NASA NB-52

Mission Profile

NASA's NB-52 Stratofortress (the B-52 designation modified to 'NB' for permanent research modification) was the air-launch carrier aircraft for the X-15 hypersonic research aircraft program, conducting 144 X-15 launch missions between 1959 and 1968. The modified B-52B bombers carried the X-15 on an underwing pylon and released it at approximately 14 km altitude and Mach 0.8, allowing the X-15's own rocket engine to accelerate the vehicle to its research speed and altitude without burning propellant during atmospheric climb. Two NB-52s (52-0003 'The High and Mighty One' and 52-0008 'Balls 8') were used, with Balls 8 serving an extraordinary career spanning both the X-15 program and later space shuttle approach and landing test and other research programs, finally retiring in 2004 after 106 research flights.