Maximum Speed - 5,971 km/h. Maximum Altitude - 106,010 m. 80 cm diameter balloon towed on 30 m line to measure air density. First X-15 flight over 100 km (a height known as the
Kármán line). This made Walker the first US civilian in space. This was also the first
spaceflight of a
spaceplane in aviation history. First flight launched over Smith Dry Lake, NV. Experiments: Towed balloon, horizon scanner, photometer, infrared and ultraviolet. Balloon instrumentation failed. The mission was flown by
X-15 #3, serial 56–6672 on its 21st flight. Launched by: NB-52B #008, Pilots Fulton & Bement. Takeoff: 17:19. UTC Landing: 19:04 UTC. Chase pilots: Crews, Dana, Rogers, Daniel and Wood. The X-15 engine burned about 85 seconds. Near the end of the burn, acceleration built up to about 4
g (39 m/s²). Weightlessness lasted for 3 to 5 minutes. Re-entry heating warmed the exterior of the X-15 to 650 °C in places. During pull up after re-entry, the acceleration built up to 5
g (49 m/s²) for 20 seconds. The entire flight lasted about 12 minutes from launch to landing. ==Notes==