14 DAY TRIAL // After 38 years of service, and 33,004.1 hours of flight, one of only two NASA Shuttle Carrier Aircraft (SCA) is being retired from active service. Codenamed NASA 911, the heavily-modified Boeing 747 saw plenty of action during the days of the Space Shuttle Program (SSP).
The SCA were responsible for carrying the shuttles around the country in special cases, such as for example when the spacecraft landed in California, rather than Florida. They were also used during the first glide tests conducted with shuttle Enterprise, Space reports.
The remaining SCA, codename NASA 905, will remain in active service until Atlantis, Endeavour and Discovery are made safe for public display at their respective museums. The aircraft will then carry the orbiters to Washington and Los Angeles, before being retired from active duty itself.