X-15 sets world altitude record on Aug. 22, 1963

On Aug. 22, 1963, U.S. Air Force Captain Joe Walker flew an X-15 rocket plane to an altitude of over 67 miles (108 km), setting a world record. The flight was the second and final suborbital mission of the X-15 program, making Walker the first person to go to space twice. The program's lessons aided NASA's Mercury, Gemini, and Apollo missions, and the X-15's reusability foreshadowed the Space Shuttle and SpaceX's Falcon 9.