Joseph A. Walker - X-15 Program

X-15 Program

In 1958, Walker was one of the pilots selected for the U.S. Air Force's Man In Space Soonest (MISS) project, but that project never came to fruition. That same year, NACA became the National Aeronautics and Space Administration (NASA), and in 1960, Walker became the first NASA pilot to fly the X-15, and the second X-15 pilot, following Scott Crossfield, the manufacturer's test pilot. On his first X-15 flight, Walker did not realize how much power that its rocket engines had, and he was crushed backward into the pilot's seat, screaming, "Oh, my God!". Then, a flight controller jokingly replied "Yes? You called?" Walker would go on to fly the X-15 24 times, including the only two flights that exceeded 100 kilometers (62.2 miles) in altitude, Flight 90 (on 19 July 1963: 106 km) and Flight 91 (on 22 August 1963: 108 km).

Walker was the first American civilian to make any spaceflight, and the second civilian overall, preceded only by the Soviet Union's cosmonaut, Valentina Tereshkova one month earlier. Flights 90 and 91 made Walker the first human to make multiple spaceflights.

Walker flew at the fastest speed in the X-15A-1: 4,104 mph (Mach 5.92) during a flight on 27 June 1962 (the fastest flight in any of the three X-15s was about 4,520 mph (Mach 6.7) flown by William J. Knight in 1967).