SM-68B Titan II
The Titan II, manufactured by the Martin Company, was a large two-stage, liquid-fueled, rocket-powered ICBM that incorporated significant performance improvements over the earlier model Titan I weapon system. Titan II had more powerful engines (first stage - 430,000 pounds of thrust, second stage - 100,000 pounds of thrust, compared to 300,000 pounds and 80,000 pounds for the Titan I), a larger warhead, all-inertial guidance, hyperbolic fuel. and an on-board oxidizer, and the capability of being fired from a hardened underground-silo launcher.
Even as the first Titan I missiles were rolling off the assembly line, the Air Force was searching for a way to modify the missile to use an oxidizer other than liquid oxy-gen. Searching for a way to improve the Titan I at a reasonable cost, in January 1959 the Air Force Ballistic Missile Division (AFBMD-the name was changed from WDD on June 1, 1957) found that with minor modifications Titan I could be modified to use a noncryogenic, storable propellant. That amounted to a major breakthrough, for it enabled the propellant to be stored within the missile itself, thereby permitting the Titan II to be fired in a single minute. Moreover, the new propellant made it possible to launch the missile from within the silo, simplified maintenance, and reduced the risk of accidents.
In November 1959 the Department of Defense (DoD) authorized the development of the new Titan II (SM-68B/LGM-25C) and at the same time directed that the Titan I program be discontinued after six squadrons. As planned, Titan II would be a larger, more advanced missile than its predecessor. It would be equipped with an all-inertial guidance system, a-silo launch capability.
In June 1960 the Air Force awarded the Martin Company the Titan II contract. Developed in parallel with the Titan I program, the Titan II took shape rapidly. Captive flight tests began in December 1961, and in February 1963 a Titan II fired from the Air Force Missile Test Center (AFMTC) in Florida logged a successful 6,500-mile flight.
In October 1957, Congress authorized the Air Force to deploy four Titan I squadrons. Later that number increased to 12 squadrons, evenly split between Titan I and Titan II. With their 6,300-mile range, the Air Force based the Titan Is between Colorado and Washington state. The Titan Hs, on the other hand, had a 9,000-mile range and could be based farther south. By locating the Titan II bases in Arizona, Kansas, and Arkansas, the Air Force achieved a wider national dispersal pattern. Other factors that affected the location of the Titan launch facilities were population density under the missile's projected flight path, and the location of existing bases to provide logistical support.
The Titan II was deployed in a 1x9 configuration. Each squadron consisted of nine separate launch facilities, each housing a single missile. Each Titan II silo was directly connected to an underground launch control capsule manned by a missile combat crew of two officers and two airman. The Titan II silos were markedly different from the Titan I launch complexes. Most notably, the Titan II's all-inertial guidance system no longer required that the missiles remain tethered to a ground-based guidance system. Instead the Titan IIs were based separately, and each silo was at least 7 miles from its closest neighbor. The Air Force deployed six squadrons of Titan II missiles. Each squadron contained nine missiles, and to save money, the squadrons were grouped in pairs, forming an operational base. All of the logistic and support functions were based at existing SAC bases, and the missiles were located nearby.
On the surface, the Titan II launch facilities covered an area of approximately 600 feet by 600 feet. All of the launch facilities were underground. The silo was built of heavily reinforced concrete, and was 147 feet deep and 55 feet in diameter. It was wider than a Titan I silo because the Titan II was designed to be "hot launched" from within the silo. To deflect and channel the exhaust gases, each silo was fitted with a flame deflector at the base and two exhaust ducts that ran up the length of the silo and vented to the surface. Inside the silo there were nine levels of equipment rooms and missile access spaces. The silo was covered with a steel and concrete door that weighed 740 tons and could be opened in 17 to 20 seconds.
The silo was connected to the missile control center by a 250-foot long access tunnel. Between the silo and the launch control center was the blast lock, a single level, heavily reinforced concrete structure containing three rooms. To enter the launch facility the missile crews descended through a 35-foot deep access portal that opened into the blast lock area. Each end of the blast lock was covered by a pair of large steel blast doors, each weighing 6,000 pounds, designed to protect the launch center from either a surface nuclear blast, or the explosion of the missile within the silo. The doors were designed to withstand an overpressure of 1000 psi.
The launch control center was a dome-shaped reinforced concrete structure 37 feet in diameter and containing three levels. The three floors within the launch center were suspended from the ceiling to minimize blast shock. These shock mounts were designed to permit a static floor load of 100 psi. The control center provided space for all of the launch control and communications equipment, as well as a mess and sleeping quarters for the 4-person combat crew.
The Air Force had approved the development of the Titan II ICBM in October 1959. SAC activated the first Titan II squadron on 1 January 1962 and during the next eight months activated five more squadrons. On 8 June 1963, the 570th Strategic Missile Squadron at Davis-Monthan became the first Titan II unit to achieve operational status. In October 1963 the AFBMD's site activation task force turned over the first Titan II strategic missile wing to the Strategic Air Command (SAC). By December 1963 all six Titan II squadrons were on operational alert. Headquarters SAC completed the deployment of the second-generation ICBM weapon system on the last day of 1963 when it declared the sixth and last Titan II unit, the 374th Strategic Missile Squadron at Little Rock Air Force Base, Arkansas, operational.
By 1981, the Titan II weapon system had served the nation for eighteen years, eight years longer than its predicted service life. The system's advanced age, combined with three accidents that destroyed two sites and killed four airmen, had cast doubts on its safety and effectiveness. SAC, anticipating a Department of Defense (DOD) initiative, began to consider replacement options in October 1980. One month later, the Senate Armed Services Committee asked the Defense Department to prepare a formal Titan II safety report. SAC's replacement options review became the basis for the DOD safety report released in February 1981. The DOD study acknowledged Titan II's significant, albeit declining usefulness in preserving nuclear deterrence, and recommended deactivation of the Titan system as part of the ICBM modernization plan. During the interim, SAC would continue to improve Titan hardware and safety procedures.
On 2 October 1981, Deputy Secretary of Defense Frank C. Carlucci directed the retirement of the Titan II at the earliest possible time. The deactivation program, designated Rivet Cap, formally began with the removal from alert of site 571-6 at Davis-Monthan AFB, Arizona, on 30 September 1982. Titan II deactivation was completed on 23 June 1987 when technicians removed the last Titan II missile from its silo at Little Rock AFB, Arkansas. The era of liquid propellant ICBMs came to a close on 18 August 1987 with the inactivation of the last Titan II wing, the 308th Strategic Missile Wing at Little Rock AFB.
|Join the GlobalSecurity.org mailing list|