An Untaken Road. Steven A. Pomeroy
required a very substantial ground installation which was highly vulnerable and we wanted to get rid of that as soon as we could.”35
The distance between a missile warhead and its target at impact measures the accuracy of the ICBM’s guidance. “Circular error probable” (CEP) is the unit of measurement. CEP is “the radius of the circle around the target within which fifty-percent of the warheads will fall in repeated firings.” The definition is somewhat disputed, and in another view CEP is “the distance from a target in which there is a fifty-percent chance of a warhead directed at that target exploding.” This accuracy does not ensure target destruction. That depends upon the ability, or hardness, of a target to resist a nuclear detonation and its associated effects, as well as the effectiveness of any in-place defenses, weather, and geography. Any unit of distance measurement applies to CEP, but the nautical mile measured early ICBM CEPs (a nautical mile equates to 6,076 feet). As accuracy improved, feet measured CEP. A smaller CEP indicates better accuracy than a large CEP. By the 1980s, ICBM CEPs measured in the low hundreds of feet.36
Propulsion challenged engineers. A rocket’s forward energy depends upon combusting oxidizer and fuel to generate an opposing reaction. The earliest method of energizing large missiles involved liquid fuels and oxidizers. The American ICBMs of the Atlas and Titan I types, as well as the Soviet R-7 that orbited Sputnik, used liquid oxygen for the oxidizer and a form of kerosene the Americans called Rocket Propellant 1 (RP-1) as fuel.37 Although RP-1 alone posed no difficult problems, the safe handling, operation, and integration of the two liquids into an operational weapon system was dangerous. Also difficult was developing technology that could feed oxidizer and fuel at high enough volumes, pressures, and speeds to support the combustion needed for thrust. Liquid oxygen could not indefinitely remain on board a rocket, because it boiled away and required continual refills. Such a system was unwieldy if one wanted to remain indefinitely in a launch configuration.
The introduction of storable oxidizers and liquids, which can remain on board the rocket for indefinite periods, overcame this limitation. The American Titan II, introduced to the operational inventory in 1963, used hydrazine, specifically Aerozine-50 (A-50, a mixture of hydrazine and unsymmetrical dimethylhydrazine, or UDMH) as the fuel and nitrogen tetroxide (N2O4) as the oxidizer. The two materials, known as “hypergolics,” caused a thrust-generating explosion when combined, but if kept apart until launch they were suitable for long-term storage on a rocket. Handlers learned special handling and safety precautions. Small mistakes caused accidents. On September 19, 1980, a Titan II developed a leak and blew up in its underground launch facility near Little Rock, Arkansas. One service member died, twenty-one others were injured, and the explosion blew the nine-megaton warhead more than two hundred yards into a field. Ultimately, the Air Force ceased further development of liquid-fueled ICBMs in favor of solid fuels, although because of its target-killing power, the liquid-fueled Titan II remained in the ICBM inventory until 1987.38
The military used solid-fuel rockets during World War II, notably to aid the takeoff of heavily loaded aircraft. Solid fuel’s advantage was that the rocket came to the launch site loaded with fuel and oxidizer. The manufacturer mixed, poured, and cast these as one mixture within the missile motor or stage casing. Missile operation, handling, and maintenance were simplified in comparison to working with liquids. The design improved reaction time, because there was no need to wait for fuel and oxidizer loading. The solid-fuel missile was easier to transport. It was smaller, lighter, and required fewer people to operate and maintain. Because the propulsion system did not have complex tanks, valves, pumps, and piping, it had greater reliability. Solids eliminated the problems associated with toxic substances such as N2O4 or A-50 (unless these hypergolics were used in a small maneuvering platform, or bus, placed on top of the missile). There was another problem, however. Solid fuel has a built-in oxidizer. Once ignited, there is no way to stop combustion, even if placed under water. Nevertheless, as ICBMs developed, the Navy and the Air Force adapted solid-fuel technology for operational use.39
An Innovative Mental Architecture
Small fusion weapons and reliable long-range rockets, for which improvements in guidance and propulsion were critical, catalyzed the ICBM’s technical development. In June 1953, Secretary of Defense Charlie Wilson responded to President Eisenhower’s desire to reduce spending via the New Look. At the time, the cruise missiles showed poor results, despite generous funding. Wilson directed Secretary of the Air Force Harold E. Talbott to form a committee to compare and analyze all guided missiles. Talbott looked for a leader to do this job, and he chose wisely. He anointed Trevor Gardner, his assistant for research and development. Gen. Jimmy Doolittle, a giant of American aerospace, described Gardner as a “sparkplug,” a man of action uninterested in roles-and-missions controversies. Gardner focused on missile performance and program improvement by pursuing promising technologies, standardization of production, and elimination of waste. He cared little for making friends, a trait that led some to describe him as “sharp, abrupt, irascible, cold, unpleasant, and a bastard.” Not a cruise-missile advocate, he favored ballistic missiles, and he reformed the American ICBM effort into an effective crash program. Historian Beard adds that Gardner, a thirty-seven-year-old civilian, was not only “suddenly giving orders to . . . general officers . . . on how to run the Air Force, but [his orders] were also contrary to the way the Air Force had been operating.” Gardner won few friends, but he did the job. Top-down direction provided a new sense of urgency to develop ICBMs.40
When Lewis Mumford wrote that the military possessed “third-rate minds” (see chapter 1), he could not have foreseen the ICBM program. The crème de la crème of academe, industry, and government participated. Concurrent with Secretary Wilson’s committee, the Air Force formed a nuclear weapons panel to assist its Scientific Advisory Board to learn how to adapt fusion weapons to missiles. Jimmy Doolittle convinced the omnipresent and omniscient Princeton mathematician John von Neumann to lead it. By June 1953, von Neumann’s panel was discussing new weapons “expected to weigh approximately 3,000 pounds, measure 45 inches in diameter, and yield 0.5 MT [megatons].”41 Rapid development followed, and by September the Air Force Special Weapons Center believed it could produce a warhead weighing as little as 1,500 pounds. A Research and Development Corporation (RAND, the Air Force’s “think tank”) memorandum dated February 8, 1954, supported this conclusion, stating, “It should be possible to produce in much smaller weights than was considered possible in the past. It is expected that we will get these weapons to weigh 3,000 lbs and probably even somewhat less.”42 These developments occurred within ten years, a dizzying pace of change. Such weight reductions meant payload-carrying rockets could be smaller than had been thought.
Important as this was, a long-range rocket to deliver the payload had yet to fly. In 1954, ten years after Hap Arnold first asked von Karman to study Axis technology, Gardner convinced von Neumann to chair another remarkable working group, the Teapot Committee. This assembled the ICBM’s major players, among them Air Force brigadier general–select Bernard A. Schriever, a disciple of Hap Arnold and a man sharing Gardner’s vision. No single innovator creates a technological innovation, but as a touchstone of space and missile technologies, Bernard Schriever did as much as anyone to create American space and missile power. His name should be as well known to Americans as is that of Wernher von Braun. One cannot reasonably compare such titans—the exercise is pointless. Today, Schriever’s infrastructure, weapons, and rockets still serve. His ICBMs and intermediate-range ballistic missiles formed the basis of American space launch for decades, orbiting the Mercury and