India Successfully Tests K-4 Missile from INS Arighaat in Bay of Bengal

India advances sea-based nuclear capability with K-4 missile test

India has taken a major step in reinforcing the sea-based leg of its nuclear deterrence by successfully testing the K-4 intermediate-range submarine-launched ballistic missile (SLBM) from its nuclear-powered submarine INS Arighaat . The test was conducted in the Bay of Bengal off the coast of Visakhapatnam , according to defence sources, though the Ministry of Defence has not issued an official statement.

Strategic importance of the K-4 missile

The solid-fuelled K-4 missile is designed to strike targets at a range of up to 3,500 km while carrying a nuclear payload of up to two tonnes . Its induction is crucial for operationalising India’s sea-based nuclear deterrent and strengthening the credibility of the country’s nuclear triad —land, air and sea. As with most submarine-launched ballistic missiles, multiple trials are required before full operational clearance, and a detailed post-launch technical evaluation will determine the success parameters of the test.

INS Arighaat and the SSBN programme

INS Arighaat , India’s second nuclear-powered ballistic missile submarine (SSBN) , is operated by the Strategic Forces Command . Commissioned on August 29 last year , the 6,000-tonne submarine follows INS Arihant , which became fully operational in 2018 but primarily deploys the shorter-range K-15 missile with a range of about 750 km. The latest test marks the first reported K-4 launch from INS Arighaat after earlier trials conducted from submerged pontoons.

Future submarines and missile development

India plans to induct its third SSBN, INS Aridhaman, in early 2026 , followed by a fourth by 2027–28 under the Advanced Technology Vessel (ATV) programme . These submarines will be larger, with a displacement of around 7,000 tonnes , and future plans include 13,500-tonne SSBNs with more powerful reactors. Missile development will also progress to K-5 and K-6 SLBMs in the 5,000–6,000 km range , further enhancing deterrence.

Important Facts for Exams

• K-4 is an SLBM with a range of ~3,500 km

• INS Arighaat is India’s second SSBN under the ATV programme

• SSBNs are the most survivable leg of a nuclear triad

• India follows a declared No First Use nuclear doctrine