Edge of Space Reached: Joe Walker’s Historic Dual X-15 Flight in 1963

On Aug. 22, 1963, U.S. Air Force Captain Joe Walker piloted the X-15 #3 to an altitude over 67 miles (108 km), about 5 miles above the edge of space, making him the first person to reach space twice. The second suborbital X-15 flight demonstrated reuse potential and informed NASA’s Mercury, Gemini and Apollo programs, as well as later Shuttle design and today’s reusable boosters like SpaceX’s Falcon 9.