|
The Shuttle Carrier Aircraft (SCA) were two extensively modified Boeing 747 airliners that NASA used to transport Space 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 the Shuttle Landing Facility at the Kennedy 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 by Mate-Demate Devices, large gantry-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, the test shuttle ''Enterprise'' was released from an SCA during flight and glided to a landing under its own control. ==Design and development== The Lockheed C-5 Galaxy was considered for the shuttle-carrier role by NASA, but rejected in favor of the 747—in part due to the 747's low-wing design in comparison to the C-5's high-wing design, and also because the U.S. Air Force would have retained ownership of the C-5, while NASA could own the 747s outright. The first aircraft, a Boeing 747-100 registered N905NA, was originally manufactured for American Airlines and still carried visible American cheatlines while testing ''Enterprise'' in the 1970s. It was acquired in 1974 and initially used for trailing wake vortex research as part of a broader study by NASA Dryden, as well as Shuttle tests involving an F-104 flying in close formation and simulating a "release" from the 747. The aircraft appears in the background of a scene from ''The Six Million Dollar Mans second season episode "The Deadly Replay", filmed in 1974 at Edwards AFB. The aircraft was extensively modified by Boeing in 1976.〔Jenkins 2000, pp. 36-38.〕 While first-class seats were kept for NASA passengers, its main cabin and insulation were stripped, 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. Flying with the additional drag and weight of the Orbiter imposed significant fuel and altitude penalties. The range was reduced to 1,000 nautical miles (1,850 km), compared to an unladen range of 5500 nautical miles (10,100 km), requiring an SCA to stop several times to refuel on a transcontinental flight.〔Jenkins 2000, pp. 38-39.〕 Without the Orbiter, the SCA needed to carry ballast to balance out its center of gravity. The SCA had an altitude ceiling of 15,000 feet and a maximum cruise speed of Mach 0.6 with the orbiter attached.〔 A crew of 170 took a week to prepare the shuttle and SCA for flight. Studies were conducted to equip the SCA with aerial refueling equipment, a modification already made to the U.S. Air Force E-4 (modified 747-200s) and 747 tanker transports for the IIAF. 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 tricolor cheatline. NASA replaced it with its own livery, consisting of a white fuselage and a single blue cheatline.〔Comparison of photos taken in (1982 ) and (1983 ) at Airliners.net〕 That year, this aircraft was also used to fly ''Enterprise'' on a tour in Europe, with refuelling stops in Goose Bay, Canada; Keflavik, Iceland; England; and West Germany. It then went to the Paris Air Show.〔http://www.slate.com/id/2124238/〕 In 1988, in the wake of the ''Challenger'' accident, NASA procured a surplus 747-100SR from Japan Airlines. Registered (N911NA ) it entered service with NASA in 1990 after undergoing modifications similar to N905NA. It was first used in 1991 to ferry the new shuttle ''Endeavour'' from the manufacturers in Palmdale, California to Kennedy Space Center. Based at the Dryden Flight Research Center within Edwards Air Force Base in California 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".〔(2003 Edwards Air Force Base Air Show ), see Shuttle Carrier images.〕〔(Shuttle Carrier Aircraft N911NA album on Photobucket )〕 Shuttle Carriers were capable of operating from alternative shuttle landing sites such as those in the United Kingdom, Spain, and France. 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. Boeing transported its Phantom Ray unmanned combat aerial vehicle (UCAV) demonstrator from St. Louis, Missouri, to Edwards on a Shuttle Carrier on December 11, 2010.〔(Boeing Phantom Ray to catch shuttle ride at Lambert )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Shuttle Carrier Aircraft」の詳細全文を読む スポンサード リンク
|