NASA used modified Boeing 747-100 variants as Space Shuttle Carrier Aircraft

NASA used two modified Boeing 747-100 variants as Space Shuttle Carrier Aircraft. The first, NASA 905, was acquired from American Airlines in 1974, while NASA 911 was purchased from Japan Air Lines in 1989. Both were retired in 2012. NASA 905 flew 70 of 87 missions and was the primary carrier for many years. NASA 911, which operated from 1990, completed 386 flights, including 66 ferrying missions. Both aircraft are now on display in museums. The modifications included additional stabilizers and struts for carrying the shuttles. The 747-100SR variant was designed for short-range flights, accommodating more takeoffs and landings.