The Agena satellite launch system, initiated by the United States Air Force in 1955 as the Weapons System 117L program, made its first successful launch in February 1959, when it put the Discoverer 1 satellite into orbit. Powered by Bell rocket engines capable of delivering up to 15,500 pounds of thrust, Agena missiles launched many of the United States government’s reconnaissance and early-warning satellites in the 1960s and 1970s. Later versions, including the Agena D, had the ability to launch customized payloads. In 1966, NASA used the Agena D to launch docking target vehicles for its experiments in docking spacecraft.
In total, the Air Force and NASA launched 365 Agena missiles into space. The last of these was mounted on a Titan 34B booster and lifted off on February 12, 1987, carrying SDS communications satellite #7 for the Air Force.