U.S. Navy Fact Sheet
Trident II (D5) Missile
The Trident II Strategic Weapon System (SWS) is deployed aboard Ohio-class (Trident) submarines and consists of: the Trident II (D5) Submarine Launched Ballistic Missile (SLBM); Reentry System; and supporting Shipboard Systems.
The Trident II SWS is deployed aboard Ohio- class submarines, each capable of carrying 20 D5 missiles. Under the provisions of the Polaris Sales Agreement, it is also carried aboard the United Kingdomís Vanguard-class submarines.
The Trident II D5 SLBM is a three-stage, solid-fuel, inertially-guided missile with a range of 4,000 nautical miles capable of carrying multiple W76-Mk4/Mk4A or W88-Mk5 reentry bodies. The missile is launched by the pressure of expanding gas within the launch tube. When the missile broaches the waterline, it enters the boost phase, expending its first-, second-, and third-stage rocket motors. Following third-stage motor separation, the missile deploys the reentry bodies.
The Trident II SWS, originally designed to have a service life of about 25 years, has proven itself as a highly accurate and reliable system. To address aging and obsolescence issues, the Trident II SWS was life extended. Life-extended Trident II D5 missiles (D5LE) were introduced to the Fleet in early 2017. These D5LE missiles will serve throughout the remaining service life of the U.S. Ohio-class and UK Vanguard-class submarines and they will be initially carried aboard the U.S. Columbia-class and UK Dreadnought-class submarines.
The SLBM has been an integral part of our Nationís strategic nuclear deterrent Triad. As the most survivable leg of the Triad, the SLBM provides the Commander, U.S. Strategic Command, the National Command Authority, and the President with assured second-strike capability. Starting in 1956 with the Polaris (A1) and evolving through five subsequent generations including Polaris (A2), Polaris (A3), Poseidon (C3) Trident I (C4) and today's force of Trident II (D5), each generation of the missile has increased in range, payload, and accuracy.