The United States Navy is accelerating development of a ballistic missile designed to maintain its submarine-launched nuclear deterrent for decades. The service granted an $850 million contract modification for the Trident II D5 Life Extension 2 (D5LE2) program in April 2026, manufacturer Lockheed Martin said in a July news release.
The D5LE2 work comes as initial construction of the next-generation Columbia-class ballistic missile submarines (SSBNs) continues. The U.S. Navy commissioned the present fleet of 14 Ohio-class SSBNs in the early 1980s. Each Ohio-class submarine carries 20 current-generation Trident II D5LE missiles. The United Kingdom’s Vanguard-class submarines also carry the missiles.
The D5LE will remain in service through the 2040s on both the Ohio-class fleet and the Columbia class, the first of which is expected in 2028. The Columbia-class and the Royal Navy’s future Dreadnought-class submarines will share the Common Missile Compartment developed collaboratively, enabling them to carry the same Trident II D5LE/D5LE2 missiles.
Experts consider SSBNs the most survivable leg of the U.S. nuclear triad alongside land-based intercontinental ballistic missiles and nuclear-capable bombers. The U.S. Navy and prime contractor General Dynamics Electric Boat designed the Columbia class to improve stealth, time at sea and sustainability compared with Ohio-class boats. The Columbia class will ensure continuous deterrence into the 2080s, according to the U.S. Navy.
“The importance [of SSBNs] to our deterring capability, I can’t overstate that,” U.S. Navy Adm. Richard Correll, Commander of U.S. Strategic Command (USSTRATCOM), told the U.S. Senate Armed Services Committee in March 2026. “For the SSBN, that assured second-strike capability that’s always at sea, always ready to respond, deters effectively.”
The recent D5LE2 contract award supports modernization of the submarine-based nuclear arsenal by the U.S. Navy’s Portfolio Acquisition Executive Strategic Systems Programs (PAE SSP). The programs provide “cradle-to-grave lifecycle support for the sea-based leg of the nation’s nuclear triad. This includes training, systems, equipment, facilities and personnel,” according to a PAE SSP news release. The hybrid design of the D5LE2 combines “proven propulsion components with redesigned avionics, guidance systems and system architecture,” according to the technology website Interesting Engineering.
In mid 2025, the U.S. Department of War approved the D5LE2 program for Milestone B, the point at which a project transitions into the engineering and manufacturing development phase. “We keep pushing forward, working collaboratively with our industry partners to accelerate D5LE2 development at an aggressive pace, embracing a wartime mindset,” Kelly Lee, executive director for PAE SSP, said in a public affairs story.
Alongside the missile, the U.S. Navy is working with the National Nuclear Security Administration (NNSA) on the development of a new warhead (W93) and reentry vehicle (Mk7) — the first all-new U.S. nuclear warhead program in decades, according to Interesting Engineering. The warhead will reduce reliance on the current “W76/W88 families of nuclear warheads” and help counter evolving adversary threats, according to the Department of Energy and the PAE SSP.
The U.S. Navy regularly tests the current D5LE to ensure its reliability and accuracy. In September 2025, an Ohio-class submarine conducted four unarmed launches in the waters off Florida — raising the total number of successful Trident II test flights to 197, according to a service news release.