US Develops First New Nuclear Warhead in 40 Years, Upgrades Trident Missiles

The United States is embarking on its first new nuclear warhead development in almost four decades, a move that signals a significant modernization of its sea-based nuclear deterrent.

The U.S. Navy's Strategic Systems Programs office, in collaboration with the National Nuclear Security Administration, is spearheading the development of the new W93/Mk7 nuclear warhead. This initiative is distinct from previous efforts, which focused on extending the life or modifying existing warheads. The U.S. Navy emphasized that this marks the first time in nearly 40 years a completely new nuclear warhead design is being pursued.

Simultaneously, the Trident II (Trident D5) submarine-launched ballistic missile system is undergoing a second phase of life extension (D5LE2). The current Trident II D5 missiles, in service since 1990, have already undergone a first phase of life extension (D5LE) to replace aging components. The D5LE2 phase aims to update critical components, ensuring the missile's reliability, safety, and readiness for decades.

The modernized Trident II D5 missiles will continue to arm the Ohio-class submarines and will serve as the initial weapon system for the new Columbia-class strategic submarines. The D5LE2 variant will eventually replace the D5LE missiles, guaranteeing the continuation of the U.S. sea-based nuclear deterrent.

Notably, the United Kingdom will also adopt the W93/Mk7 warhead as the basis for its next-generation sea-based nuclear system, continuing a long-standing bilateral cooperation in submarine-launched nuclear programs. The U.S. Navy stressed that the overall plan involves upgrading the existing Trident II system through life extension and the development of a new warhead, rather than designing an entirely new missile.

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This marks the first time in nearly 40 years that the United States has undertaken the development of a completely new nuclear warhead, rather than extending the life or modifying existing warheads.