Shuttle Studies Begin
The concept of a reusable space plane to carry people and equipment into orbit has a long history, and both NASA and the Department of Defense in the 1960s devoted significant attention to whether such a vehicle was technologically feasible.2 But the first high-level designation of such a concept as a “space shuttle” came from NASA’s Associate Administrator for Manned Space Flight George Mueller as he addressed the British Interplanetary Society in August 1968. Mueller projected that “the next major thrust in space will be the development of an economical launch vehicle for shuttling between Earth and the installations, such as the orbiting space station, which will soon be operating in space.” Mueller was of course aware of the various studies of reusable space vehicles, and realized that the space station program he saw as a major next step in space development would not be economically feasible unless there was a low-cost transport to “shuttle” crew and supplies to and from such an outpost. Mueller’s concept for such a system was a fully reusable vehicle capable of “airline type” operations.3
Mueller decided to fund several of what NASA designated Phase A feasibility studies to carry out an initial examination of the technical feasibility of what was at that point called the integral launch and reentry vehicle (ILRV). NASA set out an initial set of performance requirements to guide these contractor studies. They included the capability to carry up to 25,000 pounds of cargo or ten passengers to the 270 nm, 55 degree orbit then being planned for a space station. The payload bay was to provide a volume of at least 3,000 cubic feet. The ILRV was to be able to launch within 24 hours of the decision to do so, and to be capable of returning from orbit to a designated runway within a day after a deorbit decision. To achieve such a return, a cross-range capability of 450 nm was specified. NASA initially told its contractors to assume a flight rate of 8 to 12 missions to a space station per year; the use of the system to launch other NASA missions or national security missions was at this point not part of the space agency’s thinking.4
NASA’s ability to design a space shuttle solely to meet its own requirements was short-lived. One of the first decisions of the Space Task Group (STG) as it began its review of the U. S. space program in March 1969 was to direct NASA and the Department of Defense to jointly investigate whether a single, lower-cost vehicle could meet the needs of both organizations. A charter for the joint study was signed in early April by NASA Administrator Tom Paine and Secretary of the Air Force Robert Seamans. NASA’s George Mueller and Air Force Assistant Secretary for Research and Development Grant Hansen were named as the study’s co-chairs.
There were a number of formal and informal meetings during the April-June period between Mueller and Hansen to discuss top-level shuttle requirements. At one of these meetings, Hansen’s top assistant Michael Yarymovych told Mueller that, if NASA wanted national security community support for the shuttle, the vehicle would have to carry payloads up to 60 feet long and would have to be able to operate from the Vandenberg Air Force Base on the California coast. After a California launch, the shuttle would have to be able to carry out a one-orbit mission without overflying the Soviet Union, so that it would not be exposed to potential Soviet interference, and then be able to return to land at Vandenberg. During the shuttle’s 90-minute or so orbit, the Earth would have rotated eastward some 1,100 nm, and thus the shuttle would have to have at least that amount of cross-range maneuvering capability to be able to land back at Vandenberg. Yarymovych told Mueller “we’d support the shuttle, but only if he gave us the big payload bay and the cross-range capability.” Mueller knew that this would mean changing the shuttle design that he and his NASA engineers preferred, “but he had no choice.”5
Following his meetings with the Air Force, Mueller called together the ILRV study contractors to inform them that the requirements originally specified for their studies had to be changed in light of national security preferences. He told the group that the vehicle should now be able to launch 50,000 pounds of payload to the space station orbit, rather than 25,000 pounds, and should have a payload bay providing 10,000 rather than 3,000 cubic feet in volume, which was translated into a bay 15 feet wide and 60 feet long.6