Transition to space - A history of 'space plane' concepts at Langley Aeronautical Laboratory 1952-1957
The supersonic speeds of X-series aircraft and wind tunnel data in the early 1950s demonstrated that hypersonic flight was an achievable goal. A blunt-nosed vehicle was found to form a bow shock that deflected much of the heating an aircraft would otherwise experience at high speeds. It was felt that critical aspects of hypersonic flight, e.g., aerodynamic performance and heating, controllability, etc., could not be fully explored in wind tunnels. The X-15 project was initiated by NASA in 1954 to produce a vehicle capable of Mach 7 flight to altitudes that would permit short evaluations of human performance in microgravity. Design tradeoffs examined in the program are discussed, with emphasis on lifting bodies and winged vehicles with high L/D ratios. Political pressures created by the public triumph of the Sputnik in 1958 removed much of the impetus for development of a manned spaceplane, and long-term goals that eventually led to the Shuttle were delayed by a short-term program oriented toward ballistic manned capsules.