The Arihant-class submarines represent India's advancements in nuclear-powered ballistic missile technology, with significant developments in their design and capabilities over time. The class includes the submarines INS Arihant (S2), INS Arighaat (S3), and the upcoming INS Aridhaman (S4).

INS Arihant (S2): Commissioned in August 2016, this submarine is the first of its kind built by India under the Advanced Technology Vessel (ATV) project. It features a displacement of approximately 6,000 tons and is powered by an 83 MW pressurised water reactor. It can carry K-15 missiles with a range of about 750 km.

INS Arighaat (S3): Launched in November 2017 and commissioned on August 29, 2024, INS Arighaat shares similar dimensions and reactor specifications with INS Arihant but has enhancements that allow it to carry more K-15 missiles. It maintains a displacement of around 6,000 tons and is equipped with advanced systems developed under the ATV project.

INS Aridhaman (S4): Currently undergoing sea trials, INS Aridhaman is expected to be commissioned in early 2025. This submarine is larger than its predecessors, with a displacement of approximately 7,000 tons. It will be equipped with K-4 missiles, which have a significantly greater range of about 3,500 km, enhancing India's second-strike capability.

Key Features And Upgrades

Reactor and Dimensions: Both INS Arihant and INS Arighaat utilize the same reactor technology, while INS Aridhaman features an improved reactor design. The dimensions for S2 and S3 are consistent at approximately 111 meters in length, whereas S4 measures about 130 meters.

Missile Weaponry: While both S2 and S3 can carry K-15 missiles, S4 will have the capacity to launch K-4 missiles from its vertical launch systems. This upgrade is crucial for extending India's deterrent capabilities against potential adversaries.

The advancements from S2 to S3 include increased indigenous content and refined capabilities, although specific details remain classified. The improvements are aimed at bolstering India's strategic deterrence posture as part of its nuclear triad.

The Arihant-class submarines signify a critical step in enhancing India's naval capabilities and strategic deterrence. With the commissioning of INS Arighaat and the upcoming INS Aridhaman, India is poised to strengthen its underwater nuclear deterrent significantly. The ongoing developments reflect a commitment to advancing indigenous military technology while ensuring national security through robust maritime defence systems.