When NASA sought a solution for transporting its approximately 100-ton space shuttles, it turned to the aviation industry for a robust transport vehicle. The agency evaluated two contenders: the gigantic Lockheed C-5 Galaxy and the iconic Boeing 747. Ultimately, NASA chose the 747 due to its superior design and performance capabilities.
The selection of the Boeing 747 hinged on its structural advantages. The aircraft’s airframe featured a low-wing design, making it a more stable platform for carrying the shuttle. In contrast, the C-5 Galaxy’s high-wing configuration posed challenges for mounting the shuttle securely. The 747 was a four-engine jumbo jet that entered commercial service in 1969, quickly establishing itself as one of the largest and most powerful commercial jets in history.
Each of the four Pratt & Whitney engines on the 747 produced 48,600 pounds of thrust, allowing the aircraft to undertake a maximum gross taxi weight of 713,000 pounds. Given that the modified 747s themselves weighed over 300,000 pounds when empty, the plane was well-equipped for this demanding task.
NASA modified two Boeing 747s specifically for shuttle transport. The first, designated NASA 905, was a 747-123 model acquired from American Airlines in 1974 for approximately $15.6 million. A second aircraft, the NASA 911, was added in 1989, a 747-100SR-46 sourced from Japan Air Lines. Both planes underwent extensive modifications to accommodate the shuttle.
To securely mount the shuttle, Boeing engineers installed three large struts on the fuselage, necessitating significant internal structural reinforcement. The addition of the shuttle altered the aircraft’s aerodynamics, prompting the installation of two extra vertical stabilizers on the tail to improve directional stability. These modifications were critical, as the shuttle’s delicate thermal protection tiles required careful handling during transport.
NASA’s initial tests in 1977 also featured an innovative crew escape system on the NASA 905, complete with pyrotechnics designed for emergencies. Transporting the shuttle involved complex procedures using structures known as Mate-Demate Devices, which lifted the shuttle high enough for the 747 to be driven underneath and attached securely.
The NASA 905 operated independently for over a decade, transporting shuttles to various destinations. In late 1990, the NASA 911 began sharing the responsibility, marking a new chapter in shuttle transport history. Following the retirement of the shuttle fleet, both planes had one final mission: ferrying the orbiters to their respective museum homes. Notably, the NASA 905 delivered the Discovery to the Smithsonian’s National Air and Space Museum, culminating in a celebratory flyover of Washington D.C. at approximately 1,500 feet.
The NASA 911 was retired in February 2012 and is now displayed at the Joe Davies Heritage Airpark. The NASA 905 followed suit later that year, becoming a centerpiece of an exhibition at the Space Center Houston. Through their service, these 747s have become iconic symbols of NASA’s space exploration efforts, forever linked to the legacy of the space shuttle program.
