On August 16, 1960, Air Force Captain Joseph Kittinger stepped into the near-vacuum above 99% of Earth's atmosphere, plunging 102,800 feet back to Earth. Suspended in an open gondola beneath a massive helium balloon, Kittinger gazed at the curvature of the planet against a black sky before committing to a four-and-a-half-minute free fall through the stratosphere, reaching speeds exceeding 600 miles per hour.
This was not mere daredevilry; it was pioneering human-factors testing for the nascent space age. Before NASA could safely launch astronauts into orbit, aerospace engineers desperately needed empirical data to prove that pressurized pressure suits, telemetry, and drogue parachutes could survive high-altitude emergencies. Kittinger’s swollen, depressurized right hand became vital physiological evidence. In a single historic leap, Excelsior III established the baseline survivability protocols that enabled human spaceflight.