HGM-25A Titan I

The HGM-25A Titan I, also designated SM-68A, was the first multistage intercontinental ballistic missile of the United States and the first member of the Titan family. The Air Force named the Glenn L. Martin Company, then known as the Martin Company, as contractor for the Titan missile in September 1955, originally as a backup in case the Atlas program ran into trouble. It was a two-stage, liquid-fueled missile burning liquid oxygen and RP-1, and its first successful launch was on 5 February 1959. Titan I was in use as an ICBM for only a few years: the storable-propellant Titan II and the solid-fueled Minuteman I made it obsolete and it was retired from service in early 1965. Unlike its successor it was never adapted for space launch.