America’s Trident D5 missiles represent a bedrock of America’s national defense—meaning that they must occasionally be tested.
The Trident II D5 missile, officially designated the UGM-133A, was developed in the 1980s as an improvement over the earlier Trident I C4, with initial deployment in 1990. This weapon represents the sixth-generation of US Navy fleet ballistic missiles, building on an incredible legacy that began with the Polaris A1 in 1955.
Last weekend, the Navy reportedly tested one of these Trident II D5LE missiles fired from an Ohio-class ballistic missile submarine, the USS Louisiana (SSBN-743), operating off the coast of Florida.
An official Navy press release details that the Trident launch was a routine weapons test involving an unarmed missile. The goal was to test the flight capabilities of the missile; it certainly was not intended as a nuclear weapons test.
Indeed, it should be noted that, since 1992 the US has maintained a self-imposed moratorium on nuclear testing. Instead, the US military relies upon computer modeling and other non-nuclear tests to maintain its nuclear weapons arsenal—a prohibition that defies logic, given that no other major power is committed to it.
Understanding the Trident D5 Missile Series
Like any piece of advanced technology, if the D5s are not adequately tested routinely they might fall into disrepair—which would be hugely detrimental to the American military if the United States needed to launch them in a real-world combat situation.
Testing the missile’s flight capabilities, while helpful, does not ensure that America’s nuclear weapons are ready to go. It’d be like purchasing a high-end sports car and then leaving it turned off in the garage but periodically rotating the tires without ever even turning the car on to make sure the engine was in working order. Unpopular though it may be, America must sometimes test its nuclear weapons, as well as the missiles they ride into battle on.
Anyway, Lockheed Martin has been the prime contractor since the program’s inception, handling design, manufacture, assembly, testing, deployment, and sustainment in close partnership with the Navy’s Strategic Systems Programs (SSP).
The SSP is the organization charged with the lifecycle support of the country’s sea-based nuclear triad. This encompasses research, development, production, testing, training, systems integration, facilities, personnel, and sustainment of the sea-based leg of the nuclear triad.
The missile is used by the United Kingdom aboard its Vanguard-class submarines, with missiles drawn from a shared US-UK pool maintained at the Strategic Weapons Facility Atlantic in King’s Bay, Georgia. Lockheed’s Trident II D5 intercontinental ballistic missile (ICBM) has achieved 197 successful flight test launches since its inception, underscoring its importance to the Navy.
Regarding the Trident II D5 missile itself, this weapon is a three-stage, solid-propellant, sea-launched ballistic missile (SLBM) designed with enhanced accuracy, payload capacity, and range compared to its predecessors. The weapon has a mass of 130,000 pounds. Three solid-fuel rocket motors powering this devastating device, and NEPE-75 propellant is used to blast this weapon from the submarines to their distant targets.
The Trident II missile has an operational range exceeding 7,500 miles, with a terminal phase speed of around 18,000 miles per hour. An MK 6 astro-inertial system guides this weapon to target. Onboard this mighty missile rides between one and 12 reentry vehicles (RVs), typically configured with an average of four warheads under the New START treaty limits. Options include Mk-5 RVs with W88 warheads (each with a 475-kiloton yield), Mk-4A RVs with W76-1 (90 kiloton warheads), or W76-2 (five-to-seven kilotons). The weapon carries 100 kiloton Holbrook warheads for the UK.
Interestingly, this missile was the first ballistic missile to incorporate 3D-printed components.
Why Is America Testing the Trident Missile Now?
The D5LE that was tested off the coast of Florida this last weekend was part of a service life extension the SSP has overseen for years. The D5LE was initiated around 2017, this program refreshed components, like the MK6 guidance system—updated by Draper with new inertial sensors, stellar camera, and electronics for modular upgrades, extending the missile’s service life into the 2040s.
DL5E includes warhead upgrades, such as converting W76-0 warheads to W761-1 with new Mk-4A reentry vehicles and MC4700 arming systems. The D5LE missiles are now being deployed across the fleet and will support the initial loadouts for the upcoming American Columbia-class submarines and the British Dreadnought-class SSBNs—potentially extending sea-based deterrence through 2084!
Then there’s the SSP’s D5LE2, a next-generation extension focused on further modernizing the guidance subsystem (unchanged since the 1980s) for increased flexibility, adaptability, and cost-effectiveness against future threats. In January 2025, Lockheed Martin received a $383 million contract modification from the Navy for the D5LE2 development. In February of this year, a new production facility in Titusville, Fla., was announced for producing related components.
Draper serves as the prime contractor for guidance updates.
America’s Trident D5 missile series represents a bedrock of America’s national defense. It is the essential sea-based leg of the nuclear triad without which the United States would lack credible second-strike capacity, meaning that America’s nuclear-armed enemies (notably China and Russia) would have added incentive to seek a nuclear first-strike against us without the existence of the D5 SLBMs.
Testing the D5LE in real-world conditions, such as off the coast of Florida, is the least the Navy could be doing to ensure its wing of the nuclear triad is ready if it is ever called into action against America’s foes.
About the Author: Brandon J. Weichert
Brandon J. Weichert is a senior national security editor at The National Interest. Recently, Weichert became the host of The National Security Hour on America Outloud News and iHeartRadio, where he discusses national security policy every Wednesday at 8pm Eastern. He is also a contributor at Popular Mechanics and has consulted regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including The Washington Times, National Review, The American Spectator, MSN, The Asia Times, and others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
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