North Atlantic. On 10 May 2016 Airbus and Safran signed a joint 50-50 partnership to develop the M51.3 upgrade intended to enter service around 2025. On 12 June 2020, a successful test launch of an M51.3 missile (supposedly) was conducted from the Le Téméraire Triomphant-class submarine off the south-west tip of Finistère (Brittany). On April 28, 2021 French Ministry of Armed Forces announced that it had tested an M51 submarine-launched ballistic missile (SLBM). The test was not launched from a French Navy Le Triomphant-class submarine but from a land based facility located in South Western France. Operators French Navy – Primary armament for the Triomphant-class SSBN and the future SNLE 3G SSBN See also M45 (missile) R-29 Vysota R-29RM Shtil R-29RMU Sineva R-29RMU2 Layner RSM-56 Bulava UGM-133 Trident II JL-2 JL-3 R-39 Rif R-39M Sources and references External links nrdc.org: Table of French Nuclear Forces, 2002 globalsecurity.org M-5 / M-51 M51 Gives France More Flexible Deterrent To Meet Changing Threats, Aviation Week M51 test launch (YouTube) Submarine-launched ballistic missiles of France Nuclear weapons of France Military equipment introduced in the 2010s