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A Manned Maneuvering Unit (MMU) is a rocket pack (propulsion backpack that snaps onto the back of the spacesuit) which has been used on spacewalks (EVAs) from NASA's space shuttle, allowing an astronaut to move independently from the shuttle. The MMU has not been used since the Challenger disaster in 1986. Image File history File links Download high resolution version (3072x3072, 7575 KB) matthew is aaqwz NASA Photo ID: S84-27017 Program: Shuttle Mission: STS-41-B Date Taken: February 11, 1984 Film Type: 70mm Title: Views of the extravehicular activity during STS 41-B Description: Astronaut Bruce McCandless, mission specialist...
Image File history File links Download high resolution version (3072x3072, 7575 KB) matthew is aaqwz NASA Photo ID: S84-27017 Program: Shuttle Mission: STS-41-B Date Taken: February 11, 1984 Film Type: 70mm Title: Views of the extravehicular activity during STS 41-B Description: Astronaut Bruce McCandless, mission specialist...
McCandless helped develop the MMU and was first to test it on STS-41-B in 1984 Captain Bruce McCandless II (born June 8, 1937 in Boston, Massachusetts) is a former naval aviator with the United States Navy and NASA astronaut. ...
A jet pack is a technology that is not yet practical but often appears in fiction. ...
A remote camera captures a close-up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is used to change the velocity of spacecraft and artificial satellites, or in short, to provide delta-v. ...
A backpack A backpack is, in its simplest form, a cloth sack carried on ones back and secured with two straps that go over the shoulders (called shoulder straps) and below the armpits. ...
Apollo 15 space suit A spacesuit is a complex system of garments, equipment, and environmental systems designed to keep a person alive and comfortable in the harsh environment of outer space. ...
Astronaut Bruce McCandless on an untethered EVA Extra-vehicular activity (EVA) is work done by an astronaut away from the Earth and outside of his or her spacecraft. ...
The National Aeronautics and Space Administration (NASA) is an agency of the United States Government, responsible for that nations public space program. ...
NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ...
For other uses, see Astronaut (disambiguation). ...
For further information about Challengers mission and crew, see STS-51-L. The iconic image of Space Shuttle Challengers smoke plume after its breakup 73 seconds after launch. ...
Overview
The unit featured redundancy to protect against failure of individual systems. It was designed to fit over the life-support system backpack of the Space Shuttle Extravehicular Mobility Unit (EMU). When carried into space, the MMU was stowed in a support station attached to the wall of the payload bay near the airlock hatch. Two MMUs were carried on a mission, with the second unit mounted across from the first on the opposite payload bay wall. The MMU controller arms were folded for storage. When an astronaut backed into the unit and snapped the life-support system into place, the arms were unfolded. NASA portrait of American Astronaut Thomas Akers, wearing a Shuttle EMU. The Space Shuttle/International Space Station Extravehicular Mobility Unit (EMU) is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for a Shuttle or ISS crew member to perform extra-vehicular activity (EVA) in earth...
To adapt to astronauts with different arm lengths, controller arms could be adjusted over a range of approximately 13 centimetres. The MMU was small enough to be maneuvered with ease around and within complex structures. With a full propellant load, its mass was 148 kilograms (326 pounds).
Gaseous nitrogen was used as the propellant for the MMU. Two aluminium tanks with Kevlar wrappings contained 5.9 kilograms of nitrogen each, enough propellant for a six-hour EVA depending on the amount of maneuvering done. Typical MMU delta-V (velocity change) capability was about 80 feet per second (24.4 meters/sec). General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Atomic mass 14. ...
General In general physics delta-v is simply the change in velocity. ...
There were 24 nozzle thrusters placed at different locations on the MMU. To operate the propulsion system, the astronaut used his fingertips to manipulate hand controllers at the ends of the MMU's two arms. The right controller produced rotational acceleration for roll, pitch, and yaw. The left controller produced acceleration without rotation for moving forward-back, up-down, and left-right. Coordination of the two controllers produced intricate movements in the unit. Once a desired orientation was achieved, the astronaut could engage an automatic attitude-hold function that maintained the inertial attitude of the unit in flight. This freed both hands for work.
