Trident II Missile

The Trident II, designated D5, is an American submarine-launched ballistic missile built by Lockheed Martin and deployed aboard United States Navy Ohio-class and, since the 1990s, British Royal Navy Vanguard-class ballistic missile submarines, entering service in 1990 as the successor to the earlier, shorter-ranged Trident I. A three-stage, solid-fuel missile capable of carrying multiple independently targetable nuclear warheads over a long intercontinental range, the D5 forms the sea-based leg of both the American and British nuclear deterrent forces, launched while the submarine remains submerged, which gives it a survivability advantage over land-based missile systems that a first strike could more readily locate and destroy. The missile has undergone a series of life-extension and guidance upgrades since introduction to keep it in service well into the twenty-first century, and it remains, alongside land-based intercontinental ballistic missiles and bomber-delivered weapons, one of the three legs of the American nuclear triad.