INS Arihant, the indigenously-built nuclear-propelled submarine that completed its first deterrence patrol, is capable of firing ballistic missiles and can stay under water for months.
The Strategic Strike Nuclear Submarine (SSBN) Arihant is a 6,000-tonne submarine with a length of 110 metres and a breadth of 11 metres. The underwater warship is capable of carrying 12 K-15 submarine-launched ballistic missiles having a range of over 700 km.
It can dive to 300 metres and is powered with a 83 MW nuclear power reactor.
SSBNs are usually bigger in size and are powered by a nuclear reactor, as a result they can remain submerged for months without having to surface. This allows them to travel farther and with greater stealth.
They are supposed to be the best guarantee for a second-strike capability in a possible nuclear exchange scenario.
India follows the policy of not using nuclear weapons first.
INS Arihant was launched on July 26, 2009, the anniversary of Kargil War Vijay Diwas, by then Prime Minister Manmohan Singh.
Four years later, in August 2013, the submarine's atomic reactor was activated. Since then, it has undergone extensive sea trials. It was quietly inducted in the Indian Navy in 2016.
It is another fine example of a joint mission of the scientists from the Defence Research and Development Organisation (DRDO) and the country's nuclear establishment.
There are plans to induct Aridhaman, the second SSBN.