The Pegasus rocket is an air-launched winged space launch vehicle capable of carrying small, unmanned payloads (443 kilograms (980 lb)) into low Earth orbit. It became operational in 1990 and remains so as of 2013. It is air-launched, as part of an expendable launch system developed by Orbital Sciences Corporation (Orbital). Three main stages burning solid propellant provide the thrust.
The Pegasus is carried aloft below a carrier aircraft and launched at approximately 40,000 ft (12,000 m). The carrier aircraft provides flexibility to launch the rocket from anywhere rather than just a fixed pad. A high-altitude, winged flight launch also allows the rocket to avoid flight in the densest part of the atmosphere where a larger launch vehicle, carrying more fuel, would be needed to overcome air friction and gravity.
In this illustration, I posed the Pegasus in its free fall phase after being released from the mother aircraft, prior to main engine start.
