The world's first privately-developed spacecraft-launch vehicle. It carried out its first mission in 1990, and had conducted a total of 35 by 2004. The three-stage, delta-wing rocket is first carried to about 12 200 m by aeroplane, and then released with its payload to free-fall for five seconds before its motor is fired. The satellites, which each weigh up to 450 kg, are placed into a low orbit. Recent satellite launches include NASA's Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) on 5 February 2002 and the Canadian Space Agency's Science Satellite (SCISAT-1) on 12 August 2003.
The launcher was created and built by the US Orbital Sciences Corporation, and it is Orbital's Stargazer L-1011 aircraft that carries Pegasus. The rocket is the first winged vehicle to reach eight times the speed of sound. Orbital's Hyper-X launch vehicle was flight-proven on a Pegasus rocket before it launched NASA's X-43A hypersonic research aircraft which set the aeronautical speed record on 27 March 2004.
http://www.dfrc.nasa.gov/gallery/photo/Pegasus/index.html Captioned photographs of the Pegasus air-launched space booster rocket.
Subjects: Astronomy and Astrophysics.