The Titan IIIC was an expendable launch system used by the United States Air Force from 1965 until 1982. It was the first Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the Dyna-Soar, though the spaceplane was cancelled before it could fly. The majority of the launcher's payloads were DoD satellites, for military communications and early warning, though one flight (ATS-6) was performed by NASA. The Titan IIIC was launched exclusively from Cape Canaveral while its sibling, the Titan IIID, was launched only from Vandenberg AFB.
History
The Titan rocket family was established in October 1955 when the Air Force awarded the Glenn L. Martin Company (later Martin Marietta and now Lockheed Martin) a contract to build an intercontinental ballistic missile (SM-68). It became known as the Titan I, the nation's first two-stage ICBM, and replaced the Atlas ICBM as the second underground, vertically stored, silo-based ICBM. Both stages of the Titan I used kerosene (RP-1) and liquid oxygen (LOX) as propellants. A subsequent version of the Titan family, the Titan II, was similar to the Titan I, but was much more powerful. Designated as LGM-25C, the Titan II was the largest USAF missile at the time and burned Aerozine 50 and nitrogen tetroxide (NTO) rather than RP-1 and LOX.
The Titan III family consisted of an enhanced Titan II core with or without solid rocket strap-on boosters and an assortment of upper stages. All Solid Rocket Motor SRM-equipped Titans (IIIC, IIID, IIIE, 34D, and IV) launched with only the SRMs firing at liftoff, the core stage not activating until T+105 seconds, shortly before SRM jettison. The Titan IIIA (an early test variant flown in 1964–65) and IIIB (flown from 1966 to 1987 with an Agena D upper stage in both standard and extended tank variants) had no SRMs. The Titan III launchers provided assured capability and flexibility for launch of large-class payloads.
All Titan II/III/IV vehicles contained a special range safety system known as the Inadvertent Separation Destruction System (ISDS) that would activate and destroy the first stage if there was a premature second stage separation. Titans that carried Solid Rocket Boosters (SRBs) (Titan IIIC, IIID, 34D, and IV) had a second ISDS that consisted of several lanyards attached to the SRBs that would trigger and automatically destroy them if they prematurely separated from the core, said "destruction" consisting mainly of splitting the casings open to release the pressure inside and terminate thrust. The ISDS would end up being used a few times over the Titan's career.
Another slight modification to SRB-equipped Titans was the first stage engines being covered instead of the open truss structure on the Titan II/IIIA/IIIB. This was to protect the engines from the heat of the SRB exhaust.
Titan III/IV SRBs were fixed nozzle and for roll control, a small tank of nitrogen tetroxide was mounted to each motor. The would be injected into the SRB exhaust to deflect it in the desired direction.
As the IIIC consisted of mostly proven hardware, launch problems were generally only caused by the upper stages and/or payload.
Launch history
thumb|First Titan IIIC rocket with technological stage Transtage 4, June 18 1965.
The first Titan IIIC (3C-7) flew on June 18, 1965,
On March 25, 1978, a launch of two DSCS II satellites (3C-35 with DSCS-2 9 and DSCS-2 10) ended up in the Atlantic Ocean when the Titan second stage hydraulic pump failed, resulting in engine shutdown approximately 470 seconds after launch. Solid motor jettison occurred at approximately 116 seconds.
The first core stage ignited about 5 seconds before SRM jettison. Designated the Titan 3A-1, this stage was powered by a twin nozzle Aerojet LR-87-AJ9 engine that burned about of Aerozine 50 and nitrogen tetroxide (NTO) and produced thrust over 147 seconds. The Aerozine 50 and NTO were stored in structurally independent tanks to minimize the hazard of the two mixing if a leak should have developed in either tank.
The second core stage, the Titan 3A-2, contained about of propellant and was powered by a single Aerojet LR-91-AJ9,