The M2 MSBS was the second French

submarine-launched ballistic missile A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead ...

. In French, MSBS is the abbreviation for ''Mer-Sol Balistique Stratégique'', or Sea-Ground Strategic Ballistic Missile. It has two stages. It was deployed on the ''Redoutable''-class SNLEs (''Sous-marin Nucléaire Lanceur d'Engins'') (Device-launching Nuclear Submarine) or

SSBN A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. The United States Navy's hull classification symbols for ballistic missile submarines are SSB and SSBN – ...

s from 1974 to 1978, replacing the M1 MSBS. The M2 was itself replaced by the M20 MSBS beginning in 1977.MSBS M2 at Astronautix.com

References

Submarine-launched ballistic missiles of France Nuclear weapons of France Military equipment introduced in the 1970s {{France-hist-stub