Discovery in the Orbiter Processing Facility

The Orbiter Processing Facility (OPF) is the hangar where NASA's Space Shuttle Orbiter undergoes maintenance between flights.

When a mission is completed, the orbiter is parked in its OPF. Its previous mission payloads are removed and the vehicle is fully inspected, tested, and refurbished, including re-tiling of the Thermal Protection System. Then part of the payloads for its next mission are installed and checked out.

There are three such facilities, OPF-1, OPF-2, and OPF-3, at the Kennedy Space Center in Florida. OPF-1 and OPF-2 are connected together with a low bay in between them, while OPF-3 is across the street. They are located west of the Vehicle Assembly Building, where the orbiter is mated with its External Tank and Solid Rocket Boosters before launch.

OPF-1 is assigned to Atlantis, OPF-2 to Endeavour and OPF-3 to Discovery.