India Successfully Tests K-4 SLBM from INS Arighaat

The Defence Research and Development Organisation (DRDO) successfully conducted a test of the K-4 intermediate-range submarine-launched ballistic missile (SLBM) from India’s nuclear-powered ballistic missile submarine (SSBN) INS Arighaat on December 23, in the Bay of Bengal off the coast of Visakhapatnam.

About the K-4 Missile

• The K-4 is an intermediate-range ballistic missile with a strike range of up to 3,500 km.
• It is capable of carrying a nuclear payload weighing up to 2.5 tonnes.
• The missile is derived from the Agni-III ballistic missile.
• The ‘K’ series of missiles is named in tribute to Dr APJ Abdul Kalam, the architect of India’s Integrated Guided Missile Development Programme (IGMDP).

Strategic Significance

• The successful test significantly enhances India’s sea-based nuclear deterrence.
• It further consolidates India’s status as one of the few nations with a fully operational nuclear triad—land, air, and sea-based nuclear delivery systems.
• The missile can be deployed from Arihant-class SSBNs, ensuring credible second-strike capability.

INS Arighaat and Arihant-class Submarines

• INS Arighaat, India’s second SSBN, was inducted into service in 2024.
• Except for INS Arihant, which carries K-15 missiles (750 km range), all other submarines in the Arihant class are equipped with K-4 missiles.
• The K-4 SLBM was inducted into the Indian Navy on August 29, 2024.

Future Developments

• India is set to commission INS Aridhaman, the third Arihant-class SSBN, in the first quarter of 2026.
• On October 16, Defence Minister Rajnath Singh launched S4*, the last submarine of the Arihant class, which is expected to be commissioned into the Strategic Forces Command (SFC) by the end of the decade.
• The next generation of SSBNs, weighing around 10,000 tonnes, will be armed with K-5 missiles having a range of over 5,000 km.