America's Space Shuttle: Reaction Control System NASA Astronaut Training Manual (RCS 2102A‪)‬

This unique and historic document provides extraordinary detail about the Space Shuttle's reaction control system (RCS). The official NASA astronaut training manuals comprised a major part of the formal flight crew training process, and were used by flight controllers as well. These internal NASA manuals were produced by the Mission Operations Directorate (Space Flight Training Division branch) at NASA's Johnson Space Center. The manuals and workbooks are extremely detailed and comprehensive, and are designed for self-study. A full listing of all acronyms and abbreviations used in the text is included. They provide a superb way to learn about Shuttle systems, hardware, and operational procedures. Special emphasis on crew interaction with the displays, controls, and hardware is included.

The reaction control system (RCS) is located in three separate modules in the vehicle: forward, left, and right. The forward module is contained in the nose area, forward of the cockpit windows. The left and right modules are collocated with the orbital maneuvering system (OMS) in the left and right OMS pods, near the tail of the vehicle.

The RCS provides propulsive forces from a collection of jet thrusters in order to control the motion of the Space Shuttle vehicle. Each jet is permanently fixed to fire in a particular direction, either up, down, left, right, forward, or aft. The selective firing of individual jets (or specific combinations of jets) will provide the Orbiter with rotational movement (about an axis) or translational movement (along an axis). Refer to figure 1-2 for jet fire directions.

Rotational movement is primarily utilized for attitude control. RCS attitude control is used during orbital conditions, except during OMS burns when OMS gimballing provides attitude control. (The RCS can assist the OMS with attitude control if OMS gimballing is inadequate due to failures). During ascent, the RCS can assist the main propulsion system (MPS) during off-nominal situations with additional roll control. During entry, the RCS provides attitude control until the flight control surfaces become effective.

Translational movement is primarily utilized for velocity changes. Rendezvous and proximity operations on orbit may require a combination of both rotation and translation.

The RCS has a total of 44 jets. There are 38 primary jets and 6 vernier jets. Each primary jet is rated at 870 lb of thrust and each vernier jet is rated at 24 lb of thrust. The vernier jets are only used on orbit for fine attitude control. The forward RCS has 14 primary jets and 2 verniers while each aft module has 12 primary jets and 2 verniers.