Shown here is a mock-up of a reaction control system (RCS) engine developed for use on the Apollo Service Module. RCS thrusters like this one were mounted externally in groups of four--called "quads"--with each engine nozzle facing outward. Collectively, the RCS thrusters helped the service module maneuver in space. Each engine burned hypergolic (storable) propellants (monomethyl hydrazine and nitrogen tetroxide) and produced 100 pounds of thrust and could be fired continuously or in short spurts (milliseconds in duration).
North American Aviation, the Apollo service module's primary contractor, selected the Marquardt Corporation to develop the RCS system in March 1962. Prototype testing began in July 1963, and the RCS engines Marquardt produced performed flawlessly throughout the Apollo program and during subsequent Saturn V missions.
Transferred from NASA's Marshall Space Flight Center.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.