Shuttle Carrier Aircraft
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The Shuttle Carrier Aircraft (SCA) are two extensively modified Boeing 747 airliners that NASA uses to transport space shuttle orbiters. 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, or more specifically, the NASA Shuttle Landing Facility, 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.
In early test flights, the shuttle was released from SCA during flight, and the shuttle glided to a landing under its own control.[1]
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[edit] Development
The first aircraft, a Boeing 747-100 registered 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 an F-104 flying in close formation and simulating a "release" from the 747.
The aircraft was extensively modified in 1976: its cabin was 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 similar to that used on Boeing's first 747 test flights was added to ship N905NA. 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.
The 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 due to the consideration that U.S. Air Force would have retained ownership of the C-5 aircraft, while NASA would have been able to own the 747s outright.
Flying with the additional drag and weight of the Orbiter imposes fuel and altitude 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), requiring an SCA to stop several times to refuel on a transcontinental flight. The SCA has an altitude ceiling of 25,000 feet and a maximum cruise speed of 0.7 mach, with or without the orbiter attached. It takes a crew of about 170 a week to prepare the shuttle and SCA for flight.[2]
Studies were conducted to equip the SCA with aerial refueling equipment, a modification already made to several U.S. Air Force 747s. 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 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.
In 1988, in the wake of the Challenger accident, NASA procured a surplus 747-100SR N911NA from Japan Airlines. Registered N911NA it entered service with NASA in 1990 after similar modifications to N905NA. 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 N911NA has five upper-deck windows on each side, while N905NA only has two. N905NA is depicted in both the photograph and the diagram on this page.
One Shuttle Carrier currently resides at the Dryden Flight Research Center at Edwards Air Force Base, California (likely N911NA). The other Shuttle Carrier is located at Pinal Airpark in Arizona (KMZJ) (likely N905NA). On N905NA the rear mounting point is labeled with a tongue-in-cheek instruction to "Attach Orbiter Here" — clarified by the precautionary warning "Black Side Down".[3]
[edit] Popular culture
In the pre-credit sequence of the 1979 James Bond film Moonraker, a Space Shuttle is launched off the top of a 747-100 in mid-flight, causing the 747 to explode (which is not possible with a real shuttle as the fuel for its main engines is only carried in its external tank).
A Lego set was produced with a large four-engine aircraft that would carry a space shuttle on it.[4]
[edit] See also
[edit] References
- ^ NASA - Dryden Flight Research Center (1977). Shuttle Enterprise Free Flight. NASA. Retrieved on November 28, 2007.
- ^ Felix Gilette (9 August 2005). How Does the Space Shuttle Fly Home?. Retrieved on 2007-11-23.
- ^ 2003 Edwards Air Force Base Air Show, see Shuttle Carrier images.
- ^ Brickset.com: 6544 Shuttle Transcon 2.
[edit] Bibliography
- Space Shuttle: History of the National Space Transportation System - The First 100 Missions. Jenkins, Dennis R. Midland Publishing, 2003. [Third edition]
[edit] Media
 Aft end of the interior. Note the large stuffed spider mounted on the aft pressure bulkhead. |
 SCA approaching Space Shuttle Endeavour suspended in the Mate-Demate Device (MDD), April, 1994 |
 SCA mating with Space Shuttle Endeavour in the Mate-Demate Device (MDD), April, 1994 |
 SCA ferry flights, 1992 |
 Takeoff of the Shuttle Carrier Aircraft and on its back the Space Shuttle Enterprise |
 Atlantis transported by a Shuttle Carrier Aircraft. |
.jpg/120px-Shuttle_Atlantis_heads_home_on_a_modified_747_(2007-07-01).jpg) Atlantis atop a Shuttle Carrier. |
 Atlantis being mated to the SCA at Dryden Flight Research Center. |
 One of the SCA's at its Dryden Flight Research Center home, with a very wet Rogers Dry Lake behind it. |
 SCA 3 view Schematic |
[edit] External links
- NASA fact sheet
- NASA SCA images
- Interview with SCA Pilot and Former Astronaut Gordon Fullerton
- Interview with SCA Crew Chief Pete Seidl
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