The Titan program began development in 1955 as a back up option in case the Atlas program failed. It would become the second Intercontinental Ballistic Missile (ICBM) deployed by the U.S. Air Force. Also a liquid fueled giant, the Titan was the first multi-stage ICBM put on operational alert.
Based within super-hardened silos, deep beneath the ground, the Titan's concrete and steel reinforced facilities were able to withstand the massive pressure of a nuclear blast. This gave it a survivability from nuclear attack, that the Atlas lacked.
The first successful test of a Titan took place in January of 1960. A little over two years later, the first Titan I's became operational, based out of Lowry Air Force Base in Denver, Colorado in April 1962.
The Titan I was 98 feet tall - 16 feet taller then the Atlas D - yet actually weighed 40,000 pounds less then its predeccessor. The innovative, two stage rocket design could deliver a warhead 6,300 miles.
The Titan I could hold a W38 or W49 warhead with explosive power of 3.75 megatons or 1.44 megatons respectively. Titan I's were configured with three missiles per site, with the first missile taking at least 15 minutes, and the 2nd and 3rd missiles in 7 1/2 minutes to launch. The missiles had to be fueled before launch with an extremely flammable combination of highly refined kerosene and liquid oxygen.
The Titan I was quite vulnerable to nuclear attack. The sites were only hardened to 100 psi. The missile was also sitting exposed on the surface for several minutes before a launch. It was also very labor intensive to operate. In an average day, Titan crews had over 80 operations to go through.
The Titan I was stored in silo-lift configurations and would be raised to the surface for launch. There were 54 Titan I's operational from 1962-65, based in California, Colorado, Idaho, South Dakota and Washington.
The Titan II was the largest ICBM ever deployed by the U.S. Air Force. Standing 103 feet tall and weighing a colossal 330,000 pounds, it had a range of up to 9,300 miles away (3,000 miles greater then the Titan I).
The Titan II held a W53 warhead with 9 megatons of explosive power. This was twice the explosive force of any other ICBM warhead. Titan II's were configured with one missile at per site. Each site was at least seven miles from the next closest site.
A major innovation of the Titan II, was that it had storable liquid propellant. This allowed the Titan II to launch within about a minute, a considerable upgrade over the Titan I's 15 minute launch response time.
The Titan II had several notable accidents during its long service. Yet becasue the missiles held 30% of the Air Force's nuclear warhead megatonnage, it was kept in service for nearly 25 years. There were 54 Titan II's operational from 1963-87, based in Arizona, Arkansas and Kansas.