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Rocket Engine, Liquid Fuel, Auxiliary Propulsion System (APS), Thruster, Saturn


Display Status:

This object is on display in the Rockets and Missiles exhibition at the Steven F. Udvar-Hazy Center in Chantilly, VA.

Collection Item Summary:

This is an attitude control motor, or APS (Auxiliary Propulsion System), for the third stage of the Saturn V launch vehicle that took men to the Moon in Project Apollo. APS motors provided control in the three axes of roll, pitch and yaw control during Earth orbit and injection into lunar orbit. They produced 150 pounds of thrust generated as pulses, as required.

The propellant was hypergolic (self-igniting) nitrogen tetroxide as the oxidizer and monomethyl hydrazine as the fuel. This motor has been fired in tests. APS motors were used in all the Apollo Saturn V flights from 1967 to 1972 and for orbiting Skylab in 1973. This object was donated to the Smithsonian in 1974 by McDonnell Douglas Astronautics.

Collection Item Long Description:

Data Source

National Air and Space Museum


Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum

Credit Line

Gift of McDonnell Douglas Astronautics Company


Nozzle and chamber, phenolic impregnated silica with fiberglass overwrap; nozzle, sprayed zirconia coating; propellant inlets and valves, metal


Overall: 1 ft. 7 in. long x 1 ft. 2 1/2 in. diameter (48.26 x 36.83cm)

Country of Origin

United States of America


PROPULSION-Rocket Engines

Inventory Number