Trident D-5

The UGM-133 Trident D-5 is a three-stage, solid-fueled submarine-launched intercontinental-range ballistic missile. The Trident D-5 missile is currently deployed by both the United Kingdom and the United States on their respective Vanguard- and Ohio-class nuclear missile submarines.

Trident D-5 at a Glance

Originated From: United States
Possessed By: United States, United Kingdom
Alternate Name: Trident 2
Class: Submarine Launched Ballistic Missile (SLBM)
Basing: Submarine launched
Length: 13.42 m
Diameter: 2.11 m
Launch Weight: 59,090 kg
Payload: up to 8 MIRV Mk 4 or Mk 5 warheads, 2,800 kg
Warhead: W76 100 kT or W88 475 kT
Propulsion: Three-stage solid propellant
Range: Minimum 2,000 km, Maximum 12,000 km
Status: Operational
In Service: 1990

tridentThe Trident D-5 has a maximum range of 12,000 km, similar to that of ground, silo-based systems, and can have a payload as large as 2,800 kg. Its payload carries a Post-Boost Vehicle (PBV) which can carry up to 12 Reentry Vehicles (RVs), though New START limits the number to eight. These RVs can be either the Mk 4 with a W76 100 kT yield warhead or the Mk 5, which has a W88 475 kT yield warhead. It is the first U.S. submarine-based missile to have a capability against hardened targets. The system uses an inertial navigation system combined with a stellar reference system that provides an accuracy of 90 m CEP. The missile has a length of 13.42 m, a width of 2.11 m, and a launch weight of 59,090 kg.1

The UGM-133 Trident D-5 entered service in the U.S. Navy in 1990. The first test launch took place in January 1987 and the first sea trial, which was unsuccessful, occurred in March 1989. The Navy purchased 437 Trident II (D-5) missiles through FY2008, and planned to purchase an additional 24 missiles per year through FY2012, for a total force of 533 missiles. Under the requirements of New START, the United States expects to maintain 280 total missiles, with 240 deployed, and 1,090 warheads.2

In 1999, the United States extended the life span of the Trident missiles and Ohio-class submarines by 42 years.3 According to the 2010 Nuclear Posture Review, the United States will maintain 14 Ohio-class submarines, with two in repair at any time. Each of these SSBNs will carry 20 missiles for a total fleet of 240 deployed Tridents. As of 2016, nine Trident-armed submarines are deployed in the Pacific and five in the Atlantic.4

The Trident D-5 has undergone extensive improvement programs. More accurate GPS systems have been tested on Trident missiles since 1993 and an earth penetrator version was considered in 1994 to attack underground facilities. Improved air-burst fuses were considered for the Mk 4 RV in 1998. New third-stage propellant motors were developed and tested and will likely be included in future versions. An extensive upgrade for 300 missiles is planned in 2020 in order to upgrade them to the Trident D-5A or D-5LE versions with improved capabilities and an extended service life to 2042.5

The U.S. Navy initially planned to keep Trident submarines in service for 30 years, but has had to extend their service life to 42 years until 2027. The Navy expects to spend $4.8 billion on Trident II modifications between FY2018 and 2021. Furthermore, the United States is designing a new submarine to replace the current Ohio-class fleet beginning in 2031. A total of 300 Trident D-5 missiles are expected to be converted to the life-extension D-5A or D-5LE by upgrading all of the subsystems, which will allow the missiles to remain in service until 2042.6

The Trident D-5 also entered service in the UK on four Vanguard-class missile submarines in 1994. Each submarine can carry 16 missiles and are equipped with UK warheads believed to be similar to the W76 100 kT US warheads. An unknown number of the missiles are also planned for deployment for non-strategic roles with 10 kT warheads. A 1999 UK statement limited the number of warheads to be deployed on each submarine to 48, an average of 3 warheads per missile.7 In July 2016, Parliament voted to approve new SSBNs to preserve the UK nuclear deterrent, ensuring that Trident will be deployed into 2050s.8

    1. “UGM-133 TRIDENT D-5,” in IHS Jane’s Weapons: Strategic 2015-2016, ed. James C. O’Halloran (United Kingdom: IHS, 2015), 112-114.
    2. Amy F. Woolf, “U.S. Strategic Nuclear Forces: Background, Developments, and Issues Specialist in Nuclear Weapons Policy,” Congressional Research Service, March 10, 2016,
    3. “UGM-133 TRIDENT D-5,” in IHS Jane’s Weapons: Strategic 2015-2016, ed. James C. O’Halloran (United Kingdom: IHS, 2015), 112-114.
    4. Hans M. Kristensen & Robert S. Norris (2016) United States nuclear forces, 2016, Bulletin of the Atomic Scientists, 72:2, 63-73, DOI: 10.1080/00963402.2016.1145901,
    5. Ibid.
    6. Hearing on Department of Defense Nuclear Acquisition Programs and the Nuclear Doctrine before the Senate Armed Services Strategic Forces Subcommittee, 114th Congress. February 9, 2016 (Statement of Vice Admiral Terry Benedict, Director of Strategic Systems Programs)
    7. “UGM-133 TRIDENT D-5,” in IHS Jane’s Weapons: Strategic 2015-2016, ed. James C. O’Halloran (United Kingdom: IHS, 2015), 112-114.
    8. Sam LaGrone, “Britain Votes to Keep Trident Nuclear Deterrent, Approves New U.K. SSBNs,” USNI News, July 19, 2016, Accessed on