Commercial Titan III

The Commercial Titan III, also called CT-3 or CT-III, was an American expendable launch system that Martin Marietta developed in the late 1980s from the Titan 34D. It was first proposed as a medium-lift vehicle for the US Air Force, which chose the Delta II instead, and the company carried on with it as a commercial launcher. It differed from the Titan 34D in having a stretched second stage and a larger payload fairing that could hold two satellites at once. Four rockets flew from Launch Complex 40 at Cape Canaveral between 1990 and 1992, carrying Skynet 4A and JCSAT-2, then Intelsat 603 and Intelsat 604, and finally NASA's Mars Observer. On the second launch the upper stage failed to separate, which stranded Intelsat 603 in low orbit until astronauts on Space Shuttle Endeavour fitted it with a new kick motor during STS-49. Costs higher than rivals such as the Ariane 4 meant no orders followed, and the vehicle was retired in 1992.