New Delhi. Sea trials of India’s fourth ballistic missile Submarine-S have started. This submarine weighing 7000 tonnes left for sea trials from the Shipbuilding Center (SBC) located at Visakhapatnam port last week. S4 Sitara (Four Star) is the last submarine in the series of Arihant class ballistic missile submarines and is armed with eight nuclear-tipped K-4 submarine-launched ballistic missiles (SLBMs) with a range of over 3500 km.
More than 80 per cent of the S4 Sitara submarine’s equipment is made up of indigenous components, the highest among the four units. The submarine’s trials are expected to last for a year, after which it may enter service by early 2027.
India now has four SSBNs at sea, of which two are in service and two are undergoing trials. The third SSBN, INS Aridhaman, has completed her sea trials and is set to be commissioned in late 2026. This strategic achievement is the culmination of a project that began in 1984 with the establishment of the Advanced Technology Vessel (ATV) project for the supply of three SSBNs. The S4 Sitara was ordered more than a decade ago as an interim solution between the S4 and the larger S5 SSBN project.
