NASA faced a unique challenge when it required a method to transport its approximately 100-ton space shuttles. Without the option of calling a taxi service, the agency evaluated potential aircraft and selected the Boeing 747 over the Lockheed C-5 Galaxy. The decision centered on the 747’s design and power capabilities, which made it the ideal candidate for ferrying the iconic spacecraft.
The Boeing 747’s airframe, with its wings positioned below the main fuselage, provided a stable platform for mounting the shuttle. In contrast, the C-5’s high-wing design could have complicated the shuttle’s placement. The 747 not only excelled in design but also in power. With its four Pratt & Whitney engines, each capable of producing 48,600 pounds of thrust, the 747 had the necessary strength to transport heavy loads. This capability allowed it to handle a maximum gross taxi weight of 713,000 pounds, showcasing its robust engineering.
NASA modified two 747 aircraft for the shuttle transport role. The first, known as NASA 905, was a Boeing 747-123 model acquired from American Airlines in 1974 for $15,601,192. A second aircraft, the NASA 911, was added in 1989, a 747-100SR-46 sourced from Japan Air Lines. Both planes underwent extensive modifications, which included the installation of three large struts to secure the shuttle, necessitating significant structural reinforcement.
To improve aerodynamics, particularly with the added weight of the shuttle, engineers attached two extra vertical stabilizers to the tail. They also equipped the aircraft with instrumentation to monitor the orbiter’s electrical loads during flight. For the initial tests in 1977, NASA 905 even featured a crew escape system that used pyrotechnics, highlighting the innovative engineering involved in the shuttle transportation process.
The process of mounting the orbiter onto the 747 required specialized equipment known as Mate-Demate Devices. These structures raised the shuttle high enough to allow the 747 to be positioned beneath it for attachment. For over a decade, NASA 905 was the primary transport aircraft for the shuttle fleet, while NASA 911 joined operations in late 1990. Together, they shared the responsibility of ferrying the shuttles.
As the shuttle program came to a close, NASA 905 completed three final missions to deliver the orbiters to their respective museum locations. Notably, it transported the shuttle Discovery to the Smithsonian’s National Air and Space Museum, performing a celebratory loop around Washington D.C. at an altitude of approximately 1,500 feet. NASA 911 was retired in February 2012 and is now displayed at the Joe Davies Heritage Airpark. NASA 905 followed suit later that same year and became part of an extensive exhibit at Space Center Houston.
The Boeing 747’s role in the Space Shuttle program reflects the aircraft’s significant engineering and operational capabilities. Its legacy continues to be celebrated as an integral part of NASA’s history, demonstrating the innovative spirit of aerospace transportation.
