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News: Last week, India’s fourth nuclear-powered ballistic missile submarine (SSBN), referred to as S4, was launched into water at the Ship Building Centre in Visakhapatnam.
1. S4 features about 75% of indigenous content.
2. It is armed exclusively with K-4 nuclear ballistic missiles, which have a range of 3,500Km.
3. The K-4 will be mainstay of India’s undersea nuclear deterrence as it provides standoff capability to launch nuclear weapons while submerged in Indian waters.
4. Currently, India has two SSBNs operational: INS Arihant (commissioned in 2016) and INS Arighaat (commissioned in 2024). The third SSBN Aridhman is undergoing sea trials and is expected to be commissioned into service next year.



