Space Shuttle Orbiter Diagram

The forward rockets of the Reaction Control System, located near the nose of the Space Shuttle orbiter, included 14 primary and two vernier RCS rockets. The aft RCS engines were located in the two Orbital Maneuvering System (OMS) pods at the rear of the orbiter, and these included 12 primary (PRCS) and two vernier (VRCS) engines in each pod. The PRCS system provided the pointing control of the Orbiter, and the VRCS was used for fine maneuvering during the rendezvous, docking, and undocking maneuvers with the International Space Station, or formerly with the Russian Mir space station. The RCS also controlled the attitude of the orbiter during most of its re-entry into the Earth’s atmosphere – until the air became dense enough that the rudder, elevons and body flap became effective.