Project Manhigh

Manhigh II balloon gondola displayed at the National Museum of the U.S. Air Force, Wright-Patterson AFB, Ohio
As displayed in 2018

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.