The Hand-Held Maneuvering Unit (HHMU), also known as the maneuvering gun, or informally as "the zip gun", was used by astronaut Edward H. White in the first American "spacewalk" (extra-vehicular activity, EVA), on Gemini 4, June 3, 1965. Different models of HHMU were present on Gemini 4, 8, 10, and 11, but were only used on Gemini 4 and 10. It was also used aboard Skylab. Richard Gordon did not get to use his HHMU on Gemini 11, because his EVA had to be cut short when he became fatigued. * Gemini 4 HHMU * Gemini 8 HHMU