This story is from January 20, 2020

Representational photo.

NEW DELHI: India tested its nuclear-capable K-4 submarine-launched ballistic missile (SLBM), designed to have a strike range of 3,500 km, from an undersea platform in the shape of a submersible pontoon off the coast of Andhra Pradesh on Sunday.

Though there was no official word on the test of the ‘strategic missile’, which will equip the country’s nuclear-powered submarines, sources said the solid-fuelled K-4 was test-fired for a range of around 2,200 km “successfully” in the Bay of Bengal around noon on Sunday.

“Though K-4 has been tested a few times before, this was the first time it was fired for a long range. The problem of the missile tilting after emerging from under water has been resolved,” said a source.

India’s solitary nuclear-powered submarine with ballistic missiles (SSBN), INS Arihant , is currently armed with K-15 missiles with a strike range of 750 km. The Navy also operates another nuclear-powered submarine, INS Chakra, acquired on a 10-year lease from Russia , but it does not have nuclear-tipped missiles because of international treatises.

INS Arihant had become fully operational in November 2018 after completing its first ‘deterrence patrol’ to complete the country’s long-awaited nuclear triad or the capability to fire nuclear weapons from land, air and sea. India for long has had the land-based Agni missiles, with the over 5,000 km Agni-V inter-continental ballistic missile now in the process of being inducted, and fighter jets jury-rigged to deliver nuclear weapons.

But INS Arihant gives the country’s nuclear deterrence posture much more credibility since SSBNs are the most secure, survivable and potent platforms for retaliatory strikes. Though INS Arihant’s K-15 missiles are currently dwarfed by the well over 5,000 km range SLBMs present with the US, Russia and China, the K-4 missiles will add much more teeth to the follow-on submarines.

The K-4 missiles are to be followed by the K-5 and K-6 missiles in the 5,000 to 6,000 km range. The 6,000-tonne INS Arihant, which is propelled by an 83 MW pressurised light-water reactor at its core is to be followed by INS Arighat, which was launched in 2017. The next generation of nuclear submarines, currently called S-4 and S-4*, will be much larger in size.

