Commercial Titan III

Commercial Titan III

180px Launch of the last CT-3 with Mars Observer
Function	Medium carrier rocket
Manufacturer	Martin Marietta
Country of origin	USA
Associated rockets
Family	Titan
Launch history
Status	Retired
Launch sites	LC-40, CCAFS
Total launches	4
Successes	3
Partial failures	1
First flight	1 January 1990
Last flight	25 September 1992
Notable payloads	Mars Observer

The Commercial Titan III, also known as CT-3 or CT-III was an American expendable launch system, developed by Martin Marietta during the late 1980s and flown four times during the early 1990s. It was derived from the Titan 34D, and was originally proposed as a medium-lift expendable launch system for the US Air Force, who selected the Delta II instead. Development was continued as a commercial launch system, and the first rocket flew in 1990. Due to higher costs than contemporary rockets such as the Ariane 4, orders were not forthcoming, and the CT-3 was retired in 1992.

The Commercial Titan III differed from the Titan 34D in that it had a stretched second stage, and a larger payload fairing to accommodate dual satellite payloads.

All four launches occurred from LC-40 at Cape Canaveral Air Force Station. The first carried two communications satellites, Skynet 4A and JCSAT-2, and was launched at 00:07 GMT on 1 January 1990, which was 19:07 local time on 31 December 1989, making it the only orbital launch to have occurred in different years between the launch site and GMT. The launch received the International Designator 1990-001, using the GMT date.

The second launch occurred on 14 March, and carried the Intelsat 603 satellite. The rocket's second stage failed to separate, and the payload could only be released from the rocket by means of jettisoning its kick motor. It was later visited by Space Shuttle Endeavour, on mission STS-49. Astronauts attached a new kick motor, which raised the satellite into a geosynchronous transfer orbit, as had originally been planned.

The third launch, on 23 June, carried Intelsat 604, and was successful. There was no Commercial Titan III launch in 1991, due to maintenance work at Launch Complex 40.

The final flight of the Commercial Titan III occurred on 25 September 1992, and placed NASA's Mars Observer spacecraft into heliocentric orbit, by means of a Transfer Orbit Stage.

Launch history

Main article: List of Titan launches

Date/Time (GMT)	S/N	Payload	Outcome	Remarks
1 January 1990 00:07	CT-1	Skynet 4A JCSAT-2	Successful
14 March 1990 11:52	CT-2	Intelsat 603	Partial failure	Second stage failed to separate from kick motor, spacecraft later reboosted by Space Shuttle Endeavour on mission STS-49.
23 June 1990 11:19	CT-3	Intelsat 604	Successful
25 September 1992 17:05	CT-4	Mars Observer	Launch success Mission failed	Used Transfer Orbit Stage for boosting to heliocentric orbit. Probe failed prior to reaching Mars.