NEW DELHI, Dec. 3 -- India is on course to strengthen its strategic forces with a new locally made nuclear-powered ballistic missile submarine named Aridaman, with navy chief Admiral Dinesh K Tripathi on Tuesday confirming that it will be commissioned into service soon. "Aridaman is in the final stages of trials and it will be commissioned soon," Tripathi said. The navy chief's comments on the latest development in India's top secret nuclear submarine programme came at his annual media briefing ahead of Navy Day on December 4. Aridaman will be the navy's third Arihant-class submarine, and will serve as an undetectable launch platform for missiles armed with nuclear warheads. Aridaman is set to be commissioned early next year, followed by a fourth SSBN codenamed S-4* in 2027, Hindustan Times has learnt. SSBN stands for ship submersible ballistic nuclear or nuclear-powered ballistic missile submarines. The navy commissioned its second indigenous SSBN, INS Arighaat, at Visakhapatnam in August 2024, strengthening India's nuclear triad or ability to launch strategic weapons from land, sea and air. The United States, Russia, the United Kingdom, France and China are the only other countries that can deliver nuclear warheads from a submarine. India's first indigenous SSBN, the 6,000-tonne INS Arihant, was commissioned nine years ago and it successfully completed its first deterrence patrol in 2018, with Prime Minister Narendra Modi then triumphantly announcing that the success of the submarine "gives a fitting response to those who indulge in nuclear blackmail". The fully operational submarine then completed the sea leg of India's nuclear triad. Arihant is armed with 12 B-05 submarine-launched ballistic missiles (SLBMs) capable of delivering nuclear warheads up to 750 km away. Both INS Arihant and INS Arighaat stay on continuous deterrence patrols....