Trident I

The Trident I, also known as the C-4, was an American-made submarine-launched ballistic missile (SLBM) that began development in the late 1960s. It succeeded the Polaris and Poseidon missiles. The Trident I measured 34 feet (10.4 meters) in length and 6 feet (1.8 meters) in diameter. It was capable of delivering eight independently targetable 100-kiloton nuclear warheads over a range of 4,000 nautical miles (7,400 km).1

This missile was a crucial part of the United States' nuclear forces and is the sole strategic-range nuclear weapon of the United Kingdom. Its accuracy, refined by stellar or satellite navigation, allowed it to threaten hardened targets, and its extended range enabled submarines to patrol widely, making detection difficult. The Trident I was fitted onto U.S. submarines starting in 1979.1