The Titan rocket was developed by the US Air Force as an ICBM (intercontinental
ballistic missile), at the end of the 1950's when the U.S.A. and the Soviet Union were
respectively proceeding to station their nuclear weapons. It's mission was to carry
nuclear weapons. It later saw heavy use as a workhorse of the US Space
Program.
The Titan I, of 1951, was never launched.
It was a mockup used to conduct experiments with the first stage engine. It
was also planned to be used for the Dyna Soar program which was the basis of the Space
shuttle program, but was later converted to the Titan IIIC due to its limited capacity.
Furthermore the Dyna Soar program itself was also abandoned.
The Titan II, 1962, was a two stage vehicle and
was used as an ICBM. More than 140 missiles of the Titan II series were
produced and some were used in the Gemini Program. By 1987, the threat of nuclear
war was virtually eliminated, so the following year, many Titan IIs were modified to be
reused as launch vehicles.
The Titan III has various versions such as the
Titan IIIA, a two stage rocket with a special transtage, the Titan IIIB, Titan IIIC with
huge solid propellant boosters on the first stage, the Titan IIID which removed the
transtage from IIIC, the Titan IIIE with the Centaur replaced by
the original third stage.
The Titan IV, was developed by the USAF for a
large sized satellite launch after the accident of the Challenger, which has become the
indispensable vehicle for launching satellites and space probes.
