Vanguard-class submarine

The Vanguard class is a class of four British nuclear-powered ballistic missile submarines that carry the United Kingdom’s Trident nuclear deterrent.

Trident II D-5: A submarine-launched ballistic missile used by the United States and United Kingdom. Each Vanguard-class submarine is designed to carry this missile as the deterrent’s delivery system.
Nuclear submarine: A submarine powered by a nuclear reactor rather than conventional propulsion. Vanguard is a specialized nuclear submarine built to carry strategic missiles.
Resolution-class submarine: A class of four British nuclear-powered ballistic missile submarines that carried the Polaris missile. Resolution was the predecessor class that Vanguard replaced in Britain’s deterrent fleet.
Astute-class submarine: A class of British nuclear-powered attack submarines designed for roles including anti-submarine warfare and land attack. Astute submarines are nuclear-powered but do not carry the strategic ballistic-missile mission of Vanguard.
Ballistic missile submarine: A submarine designed to carry and launch ballistic missiles, often with nuclear warheads. The Vanguard class is Britain’s current example of this strategic submarine type.
Nuclear warhead: The explosive component of a weapon that releases energy through nuclear fission or fusion. Warheads, rather than the missiles alone, constitute the nuclear payload of the deterrent.
Polaris Sales Agreement: The 1963 agreement under which the United States supplied Polaris missile systems to the United Kingdom. The agreement established the missile-sharing precedent later extended to the Trident system.
Dreadnought-class submarine: A British class of nuclear-powered ballistic missile submarines intended to replace the Vanguard class. Dreadnought is the planned successor to Vanguard in the United Kingdom’s deterrent force.
Nuclear marine propulsion: The use of a nuclear reactor to generate power for a ship or submarine. Nuclear propulsion lets Vanguard submarines remain submerged for long periods without refueling.
Nuclear deterrence: A strategy that seeks to prevent attack by threatening unacceptable nuclear retaliation. The Vanguard fleet is an instrument of Britain’s nuclear-deterrence strategy.

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Borei-class submarineCompared with: It performs a comparable national deterrence mission for the United Kingdom.