India’s Defense Research and Development Organization (DRDO) on Sunday launched a K-4 intermediate-range, nuclear-capable submarine-launched ballistic missile (SLBM) from a submerged platform off the coast of Andhra Pradesh in southeastern India, according to local media reports.
Citing Indian government sources, ANI reports that the test firing of the K-4 SLBM was a success. Neither DRDO nor the Indian Ministry of Defense (MoD) officially confirmed the missile launch to date.
A Notice to Airmen (NOTAM) was issued earlier this month over a 3400-kilometer flight corridor over the Bay of Bengal for January 19 to 21. India had issued a similar notification for November 2019 leading to the speculation that a K-4 launch was imminent at the time but none occurred.
A K-4 test launch was reportedly also planned for October 2019 but then postponed for unknown reasons.
Developmental testing of the missile, which has an estimated maximum range of 3,500 kilometers and can be fitted with a 2,000-kilogram sub-kiloton nuclear or conventional payload, began in 2010.
A K-4 SLBM flight-test attempt from a submerged pontoon in December 2017 failed as a result of a battery malfunction.
The K-4 was last successfully test fired in full operational configuration from India’s first domestically developed and built nuclear-powered ballistic missile submarine (SSBN), the INS Arihant, in April 2016.
It is, however, unclear whether the Arihant’s launcher is capable of supporting the K-4 in operational configuration due to the 12-meter SLBM’s length and the 10.4-meter diameter of the SSBN’s hull, as Jane’s has pointed out in an April 2019 analysis. All subsequent tests were reportedly conducted from submerged pontoons.
Notably, the K-4 has been tested using depressed trajectories, according to Indian government sources.
DRDO officials in the past have stated that the circular error probable (CEP) of the K-4 to be 40 meters or less, which would make it an ideal weapon system for a sea-based counter-force capability from stand-off ranges.
The INS Arihant, the first-of-class of a planned fleet of four to five SSBNs based on the Russian Project 971 Akula I-class nuclear-powered attack submarine (SSN), has been designed to carry up to four K4s or 12 K-15 (B-05) short-range ballistic missiles (SLBM).
Three K-15s were successfully launched from the Arihant in August 2018. The K-15 Sagarika is a solid-fueled two-stage SLBM capable of carrying a single warhead and has a reported maximum range of 700 to 750 kilometers. It has been under development by India’s DRDO since the 1990s. Another test firing of a K-15 SLBM from the INS Arihant took place in November 2015.
Given the Arihant’s primary role as a technology demonstrator, it will likely take the Indian Navy at least until 2021–when the second Arihant-class SSBN the future INS Arighant (originally assumed to be named Aridhaman) is set to enter service — to achieve an operational long-range nuclear strike capability.