SOURCE: AFI
India’s growing nuclear triad is poised for another significant milestone as the country prepares to commission its third nuclear-powered ballistic missile submarine (SSBN), likely to be named INS Aridhaman, in 2025. Based on the design of the Arihant-class, INS Aridhaman is often referred to as S4, its classified designation, and will feature significant enhancements over its predecessors. The submarine, a crucial component of India’s strategic deterrence, will mark a substantial leap in capability, complementing India’s existing sea-based nuclear arsenal.
INS Aridhaman is a stretched variant of the INS Arihant, with an estimated additional displacement of 1,000 tons compared to the earlier Arihant class submarines. The increased displacement enhances the vessel’s capacity to accommodate more Submarine Launched Ballistic Missiles (SLBMs), providing greater firepower and extending India’s second-strike capability. This improvement will also allow the submarine to stay submerged for longer durations, increasing its survivability during patrols.
The enhanced displacement has been made possible through modifications to the submarine’s hull, incorporating advanced structural reinforcements to handle the increased size and weight without compromising on stealth and speed. This improvement is pivotal for India’s nuclear deterrent strategy, as it enables INS Aridhaman to carry more missiles and thereby deliver a more potent nuclear strike in the event of a retaliatory mission.
The most critical upgrade that INS Aridhaman will offer is its enhanced SLBM payload. Unlike the Arihant class, which is believed to carry up to 12 K-15 SLBMs or 4 K-4 SLBMs, INS Aridhaman will feature an enlarged missile bay capable of hosting a greater number of missiles. The submarine is expected to be equipped with a combination of longer-range K-4 missiles (with a range of 3,500 km) and potentially the newer K-5 missiles, which are under development and rumored to have a range exceeding 5,000 km.
INS Aridhaman will feature several technological advancements over its predecessors, particularly in terms of stealth and survivability. The submarine is believed to incorporate improved sonar-absorbent coatings, advanced noise-reduction technologies, and better shielding for its nuclear reactor to minimize its acoustic signature, making it harder to detect by adversary submarines and anti-submarine warfare assets.
Additionally, the SSBN will benefit from more sophisticated onboard electronics and command and control systems, providing enhanced capabilities for communication with India’s nuclear command structure while submerged. The submarine’s reactor, an upgraded version of the one used in the Arihant-class, is expected to be more efficient, delivering greater endurance and allowing the submarine to operate for longer durations without the need to surface.