India Tests the Intermediate-Range Ballistic Missile K-4 Missile From INS Arighaat

India has successfully tested the intermediate-range ballistic missile K-4 from its nuclear-powered submarine INS Arighaat in the Bay of Bengal, marking a significant step in strengthening the sea-based leg of the country’s nuclear deterrence. The test was conducted off the coast of Visakhapatnam, though no official statement was issued by the Ministry of Defence.

K-4 Missile and Strategic Significance

Sources confirmed that the missile tested was the solid-fuelled K-4, capable of striking targets up to 3,500 km away while carrying a nuclear payload of up to two tonnes. The missile is critical for operationalising India’s sea-based nuclear deterrent and enhancing the credibility of its nuclear triad. A detailed technical assessment will determine whether the test met all mission objectives, as submarine-launched ballistic missiles typically require multiple trials before achieving full operational status.

Role of INS Arighaat in India’s Nuclear Triad

INS Arighaat is India’s second nuclear-powered ballistic missile submarine (SSBN) and 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 is limited to the shorter-range K-15 missiles with a reach of 750 km. The recent K-4 test represents the first such launch from INS Arighaat after earlier trials from submerged pontoons.

Future SSBNs and Missile Development

India plans to commission its third SSBN, INS Aridhaman, in the first quarter of 2026, followed by a fourth submarine in 2027–28 under the Advanced Technology Vessel programme. These next-generation submarines will be larger, with a displacement of around 7,000 tonnes, compared to the first two boats. Longer-term plans include even bigger 13,500-tonne SSBNs equipped with more powerful reactors. Operational deployment of K-4 missiles will be followed by K-5 and K-6 missiles in the 5,000–6,000 km range class, narrowing the strategic gap with major nuclear powers.

Imporatnt Facts for Exams

• K-4 is a submarine-launched ballistic missile with a range of about 3,500 km.
• INS Arighaat is India’s second SSBN under the Advanced Technology Vessel programme.
• SSBNs form the most survivable leg of a nuclear triad.
• India follows a declared “no first-use” nuclear doctrine.

India’s Deterrence Posture

While India’s land-based missiles such as Agni-5 and air-delivered nuclear capabilities are well established, SSBNs provide the most secure and survivable retaliatory option. The induction of K-4-equipped submarines significantly enhances India’s second-strike capability, reinforcing credible minimum deterrence against nuclear adversaries.