NASA Missions at Mach 3, Dryden history gallery

Dryden researchers conducted several programs involving aircraft capable of attaining altitudes above 70,000 feet and cruising at Mach 3 (more than 2,000 mph, or three times the speed of sound). Airplanes such as the XB-70, YF-12 and SR-71 served as unique assets for research in the areas of propulsion, heating and aerodynamics because their performance characteristics exceeded those of conventional jet aircraft. The B-70 Valkyrie was designed to be the ultimate high-altitude, high-speed strategic bomber. It was, however, in development at a time when the future of the manned bomber was uncertain because military planners felt that the future belonged to guided missiles. As a result, only two experimental XB-70 prototypes were built. During the mid- to late 1960s they served as testbeds for development of technology applicable to a commercial supersonic transport, or SST. The XB-70 was the about same size as projected SST designs and featured similar structural materials, such as brazed stainless steel honeycomb and titanium. In a joint program with the Air Force, NASA used the XB-70 for research on high-speed aerodynamics, sonic booms, high-altitude turbulence and SST flight profiles. Beginning in 1969, two Lockheed YF-12A aircraft were flown at Dryden in a joint NASA-Air Force program aimed at learning more about the capabilities and limitations of high-speed, high-altitude flight. The YF-12s were prototypes of a planned interceptor aircraft that was based on a design that later evolved into the SR-71 reconnaissance aircraft. Following the loss of a YF-12A in 1971, an SR-71A joined the project under the designation YF-12C. Research data from the project helped validate analytical theories and wind-tunnel test techniques that improved design and performance of future military and civil aircraft. Experiments included research on aerodynamic and heating loads, aerodynamic drag and skin friction, heat transfer, thermal stresses, airframe and propulsion system interactions, inlet control systems, high-altitude turbulence, boundary-layer flow, landing gear dynamics, measurement of engine effluents for pollution studies, noise measurements, and evaluation of a maintenance monitoring and recording system. On many YF-12 flights medical researchers obtained information on physiological and biomedical aspects of crews flying at sustained high speeds. The program concluded in 1979. In the 1990s, two SR-71 aircraft were flown at Dryden as testbeds for high-speed, high-altitude research. With the capability to cruise at speeds of Mach 3.2 (nearly 2,200 mph) and attaining altitudes up to 85,000 feet, the aircraft served as platforms for carrying out research in aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. Other experiments included those on a laser air-data collection system, an upward-looking ultraviolet video camera to study celestial objects in wavelengths blocked to ground-based astronomers, atmospheric ozone research, satellite communications, and development of a linear aerospike rocket engine. Photo Description YF-12C in flight at sunset NASA Photo
NASA Identifier: 299360main_EC74-4111_full