View source for Orbiter Processing Facility

{{Short description|Hangars formerly used for Space Shuttle maintenance at NASA's Kennedy Space Center}}
{{Infobox military installation
| name = Orbiter Processing Facility
| partof = [[Launch Complex 39]]
| country = United States
| image = Orbiter Processing Facility.jpg
| caption = {{OV|102}} at the entrance of Orbiter Processing Facility 3
| type = Facility
| coordinates = {{Coord|28.585803|-80.654991|region:US_type:landmark|display=inline,title}}
| operator = {{Unbulleted list
  | [[NASA]] (1981–2012)
  | [[Boeing]] (2014–present)
}}
| height = {{cvt|29|m}}
| length = {{cvt|121|m}}
| website = http://science.ksc.nasa.gov/facilities/opf.html
}}

'''Orbiter Processing Facility''' ('''OPF''') is a class of [[hangar]]s where U.S. [[Space Shuttle orbiter]]s underwent maintenance between flights. They are located west of the [[Vehicle Assembly Building]], where the orbiter was mated with its [[external tank]] and [[Space Shuttle Solid Rocket Booster|Solid Rocket Booster]]s before transport to the launch pad. OPF-1 and OPF-2 are connected with a low bay between them, while OPF-3 is across the street.

OPF-3 was previously called the Orbiter Maintenance & Refurbishment Facility (OMRF), but was upgraded{{when|date=December 2018}} to a fully functioning OPF.

== Processing flow ==
[[Image:STSdiscoveryinopf.jpg|thumb|''[[Space Shuttle Discovery|Discovery]]'' inside OPF-3 following the completion of mission [[STS-114]]]]

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. Any remaining [[Payload (air and space craft)|payload]]s from the previous mission were removed and the vehicle was fully inspected, tested, and refurbished.<ref name=afterlandingpao>{{cite web|title=From Landing to Launch Orbiter Processing|url=http://www-pao.ksc.nasa.gov/kscpao/nasafact/pdf/orbiterprocessing2002.pdf|publisher=NASA Public Affairs Office|url-status=dead|archive-url=https://web.archive.org/web/20110721053142/http://www-pao.ksc.nasa.gov/kscpao/nasafact/pdf/orbiterprocessing2002.pdf|archive-date=2011-07-21}}</ref>

* The orbiter's [[RS-25|main engines]] were purged to remove the moisture that was a by-product of liquid oxygen and liquid hydrogen combustion.  
* payload bay doors were opened and any hazardous payloads were processed for safety
* fuel cell tanks were drained of remaining cryogenic reactants.  The oxygen system was rendered inert with gaseous nitrogen and the hydrogen system with gaseous helium.
* high-pressure gases were vented from the environmental control and life support systems.
* refuse and other waste products including draining of the potable water system were offloaded
* heat shields were removed from the engines and aft access were opened 
* main engines were locked in place and covers installed.
* scaffolding was installed around the orbiters aft to allow technicians to access the main engines
* main engines were removed and transferred to the [[Main Engine Processing Facility]] for checkout and service
* any needed repairs on the orbiter's thermal protection system including the thermal blankets and the silica tiles were completed.<ref name="USA Newsletter">{{cite web|title=Reliable Shuttle Orbiters Need Special Care|url=http://www.unitedspacealliance.com/news/newsletters/issue080/Articles/ReliableShuttleOrbitersNeedSpecialCare.asp|publisher=United Space Alliance|url-status=dead|archive-url=https://web.archive.org/web/20110522111605/http://unitedspacealliance.com/news/newsletters/issue080/Articles/ReliableShuttleOrbitersNeedSpecialCare.asp|archive-date=2011-05-22}}</ref> 
* 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 modifications to the orbiter were completed in the OPF.
* After all its flights, the orbiter went through "Down Mission Processing."

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.  Remaining payloads, fuels and fluids were installed on the pad closer to launch day.  The last step before rollover to the VAB was weighing the orbiter to determine its center of gravity.<ref name=afterlandingpao/>

==Current status==
OPF-1 was closed following ''Atlantis'''s rollout on June 29, 2012. OPF-2 is now inactive following ''Atlantis''{{'}}s departure on October 18, 2012. OPF-3 is under lease to Boeing for the manufacture and testing of their [[CST-100 Starliner]] spacecraft.<ref>{{cite web |title=Boeing to Build Private Space Taxis in Old NASA Shuttle Hangar |date=2011-10-31 |website=[[Space.com]] |archive-url=https://web.archive.org/web/20230627052514/https://www.space.com/13453-nasa-leases-shuttle-hangar-boeing-space-taxi.html |archive-date=2023-06-27 |url-status=live |url=http://www.space.com/13453-nasa-leases-shuttle-hangar-boeing-space-taxi.html}}</ref>

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. Boeing had said the space planes would use OPF-1 in January 2014, and the Air Force had previously said it was considering consolidating X-37B operations, housed at Vandenberg Air Force Base in California, nearer to their launch site at Cape Canaveral. NASA also stated that the program had completed tests to determine whether the X-37B, one-fourth the size of the Space Shuttle, could land on the former Shuttle runways.<ref name="floridatoday20141008"/> NASA furthermore stated that renovations of the two hangars would be completed by the end of 2014; the main doors of OPF-1 were marked with the message "Home of the X-37B" by this point.<ref name="floridatoday20141008">{{cite news |url=http://www.floridatoday.com/story/tech/science/space/2014/10/08/secretive-x37b-space-plane-will-use-nasa-space-shuttle-hangars/16930223/ |title=NASA: Secret X-37B space plane will use shuttle hangars |work=[[Florida Today]] |first=James |last=Dean |date=8 October 2014 |access-date=9 October 2014}}</ref>

==References==
{{Include-NASA}}
<references/>

== External links ==
{{portal|Spaceflight}}
*[http://science.ksc.nasa.gov/facilities/opf.html Kennedy Space Center page on the Orbiter Processing Facility] (as of 1997–99)
*[http://science.ksc.nasa.gov/payload/lssm/facility/handbooks/opf.pdf Orbiter Processing Facility Payload Processing and Support Capabilities Handbook]

{{Kennedy Space Center}}
{{Space Shuttle}}

[[Category:Buildings and structures in Merritt Island, Florida]]
[[Category:Kennedy Space Center]]
[[Category:Space Shuttle program]]