December 10, 1954

1954:          On a rocket-propelled sled run, Lt Col John P. Stapp attains 632 MPH (equal to Mach 1.7 at 35,000 feet) and decelerates to zero in 1.4 seconds. He experiences the greatest G-force ever endured by man (40 Gs) in recorded tests. The test proves that humans could survive ejection from an aircraft at supersonic speeds.