The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

440
Alarge intercontinental ballistic missile (ICBM)
that, like the Atlas and Thor, evolved into an
important family of space launch vehicles that remain
in use today. Its story begins with the U.S. Air Force
seeking an ICBM that would surpass the Atlas in
sophistication and delivery capacity. 228 (See table,
“Titan Series,” on page 442.)
Titan I
A silo-based missile, active from 1962 to 1966. A
development contract for what would become the
Titan ICBM went to the Martin Company in October
1955; subsequently, the missile was named after the
Greek mythological father of Zeus. Unlike the oneand-a-half
stage Atlas, Titan I used two stages, both
equipped with Aerojet engines that burned liquid
oxygen and RP-1 (kerosene mixture), and could
deliver a four-megaton warhead over a distance of
12,900 km. Its all-inertial guidance system incorporated
groundbreaking digital computer technology.
The first Titan was test-launched on February 6, 1959,
with a dummy second stage ballasted with water. In
April 1962, the missile was declared operational and
remained in active service for the next four years. It
was also to have been used for suborbital tests of the
X-20 Dyna-Soar; however, in the end, it was never
modified for spaceflight—unlike its successor.
Titan II
The largest U.S. missile ever deployed and, in modified
form, the launch vehicle for the Gemini program.
In 1958, the Air Force gave Martin the go-ahead
to develop an improved and a far more powerful version
of the Titan I that would burn fuels that could
remain in the missile’s tanks for long periods,
enabling the missile to be fired almost immediately to
counter any Soviet threat. Aerojet-General first- and
second-stage engines based on those of the Titan I
were modified to burn UDMH (a type of hydrazine)
and nitrogen tetroxide, substances that could be
stored at room temperature for months. Furthermore,
since they were hypergolic (self-igniting on coming
into contact), the Titan II didn’t need a complex igni-
Titan
tion system. Designed to be fired from within its
underground silo (unlike its predecessor, which had to
be raised to the surface), the Titan II could be readied
for firing in under 60 seconds and could carry an 18megaton
warhead over a range of 15,000 km. The first
successful launch took place in March 1962, and the
missile was declared operational the following year.
Yet, the Titan II was destined to serve not only as a
weapon. In modified form, as the Gemini-Titan II, it
became the launch vehicle for the two-man successor
to Project Mercury. It was also eventually used to
place satellites in orbit. When the Titan missile fleet
was deactivated in the mid-1980s, the remaining Titan
Titan A Titan IV carrying the second Milstar satellite on
the launch pad at Cape Canaveral. Lockheed Martin Missiles &
Space Co./Russ Underwood