Joe Kittinger breaks the sound barrier without a plane

By the mid-1950s, aircraft were being produced or planned that could fly to the outer reaches of the Earth's atmosphere. While the need for pressure suits was understood, there were still many variables that were not, such as the strength & effect of cosmic rays.

In Dec. 1955, the Air Force established Project Manhigh to study these unknowns. Manhigh would be a series of manned, high-altitude balloon flights launched from White Sands Proving Ground (now White Sands Missile Range) in the New Mexico desert. The balloons would fly as high as 100,000 ft, above 99% of the Earth's atmosphere, where there was less air to filter out many of the rays in question.

"Lord, take care of me now...." Aug. 16, 1960. Joe Kittinger jumps from Excelsior III at 102,800 ft.

Joe was in freefall for 4 min 36 sec-and nearly 17 miles....during this plummet from the edge of space, he reached a speed of 714 MPH, becoming the first man to break the sound barrier without the aid of any kind of vehicle. His parachute opened automatically at 12,000 ft.

Manhigh II instrument panel.

the site