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

Shown here is a test-fired attitude control motor of the APS (auxiliary propulsion system) for the S-IVB (third) stage of the Saturn V launch vehicle. APS motors like this one provided three axis control of roll, pitch, and yaw during Earth orbit and injection into lunar orbit. Each engine produced 150 pounds of thrust in pulses on request for a cumulative total of 5 minutes. The propellants consisted of hypergolic (self igniting) monomethyl hydrazine and nitrogen tetroxide. Each APS module on the S-IVB stage contained three 150 pound thrust motors.TRW (Thomson-Ramo-Woolridge) began developing the APS system for NASA in 1963. The system performed to specifications on all Saturn V flights from the unmanned Apollo 4 in 1967 through the last Apollo lunar mission in 1972.Donated by McDonnell Douglas Astronautics Co.