The French Ministry of Armed Forces announced that the third version of the M51 strategic ballistic missile, M51.3, entered operational service on 28 October 2025. The new missile will be deployed aboard the French Navy’s Triomphant-class nuclear submarines, thereby enhancing the continuity of France’s strategic deterrence.
Developed by ArianeGroup, the M51.3 offers significant improvements in range, accuracy, and penetration compared to earlier versions. The missile is equipped with the TNO-2 nuclear warhead, designed by the French Atomic Energy Commission (CEA). Vincent Pery, Director of Defence Programs at ArianeGroup, stated: “In today’s evolving geopolitical context, deployment of the M51.3 helps ensure the continued credibility of France’s oceanic nuclear deterrent.”
First brought into service in 2010, the M51 series represents the fifth generation of French ballistic missiles. The M51.1 and M51.2 versions are currently operational, and the M51.3 will gradually replace them. Its successful qualification flight took place in November 2023 at the Ballistic Launch Base (BLB) and the DGA missile test range in Biscarrosse. Over the following two years, efforts focused on validating the missile’s performance and ensuring compliance with nuclear safety standards. This process was completed in September 2025, alongside full production ramp-up to prepare the missile for deployment aboard SSBNs.
The M51 program follows an incremental development approach to keep pace with changing geostrategic needs. ArianeGroup, the only European company capable of designing and producing a strategic missile, aims to remain at the forefront of technology while maintaining the highest performance standards. The company is involved in all phases of the program lifecycle, including design, production, maintenance, in-service support, and end-of-life decommissioning and dismantling.
With its three-stage engine and advanced TNO-2 warhead, the M51.3 strengthens France’s strategic deterrent against evolving missile defense systems. According to open sources, the missile weighs approximately 52 tons, is 12 meters long, and has a diameter of 2.3 meters. It has an operational range of 8,000–10,000 kilometers and can reach speeds of around Mach 25.
In September 2025, ArianeGroup was awarded the contract to design and produce the fourth version, M51.4. Its enhanced range, accuracy, and penetration capabilities will further strengthen France’s strategic deterrent and ensure its effectiveness against emerging geostrategic threats.
This operational deployment marks a key milestone in the modernization of France’s nuclear strategy and helps secure the long-term sustainability of the country’s strategic deterrence capabilities.
