The Hand-Held Maneuvering Unit (HHMU), also known as the maneuvering gun, or informally as "the zip gun", was first astronaut propulsion unit. It was first used by astronaut Ed White during 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.[1][2] It was also used aboard Skylab.
Astronaut Ed White uses the first Hand-Held Maneuvering Unit during his spacewalk on Gemini 4
Astronauts[who?] described the gun as easier to use than other methods of maneuvering during space-walking. It provided an impulse to send the space-walker away from and back to the spacecraft, and was the easiest way for them to control their motions in the microgravity environment. The device received its propellant from tanks on the device and used pressurized oxygen to control and propel the astronaut via conservation of momentum.[1][3]
History
Gemini 4
Ed White enjoyed using the gun[4] and found it useful,[5] but quickly ran out of propellant, forcing him to pull on his tether to continue maneuvers. However, fellow crewman James McDivitt recalled the gun as being "hopeless" and "utterly useless" as it required precise aim through the user's center of mass in order to translate in a straight line without inducing unwanted rotation.[4]
Gemini 8
The device carried on Gemini 8 (March 16–17, 1966) received its Freon 14 propellant from a tank to be carried on the astronaut's back.[1] Astronaut David Scott never got a chance to use it, because the mission had to be terminated before his EVA due to a critical thruster problem.
Gemini 10
The Gemini 10 device used by Michael Collins received its nitrogen gas propellant from inside the spacecraft, through a hose bundled with the astronaut's umbilical connector.[1] Collins successfully used it to move back and forth between the Gemini and the Agena Target Vehicle.
Gemini 11
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
References
^ abcd"More Favored than the Birds The Manned Maneuvering Unit in Space". history.nasa.gov. Retrieved 2021-05-14.
^Kenneth S. Thomas & Harold J. McMann (2006). US Spacesuits. Chichester, UK: Praxis Publishing Ltd. ISBN0-387-27919-9.{{cite book}}: CS1 maint: uses authors parameter (link)
^Gemini 4 Extravehicular Activity summary from NASA
^ abOral History Transcript / James A. McDivitt / Interviewed by Doug Ward / Elk Lake, Michigan - 29 June 1999
hand, held, maneuvering, unit, hand, held, maneuvering, unit, hhmu, also, known, maneuvering, informally, first, astronaut, propulsion, unit, first, used, astronaut, white, during, first, american, spacewalk, extra, vehicular, activity, gemini, june, 1965, dif. The Hand Held Maneuvering Unit HHMU also known as the maneuvering gun or informally as the zip gun was first astronaut propulsion unit It was first used by astronaut Ed White during 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 1 2 It was also used aboard Skylab Astronaut Ed White uses the first Hand Held Maneuvering Unit during his spacewalk on Gemini 4 Contents 1 Utility and design 2 History 2 1 Gemini 4 2 2 Gemini 8 2 3 Gemini 10 2 4 Gemini 11 3 References 4 External linksUtility and design EditAstronauts who described the gun as easier to use than other methods of maneuvering during space walking It provided an impulse to send the space walker away from and back to the spacecraft and was the easiest way for them to control their motions in the microgravity environment The device received its propellant from tanks on the device and used pressurized oxygen to control and propel the astronaut via conservation of momentum 1 3 History EditGemini 4 Edit Ed White enjoyed using the gun 4 and found it useful 5 but quickly ran out of propellant forcing him to pull on his tether to continue maneuvers However fellow crewman James McDivitt recalled the gun as being hopeless and utterly useless as it required precise aim through the user s center of mass in order to translate in a straight line without inducing unwanted rotation 4 Gemini 8 Edit The device carried on Gemini 8 March 16 17 1966 received its Freon 14 propellant from a tank to be carried on the astronaut s back 1 Astronaut David Scott never got a chance to use it because the mission had to be terminated before his EVA due to a critical thruster problem Gemini 10 Edit The Gemini 10 device used by Michael Collins received its nitrogen gas propellant from inside the spacecraft through a hose bundled with the astronaut s umbilical connector 1 Collins successfully used it to move back and forth between the Gemini and the Agena Target Vehicle Gemini 11 Edit 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 HHMUReferences Edit a b c d More Favored than the Birds The Manned Maneuvering Unit in Space history nasa gov Retrieved 2021 05 14 Kenneth S Thomas amp Harold J McMann 2006 US Spacesuits Chichester UK Praxis Publishing Ltd ISBN 0 387 27919 9 a href Template Cite book html title Template Cite book cite book a CS1 maint uses authors parameter link Gemini 4 Extravehicular Activity summary from NASA a b Oral History Transcript James A McDivitt Interviewed by Doug Ward Elk Lake Michigan 29 June 1999 Biography of Ed White from NASA history archive External links EditSuited for spacewalking NASA Retrieved from https en wikipedia org w index php title Hand held maneuvering unit amp oldid 1025153982, wikipedia, wiki, book, books, library,
