The orbit attitude and maneuvering system (OAMS) was a propulsion

Spacecraft propulsion

Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...

 system used in orbit

Orbit

In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

 by the Gemini

Project Gemini

Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....

 spacecraft

Spacecraft

A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

.

Operations

Besides providing rotation

Rotation

A rotation is a circular movement of an object around a center of rotation. A three-dimensional object rotates always around an imaginary line called a rotation axis. If the axis is within the body, and passes through its center of mass the body is said to rotate upon itself, or spin. A rotation...

 control to let a pilot steer the spacecraft, the OAMS provided translation

Translation (physics)

In physics, translation is movement that changes the position of an object, as opposed to rotation. For example, according to Whittaker:...

 control for the Gemini spacecraft, moving it linearly up, down, sideways, forward or aft relative to a nearby object in space. It provided the spacecraft with the capability of changing its orbit, and of performing rendezvous

Space rendezvous

A space rendezvous is an orbital maneuver during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance . Rendezvous requires a precise match of the orbital velocities of the two spacecraft, allowing them to remain at a constant...

 and docking with another spacecraft.
The system was also used at the start of the mission to push the spacecraft away from the spent second stage of the launch vehicle, and on occasion, to augment the retrorocket

Retrorocket

A retrorocket is a rocket engine providing thrust opposing the motion of a spacecraft, thereby causing it to decelerate.-History:...

s to bring the craft out of orbit.

The complete OAMS had 16 small rocket engine

Rocket engine

A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...

s which burned hypergolic propellants fed under pressure from one monomethylhydrazine

Monomethylhydrazine

Monomethylhydrazine is a volatile hydrazine chemical with the chemical formula CH3 NH2. It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide and nitric acid...

 fuel, and one nitrogen tetroxide oxidizer tank. All engines were mounted in fixed positions and were run at fixed levels of thrust.

• The eight rotational control engines were mounted off the spacecraft's center of mass
  Center of mass
  In physics, the center of mass or barycenter of a system is the average location of all of its mass. In the case of a rigid body, the position of the center of mass is fixed in relation to the body...
  
   around the aft section of the spacecraft's equipment adapter, pointed at 90 degree positions up, down, left and right. These were rated at 25 pound-forces (111.2 N) thrust and fired in pairs, causing it to pitch, roll, or yaw 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. These were rated at 100 pound-forces (444.8 N) thrust. One was pointed in each direction up, down, left or right, while two were pointed forrward to provide aft thrust.
• The two 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. These were rated at 85 pound-forces (378.1 N) (reduced from 100 pound-forces (444.8 N) in July 1962).

Events

During Gemini 8

Gemini 8

-Backup crew:-Mission parameters:* Mass: * Perigee: * Apogee: * Inclination: 28.91°* Period: 88.83 min-Objectives:Gemini VIII had two major objectives, of which it achieved one...

, 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.