The Boeing 747 has taken many forms over its decades of service. First introduced in 1970, the Queen of the Skies has flown for airlines around the world. It’s also had a handful of side gigs over the past 55 years, serving as the iconic Air Force One, a command and control post and even an airborne firefighter. Some proposals have become as crazy as Boeing’s to transform the 747 into a flying aircraft carrier. Although it never made it past the study phase, NASA would eventually take advantage of the plane’s low wing profile and streamlined tail configuration to give the plane the task of carrying a plane like no other: the Space Shuttle.
For three decades, the iconic space shuttles were the flagships of American spaceflight. During their 135 missions, the five shuttles achieved major milestones, including launching the first American woman into space and launching a spacecraft deep into our solar system. They deployed and repaired the Hubble Space Telescope, which gave us never-before-seen views of our universe. Most notably, they helped unite nations as workhorses behind the construction of the International Space Station.
However, none of these missions and moments would be possible without a pair of hot rodded Boeing 747s. While five orbiters could carry 8 tons of cargo into low Earth orbit before returning home, only two jumbo jets could get them back into position for their next mission. Meet the 747 Shuttle Carrier Aircraft, or SCA.
Need an elevator?
Each of the shuttle’s 135 missions began at the Kennedy Space Center at Cape Canaveral. It’s an easy trip to make if the shuttle lands in Florida, but 54 times weather disruptions have forced a landing at the backup site at Edwards Air Force Base in California. If things got really bad, emergency landing sites were prepared along the East Coast and across the Atlantic. NASA quickly realized it needed a way to get its shuttles back to Florida, and its cavernous Apollo-carrying Super Guppy was nowhere near big enough to carry them.
For the SCA, NASA landed the two largest aircraft on the market: Lockheed’s C-5 Galaxy military transport or the Boeing 747. Boeing’s low-wing design and tail configuration were preferred, so it was deemed more appropriate to have an orbiter on its back. Additionally, any C-5 would be loaned to the agency by the Air Force, while NASA could have full ownership of a 747. This made the Queen of the Skies an easy choice.
To mount the orbiter to the rear of the aircraft, three struts would be installed on top of the fuselage, using the same attachment points that the orbiter used to attach the orange external fuel tank at launch. However, the presence of a shuttle at the rear of the jet obstructed airflow to the vertical stabilizer, so two additional stabilizers were installed on the tail section to increase stability.
Inside the jet, a host of modifications were made to allow the 747 to carry an additional 170,000 pounds of Space Shuttle. In addition to the structural strengthening of the fuselage, insulation, seats and interior panels were removed from the jet’s interior to save weight. Only first class seats remained on board to transport NASA personnel during missions.
Alpha and Omega
NASA and Boeing began converting an old 747-100 into the first of the carriers in 1974. Formerly flying for American Airlines, the first SCA, dubbed NASA 905, would play a central role in the development and testing of the shuttle, as it would take it off the ground during approach and landing tests. A series of missions in 1977 saw the shuttle and 747 separate in mid-air, allowing the orbiter to return to earth for its very first flights.
After testing, the SCA began transporting the shuttles that landed in California to Cape Canaveral. Although much faster than any rail or land transport, delivery was far from simple. Upon landing, more than 170 engineers had to help load and unload the shuttle from behind the SCA. This orbiter also made the 747 incredibly bulky. While most 747s could easily fly from New York to London, the orbiter reduced the SCA’s range to around 1,000 miles, with speed and ceiling limited to only Mach 0.6 and 15,000 feet. The limited range meant that returning a shuttle to Florida took up to three days.
Fortunately, help was on the way. In 1989, a 747-100SR acquired from Japan Airlines would begin the modification process to enter service as NASA 911. Together, the two aircraft would shuttle from the Pacific to the Atlantic a total of 87 times during the shuttle program, allowing them to return to space within a few months.
After their final missions in 2011, the SCAs would take the three remaining shuttles to their retirement homes in museums across the country, marking the end of one of NASA’s most beloved programs and the two Boeings that kept them alive.