In a docked configuration it is common for starships to achieve low-velocity attitude and translational control with the use of reaction control engines. The reaction control system (RCS) is primarily designed for sublight operations including station-keeping, drift mode three axis stabilisation and space dock manoeuvring. The engines them selves are not as complicated as the larger Impulse drive systems but use the same principles of exhausting hot gasses to achieve a propulsive effect.

Starships have reaction control thrusters positioned on key parts of the ship typically in multiples of 6 controlling the primary axis. Federation ships however have RCS thrusters in multiples of four as the thrusters have upper and lower vectored modes. These groups of reaction control engines are commonly referred to in the Federation as Thruster Quads for obvious reasons.

Each individual RCS engine consists of a gas fusion reaction chamber, an energy field trap, and upper and low exhaust nozzles. Duterium for each of the engines is stored in six immediate use tanks, which are normal tied to the main deuterium tank for replenishment. Ignition energy for the reaction chamber is supplied by the ships power distribution net which initiates a burst of gas fusion from the chamber.

A two stage MHD field trap lies just downstream from the main reaction chamber. The first stage acts as an energy recovery system returning some of the undifferentiated plasma back to the power net. The second stage performs partial throttle control in concert with fuel flow regulators, to control the exhaust products as they enter the thrust nozzle. Both stages are manufactured as a single module 4 X 4 X 2 meters.

The vectored nozzles direct the exhaust products at the proper angle for the desired force on the ships spaceframe. Each nozzle produces a maximum of 3 million Newtons thrust with one nozzle active, and 5.5 million Newtons with both nozzles active. Kreigerium plate valves regulate the relative proportions of exhaust products flowing through the upper and lower nozzle components.

Also incorporated into the RCS quads are precision mooring beam tractor emitters used for close-quarters and docking maneuvers when starbase equivalent beams are not available.