The idea of maneuvering in space with a personal propulsion system predates the space age. As early as the 1920s and 1930s, science fiction stories featuring jet pack-wearing heroes brought this futuristic idea to the public.
But jetpacks didn’t start the transition from science fiction to science fact until the space age had properly begun. After the Soviet Union launched Sputnik and the United States launched Explorer I, it was clear that both nations would begin launching men into orbit before long. In anticipation of Americans living and working in space, the US Air Force began researching ways these men might maneuver around in the vacuum of space.
The very first astronaut propulsion systems were hand-held units that used compressed air. They were far from perfect. Test subjects routinely found it was nearly impossible to line up the gun’s directive propulsion with their own centre of gravity; every time they fired the gun, they spun as much as they moved forwards or backwards. Though troublesome in testing, the hand-held compressed air gun was the first personal propulsion unit NASA used in space. Completing agency’s first spacewalk was among the goals for the Gemini 4 mission, the second flight of America’s second manned space fight program.