Shuttle Carrier Aircraft

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Atlantis transported by a Boeing 747 Shuttle Carrier Aircraft

Schematic 3-view

The Shuttle Carrier Aircraft (SCA) are two extensively modified Boeing 747 jetliners that NASA uses to transport a space shuttle orbiter. One is a 747-100 model, while the other is a short range 747-100SR.

The SCAs are used to ferry space shuttles from landing sites back to the launch complex at the Kennedy Space Center, and to and from other locations too distant for the orbiters to be delivered by ground transport. The orbiters are placed on top of the SCAs by Mate-Demate Devices, large gantry-like structures which hoist the orbiters off the ground for post-flight servicing, and then mate them with the SCAs for ferry flights.

The first aircraft, N905NA, was originally manufactured for American Airlines and still carried visible American markings 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 a F-104 flying in close formation and simulating a "release" from the 747.

The aircraft was extensively modified in 1976, with the cabins being stripped, mounting struts added, and the fuselage strengthened; vertical stabilizers were added to the tail to aid stability when the Orbiter was being carried. (In practice, these were very rarely removed). The avionics and engines were also upgraded, and an escape system added to ship N905NA similar to that used on Boeing's first 747 test flights, the flight crew escape tunnel system was later removed following the completion of the Approach and Landing Tests (ALT) due to concerns regarding possible engine ingestion of an escaping crew member.

Space Shuttle Columbia, returning to Kennedy Space Center (KSC) after the successful STS-32 mission, is poised atop the Shuttle Carrier Aircraft (SCA) as the duo fly by the Vehicle Assembly Building (VAB) at KSC.

Flying with the drag of the Orbiter imposes fuel penalties - the range is reduced to just over 1000 nautical miles (1900 km), compared to an unladen range of 5500 nautical miles (10,000 km), meaning the SCAs normally have to stop several times on a transcontinental flight to refuel. The combination 747-shuttle travels about 125 feet per US gallon of fuel (about half the length of the plane, approximately .024 miles/gal or 100 L/km) It takes a crew of about 170 a week to prepare the shuttle and SCA for flight, and each transcontinental trip costs about $230,000[link]. Studies were made to equip the aircraft with aerial refueling equipment, a practice used for several US Air Force 747s. However, during formation flying with a tanker aircraft to test this, some minor cracking was found on the tailfin of N905NA. It was felt that, whilst this was not likely to be due to the test flights, there was no sense pushing matters too far; as there was no urgent requirement to provide an aerial refuelling capacity, the tests were suspended.

In 1988, in the wake of the Challenger accident, NASA procured a surplus 747-100SR from JAL. N911NA, as it was newly registered, entered service with NASA in 1990 after similar modifications; it was first used in 1991 to ferry the new shuttle Endeavour from the manufacturers in Palmdale, California to Kennedy Space Center.

The two aircraft are functionally identical, although careful examination can differentiate between them; N911NA has five upper-deck windows, whilst N905NA only has two. N905NA is depicted in both the photograph and the diagram on this page.

The C-5 Galaxy was considered for the role by NASA, but rejected in favour of the 747.

The 747-100 Shuttle Carrier currently resides at the Dryden Flight Research Center at Edwards Air Force Base, California.

Media

See also

• Captive carry

External links

• [NASA fact sheet]
• [NASA SCA images]

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