Editing Orbit Attitude and Maneuvering System

{{Short description|Gemini Spacecraft attitude control system}}
{{redirect|OAMS|the airport with ICAO code OAMS|Mazar-i-Sharif Airport}}
{{hatnote|For the similarly-named Space Shuttle component, see [[Space Shuttle Orbital Maneuvering System|Orbital Maneuvering System]].}}
[[File:Rcs-gemini.jpg|thumb|right|Gemini Orbit Attitude and Maneuvering System location]]

The '''Orbit Attitude and Maneuvering System''' ('''OAMS''') was a [[reaction control system]] used in [[low Earth orbit|Earth orbit]] by the [[Project Gemini]] [[spacecraft]]. It provided both automatic and manual [[rotation]] and [[translation (geometry)|translation]] by means of 16 [[vernier thruster]]s using [[hypergolic]] propellants.

==Operations==
The OAMS had 16 small, fixed-position, fixed-thrust [[rocket engine]]s which burned [[hypergolic]] propellants ([[monomethylhydrazine]] fuel using [[nitrogen tetroxide]] as [[oxidizer]]) fed under pressure from a pair of tanks located in the aft Equipment Module. 
Besides providing [[Spacecraft attitude control|attitude control]], the OAMS provided for linear up, down, sideways, forward or aft [[translation (physics)|translation]] of the spacecraft. This gave the spacecraft the capability to change its orbit, required for [[space rendezvous]] and [[docking and berthing of spacecraft|docking]] with another spacecraft, the [[Agena Target Vehicle]].
The system was also used to push the spacecraft away from the spent second stage of the [[Titan II GLV|Titan II launch vehicle]] on first reaching orbit.

*The eight rotational control engines were mounted off the spacecraft's [[center of mass]] around the aft section of the Equipment Module, pointed at 90 degree positions up, down, left and right. These were rated at {{convert|25|lbf|N}} thrust and fired in pairs, causing it to [[yaw, pitch, or roll]] to control attitude.
*Six of the translational control engines were mounted on the side of the Retrorocket Module, near the spacecraft's center of mass. Four of these were rated at {{convert|100|lbf|N}} thrust, one each pointed up, down, left or right. The other two were pointed forward, at the three o'clock and nine o'clock positions, to provide aft thrust. These were rated at {{convert|85|lbf|N}} (reduced from the original spec of {{convert|100|lbf|N}} in July 1962).
*The two {{convert|100|lbf|N|adj=on}} thrust forward translation control engines were mounted on the inside of the aft end of the equipment adapter, at the twelve o'clock and six o'clock positions.

[[Project Mercury]] astronauts could only adjust yaw, pitch, or roll, but Gemini crewmen had full manual control over their flight path. [[Walter Schirra]] said that on [[Gemini 6]] "I was amazed at my ability to maneuver. I did a fly-around inspection of [[Gemini 7]], literally flying rings around it, and I could move to within inches of it in perfect confidence". Because there is no turbulence in space "It was like the [[Blue Angels]] at 18,000 miles per hour, only it was easier".<ref name="agle199809">{{Cite magazine |last=Agle |first=D. C. |date=September 1998 |title=Flying the Gusmobile |url=https://www.airspacemag.com/flight-today/flying-the-gusmobile-218187/?all |magazine=Air & Space |language=en}}</ref>

==Events==
During [[Gemini 8]], on March 16, 1966, OAMS engine number 8 became stuck on, resulting in uncontrollable spinning of the spacecraft. The entire OAMS had to be shut down and the mission was terminated prematurely. This resulted in modifications to OAMS to permit engine isolation.

==References==
{{Include-NASA}}
* [http://www.hq.nasa.gov/office/pao/History/SP-4203/cover.htm ''On Shoulders of Titans: A History of Project Gemini''] {{Webarchive|url=https://web.archive.org/web/20031207111557/http://www.hq.nasa.gov/office/pao/History/SP-4203/cover.htm |date=2003-12-07 }}
{{reflist}}

{{Gemini program|state=expanded}}
{{NASA space program}}

{{Use American English|date=January 2014}}

{{DEFAULTSORT:Orbit Attitude And Maneuvering System}}
[[Category:Project Gemini]]
[[Category:Spacecraft attitude control]]


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