9. The B-52 operated in support of NASA and the Space Race in the 1960s
The B-52 was and is a subsonic airplane, incapable of surpassing the speed of sound. Yet it made considerable contributions to the study of supersonic and hypersonic flight as part of the X-15 program. The X-15 was operated from 1959 to 1968 in a joint program conducted by the United States Air Force and the National Aeronautics and Space Administration (NASA). Three X-15s were built, and there were differences between each. It was essentially a hypersonic rocket, which flew into the edge of space, where the air is so thin that the normal means of aircraft control were unavailable. Rather than using surfaces to control yaw, pitch, and roll, thrusters were required to operate the aircraft during much of its flight. It returned to earth in an unpowered glide. In fact, the entire powered phase of its flight was less than two minutes.
The X-15 did not take off conventionally, accelerating down a runaway until its wings generated sufficient lift to allow it to fly. Instead, it was carried into the air under the wing of a mother ship. In June 1959, test pilot Scott Crossfield flew the X-15 for the first time, though the vehicle was carried into the air and released for an unpowered test flight. Its first powered flight occurred in September 1959. The X-15 was carried into the air by one of two B-52s assigned to NASA and modified for the purpose. The ex-bombers were designated NB-52A (nicknamed The High and Mighty One) and NB-52B (Balls Out). Both exist as museum displays today, with NB-52A at the Pima Air and Space Museum, Tucson, Arizona and NB-52B at Edwards Air Force Base, in California.