Trident missile

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The Trident missile, named after the trident, is an intercontinental ballistic missile (ICBM) which is armed with nuclear warheads and is launched from submarines (SSBNs), making it a SLBM.

The Trident was built in two variants: the I (C4) UGM-96A and II (D5) UGM-133A. The C4 and D5 designations put the missiles within the "family" that started in 1960 with Polaris (A1, A2 and A3) and continued with the 1971 Poseidon (C3).

Both Trident versions are three-stage, solid-propellant, inertially guided missiles whose range is increased by an aerospike, a telescoping outward extension that halves frontal drag.

The Trident is carried by fourteen active US navy Ohio class submarines and (with British warheads) four Royal Navy Vanguard class submarines.

The launch from the submarine occurs below the ocean surface. The missiles are ejected from their tubes by gas pressure created by a "gas generator", a solid-fuel rocket motor attached to the bottom of the missile tube which heats a pool of water creating steam. After the missile leaves the tube and rises through the water over the submarine, the first stage motor ignites, the aerospike extends, and the boost stage begins. Ideally, the missile is "sheathed" in gas bubbles for its entire time in the water, so liquid never touches its fuselage. Within about two minutes, after the third stage motor fires, the missile is traveling faster than 20,000 ft/s (6,000 m/s).

Trident I (C4) was deployed in 1979 and phased out in the 1990s and early 2000s. Trident II (D5) was deployed in 1990; it is planned to be in service past 2020. As of 2005, a decision is expected soon about whether or not to replace the UK's missiles and submarine fleet. Critics from the peace movement and within the military establishment have questioned the usefulness of such a weapon in the current military climate. The use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, according to an Advisory Opinion issued by the International Court of Justice in 1996.

Contents

1 Trident I (C4) UGM-96A
2 Trident II (D5) UGM-133A
3 Conventional Trident
4 References
5 See also
6 External links

Trident I (C4) UGM-96A

The first eight Ohio-class subs were built with the Trident I missiles. Trident Is were also backfitted onto 12 SSBNs of the James Madison and Benjamin Franklin classes, replacing Poseidon missiles.

Trident I first launch on 18 January 1977 at Cape Canaveral

Characteristics

Purpose: strategic nuclear deterrence
Contractor: Lockheed Martin Space Systems, Sunnyvale, California
Propulsion: three-stage solid-propellant rocket
Length: 34 ft (10.2 m)
Weight: 73,000 lb (33,142 kg)
Diameter: 74 in (1.8 m)
Range: 7400 km (4,600 statute miles)
Guidance system: inertial
CEP: 1250 ft (380 m)
Warhead: nuclear multiple independently targetable reentry vehicles (MIRV). Eight W76 (100 kt) warheads (Mark 4).
Date deployed: 1979

Trident II (D5) UGM-133A

The second variant of the Trident is more sophisticated and can carry a heavier payload. It is accurate enough to be a first strike weapon. All three stages of the Trident II are made of graphite epoxy, making the missile much lighter. The Trident II was the original missile on the British Vanguard and later Ohio SSBNs. Characteristics

Purpose: strategic nuclear deterrence
Contractor: Lockheed Martin Space Systems Co., Sunnyvale, Calif.
Unit Cost: $30.9 million
Propulsion: Three-stage solid-propellant rocket
Length: 44 ft (13.41 m)
Weight: 130,000 lb (58,500 kg)
Diameter: 83 in (2.11 m)
Range: 12000 km (7,500 statute miles)
Maximum speed: 29,030 km/h (18,000 mph)
Guidance system: inertial
CEP: 300 ft (90 m)
Warhead (in USA usage only): nuclear MIRV. Up to eight W88 (475 kt) warheads (Mark 5) or eight W76 (100 kt) warheads (Mark 4).
Date deployed: 1990

Conventional Trident

The Pentagon developed the Conventional Trident Modification program in 2006 to diversify its strategic options. The US$503 million program would have converted existing Trident II missiles (presumably those scheduled for decommissioning of their warheads) into conventional weapons. It offered the promise of accurate conventional strikes with little warning and flight time. The primary drawback would have been establishing sufficient warning systems so that other nuclear countries would not mistake it for a nuclear launch. *

References

External links