On 6 October, France carried out its first launch of the M51.3 strategic ballistic missile from the nuclear-powered submarine Le Vigilant off the coast of Finistère. According to the French Directorate General of Armaments (DGA), the non-nuclear test launch, carried out as part of Operation Smertrios, was intended to confirm the submarine’s readiness to deploy the missile system following repairs and maintenance.
Briefly about the main points
- The DGA has confirmed the first launch of version M51.3 from Le Vigilant.
- The test was a final acceptance test following the repair and maintenance of the boat.
- M51.3 was put into operational service on 24 October 2025.
- Emmanuel Macron watched the launch from a frigate.
How the test was conducted
The launch took place near the Finistère department in western France. It was carried out as part of an operation Smertrios as a commissioning test following the IPER period — a planned extended period during which the vessel is unavailable for repair and maintenance.
The aim was to test the capability Le Vigilant to use the M51 missiles again. The launch was intended to assess the performance of the submarine’s weapon system following maintenance, rather than merely the missile’s own performance.
The missile did not carry a nuclear warhead
According to the DGA, trial M51.3 It was not carrying a nuclear warhead. The flight was monitored by DGA Essais de missiles, in particular the specialised survey vessel Monge.
The rocket’s impact area was identified in the North Atlantic, several hundred kilometres from any coastline. The French Ministry of the Armed Forces stated that the test had been carried out in accordance with the country’s international obligations.
What is known about version M51.3
The M51.3 is the third version of the French M51 naval strategic missile. Development began in 2014, and the decision to bring the variant into operational service was signed on 24 October 2025.
The French Ministry of Defence states that the new version has improved range, accuracy and the ability to penetrate air defence systems, but has not publicly disclosed any specific technical details. In its combat configuration, the M51.3 is designed to carry the new TNO-2 nuclear warheads; however, the missile did not carry such a warhead during the launch on 6 October.
The M51 class has been in service with the French strategic submarine force since 2010. The DGA describes it as an intercontinental ballistic missile with multiple warheads and a mass of approximately 54 tonnes; this is a characteristic of the family as a whole, rather than a separately confirmed parameter of the M51.3.
Review of the maritime component of deterrence
Le Vigilant is one of four French Le Triomphant-class strategic nuclear submarines. According to the French Ministry of Defence, the country’s nuclear deterrent maintains a constant at-sea presence of at least one such submarine.
That is why the acceptance launch following IPER tested Le Vigilant’s overall capability to resume mission operations: the condition of the launch systems, the interaction between the missile and the vessel, flight control and the associated infrastructure. The DGA described this launch as the first underwater launch of the M51.3 variant specifically, rather than the first launch of an M51-family missile in general.
Macron watched the launch, and France is preparing the M51.4
According to the Élysée Palace, as reported by the EFE news agency, the President of France Emmanuel Macron watched the launch from aboard a Navy frigate. Following the test, he linked the country’s freedom to its strength and its ability to instil fear. Earlier, on 2 March 2026, Macron described nuclear deterrence as the cornerstone of France’s security and announced his intention to strengthen it.
The modernisation of the naval component is ongoing: in 2025, the DGA commissioned ArianeGroup to develop and manufacture the next variant, the M51.4. France is also implementing the SNLE 3G strategic submarine programme, which is intended to replace the Le Triomphant class in the future; according to Macron, the first submarine is scheduled to be launched in 2036.
