Trident missile

Trident missile. The Trident is a family of American-made submarine-launched ballistic missiles (SLBMs) that form the sea-based leg of the nuclear triad for both the United States and the United Kingdom. Designed and built by Lockheed Martin Space, these missiles are deployed aboard Ohio-class submarines of the United States Navy and the Vanguard-class submarines of the Royal Navy. Since entering service in the late Cold War, the Trident system has represented a cornerstone of strategic deterrence, capable of delivering multiple thermonuclear warheads with high accuracy over intercontinental ranges.

Overview

The Trident missile system was developed to replace the aging Poseidon and Poseidon C3 missiles, offering greater range, payload capacity, and accuracy. It is a key component of the strategic defense posture articulated during the administration of President Jimmy Carter and continued under Ronald Reagan. The system's primary role is assured second-strike capability, ensuring retaliation even after a devastating first strike, a doctrine central to MAD. Operational control and deployment are managed by the United States Strategic Command and the Royal Navy's Commander-in-Chief Fleet.

Development and design

The development of the Trident missile began in the 1970s under the program management of the United States Department of Defense and the Lockheed Corporation. The Trident I C4, initially named the EXPO (Extended Range Poseidon), first flew in 1977 and achieved initial operational capability on the USS Francis Scott Key (SSBN-657) in 1979. Its successor, the more advanced Trident II D5, was developed to counter improving Soviet ABM defenses and entered development in 1983. The D5's first successful submerged launch was from the USS Tennessee (SSBN-734) in 1989. Key design features include a three-stage, solid-propellant rocket motor, a Mark 6 guidance system using an INS supplemented by GPS satellite updates, and a Post-boost vehicle (PBV) or "bus" that maneuvers to release multiple Multiple Independently Targetable Reentry Vehicles (MIRVs) on different trajectories.

Operational history

The Trident I C4 was deployed on 12 Benjamin Franklin-class submarines and 8 Ohio-class boats, serving as a pivotal deterrent throughout the final decade of the Cold War, including during tense periods like the Able Archer 83 exercise. The Trident II D5 entered service in 1990 on the USS West Virginia (SSBN-736) and has since been the sole SLBM for the U.S. Navy's Ohio-class SSBNs and the U.K.'s Vanguard-class submarines. The system has undergone continuous life-extension programs, with the D5 achieving over 190 successful test launches, a record for reliability. Under the Polaris Sales Agreement, the United Kingdom purchased the D5 system, which is maintained and serviced at the Kings Bay Naval Submarine Base in Georgia. The missiles are a central subject in strategic arms control treaties, including START I and the New START treaty with Russia.

Technical specifications

The Trident II D5 is a large, three-stage missile measuring approximately 44 feet in length and 83 inches in diameter, with a launch weight of about 130,000 pounds. It is capable of carrying a payload of up to eight W88 or twelve W76 thermonuclear warheads, though treaty limitations typically reduce this load. Its reported range exceeds 7,500 nautical miles, and it can achieve speeds in excess of Mach 20 during its midcourse phase. Guidance is provided by a sophisticated stellar-inertial system; the missile uses observations of fixed stars via its Starfix system to correct its trajectory, yielding a CEP (circular error probable) accuracy estimated to be under 90 meters. The reentry vehicles are designed to withstand the extreme heat and pressure of reentry before detonating.

Variants

There are two main operational variants of the Trident missile. The **Trident I C4** (UGM-96A) was the initial model, with a range of about 4,000 nautical miles and a payload capacity for up to eight MIRVs. It was phased out of U.S. service by the early 2000s. The **Trident II D5** (UGM-133A) is the current and vastly more capable variant, with greater throw-weight, longer range, and significantly improved accuracy. The D5 is currently being upgraded to the D5LE (Life Extended) configuration to ensure service through the 2040s, coinciding with the introduction of new American Columbia-class submarine and British Dreadnought-class submarine platforms. No other variants have entered operational service, though studies for conventional (non-nuclear) payloads, such as the proposed Conventional Trident Modification, have been evaluated by the Pentagon.

Category:Submarine-launched ballistic missiles of the United States Category:Cold War missiles of the United States Category:Nuclear weapons of the United Kingdom