Transtage

Transtage was the upper stage of the Titan III family of American rockets, developed by Martin Marietta with Aerojet engines and given the Air Force designation SSB-10A. It was planned to carry military payloads to geostationary orbit, under a development contract issued in August 1962. The stage used a pressure-fed design with two gimbaled thrust chambers burning Aerozine 50 and nitrogen tetroxide, and it was specified to restart up to three times during the first six hours of a mission. Forty-seven Titan III launches are known to have used it, three of them failures. The first flew on a Titan IIIA on 1 September 1964 and failed to reach orbit, later flights used the Titan IIIC, and the last launch on a Titan 34D took place on 4 September 1989.