SLBMs

Submarine-launched ballistic missiles (SLBMs) are ballistic missiles designed to be fired from submarines, typically from a submerged position. They enable a stealthy, survivable second-strike capability, since missiles can be launched from hidden, mobile platforms at sea. Most modern SLBMs are solid-fuel and capable of carrying multiple independently targetable reentry vehicles, or MIRVs, though some earlier systems carried a single warhead.

Development of SLBMs began in the mid-20th century as a way to harden nuclear forces against a first strike. The United States introduced the Polaris program, followed by Poseidon and Trident, while the Soviet Union and others pursued their own programs. SLBMs and sea-based ballistic missile submarines (SSBNs) form the sea-based leg of many states’ strategic deterrent triads and are designed for extended patrols and continuous at-sea deterrence.

Typical SLBM ranges span roughly 4,000 to 12,000 kilometers, enabling global reach from sea-based patrol areas. Modern missiles commonly carry multiple independently targetable reentry vehicles, allowing several warheads to be aimed at different targets from a single launch, often with advanced penetration aids and countermeasures.

Major operators and missiles include: United States Trident II D5; United Kingdom Trident II D5; France M51 family; Russia Bulava and R-29RM Sineva/Layner; China JL-2; and India K-15/Sagarika and K-4, deployed on respective SSBNs or in development for conventional or strategic roles.