July 19, 1963: Cracking the 100-Kilometer-High Barrier … in a Plane
I must have built the X-15 model a dozen times as a kid. Living in the SF valley in those days made us witnesses to aviation glory. Sonic booms, red glare and distant roars on the horizon from a rocket engine test facility, Edwards AF base nearby….
1963: Test pilot Joe Walker takes an X-15 aircraft to an altitude of 67 miles (106 kilometers), becoming the only pilot to surpass the 100-kilometer barrier in a rocket plane until Mike Melvill, piloting SpaceShipOne, duplicates the feat in 2004.
Walker made his first X-15 flight in 1960 and was completely surprised by the plane’s power, hollering, “Oh my God!” as the afterburners kicked in (and eliciting a joking, “Yes? You called?” from a ground controller). But he would go on to make 24 flights in the X-15, including the memorable July 19 ascent, known as Flight 90.
Breaking the 100-kilometer barrier also meant penetrating the threshold of space, so the flight qualified Walker as an astronaut. When he repeated the feat a month later, he became the first person to enter space twice.
Walker also recorded the fastest speed ever reached in an X-15: On June 27, 1962, he hit 4,104 mph, or Mach 5.92.