The Scout Family of Space-Launch Vehicles, 1958-91

With its development overlapping that of Atlas and other launch ve­hicles, the Scout series of boosters was unique in being the first mul­tistage booster to operate exclusively with solid-propellant motors. It remained the smallest multistage vehicle in long-term 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 rather than space – related research. Like the Delta, with which it shared many stages, Scout proved to be long-lasting and reliable. But in contrast with Delta, it suffered through a difficult gestation and childhood.55

Because, like Delta, it used much technology that had already been developed elsewhere, Scout’s problems lay less in the design – and-development area than was true with many other rockets, al­though there were several developmental difficulties. But Scout’s problems were primarily matters of systems engineering and quality control. Following a series 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 had undertaken its development. “The biggest problem we had was denying the ex­istence of problems that we did not understand." Once the project accepted that it had such problems and examined them, it learned from the process and went on to produce a long-lived, reliable, small launcher used by NASA, the DoD, and foreign countries.

Scout’s payload capability increased almost fourfold by its fi­nal flight in 1994. At 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 two partial successes as failures, Scout had 103 successful missions out of 118 for an overall 70 8 7 percent success rate, according to one source. The 15 failures

Chapter 2 were mostly in the early years, with 12 of them occurring by June 1964. In the 91 missions since that time, only 6 failures or partial failures occurred for a 94 percent success rate.56

During 1956, the idea for Scout arose at Langley’s Pilotless Air­craft Research Division (PARD) on remote Wallops Island in the At­lantic Ocean off Virginia’s Eastern Shore. There, several engineers conceived of a four-stage solid-propellant launch vehicle. Between July 1, 1960, and March 29, 1962, Scout had nine developmental flights from Wallops, with six of them counted as successes. Several

FIG. 2.9

Launch of Scout ST-5 (Scout Test 5) on June 30, 1961, from Wallops Island, Virginia—a failure because the third stage of the Scout did not ignite, which prevented the satellite from going into orbit. (Photo courtesy of NASA)

Blue Scout Junior. All of them used the Castor I (the regular Scout second-stage motor) in place of the usual Algol I in the first stage, and the Antares I (the regular Scout third-stage motor) in the sec­ond stage. The third stage used the Aerojet 30-KS-8000 motor, also known as Alcor. The motor for the fourth stage of most Blue Scout Juniors was a unit designed by the Naval Ordnance Test Station, known as NOTS model 100A. The B version of the same motor later became the fifth-stage propulsion unit for NASA Scouts using that many stages.58

The first Blue Scout Junior launched on September 21, 1960, be­fore the fourth-stage motor’s development was complete, but ap­parently the vehicle did use a NOTS 100A. In all, there were 25 known Blue Scout Junior launches from Cape Canaveral, Vanden – berg (or the navy’s nearby Point Arguello), and Wallops Island, with the last one on November 24, 1970. All were suborbital, 22 of them successful, for an 88 percent success rate, although the telemetry and payloads sometimes failed. The configurations of the vehicles varied, depending on the mission, with some launches using only three stages and a supersonic combustion ramjet test employing only one.59

The Blue Scout 1 was a three-stage version of the Scout. Its first (successful) launch occurred at Cape Canaveral on January 7, 1961. Blue Scout 2 was a four-stage vehicle. Most sources list only three flights in 1961. But other sources continue to list launch vehicles as Blue Scouts, so the precise history of the vehicle is quite nebu­lous. The navy procured some of them at least as late as fiscal year 1967, and the air force, until fiscal year 1976. Of the first 92 Scouts, NASA paid for 54; the navy, 19; and the air force, 14, with the other 5 being funded by the Atomic Energy Commission or European us­ers. Whereas earlier Blue Scout vehicles had been launched by uni­formed (“blue suit") air force personnel, on January 10, 1970, an agreement between NASA and the DoD stated that NASA would contract for Scout launches from Vandenberg AFB for both itself 72 and the DoD. Thus, it appears that there was a gradual blurring of Chapter 2 the lines between Blue and NASA Scouts. But whichever they were called, they continued to perform launch services for the armed forces as well as the civilian space agency.60

Meanwhile, a number of Scout failures in the early years led in 1963 to a major review of the program. This revealed that no two Scout failures had been caused by the same problem. But the large number of failures, including many recent ones, suggested a need for greater procedural consistency and for requalifying all Scout vehicles then in storage awaiting launch. As Eugene Schult, head

of the Langley Scout Project Office in 1990, remembered, “We did things differently at Wallops than at the Western Test Range. The Air Force had its own way of doing things; the contractor had his ways; and we had our ways. It was a problem trying to coordinate them."61

To address these problems, a team from NASA, the LTV Missile Group of the Chance Vought Corporation (the airframe and prime contractor for Scout), and the air force initiated procedures that brought the manufacturing and launch teams in closer contact to improve coordination and quality control. (Obviously, this entailed exchange of information as well.) In addition, all 27 existing Scout vehicles went back to the LTV plant for disassembly and X-ray or microscope inspection. Standardization became the order of the day. The first recertified Scout, S-122R, with the R indicating that it had been refurbished and recertified, launched from Vandenberg December 19, 1963. It was the beginning of a series of 26 launches through October 1966 with only 1 failure, for a 96 percent success rate.62 Standardization and quality control had greatly improved re­liability, showing the value of improved management and better systems engineering.

In this period and after, Scout continued to develop, with new stages replacing those already in use. These changes increased the payload and other capabilities of the Scout system. Beginning on April 26, 1967, Scout also began launching (under agreement with Italy) from the San Marcos platform off the coast of Kenya, Africa, on the equator. From there, Scout could place satellites into orbits not achievable by launches from Cape Canaveral, let alone Wallops and Vandenberg, the three U. S. launch sites for the vehicle. As a re­sult of a long series of improvements, the payload capacity of Scout increased from only 131 pounds into a 300-mile circular orbit for the original Scout in 1960 to 454 pounds by October 30, 1979. The Scout continued in operation through August 5, 1994, with all of the remaining launches using this last (G-1) configuration.63

Operating for nearly three and a half decades, Scout obviously was successful. Neither its payload capacity nor reliability matched those of the Delta. But it filled a niche in the launch-vehicle spec­trum, or it would not have lasted so long. In the process, it had to overcome some initial growing pains. Many of its motors and other components experienced developmental problems, including the Castor I, Antares I, and Altair II, as well as heat shields, a fourth – stage frangible diaphragm, and the nozzles on the Algol IIA and IIB. Thus, like other missiles and launch vehicles, Scout also suffered from the frequent inability of designers to foresee problems their

handiwork might face. But as in so many other cases, engineers were able to correct the problems once they understood them and/ or brought their experience and knowledge to bear on available data.