History The MMU was used on three Shuttle missions in 1984. It was first tested on February 7 during mission STS-41-B by astronauts Bruce McCandless II and Robert L. Stewart. Two months later during mission STS-41-C, astronauts James van Hoften and George Nelson attempted to use the MMU to capture the Solar Maximum Mission satellite and to bring it into the orbiter's payload bay for repairs and servicing. The plan was to use an astronaut piloted MMU to grapple the SMM, null its rotation rates, and fly it into the Shuttle's payload bay for stowage. But the satellite rotation rates made it impossible for the astronaut's grapple fixture to snare the SMM. This led to an improvised plan which nearly ended the satellite's mission. The improvisation had the MMU astronaut use his hands to grab hold of a SMM solar array and null the rates by a push from MMU's thrusters. Instead, this attempt induced higher rates and in multiple axes; the satellite was tumbling out of control and quickly losing battery life. SMM Operations Control Center engineers shutdown all non-essential SMM subsystems and with a bit of luck were able to recover the SMM minutes before total failure. The ground support engineers then stabilized the satellite and nulled its rotation rates for capture with the orbiter's robotic arm, the SRMS. This proved to be a much better plan. Their successful work increased the lifespan of the satellite. February 7 is the 38th day of the year in the Gregorian Calendar. ...
// Crew Vance Brand (flew on Apollo-Soyuz, STS-5, STS-41-B & STS-35), Commander Robert L. Gibson (flew on STS-41-B, STS-61-C, STS-27, STS-47 & STS-71), Pilot Bruce McCandless II (flew on STS-41-B & STS-31), Mission Specialist Ronald E. McNair (flew on...
McCandless helped develop the MMU and was first to test it on STS-41-B in 1984 Captain Bruce McCandless II (born June 8, 1937 in Boston, Massachusetts) is a former naval aviator with the United States Navy and NASA astronaut. ...
Robert L. Stewart is a retired Brigadier General of the United States Army and former NASA astronaut. ...
STS-41-C was the 11th Space Shuttle mission and the fifth for Challenger. ...
James D. A. Ox van Hoften is a former NASA Astronaut. ...
George D. Nelson (nickname Pinky) (b. ...
The Solar Maximum Mission satellite (or SolarMax) was designed to investigate solar phenomenon, particularly solar flares. ...
The final MMU mission was STS-51-A, which flew in November of 1984. The propulsion unit was used to retrieve two communication satellites, Westar VI and Palapa B2, that did not reach their proper orbits because of faulty propulsion modules. Astronauts Joseph P. Allen and Dale Gardner captured the two satellites and brought them into the Orbiter payload bay for stowage and return to Earth. STS 51-A was the fourteenth flight of a Space Shuttle and the second flight of Discovery. ...
Westar was the name for the fleet of geosynchronous communications satellites operating in the C-band which were launched by Western Union from 1974 to 1984. ...
Palapa was a series of Indonesian communication satellites. ...
Joseph Allen was a Bishop of Bristol from 1834 to 1836. ...
Born November 8, 1948 in Fairmont, Minnesota, Dale A. Gardner is a former NASA Astronaut who flew two missions for NASA in the early 1980s. ...
After the Space Shuttle Challenger disaster, the MMU was judged too risky. NASA also discontinued using the Shuttle for commercial satellite contracts, and the military discontinued the use of the Shuttle, eliminating the main potential uses. Although the MMU was envisioned as a natural aid for constructing the International Space Station, with its retirement, NASA developed different tethered spacewalk approaches. Additionally, the MMU gas ejecta was considered too damaging for the only other ongoing task, upkeep of the Hubble Space Telescope. For further information about Challengers mission and crew, see STS-51-L. The iconic image of Space Shuttle Challengers smoke plume after its breakup 73 seconds after launch. ...
International Space Station insignia ISS Statistics Crew: 3 As of December 19, 2006 Perigee: 352. ...
The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ...
Related astronaut propulsion units
"Zip" gun The MMU can trace its origins back to the EVA "zip" gun used by Edward White on the Gemini 4 mission in 1965. The hand-held gun held several pounds of oxygen, and allowed limited movement around the Gemini spacecraft. This was also used by astronaut Michael Collins on the Gemini 10 mission in 1966. Edward Higgins White, II (Lt. ...
Gemini 4 (officially Gemini IV) was a 1965 manned space flight in NASAs Gemini program. ...
Michael Collins (born October 31, 1930) is a former American astronaut and test pilot. ...
Gemini 10 (officially Gemini X) was a 1966 manned spaceflight in NASAs Gemini program. ...
