On 8 October 2014, NASA confirmed that Boeing X-37B vehicles would be housed at Kennedy Space Center in OPF-1 and 2, hangars previously occupied by the Space Shuttle. OPF-3 is under lease to Boeing for the manufacture and testing of their CST-100 Starliner spacecraft. OPF-2 is now inactive following Atlantis 's departure on October 18, 2012. OPF-1 was closed following Atlantis's rollout on June 29, 2012. The last step before rollover to the VAB was weighing the orbiter to determine its center of gravity.

Remaining payloads, fuels and fluids were installed on the pad closer to launch day. Prior to rollout to the Vehicle Assembly Building, several weeks before scheduled launch, the orbiter was prepared for the next mission by installing mission flight kits, payloads, consumable fluids and gases where possible.

After all its flights, the orbiter went through 'Down Mission Processing.'.any modifications to the orbiter were completed in the OPF.the Orbital Maneuvering System and Reaction Control System pods were possibly removed and transferred to the Hypergol Maintenance Facility for troubleshooting, repair or other services.any needed repairs on the orbiter's thermal protection system including the thermal blankets and thousands of tiles were completed.main engines were removed and transferred to the Main Engine Processing Facility for checkout and service.scaffolding was installed around the orbiters aft to allow technicians to access the main engines.main engines were locked in place and covers installed.heat shields were removed from the engines and aft access were opened.refuse and other waste products including draining of the potable water system were offloaded.

high-pressure gases were vented from the environmental control and life support systems.

The oxygen system was rendered inert with gaseous nitrogen and the hydrogen system with gaseous helium.

fuel cell tanks were drained of remaining cryogenic reactants.

payload bay doors were opened and any hazardous payloads were processed for safety.

The orbiter's main engines were purged to remove the moisture that was a by-product of liquid oxygen and liquid hydrogen combustion.

Any remaining payloads from the previous mission were removed and the vehicle was fully inspected, tested, and refurbished. When a Shuttle mission was completed, the orbiter was towed from the Shuttle Landing Facility to its assigned OPF where it spent several months (typically less than 100 days) being prepared for the next mission. Discovery inside OPF-3 following the completion of mission STS-114

Orbiter processing facility