India is nearing the final stages of developing its indigenously built submarine-launched hypersonic ballistic missile, the K-6 (Kalam-6). The missile, which can travel at 7.5 times the speed of sound, approximately 9,261 kilometres per hour, is being developed under the aegis of the Defence Research and Development Organisation (DRDO). Unlike its predecessors, the K-4 and K-5, the K-6 is an intercontinental ballistic missile (ICBM) and is expected to be tested by 2030.
The K-6 has an estimated strike range of up to 8,000 km and is capable of carrying both conventional and nuclear warheads. It is set to become a state-of-the-art asset and the backbone of India’s naval nuclear deterrent. Designed as a submarine-launched ballistic missile (SLBM), the project is being spearheaded by the Advanced Naval Systems Laboratory (ASL) in Hyderabad, which operates under the DRDO.
The missile project began in 2017 and has achieved significant progress in just eight years, reflecting India’s rapid technological advancement, especially in the context of China’s growing presence in the Indian Ocean. China’s JL-3 SLBM, with a range of 9,000 km, has pushed India to enhance its defensive and offensive capabilities.
Given its hypersonic velocity, the K-6 can penetrate most existing missile defence systems. Like the Agni-5 missile, it features Multiple Independently Targetable Re-entry Vehicle (MIRV) technology, which allows it to strike multiple targets in a single launch. This MIRV capability, developed indigenously by India, significantly increases the missile’s lethality and reduces the need for multiple launches. India now joins an elite group of countries, namely the US, Russia, China, France and the UK, that possess MIRV technology.
A key advantage of the K-6 is its ability to strike from underwater at a safe standoff distance. It is a three-stage, solid-fuel missile measuring 12 metres in length and two metres in diameter, with a payload capacity of up to 3,000 kg.
However, India’s current fleet of nuclear submarines cannot accommodate the larger K-6 missile. As a result, India is simultaneously developing a new class of indigenous nuclear-powered submarines, codenamed the S-5. These submarines will be capable of carrying 16 K-6 missiles simultaneously and will be significantly heavier than the existing Arihant-class submarines, with an estimated displacement of 13,000 tons.
The S-5 class submarines will be powered by a 190 MW reactor designed by the Bhabha Atomic Research Centre, more than double the 83 MW reactors currently used in the Arihant class. Design and planning for the new submarines are nearly complete, with construction expected to begin by 2027. These vessels are projected to join the Indian Navy by 2030. The steel for the submarines will be supplied by the Steel Authority of India, and the submarines will feature advanced stealth capabilities.
With the K-6, India strengthens its nuclear triad, the ability to launch nuclear weapons from land, air, and sea. The K-6 is the fastest SLBM currently under development anywhere in the world. The K-series missiles represent an advanced evolution of India’s Agni missile programme. Compared to the Agni series, K-series missiles are faster, lighter, and possess superior radar-evading capabilities. All systems, including navigation, have been developed indigenously.
The K-6 has an accuracy range of within 90 to 100 metres of its target, making it one of the most precise strategic weapons in India’s arsenal.
India currently possesses the following missiles in the K-series, K-4, with a range of 3,500 km and K-5, with a range of 5,000 to 6,000 km. The K-6, once inducted, will mark a quantum leap in India’s strategic deterrent capabilities and cement its position as a formidable naval nuclear power.
