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.