SSBN

An SSBN, or submarine-launched ballistic missile submarine, is a nuclear-powered submarine designed to deploy long-range ballistic missiles from underwater. As part of a country’s strategic deterrence, SSBNs form the sea-based leg of the nuclear triad, providing a survivable and hard-to-target platform for nuclear forces. They are designed to remain at sea for prolonged patrols, moving stealthily to avoid detection while ready to launch missiles if authorized. Missiles are carried in launch tubes and can be MIRVed, allowing a single submarine to strike multiple targets.

Most modern SSBNs are powered by nuclear reactors, enabling long endurance and quiet operation. Armament varies by class but typically includes ballistic missiles with long range and multiple warheads.

Major SSBN classes include the United States Ohio class, which carries Trident missiles; the United Kingdom Vanguard class, equipped with Trident II D5 missiles; France’s Triomphant class, armed with M51 missiles; Russia’s Borei class, armed with Bulava missiles; China’s Type 094 class, armed with JL-2 missiles; and India’s Arihant class, which has been equipped with K-15 and K-4 missiles.

The first US SSBNs began patrols in the 1960s, following the deployment of Polaris missiles that armed submarine ballistic platforms. Since then, SSBNs have played a central role in strategic deterrence, with ongoing upgrades to missile and submarine technology and periodic fleet modernization.

In practice, SSBNs provide continuous at-sea deterrence through patrols that remain largely hidden from adversaries, maintaining a credible second-strike capability in a nuclear force.