TheShuttle Carrier Aircraft(SCA) are two extensively modifiedBoeing 747airliners thatNASAused to transportSpace Shuttle orbiters. One is a 747-100 model, while the other is a short range 747-100SR.The SCAs were used to ferry Space Shuttles from landing sites back to theShuttle Landing Facilityat theKennedy Space Center, and to and from other locations too distant for the orbiters to be delivered by ground transport. The orbiters were placed on top of the SCAs byMate-Demate Devices, largegantry-like structures that hoisted the orbiters off the ground for post-flight servicing then mated them with the SCAs for ferry flights.In approach and landing test flights conducted in 1977, thetest shuttle Enterprisewas released from an SCA during flight and glided to a landing under its own control.[1]Contents[hide] 1Design and development 2Retirement 3Specifications 4Ferry flights 5Gallery 6See also 7References 7.1Bibliography 8External linksDesign and development[edit]TheLockheed C-5 Galaxywas considered for the shuttle-carrier role by NASA, but rejected in favor of the 747in part due to the 747's low-wing design in comparison to the C-5's high-wing design, and also because theU.S. Air Forcewould have retained ownership of the C-5, while NASA could own the 747s outright.

Shuttle Carrier Aircraft N905NA, inAmerican Airlineslivery, withEnterprisein 1978The first aircraft, a Boeing 747-100 registered N905NA, was originally manufactured forAmerican Airlinesand still carried visible Americancheatlineswhile testingEnterprisein the 1970s. It was acquired in 1974 and initially used for trailing wake vortex research as part of a broader study byNASA Dryden, as well as Shuttle tests involving anF-104flying in close formation and simulating a "release" from the 747. The aircraft appears in the background of a scene fromThe Six Million Dollar Man's second season episode "The Deadly Replay", filmed in 1974 atEdwards AFB.The aircraft was extensively modified by Boeing in 1976.[2]While first-class seats were kept for NASA passengers, its main cabin and insulation were stripped,[3]mounting struts were added, and the fuselage was strengthened. Vertical stabilizers were added to the tail to aid stability when the Orbiter was being carried. The avionics and engines were also upgraded, and an escape tunnel system similar to that used on Boeing's first 747 test flights was added. The flight crew escape tunnel system was later removed following the completion of the Approach and Landing Tests (ALT) due to concerns over possible engine ingestion of an escaping crew member.

Atlantisbeing mated to SCA N911NA at Dryden Flight Research CenterFlying with the additional drag and weight of the Orbiter imposed significant fuel and altitude penalties. The range was reduced to 1,000 nautical miles (1,850km), compared to an unladen range of 5500 nautical miles (10,100km), requiring an SCA to stop several times to refuel on a transcontinental flight.[4]Without the Orbiter, the SCA needed to carry ballast to balance out its center of gravity.[3]The SCA had an altitude ceiling of 15,000 feet and a maximum cruise speed of Mach 0.6 with the orbiter attached.[4]A crew of 170 took a week to prepare the shuttle and SCA for flight.[5]

Columbiaatop SCA N905NA, flying by theVehicle Assembly Building(VAB) atKennedy Space Center(KSC), 1990. N905NA no longer has American Airlines' pinstriping.Studies were conducted to equip the SCA withaerial refuelingequipment, a modification already made to theU.S. Air ForceE-4(modified 747-200s) and 747 tanker transports for theIIAF. However, during formation flying with a tanker aircraft to test refueling approaches, minor cracks were spotted on the tailfin of N905NA. While these were not likely to have been caused by the test flights, it was felt that there was no sense taking unnecessary risks. Since there was no urgent need to provide an aerial refueling capacity, the tests were suspended.By 1983, SCA N905NA no longer carried the distinct American Airlines tricolorcheatline. NASA replaced it with its own livery, consisting of a white fuselage and a single blue cheatline.[6]That year, this aircraft was also used to flyEnterpriseon a tour in Europe, with refuelling stops inGoose Bay,Canada;Keflavik, Iceland;England; andWest Germany. It then went to theParis Air Show.[7]In 1988, in the wake of theChallengeraccident, NASA procured a surplus 747-100SR fromJapan Airlines. RegisteredN911NAit entered service with NASA in 1990 after undergoing modifications similar to N905NA. It was first used in 1991 to ferry the new shuttleEndeavourfrom the manufacturers inPalmdale, CaliforniatoKennedy Space Center.

