prospect of trying any of this out.

As a further distraction, the Kennedy years had begun. In his campaign and in his inaugural remarks a few months before, the new President had offered vistas of a New Frontier. In that spirit, it seemed time to move on to other scientific worlds still open to experiment. I turned to work on magnetohydrodynamic generators (don’t ask) at the Avco Everett Research Laboratory near Boston. My family was from New England, so it seemed like a good idea. I wrote up a final report on Oso, signed on as a continuing consultant to Livermore, and moved East. What a ridiculous idea that was.