Trident missile

Trident I (C4) was first deployed in 1979 and gradually phased out through the 1990s and early 2000s. Trident II (D5) was first deployed in 1990 and is planned to be deployed past 2020.

Trident I missiles were, and Trident II missiles are, deployed in Ohio-class submarines, each capable of carrying 24 missiles. The Trident II is also provided to the United Kingdom which equips the missile with their own warheads and deploys the missiles on the Royal Navys own Vanguard class submarines.

The Trident II (D5) is a three-stage, solid-propellant, inertially guided FBM with a range of more than 7400 kilometers (4600 statute miles). The range of both models of the missile is increased by an aerospike, a telescoping outward extension that reduces frontal drag by about 50 percent. Trident II is more sophisticated than Trident I (C4) with a significantly greater payload capability. All three stages of the Trident II are made of graphite epoxy, whose integrated structure means considerable weight saving.

The launch from the submarine occurs below the ocean surface, they are ejected from their launch tubes by gas pressure created by a "gas generator," a solid fuel rocket motor attached to the bottom of the missile tube and exhausting into it. After the missile leaves the tube and rises through the water over the submarine (in a bubble of gas -- water never contacts the missile) the first stage motor ignites, the aerospike extends, and the boost stage begins. Within about two minutes, after the third stage motor kicks in, the missile is traveling in excess of 6100 meters (20,000 feet) per second.

The C4 and D5 designations put the missiles within the 'family' that started in 1960 with Polaris (A1, A2 and A3) and continued through to the 1971 Poseidon (C3) to the two Trident variants.

Trident I (C4) - General Characteristics

• Primary Function: Strategic Nuclear Deterrence
• Contractor: Lockheed Martin Missiles and Space, Sunnyvale, Calif.
• Propulsion: Three-stage solid-propellant rocket
• Length: 34 feet (10.2 meters)
• Weight: 73,000 pounds (33,142 kg)
• Diameter: 74 inches (1.8 meters)
• Range: 7400 kilometers (4,600 statute miles)
• Guidance System: Inertial
• Warhead: Nuclear multiple independently targetable reentry vehicle (MIRV). Up to seven W76 (100 kt) warheads (Mark 4).
• Date Deployed: 1979

Trident II (D5) - General Characteristics

• Primary Function: Strategic Nuclear Deterrence
• Contractor: Lockheed Missiles and Space Co., Inc., Sunnyvale, Calif.
• Unit Cost: $30.9 million
• Power Plant: Three-stage solid-propellant rocket
• Length: 44 feet (13.41 meters)
• Weight: 130,000 pounds (58,500 kg)
• Diameter: 83 inches (2.11 meters)
• Range: Greater than 7400 kilometers (4,600 statute miles)
• Guidance System: Inertial
• Warhead: Nuclear MIRV. Up to eight W88 (475 kt) warheads (Mark 5).
• Date Deployed: 1990