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 The Titan 34D was a United States expendable launch vehicle used to launch a number of satellites for military applications. Service history Derived from the Titan III, the Titan 34D featured Stage 1 and Stage 2 stretched with more powerful U ...

, and was originally proposed as a medium-lift expendable launch system for the

US Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sig ...

, who selected the

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 ...

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 The Ariane 4 was a European expendable space launch system, developed by the '' Centre national d'études spatiales'' (CNES), the French space agency, for the European Space Agency (ESA). It was manufactured by ArianeGroup and marketed by Ari ...

, 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 Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

. The first carried two

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth ...

s, Skynet 4A and JCSAT-2, and was launched at 00:07 UTC on 1 January 1990, which was 19:07

local time Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solar time, but since the introduction of time zones it is generally the time as determined by the time zone in effect, with daylight s ...

on 31 December 1989, making it the only orbital launch to have occurred in different years between the launch site and UTC. The launch received the

International Designator The International Designator, also known as COSPAR ID, is an international identifier assigned to artificial objects in space. It consists of the launch year, a three-digit incrementing launch number of that year and up to a three-letter code repr ...

1990-001, using the UTC date. The second launch occurred on 14 March, and carried the

Intelsat 603 Intelsat 603 or IS-603, previously named Intelsat VI F-3, is a communications satellite operated by Intelsat. Launched in 1990, it was the second of five Intelsat VI satellites to be launched. The Intelsat VI series was constructed by Hughes Air ...

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 An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final (most commonly circular) orbit. For a satellite lau ...

. It was later visited by , on mission

STS-49 STS-49 was the NASA maiden flight of the Space Shuttle ''Endeavour'', which launched on May 7, 1992. The primary goal of its nine-day mission was to retrieve an Intelsat VI satellite, Intelsat 603, which failed to leave Low Earth orbit two y ...

. Astronauts attached a new kick motor, which raised the satellite into a

geosynchronous transfer orbit A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellites that are destined for geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step f ...

, as had originally been planned. The third launch, on 23 June, carried

Intelsat 604 Intelsat 604, previously named Intelsat VI F-4, was a communications satellite operated by Intelsat. Launched in 1990, it was the third of five Intelsat VI satellites to be launched. The Intelsat VI series was constructed by Hughes Aircraft, base ...

, 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 The ''Mars Observer'' spacecraft, also known as the ''Mars Geoscience/Climatology Orbiter'', was a robotic space probe launched by NASA on September 25, 1992, to study the Martian surface, atmosphere, climate and magnetic field. During the int ...

spacecraft into heliocentric orbit, by means of a

Transfer Orbit Stage The Transfer Orbit Stage (TOS) was an upper stage developed by Martin Marietta for Orbital Sciences Corporation during the late 1980s and early 1990s. The TOS was designed to be a lower-cost alternative to Inertial Upper Stage and Centaur G u ...

Launch history

References

* * * {{Titan rockets Space launch vehicles of the United States