This 1/50th scale model built by Robert Wisswell shows the Enterprise ALT, a Space Shuttle full size vehicle designed to test the Approach and Landing handling of the Shuttle design.

The term “747 SCA” refers to the Boeing 747 Shuttle Carrier Aircraft, a modified Boeing 747 jumbo jet used by NASA (the United States’ National Aeronautics and Space Administration) to transport the Space Shuttle orbiters. The Space Shuttle program operated from the early 1980s until 2011, and the 747 SCA played a crucial role in this program.

Here are some key points about the 747 Shuttle Carrier Aircraft (SCA):

1. Purpose: The 747 SCA was specifically modified to transport the Space Shuttle orbiters, which are large and heavy spacecraft. It was used to ferry the Space Shuttle orbiters from their landing sites back to the Kennedy Space Center in Florida or to other launch and processing facilities.
2. Modifications: To accommodate the Space Shuttle, the 747 SCA underwent extensive modifications. The most prominent change was the addition of a special mount on its fuselage, called the Shuttle Carrier Aircraft Pylon, which allowed the Space Shuttle to be securely attached to the back of the 747.
3. Piggyback Flights: The Space Shuttle orbiter was mounted on top of the 747 SCA for piggyback flights. These flights were conducted when the Space Shuttle needed to be transported between locations, such as after a mission’s landing or when being transported to a launch site. The 747 SCA essentially served as a “taxi” for the Space Shuttle.
4. Safety Precautions: The combination of the 747 SCA and the Space Shuttle was a highly visible and complex operation. Safety measures and engineering considerations were critical to ensure the safety of both the aircraft and the Space Shuttle during piggyback flights.
5. Historic Flights: The 747 SCA was involved in many historic moments during the Space Shuttle program. Notable flights included transporting the Enterprise prototype for approach and landing tests, as well as transporting operational Space Shuttles between Kennedy Space Center, Edwards Air Force Base, and other locations.
6. Retirement: Following the retirement of the Space Shuttle program in 2011, NASA retired the 747 SCA as well. The last piggyback flight took place in September 2012 when the Space Shuttle Endeavour was transported to its final destination, the California Science Center in Los Angeles.

The 747 SCA played a crucial role in the transportation and logistics of the Space Shuttle program, allowing for the safe and efficient movement of Space Shuttle orbiters between launch sites, mission landings, and other locations. It remains an important part of spaceflight history.