INS Aridhaman has been formally commissioned into service, marking a significant expansion of India’s sea‑based nuclear deterrent. The submarine, reportedly 1,000 tons heavier than its predecessors Arihant and Arighaat, was inducted at a ceremony in Visakhapatnam presided over by Defence Minister Rajnath Singh.

Unlike Arihant and Arighaat, which can carry up to a dozen K‑15 Sagarika and four K‑4 missiles (operational range 3,500 kilometres), Aridhaman is equipped to carry 24 Sagarika missiles and eight K‑4 or K‑5 missiles. This doubling of capacity makes it a formidable platform capable of deploying either nuclear or conventional warheads, reinforcing India’s deterrence posture.

The K‑15 Sagarika, also known as B‑05 or PJ‑08, is a submarine‑launched ballistic missile with a range of 750 kilometres. Developed by the Defence Research and Development Organisation and manufactured by Bharat Dynamics Limited, the missile entered service in 2018.

It measures approximately 10 metres in length, with a diameter of 0.74 metres, and weighs between 6 and 10 tonnes depending on the source. It can carry a warhead of about 1,000 kilograms. The multiple designations were deliberately used to maintain secrecy during its development.

Work on the missile began in the late 1990s, with the underwater launcher completed in 2001 and handed over to the Navy for trials. After several tests, the first full‑range trial was conducted on 11 March 2012, followed by confirmation of a successful developmental trial on 27 January 2013 after the twelfth test from a submerged pontoon.

In 2022, the Ministry of Defence confirmed a successful user training launch from INS Arihant, which validated crew competency and reinforced the credibility of India’s SSBN program. This was described as a key element of India’s nuclear deterrence capability, consistent with its doctrine of ‘Credible Minimum Deterrence’ and its ‘No First Use’ policy.

The Sagarika combines features of both cruise and ballistic missiles. After launch, it travels 50 kilometres underwater before accelerating to seven times the speed of sound. Its fins allow it to be steered to within 20 metres of its target, nearly 750 kilometres away.

The missile’s flat trajectory, hypersonic speed, and small radar cross‑section make it extremely difficult to detect until it is close to impact. Reports suggest that the K‑15s are primarily intended to hold southern Pakistani targets, including Karachi port, within range. However, its current range does not extend far enough to threaten Chinese assets from the Indian Ocean.

The program reflects India’s long‑term ambition to secure a survivable, sea‑based second‑strike capability. Defence scientists and naval personnel overcame significant technological hurdles before achieving this milestone.

The Institute of Peace and Conflict Studies noted that the successful development of the Sagarika missile completes India’s nuclear triad, ensuring retaliatory capability from land, air, and sea. This achievement underscores India’s determination to maintain a credible deterrent posture in a complex regional security environment.

IDN (With Agency Inputs)