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4 The Scout Family of Space-Launch Vehicles, 1956–1990 The Scout series of launch vehicles was unique in American experience in several ways. It was the first multistage booster to operate exclusively with solid-propellant motors. It remained the smallest multistage vehicle in longterm use for orbital launches. And it was the only launch vehicle developed under the auspices of Langley Research Center, which made many contributions to space efforts but, as the oldest of NASA’s component organizations, had a long heritage of aeronautical effort that predated its space-related research . Like the Delta, with which it shared many stages, Scout proved to be both long-lasting and reliable. But in contrast with the Delta, it suffered through a difficult gestation and early childhood.1 Since, like Delta, Scout used much technology that had been developed elsewhere, it encountered fewer design and development difficulties than did many other rockets, although there were several. But Scout’s major problems were primarily matters of systems engineering and quality control. Following a string of early failures, the program underwent a reliability-improvement and recertification process, after which one Scout engineer stated that he and his colleagues had “all underestimated the magnitude of the job” when they undertook the vehicle’s development. “The biggest problem we had was denying the existence of problems that we did not understand.” Once the project accepted that it had these problems and examined them, it learned from the process and went on to produce a long-lived, reliable small launcher used by NASA, the Department of Defense, and foreign countries. Its payload capability increased almost fourfold by its final flight in 1994. By that time, it had launched a great variety of scientific and applications payloads , Transit navigation satellites, and experiments to help understand the aerodynamics of reentry, among other types of missions. Counting partial successes as failures, by one account Scout had 104 successful missions out U.S. Space-Launch Vehicle Technology 128 of 125, for an overall 83 percent success rate. The 21 failures were mostly in the early years, however, with 15 of them occurring by June 1964. In the 91 missions since that time, only 6 failures or partial failures occurred, for a 93 percent success rate. But accounts differ and do not seem to be fully reconcilable . Thus, these figures give only an approximate tally.2 Scout operated beyond the end of the period covered by this history, but even before its last flight, a comparatively new company, Orbital Sciences Corporation, had teamed with Hercules Aerospace to develop a new launch vehicle, Pegasus, whose first flight occurred in 1990. Since Pegasus was in some sense a follow-on to Scout, even though it was not part of the Scout family of launch vehicles, a postscript to this chapter discusses the new multistage rocket. Conception and Early Development During 1956, Scout had its origins in the imaginations of a creative group of engineers at Langley’s Pilotless Aircraft Research Division (PARD) on remote Wallops Island in the Atlantic Ocean off Virginia’s Eastern Shore. This group included Maxime A. Faget, later famous as a spacecraft designer; Joseph G. “Guy” Thibodaux Jr., who promoted the spherical design of some rocket and spacecraft motors beginning in 1955; Robert O. Piland, who put together the first multistage rocket to reach the speed of Mach 10; and William E. Stoney Jr., who became the first head of the group responsible for developing Scout, which he also christened. Wallops, established as a test base for Langley in 1945, had a history of using rockets, either individually or in stages, to gather data on both aircraft models and nose cones of rockets at transonic, supersonic, and then hypersonic speeds. Such data made it possible to design supersonic aircraft and hypersonic missiles at a time when ground facilities were not yet capable of providing comparable information . It was a natural step for engineers working in such a program to conceive a multistage, hypersonic, solid-propellant rocket that could reach orbital speeds.3 In 1957, after a five-stage vehicle at Wallops had reached a velocity of Mach 15, PARD engineers including Thibodaux, Faget, Piland, and Stoney began to study in earnest how to extend the speed of solid-propellant combinations still further. The group learned that Aerojet had developed the largest solid-propellant motor then in existence as part of its effort to convert the Jupiter to a solid-propellant missile for use aboard ship. Called the Jupiter Senior...

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