Space Shuttle Orbital Maneuvering System

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The Space Shuttle Orbital Maneuvering System (OMS) is a system of hypergolic liquid-propellant rocket engines used on the Space Shuttle. Designed and manufactured in the United States by Aerojet,[1] the system allowed the orbiter to perform various orbital maneuvers according to requirements of each mission profile: orbital injection after main engine cutoff, orbital corrections during flight, and the final deorbit burn for reentry.[2] The OMS consists of two pods mounted on the orbiter's aft fuselage, on either side of the vertical stabilizer.[2] Each pod contains a single AJ10-190 engine,[3] based on the Apollo Service Module's Service Propulsion System engine,[citation needed] which produces 26.7 kilonewtons (6,000 lbf) of thrust with a specific impulse (Isp) of 316 seconds.[3] Each engine could be reused for 100 missions and was capable of a total of 1,000 starts and 15 hours of burn time.[citation needed]

Space Shuttle OMS/RCS Pod
OMS Pod removal.png
The underside of a left OMS/RCS pod.
Country of originUnited States
Used onSpace Shuttle
General characteristics
Length21.8 feet (6.6 m)
Width11.37 feet (3.47 m) (aft)
8.14 feet (2.48 m) (forward)
Launch history
Total launches135
(stage only)
Lower stage
1 (STS-51-L)
First flightSTS-1 (12 April 1981)
Last flightSTS-135 (8 July 2011)
OMS Engine
Engines1 AJ10-190
Thrust26.7 kilonewtons (6,000 lbf)
Specific impulse316 seconds (vacuum)
Burn time15 hours (maximum service life)
1250 seconds (deorbit burn)
150–250 seconds (typical burn)
Aft Primary RCS
EnginesPrimary RCS engines
Thrust3.87 kilonewtons (870 lbf)
Burn time1–150 seconds (each burn)
800 seconds (total)
Aft Vernier RCS
EnginesVernier RCS engines
Thrust106 newtons (24 lbf)
Burn time1–125 seconds (each burn)

These pods also contained the Orbiter's aft set of reaction control system (RCS) engines, and so were referred to as OMS/RCS pods. The OM engine and RCS both burned monomethylhydrazine (MMH) as fuel, which was oxidized with dinitrogen tetroxide (N2O4), with the propellants being stored in tanks within the OMS/RCS pod, alongside other fuel and engine management systems.[4] When full, the pods together carried around 8,174 kilograms (18,021 lb) of MMH and 13,486 kilograms (29,732 lb) of N2O4, allowing the OMS to produce a total delta-v of around 1,000 feet per second (300 m/s) with a 65,000-pound (29,500 kg) payload.[4][5]


  1. ^ D. Craig Judd (1992). "Capability and flight record of the versatile space shuttle OMS engine". NASA. Bibcode:1992spte.symp..107J. Cite journal requires |journal= (help)
  2. ^ a b "Orbital Maneuvering System". NASA. 1998. Archived from the original on 29 June 2011.
  3. ^ a b Encyclopedia Astronautica (2009). "OME". Encyclopedia Astronautica. Archived from the original on 13 January 2010. Retrieved 4 January 2010.
  4. ^ a b NASA (1998). "Propellant Storage and Distribution". NASA. Retrieved 8 February 2008.
  5. ^ David Palmer, Allie Cliffe and Tim Kallman (9 May 1997). "Spacecraft Fuel". NASA.