File:KSC-04-S-00217 (ksc 070704 frcs).webm

English: Just like cars and airplanes, Space Shuttles need regular maintenance to keep them shipshape and performing at their best. As part of its routine maintenance schedule, Discovery has just received its newly refurbished Forward Reaction Control System, or FRCS. Located between the nose cap and cockpit windows, the FRCS is made up of a series of thrusters and is the orbiter's most versatile propulsion system: 'The Forward Reaction Control System that we just recently installed on the vehicle is used basically in three phases of the flight: One, during ascent we use it to separate from the External Tank. The next phase is for orbiter insertion and then it's used during flight for all of the maneuvering. It has 14 primary thrusters and two vernier thrusters which are used during some of the more finite movement, during the payload, some of the docking, some of that type of work during the mission.' The system was removed from Discovery as part of the vehicle's OMM, or Orbiter Major Modification. The OMM is a periodic overhaul of the vehicle that takes place after three years or eight flights. During the OMM, the orbiters are completely stripped down, inspected, and reassembled with refurbished or new parts. The installation of the FRCS is also needed to configure other orbiter systems. 'Also, the FRCS is required to be installed to do our alignment of what we call the HUD, that is the Heads Up Display. Those displays are on the dashboard in front of the commander and pilot and are essential during the landing phase. They're used to line the vehicle up with the runway when they're finally coming in here to KSC at the end of the mission.' With the forward reaction control system back in place, Discovery is one step closer to a safe return to flight.