Context: India has launched its fourth nuclear powered ballistic missile (SSBN) codenamed S4* (S4 star) submarine at Ship Building Center in Visakhapatnam to strengthen its nuclear deterrence.
SSBN: Ballistic Missile Submarine
- Purpose: Primarily designed for strategic nuclear deterrence. Typically, the submarines patrol in deep, remote ocean and remain submerged to provide a second-strike capability, in case of a nuclear attack.
- Weapons: Armed with submarine-launched ballistic missiles (SLBMs) carrying nuclear warheads.
- Propulsion: These submarines are powered by a 83-MW pressurised light-water reactor with enriched Uranium. This nuclear propulsion system enables the submarines to operate quietly and remain submerged in oceans for extended periods. This is a significant advantage over conventional diesel-electric submarines that need to surface regularly.
- Stealth Features: These submarines have advanced stealth features like noise-reducing coatings and advanced propulsion system. This makes their detection harder by enemy submarines and ships.
Ballistic Missile Submarines (SSBN) in India
1. S2- Arihant:
- INS Arihant was commissioned into service in August 2016.
- Arihant-class submarines are indigenously designed and developed under the Advanced Technology Vessel (ATV) project.
- It measures 111.6 metres in length and has a displacement of 6000 tonnes.
- It is powered by an 83-MW pressurised light-water reactor with enriched uranium.
- INS Arihant is armed with a 750-km-range K-15 Submarine Launched Ballistic Missile (SLBM), while retro-fitting of a 3500-km-range SLBM K-4 is under development.
2. S3- Arighat:
- INS Arihant was commissioned into service in August 2024.
- It measures 111.6 metres in length and has a submerged displacement of 6000 tons.
- It is powered by a 83-MW pressurised light-water reactor with enriched uranium.
- INS Arighat is equipped with ballistic missiles capable of carrying nuclear warheads. It is armed with a 750-km-range K-15 Submarine Launched Ballistic Missile (SLBM) and 3500-km-range SLBM K-4.
3. S4- Aridhaman:
- Launched in November 2021 (expected to be commissioned in 2025).
- It is an ‘Arihant-stretch’ variant, i.e., slightly larger than INS Arihant. It measures 125.4 metres and has a displacement of 7000 tons.
- It is equipped with K-4 submarine-launched missiles which have a range of 3500 km.
- It is powered by a 83-MW pressurised light-water reactor with enriched uranium.
4. S4* (yet to be named):
- Launched in October 2024 (yet to be commissioned)
- The newly launched S4* SSBN has nearly 75% indigenous content.
- It is an ‘Arihant-stretch’ variant, i.e., slightly larger than INS Arihant. It measures 125.4 metres and has a displacement of 7000 tons.
- It is equipped with K-4 submarine-launched missiles which have a range of 3500 km.
- It is powered by a 83-MW pressurised light-water reactor with enriched uranium.
After S4*, the next class of Indian SSBNs will be double the 6000 ton displacement of Arihant class and will be carrying nuclear missiles upwards of the range of 5000 kilometres and beyond.
Main classes of submarines in service with Indian Navy
- Sindhughosh-class: Variant of the Russian Kilo-class submarines, these are diesel-electric submarines. E.g., INS Sindhurakshak, INS Sindhuvir, INS Sindhuratna.
- Shishumar-class: Based on the German Type 209 design, these are diesel-electric submarines equipped with advanced systems. E.g., INS Shishumar, INS Shankush, INS Shalki, and INS Shankul.
- Kalvari-class (Scorpène-class): Diesel-attack submarines based on the Scorpène design developed by Naval Group (France). E.g., INS Kalvari, INS Khanderi, INS Karanj, INS Vela, INS Vagir, and INS Vagsheer (to be commissioned in December 2024).
- Arihant-class (SSBN): India's indigenous nuclear-powered ballistic missile submarines (SSBNs). These submarines are equipped with nuclear propulsion and are capable of carrying ballistic missiles. Currently, INS Arihant (S2) is the operational submarine of this class. The second submarine INS Arighat (S3) was commissioned in August 2024. Two more submarines (S4 INS Aridhaman & S4* are launched but yet to be commissioned).
- Chakra-class (SSN): Nuclear-powered attack submarines leased from Russia. Currently, INS Chakra-II (S1), the submarine of this class, is in service with the Indian Navy. Chakra-III is expected to be delivered to the Indian Navy by 2025.
Significance:
- Nuclear submarines enhance India's nuclear triad, which includes the ability to launch nuclear weapons from land, air, and sea.
- The submarine's ability to launch ballistic missiles from underwater provides India with a secure second-strike capability, a crucial component of its nuclear deterrence strategy.
- In 1998, India conducted nuclear tests under Phokran-II, and in 2003, India declared its nuclear doctrine based on ‘Credible Minimum Deterrence’ (CMD) and a ‘No First Use’ policy while reserving the right of massive retaliation if struck with nuclear weapons first.
- With India’s no-first use nuclear policy, SSBNs (Submarine-Launched Ballistic Nuclear Submarines) play a key role in deterrence due to their stealth capabilities and capability to execute retaliatory strikes.
- The presence of Arihant-class submarines will strengthen India’s nuclear triad, enhance nuclear deterrence and strengthen maritime defence.