A post-refit test for Le Vigilant
The missile landed in a designated part of the North Atlantic, hundreds of kilometers off the French coast. President Emmanuel Macron observed the launch from the frigate Auvergne, calling it "a very important moment for our strategic credibility" and a step forward in modernizing France's nuclear forces.
Le Vigilant's overhaul began in fall 2023, with Naval Group serving as prime contractor, according to Meta-Defense. The maintenance and repair work included the submarine's propulsion, diving safety and control systems, as well as its hull and structures.
Such acceptance firings follow each major refit of France's ballistic missile submarines, Defence Blog reports. Le Terrible completed one in April 2023. In its coverage, Meta-Defense contrasted the successful M51.3 launch with two successive British Trident II D5 test failures, in 2016 and 2024.
Intercontinental range, not 1,000 kilometers
France's Defense Ministry has not published an official range for the M51.3. Estimates cited by Defense News put it above 9,500 kilometers, compared with more than 9,000 kilometers for the preceding M51 version. The Associated Press reports a broader estimate of 8,000 to 10,000 kilometers for the M51 family, whose exact specifications remain undisclosed.
The 1,000-kilometer figure sometimes attached to the ballistic missile instead refers to the MdCN cruise missile, also called SCALP Naval. French frigates and Suffren-class submarines can launch that weapon, but it does not follow a ballistic trajectory and is outside France's nuclear missile force. The M51.3, by contrast, serves as a strategic deterrent with intercontinental reach.
ArianeGroup developed the M51.3 as a three-stage, solid-fuel missile for France's four nuclear-powered ballistic missile submarines. Each submarine can accommodate up to 16 missiles. Data cited by Defense News indicate that each M51.3 can carry four to six independently targetable warheads. Meta-Defense puts the M51 family's weight at more than 50 metric tons and its length at about 12 meters.
From land-based testing to operational service
The submarine launch followed an initial flight test on land in November 2023. France's defense procurement agency, the DGA, fired that unarmed M51.3 from the Biscarrosse test site in southwestern France. The missile entered operational service in October 2025.
The Defense Ministry says the upgraded version has greater range, improved accuracy and a stronger ability to penetrate missile defenses. Defence Blog and Meta-Defense report that its nuclear payload is the new TNO-2 warhead, developed by the French Alternative Energies and Atomic Energy Commission, or CEA. No nuclear warhead was aboard the missile used in the October 6 test.
According to Meta-Defense, the improvements to accuracy and defense penetration are intended to enable the missile to overcome adversary missile defenses over the next 15 to 20 years.
Further upgrades to France's nuclear forces
France holds about 290 nuclear warheads for its submarine- and air-launched forces and is the European Union's only nuclear-armed member, according to Defence Blog. In March 2026, Macron announced plans to enlarge the arsenal for the first time in decades.
Work on the next missile version is already underway. ArianeGroup began developing the M51.4 in September 2025 and has a contract for that fourth variant, which is expected during the next decade.
Naval Group has also started construction of L'Invincible, the French Navy's first third-generation ballistic missile submarine, designated SNLE 3G. The new generation is intended to replace the Le Triomphant-class submarines beginning in 2037.
