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.
Gift of McDonnell Douglas Astronautics Company