India covertly launched its fourth nuclear-powered ballistic missile (SSBN) submarine this week at the Ship Building Centre (SBC) in Visakhapatnam to bolster its nuclear deterrence against its enemies amid a diplomatic disagreement with Canada.
On August 29, 2024, Defence Minister Rajnath Singh commissioned India’s second SSBN, INS Arighaat. The third SSBN, INS Aridhaman, is scheduled to be commissioned the following year. On October 9, the Cabinet Committee on Security (CCS) approved the Indian Navy’s plans to construct two nuclear-powered attack submarines to fend off potential adversaries in the Indo-Pacific region.
The fourth SSBN, codenamed S4*, was launched on October 16, one day after Defence Minister Rajnath Singh officially opened the Very Low-Frequency Naval Station for command, control, and communications with strategic Indian Navy assets in the Damagundam forest area of the Vikarabad district in Telangana. This is despite the Modi government’s tight-lipped stance on nuclear deterrence.
With just 3,500 range K-4 nuclear ballistic missiles that can be fired from vertical launching systems, the recently launched S4* SSBN has around 75% domestic components. All of its successors are enhancements of the originals and only carry K-4 ballistic missiles; however, the first of its class, INS Arihant, carries K-15 nuclear missiles with a 750 km range. Only crew weariness, maintenance, and food supplies limit the SSBN’s unbounded endurance and range. A nuclear-powered attack submarine of the Russian Akula class is scheduled to join the force on lease in 2028, while both INS Arihant and INS Arighaat are currently on deep-sea patrols.
The newly launched INS Aridhaman is the last of its class, designated S4*, with a formal name that has not yet been assigned. This is because national security planners designated India’s first leased nuclear attack submarine, INS Chakra, as S1, INS Arihant as S2, INS Arighaat as S3, and INS Aridhaman as S4. The upcoming generation of Indian SSBNs would have twice the 6,000-tonne displacement of the Arihant class and be capable of transporting nuclear missiles up to 5,000 km in range.
Given that aircraft carriers are susceptible to long-range PLA missiles like the Dong Feng-21 and Dong Feng-26 and could be sitting ducks in the worst case, the Narendra Modi administration has placed a strong emphasis on sea-based submarine deterrence against formidable foes like China. The government has prioritised nuclear assault and ballistic missile submarines over the Indian Navy’s third aircraft carrier precisely because of this. With the commissioning of the sixth diesel attack Kalvari class submarine, INS Vagsheer, in December of this year, the government has also increased the deterrent of conventional submarines.
Meanwhile, in cooperation with the French Naval Group, the government will approve the building of three further sophisticated diesel attack submarines at Mazagon Dockyards. Strategic submarines are poised to play a significant role in defending India and controlling the Indian Ocean Region (IOR), with 10-11 PLA warships in the Indian Ocean each month since last year and carrier-based long-range patrols anticipated in 2025–2026.
