Bhubaneswar: The Defence Research and Development Organisation has test fired K-15 Submarine Launched short range Nuclear capable Ballistic Missile from Dr. Abdul Kalam Island at 6:50 PM yesterday.

Also Known as “Sagrika”, it has a range more than 750 kilometers and it is currently in service with India’s SSBN Fleet. The missile forms a part of the triad in India's nuclear deterrence, and will provide retaliatory nuclear strike capability. The missile was fully operationalised in August 2018.

The Sagarik SLBM is designed for retaliatory nuclear strikes. The K-15 is a two-stage submarine-launched ballistic missile which uses a gas booster to eject out of its launch platform and rise up to the surface of water. A solid rocket motor is fired after the missile reaches a fixed altitude. The missile has a range of around 750 kilometres (466 mi).

Apart from demonstrating India's 'second strike' capability, the success of the test has proven India's command and control architecture for retaliatory strike operations.

When deployed, submarines need to remain in touch with the command and control centre to receive the orders for launch if and when required.

This becomes more critical in the case of a nuclear-armed submarine, like INS Arihant, which would need a go-ahead from the Nuclear Command Authority to launch a nuclear-tipped missile.

The test demonstrates the credibility of the sea leg of India's nuclear triad, which is the ability to launch a nuclear strike from land, air and sea. India established its nuclear triad in 2018, with the completion of the first deterrence patrol by INS Arihant that year.

Given its 'no first use' nuclear posture, India needed to demonstrate the capability to launch a second strike or the ability to respond to a nuclear attack with one of its own. An assured second-strike capability is an essential element for effective strategic deterrence.

SSBNs are believed to be the most survivable of the three legs of the nuclear triad. While land-based missiles and aircraft meant for nuclear weapons delivery can be targeted by the enemy in a first, counterforce strike, taking out SSBNs at sea is relatively more difficult.

These boats can remain underwater for long durations of time to avoid detection.

In case of a first strike that destroys land-based nuclear delivery options, India can launch a retaliatory strike with its surviving SSBNs. For this, India will need a continuous at sea deterrent, and the commissioning of the three SSBNs currently in the pipeline — Arighat, S4 and S4* — will give India this capability.