Ascent Propulsion System

The Ascent Propulsion System (APS) or LMAE (Lunar Module Ascent Engine) is a fixed thrust hypergolic rocket engine developed by Bell Aerosystems for use in the Apollo Lunar Module Ascent Stage. It used Aerozine 50 fuel, and N2O4 oxidizer. Rocketdyne provided the injector system, at the request of NASA, when Bell could not solve combustion instability problems.