Humorous note on Orbiter Mount reminding technicians how to connect the orbiter to the transportBased at theDryden Flight Research CenterwithinEdwards Air Force BaseinCalifornia[3]the two aircraft were functionally identical, although N911NA has five upper-deck windows on each side, while N905NA has only two. The rear mounting points on both aircraft were labeled with humorous instructions to "attach orbiter here" or "place orbiter here", clarified by the precautionary note "black side down".[8][9]Shuttle Carriers were capable of operating fromalternative shuttle landing sitessuch as those in theUnited Kingdom,Spain, andFrance. Due to the reduced range of the Shuttle Carrier while mated to an orbiter, additional preparations such as removal of the payload from the orbiter may have been necessary to reduce its weight.[10]

Silhouettes listing the number of ferry and free flights of the various Orbiters and the Phantom Ray on the port side of the SCABoeingtransported itsPhantom Rayunmanned combat aerial vehicle(UCAV) demonstrator from St. Louis, Missouri, to Edwards on a Shuttle Carrier on December 11, 2010.[11]Retirement[edit]Shuttle Carrier N911NA retired on February 8, 2012 after its final mission to the Dryden Aircraft Operations Facility in Palmdale, California, and will be used as a source of parts for NASA'sStratospheric Observatory for Infrared Astronomy(SOFIA).[12]Shuttle Carrier N905NA was used to ferry the retired Shuttles to their respective museums. It returned to the Dryden Flight Research Facility at Edwards Air Force Base in California after a short flight from Los Angeles International Airport on September 24, 2012. It was intended to join N911NA as a source of spare parts for NASA's SOFIA aircraft.[12][13]NASA engineers surveyed N905NA and determined that it had few parts usable for SOFIA, and 905 is now intended to be preserved and displayed in Houston. Three former NASA aircraft are on static display in the Houston area - twoT-38sat the front entrance of Space Center Houston, and the former NASAKC-135 930 Vomit Comet. In 2013, the Space Center announced plans to display SCA 905 with the mockup shuttleIndependencemounted on its back.[14]NASA 905 was erected on site at the space center, having been ferried in pieces fromEllington Field, and the replica shuttle was mounted in August 2014.[15]The display is scheduled to open in 2015.Shuttle Carrier N911NA is being loaned out for display to the Joe Davies Heritage Airpark in Palmdale, Calif., beginning in September 2014.[16]The aircraft will remain a source of spare parts for the SOFIA program.Specifications[edit]

Data fromBoeing 747-100 specifications[17]Jenkins 2000[4]General characteristics Crew:4: pilot, co-pilot, 2 flight engineers (1 flight engineer when not carrying Shuttle) Length:231 ft 4 in (70.5 m) Wingspan:195 ft 8 in (59.7 m) Height:63 ft 5 in (19.3 m) Wing area:5,500 ft (510 m) Empty weight:318,000 lb (144,200 kg) Max. takeoff weight:710,000 lb (322,000 kg) Powerplant:4 P&W JT9D-7Jturbofans, 50,000 lbf (222 kN) eachPerformance Cruise speed:Mach 0.6 (with Shuttle) (397 knots, 457 mph, 735 km/h) Range:1,150 mi (1,000 nmi, 1,850 km) while carrying Shuttle Service ceiling:15,000 ft (4,500 m) (with Shuttle)Ferry flights[edit]Further information:List of Shuttle Carrier Aircraft flightsFerry flights generally transported the orbiters fromEdwards Air Force Base, the shuttle's secondary landing site, to theShuttle Landing Facility(SLF) at theKennedy Space Centerwhere the orbiter would be processed. This was common in the early days of the space shuttle program when weather conditions at the SLF prevented the shuttle from landing there. A number of flights started at theDryden Flight Research Centerfollowing delivery of the orbiter fromRockwell Internationalto NASA from the nearby facilities in Palmdale, California.[18]At the end of the space shuttle program the SCA was used to deliver the retired orbiters from the Kennedy Space Center to their museums.Discoverywas delivered to theUdvar-Hazy Centerof theSmithsonian Institution'sNational Air and Space MuseuminChantilly, Virginia, near Washington, D.C. on April 19, 2012. On April 17, 2012, Discovery was flown atop a Shuttle Carrier Aircraft escorted by a NASA T-38 Talon chase aircraft in a final farewell flight. The 747 and Discovery flew over Washington, D.C. and the metropolitan area around 10am and arrived at Dulles around 11am. The flyover and landing were widely covered on national news media.The last ferry flight tookEndeavourfrom Kennedy Space Center toLos Angelesbetween 19 and 21 September 2012 viaEllington Fieldand Edwards Air Force Base. After leaving Edwards the SCA withEndeavourperformed low level flyovers above various landmarks across California, fromSacramentoto theSan FranciscoBay Area, and finally to Los Angeles.Endeavourwas delivered toLos Angeles International Airport (LAX). From there the orbiter would be transported through the streets of Los Angeles andInglewoodto its final destination in the California Science Center inExposition Park.