Context

• Indian navy launched nuclear capable intermediate-range submarine-launched ballistic missile K-4 or Kalam-4 missile off the coast of Visakhapatnam, Bay of Bengal. It is a solid-fuelled missile and has a strike range of 3,500 km.

K-4 Missile:

• It is a nuclear capable medium-range submarine-launched ballistic missile (SLBM) named after former President A.P.J. Abdul Kalam.
• Manufactured by: Defence Research and Development Organisation (DRDO)
• Range: Over 3,500 km
• Speed: Mach 5 (100 km/min)
• Size: 1.5 m diameter, 10 m length, weight: 20 tonnes

Nuclear-powered ballistic missile

It is a nuclear-powered submarine capable of launching ballistic missiles from underwater.

First Ballistic Missile Submarine: INS Arihant

• India's first ballistic missile submarine INS Arihant was launched by the then Prime Minister Manmohan Singh and his wife Gursharan Kaur on July 26, 2009.
• With the construction of this 6000 tonne vessel, India became the sixth country to have such submarines.
• The other five countries are the US, Russia, China, Britain and France.
• After undergoing intensive port and sea trials, INS Arihant became part of the Navy fleet in 2016.
• INS Arihant can carry K-15 nuclear missiles with a range of 750 km.

Second submarine: INS Arighat

• The second submarine of the Arihant class, INS Arighat, has double the number of missiles, giving India the capability to carry more missiles in 'water warfare'.
• This submarine was codenamed S-3.
• Launch: After several postponements, its launch took place in 2017.
• This submarine was originally known as INS Aridaman but was named INS Arighat upon launch.

Third Nuclear Submarine: INS Aridaman

• The third nuclear submarine of the Arihant class, INS Arihant, was also launched from the Ship Building Center in Visakhapatnam on November 23, 2021, in which secrecy was also maintained.
• This nuclear submarine is 13.8 meters larger than INS Arihant.
• It can carry at least 8 K-4 ballistic missiles with it. India is planning to launch at least four such submarines into the sea to increase its maritime attack capability.
• INS Arihant will be inducted into the Navy next year.

Features of SSBNs:

• Nuclear power: SSBN submarines are equipped with nuclear reactors, which gives them the ability to stay in the sea for a long time and complete the mission without surfacing.
• Ballistic missiles: These submarines carry ballistic missiles, which are capable of striking very far. These missiles can be fired from underwater and can target targets located thousands of kilometers away.
• Stealth: SSBN submarines can remain hidden inside the sea, due to which the enemy cannot easily find them. This makes them a powerful deterrent force.
• Destructive capability: The ballistic missiles installed in these submarines can be equipped with nuclear weapons, which can destroy a very large area.