India's recent successful test of the K-4 submarine-launched ballistic missile (SLBM) from the INS Arighaat marks a significant enhancement of its nuclear capabilities. This development is pivotal for several reasons:

On November 28, 2024, the Indian Navy conducted a test firing of the K-4 missile, which has a range of approximately 3,500 kilometers. This was the first time the missile was launched from a submarine, specifically the newly commissioned INS Arighaat, which adds to India's strategic deterrence capabilities. The missile is about 12 meters long, weighs around 17 tons, and can carry a warhead of up to 2 tons. It is powered by solid rocket propellant and features advanced manoeuvrability to evade missile defence systems.

Prior to this, India's submarine-launched capabilities were limited to the K-15 missile with a range of only 750 kilometers. The K-4 significantly extends this range, allowing India to cover not just all of Pakistan but also substantial parts of China.

The successful deployment of the K-4 missile strengthens India's nuclear triad—its ability to launch nuclear weapons from land, air, and sea. This capability is crucial for maintaining a credible second-strike capability under India's "no first use" nuclear policy. While India could have only covered certain parts of Pakistan with K-15, K-4 enables it to have wider range covering not just whole of Pakistan but also large part of China.

SLBMs like the K-4 are inherently more survivable than land-based missiles due to the stealth of submarines. This capability ensures that India can maintain a credible second-strike option even in the event of a nuclear first strike against it.

The INS Arighaat is equipped with advanced technologies that make it more capable than its predecessor, INS Arihant. It can carry up to four K-4 missiles or twelve K-15 missiles, thereby increasing operational flexibility and strategic depth.

India is also developing the K-5 missile, which is expected to have a range of about 5,000 kilometers, further bolstering its underwater nuclear capabilities. The third submarine in this class, expected to be inducted next year, will enhance India's deterrent posture even more.

Comparison With Other SLBMs

Missile NameCountryRange(km)Warhead (Tons)Notable Features
K-4India3,5002Solid-fuelled, capable of 3D maneuvers12.
JL-3China10,0001.5Launched from Jin-class submarines, advanced stealth5.
Trident II (D5)USA12,000450Deployed on Ohio-class SSBNs, multiple warhead capability5.
RSM-56 BulavaRussia8,000150-200Launched from Borei-class submarines, high accuracy5.
M51France10,0001Deployed on Triomphant-class submarines, multiple warhead capability5.

In conclusion, the successful test of the K-4 SLBM from INS Arighaat represents a significant leap in India's strategic military capabilities, reinforcing its position as a formidable nuclear power and enhancing its deterrence against regional adversaries.