Titan IIIM

The Titan IIIM was a planned American expendable launch vehicle in the Titan rocket family, intended to launch the Manned Orbiting Laboratory and other payloads. It was never flown: development was cancelled in 1969. Its design paired a stretched Titan core stage with a pair of seven segment UA1207 solid rocket boosters, and on 27 April 1969 one of those boosters had its first static test firing at the United Technologies Coyote Canyon test site near San Jose, California, producing 700,000 kgf of thrust for two minutes. Two uncrewed Gemini-B qualification flights had been pencilled in for 1970 and 1971. The stretched core stage found use on some versions of the Titan IIIB, and the UA1207 boosters were eventually used on the Titan IV, so the cancelled vehicle left a lasting mark on later Titans.