Titan IIIA

The Titan IIIA was an American expendable launch vehicle in the Titan rocket family, flown only four times in 1964 and 1965 as a test bed for the Transtage upper stage that was meant for the larger Titan IIIC. It stacked the Transtage on top of two core stages derived from the Titan II missile, and the same core later served as the center of the Titan IIIC. Its first flight, on 1 September 1964, ended short of orbit because the Transtage failed to pressurize and shut down early. A second test on 10 December 1964 succeeded, and two more launches in 1965 carried Lincoln Experimental Satellites before the vehicle was retired. It was built in the lineage of the Martin company, later Martin Marietta, whose Titan program it belonged to, and it is the prototype step between the Titan II and the heavier Titan III variants that followed.