The K-15 Sagarika is an Indian-developed Submarine-Launched Ballistic Missile (SLBM), also known by the code names B-05 or PJ-08, and is a key component of India's nuclear deterrent. It is a military concept and a weapon system that belongs to the secretive K Missile family. Development of the K-15 began in the late 1990s at the Defence Research and Development Organisation's (DRDO) missile complex in Hyderabad, with the goal of providing a sea-based nuclear strike capability for the Indian Navy's nuclear-powered Arihant-class submarines. This was necessary to complete India's nuclear triad—the ability to launch nuclear weapons from land, air, and sea—which is crucial for a credible, survivable second-strike capability under India's "no-first-use" policy.
The missile is a two-stage system powered by a solid-fuel rocket motor. Its mechanism involves a "cold launch" technique where a gas booster first ejects the missile out of its vertical launch tube and up to the water's surface before the main rocket motor ignites. The K-15 Sagarika has an operational range of approximately 750 kilometres and can carry a warhead of up to 1,000 kg, which can be conventional or nuclear. The final development trial was conducted on January 27, 2013, and the system officially entered service around August 2018.
The K-15 is deployed on the indigenous INS Arihant and the newer INS Aridhaman submarines. It connects directly to the broader K Missile family, which includes the longer-range K-4 (3,500 km range) and the planned K-5 (around 6,000 km range), which are intended to replace or supplement the K-15. The K-15 is considered a short-range SLBM and is often viewed as a technological stepping stone or a "stopgap measure" for the development of these longer-range missiles. A land-based version of the missile, known as Shaurya, was also successfully test-fired in 2008.