Space Shuttle Orbital Maneuvering System

The Space Shuttle Orbital Maneuvering System (OMS), is a system of hypergolic liquid-propellant rocket engines used on the Space Shuttle. Designed and manufactured in the United States by Aerojet, the system was used during launch to produce supplementary thrust and on-orbit to provide orbital injection, orbital correction and the spacecraft's deorbit burn. The OMS consists of two pods mounted on the Orbiter's aft fuselage, on either side of the vertical stabilizer. Each pod contains a single AJ10-190 engine, based on the Apollo Service Module's Service Propulsion System engine, which produces 26.7 kilonewtons (6,000 lb_f) of thrust with a specific impulse (I_sp) of 316 seconds. Each engine could be reused for 100 missions and was capable of a total of 1,000 starts and 15 hours of burn time.