Project Manhigh

Project Manhigh was a pre-Space Age military project that took men in balloons to the middle layers of the stratosphere, funded as an aero-medical research program, though seen by its designers as a stepping stone to space.

It was conducted by the United States Air Force between 1955 and 1958.

[1] The project started in December 1955 to study the effects of cosmic rays on humans.

Three balloon flights to the stratosphere were made during the program: Candidates for the Manhigh project were put through a series of physical and psychological tests that became the standard for qualifying astronauts for the Project Mercury, America's first manned orbital space program.

[1] Similar projects in which men in a gondola reached near-space altitudes were performed by Swiss physicist Auguste Piccard and Paul Kipfer, reaching 15,785 m (51,788 ft) in 1931, USSR-1 piloted by Georgy Prokofiev reaching 18,500 m (60,700 ft) in 1933, and Osoaviakhim-1 reaching 22,000 m (72,000 ft) in 1934 as well as Explorer II reaching 22,066 m (72,395 ft) in 1935.