AMU The U.S. Air Force, which was planning to use the Gemini spacecraft as part of the Manned Orbiting Laboratory, designed the Astronaut Maneuvering Unit (AMU), which was a backpack, using hydrogen peroxide as the fuel. The total delta-V capability of the AMU was about 250 feet per second (76.2 meters per second), roughly three times that of the MMU. The astronaut would strap on the AMU like a backpack, and maneuver around using two hand controllers like that of the present-day MMU. Because of the fuel, which comes out as a hot gas, the astronaut's suit had to be modified with the addition of woven steel "pants" made of Chromel-R metal cloth. The AMU was flown aboard the Gemini 9 mission, but was not tested because the astronaut, Eugene Cernan, had difficulty maneuvering from the Gemini cabin to the AMU storage place, at the back of the spacecraft, and overheated, causing his helmet faceplate to fog up. Manned Orbiting Laboratory early 1960 conceptual drawing that did not use the Gemini spacecraft. ...
Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in a dilute solution, slightly more viscous than water. ...
Gemini 9A (officially Gemini IX-A) was a 1966 manned spaceflight in NASAs Gemini program. ...
Eugene Cernan Gene in LM after EVA-3 Eugene Andrew Cernan (born March 14, 1934, in Chicago, Illinois) is a former United States astronaut. ...
The Gemini AMU was not flown after Gemini 9. In 1973, the second AMU was flown aboard the Skylab 3 mission. Tested inside of the orbiting laboratory, the Skylab AMU was identical in appearance to the Gemini version, but used nitrogen gas instead of hydrogen peroxide - the nitrogen would vent harmlessly in the oxygen-nitrogen atmosphere used in the station, and allowing both unsuited and suited testing of the unit. The Skylab AMU was the closest to the Shuttle MMU, but was not used outside of the spacecraft because the EVAs were conducted with the astronauts attached to life support umbilicals, and to prevent damage to the delicate solar arrays on the Apollo Telescope Mount. Skylab 3 or SL-3 was the second manned mission to Skylab. ...
The Apollo Telescope Mount, or ATM, is the name of a solar observatory that was attached to Skylab, the first US space station. ...
SAFER The Simplified Aid for EVA Rescue (SAFER) is a smaller backpack propulsion system intended as a safety device during space walks. It contains 1.4 kg of gaseous nitrogen, which provides much less delta-V capability than the MMU, roughly 10 feet per second (3 meters per second). However SAFER is less complex, less expensive and simpler to use than the MMU, and the limited delta-V is sufficient for the intended rescue-only task. Other Crew Self Rescue (CSR) devices of which prototypes have been developed include an inflatable pole, a telescoping pole, a bi-stem pole and a bola-type lasso device (astrorope) the drifting astronaut could throw to hook to the space station. Astronaut Mark C. Lee free floating in space with the SAFER system SAFER Simplified Aid for EVA Rescue (SAFER) is a small, self-contained, propulsive backpack system used to provide free-flying mobility for a Space Shuttle or International Space Station (ISS) crewmember during extra-vehicular activity (EVA). ...
General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Atomic mass 14. ...
General In general physics delta-v is simply the change in velocity. ...
A Bola (from Spanish and Portuguese word for ball) can be one of a number of things: Bolas, a hunting weapon. ...
Soviet SPK The former Soviet Union also used a cosmonaut propulsion system on flights to the space station Mir. The SPK (or UMK) was larger than the Space Shuttle MMU, contained oxygen instead of nitrogen and was attached to a safety tether. Despite the tether, the SPK allowed the cosmonaut, wearing the self-contained Orlan spacesuit, to "fly around" the orbiting complex, allowing access to areas nearly impossible to access otherwise. Though tested on Mir in 1990, the cosmonauts preferred using the Strela crane (equivalent to the Mobile Servicing System), and the SPK, which was left attached to the outside, was destroyed when Mir re-entered the atmosphere after decommissioning. Mir (Мир, which can mean both world and peace in Russian) was a Soviet (and later Russian) orbital station. ...
Peggy A. Whitson, Expedition Five flight engineer, in an Orlan-M space suit as she prepares for an EVA. (NASA) The Orlan space suits are a series of semi-rigid space suits designed and built by NPP Zvezda for use in the Soviet space program and Russian space program. ...
ISS Canadarm2 (NASA) Canadarm2 (left) on the ISS The Mobile Servicing System (MSS) is a robotic arm and associated equipment on the International Space Station that plays a key role in station assembly and maintenance: moving equipment and supplies around the station, supporting astronauts working in space, and servicing instruments...
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