The INS Arihant is India's first indigenously constructed nuclear-powered ballistic missile submarine (SSBN), the lead vessel of the Arihant class. Its name, which means "destroyer of enemies" in Sanskrit, signifies its role as a strategic asset. The submarine was developed under the classified Advanced Technology Vessel (ATV) project, which was sanctioned in the 1980s. The project's goal was to complete the sea-based leg of India's nuclear triad (land, air, and sea launch capability).
The INS Arihant was launched on July 26, 2009, and was commissioned into the Indian Navy in August 2016. Its creation solved the critical problem of ensuring a survivable second-strike capability for India, which is essential for the nation's No First Use (NFU) nuclear doctrine and policy of credible minimum deterrence.
The submarine is powered by an 83 MW pressurized water reactor using enriched uranium fuel, which allows it to remain submerged for extended periods, making it difficult to detect. Its primary mechanism for deterrence is its armament of submarine-launched ballistic missiles (SLBMs). It is equipped with four vertical launch system (VLS) cells that can carry either 12 K-15 Sagarika SLBMs (range about 750 km) or four longer-range K-4 SLBMs (range about 3,500 km). The project involved collaboration between the Indian Navy, DRDO, BARC, and private sector partners like Larsen & Toubro.
The most significant recent development was in November 2018, when the government announced that the INS Arihant had completed its first deterrence patrol, officially operationalizing India's nuclear triad. This milestone confirmed its status as a fully operational SSBN, placing India among a select group of nations with this capability.