Orbital Maneuvering System
Manufacturer | Aerojet |
---|---|
Country of origin | United States |
Used on | Space Shuttle |
General characteristics | |
Length | 21.8 feet (6.6 m) |
Width | 11.37 feet (3.47 m) (aft) 8.14 feet (2.48 m) (forward) |
Launch history | |
Status | Retired |
Total launches | 135 |
Successes (stage only) | 134 |
Lower stage failed | 1 (STS-51-L) |
First flight | STS-1 (12 April 1981) |
Last flight | STS-135 (8 July 2011) |
OMS Engine | |
Powered by | 1 AJ10-190 |
Maximum thrust | 26.7 kilonewtons (6,000 lbf) |
Specific impulse | 316 seconds (vacuum) |
Burn time | 15 hours (maximum service life) 1250 seconds (deorbit burn) 150–250 seconds (typical burn) |
Propellant | MMH/N2O4 |
Aft Primary RCS | |
Powered by | Primary RCS engines |
Maximum thrust | 3.87 kilonewtons (870 lbf) |
Burn time | 1–150 seconds (each burn) 800 seconds (total) |
Propellant | MMH/N2O4 |
Aft Vernier RCS | |
Powered by | Vernier RCS engines |
Maximum thrust | 106 newtons (24 lbf) |
Burn time | 1–125 seconds (each burn) |
Propellant | MMH/N2O4 |
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] Rarely the OMS were actually ignited part-way into the Shuttle's main ascent for a few minutes to aid acceleration to orbital insertion (usually while carrying heavy ISS payloads). This occurred on STS-128 and STS-135.
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]
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]
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Diagram of OMS pod components
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An OMS pod detached from an orbiter for maintenance
References
- ^ D. Craig Judd (1992). "Capability and flight record of the versatile space shuttle OMS engine". NASA. Bibcode:1992spte.symp..107J.
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(help) - ^ a b "Orbital Maneuvering System". NASA. 1998. Archived from the original on 29 June 2011.
- ^ a b Encyclopedia Astronautica (2009). "OME". Encyclopedia Astronautica. Archived from the original on 13 January 2010. Retrieved 4 January 2010.
- ^ a b NASA (1998). "Propellant Storage and Distribution". NASA. Retrieved 8 February 2008.
- ^ David Palmer, Allie Cliffe and Tim Kallman (9 May 1997). "Spacecraft Fuel". NASA.