Northrop Grumman Pegasus

Pegasus was an air-launched, small-lift launch vehicle developed by Orbital Sciences Corporation and later built and launched by Northrop Grumman. Pegasus was the world's first privately developed orbital launch vehicle. Capable of carrying small payloads of up to 443 kilograms (977 lb) into low Earth orbit, Pegasus first flew in 1990 and last flew before its retirement in 2026. It had primarily launched scientific satellites for NASA.

The vehicle consisted of three solid-propellant stages and an optional monopropellant fourth stage. Pegasus used to be released from a carrier aircraft at about 40,000 feet (12,000 m) over open ocean, where it free-falls for five seconds before igniting its first-stage motor. The first stage did not have a thrust vectoring control system, instead using a delta wing and fins for lift and attitude control within the atmosphere. Pegasus initially used the NASA-owned B-52 Stratofortress named "Balls 8" as its carrier aircraft. By 1994, launches had transitioned to a modified L-1011 TriStar named "Stargazer" purchased by Orbital.