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.

History

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. Similar projects in which men in a gondola reached near-space altitudes were performed by Swiss physicist Auguste Piccard and Paul Kipfer, reaching 15785 m in 1931, USSR-1 piloted by Georgy Prokofiev reaching 18500 m in 1933, and Osoaviakhim-1 reaching 22000 m in 1934 as well as Explorer II reaching 22066 m in 1935.