Pegasus is an air-launched multistage rocket developed by Orbital Sciences Corporation (OSC) and later built and launched by Northrop Grumman. Pegasus is the world's first privately developed orbital launch vehicle. Capable of carrying small payloads of up to 443 kg (977 lb) into low Earth orbit, Pegasus first flew in 1990 and remained active as of 2021. The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus is released from its carrier aircraft at approximately 12,000 m (39,000 ft) using a first stage wing and a tail to provide lift and altitude control while in the atmosphere. The first stage does not have a thrust vector control (TVC) system.

Stargazer is a Lockheed L-1011 TriStar built in 1974, that was modified in 1994 for use by Orbital Sciences as a mother ship launch pad for the Pegasus launch vehicle. As of October 2022, 45 rockets have been launched from it, using the Pegasus-H and Pegasus-XL configurations. As of 2019, Stargazer is the only L-1011 airframe still airworthy.