Overview
The Shuttle Carrier Aircraft (SCA) were two specially modified Boeing 747-100 jetliners operated by the National Aeronautics and Space Administration (NASA) to transport the Space Shuttle orbiters between locations. The aircraft carried the orbiter mounted atop the fuselage using a pair of structural struts. The SCA enabled rapid relocation of the orbiters for launch, landing, refurbishment, and display.
Development and Modification
- Selection of airframe: NASA chose the Boeing 747‑100 because of its high payload capacity, long-range capability, and strong airframe.
- Conversion period: Modifications were performed at Boeing’s facilities in 1975‑1976. The work included structural reinforcement of the upper fuselage, installation of twin 12‑inch‑diameter mounting struts, additional avionics for low‑altitude, low‑speed flight, and the integration of external fuel tanks to extend range when carrying a Shuttle orbiter.
- Designations:
- NASA 905 – the first SCA, tail number N905NA.
- NASA 911 – the second SCA, tail number N911NA, later designated as a “Super‑747” because of its larger external fuel tanks.
Operational History
- First use: The first SCA carried the Space Shuttle Enterprise on 12 September 1977 for a series of captive‑flight tests at Edwards Air Force Base.
- Primary missions: Throughout the Shuttle program (1977‑2011), the SCAs ferried orbiters between the Kennedy Space Center (KSC) in Florida, Edwards Air Force Base in California, and the Dryden Flight Research Center (now Armstrong Flight Research Center) in California. They also transported orbiters to museums after retirement.
- Range and performance: With a Shuttle orbiter mounted, the SCA could travel approximately 1,000 nautical miles (1,850 km) without refueling; the addition of external fuel tanks increased this to roughly 2,000 nautical miles (3,700 km). Typical cruise speed while carrying an orbiter was about 300 kt (560 km/h), and maximum altitude was limited to about 10,000 ft (3 km) to keep the orbiter within safe airflow conditions.
- Retirement: The last Shuttle ferry flight occurred on 21 July 2012, when NASA 905 delivered Atlantis to the Smithsonian National Air and Space Museum. Both aircraft were subsequently retired from active service and placed in storage.
Aircraft Specifications (as modified)
| Parameter | NASA 905 (SCA‑1) | NASA 911 (SCA‑2) |
|---|---|---|
| Base model | Boeing 747‑100 | Boeing 747‑100 |
| Length | 232 ft 10 in (71.0 m) | 232 ft 10 in (71.0 m) |
| Wingspan | 196 ft 0 in (59.7 m) | 196 ft 0 in (59.7 m) |
| Height | 63 ft 6 in (19.4 m) | 63 ft 6 in (19.4 m) |
| Maximum take‑off weight (MTOW) | 750,000 lb (340,000 kg) | 750,000 lb (340,000 kg) |
| Empty weight | 359,000 lb (162,800 kg) | 359,000 lb (162,800 kg) |
| Engines | Four Pratt & Whitney JT9D-7A turbofans (each ≈ 46,300 lbf thrust) | Same as above |
| Shuttle payload capacity | Up to 165,000 lb (75,000 kg) – the typical mass of an orbiter | Same |
| Range with orbiter (no external tanks) | ≈ 1,000 nmi (1,850 km) | ≈ 1,000 nmi (1,850 km) |
| Range with external tanks | ≈ 2,000 nmi (3,700 km) | ≈ 2,000 nmi (3,700 km) |
Notable Missions and Events
- Captive‑flight tests (1977‑1979): Demonstrated the aerodynamic compatibility of the Shuttle mounted atop the aircraft.
- First operational transport (1979): Moved Columbia from the Virgin Islands to KSC after a post‑flight inspection.
- International ferry (1990): Delivered Atlantis to the European Space Agency’s launch site in French Guiana for integration testing (orbiters never launched from there, but the flight demonstrated global reach).
- Post‑Shuttle use (2012‑present): Both SCAs have been used for transport of large aerospace components, including Hughes‑Lloyd’s aircraft structures, under special NASA contracts.
Retirement and Legacy
Following the conclusion of the Space Shuttle program, NASA retired the SCAs. Their unique role as the only aircraft ever designed to carry a full‑size spaceplane on its back remains a singular achievement in aerospace engineering. The aircraft are preserved as historic artifacts, with NASA 905 displayed at the Smithsonian’s National Air and Space Museum’s Steven F. Udvar-Hazy Center and NASA 911 stored at the Armstrong Flight Research Center pending future display decisions.
References
- NASA, “Shuttle Carrier Aircraft (SCA),” NASA Fact Sheet, accessed 2023.
- Boeing Commercial Airplanes, “747‑100 Technical Data.”
- NASA History Office, “The Space Shuttle: The “Space Shuttle Carrier Aircraft” (SCA).”
All information reflects data available from official NASA and Boeing publications up to 2023.
