Varunastra is an Indian-designed heavyweight, ship-launched anti-submarine torpedo developed by the Naval Science and Technological Laboratory (NSTL), a DRDO laboratory, in partnership with Bharat Dynamics Limited for production. Formally inducted into the Indian Navy on 26 June 2016, it is the Navy’s primary indigenous heavyweight torpedo for engaging submarines from surface combatants.[1]
Varunastra’s development began in the mid-2000s and took approximately eleven years to mature from initial design work to formal induction in 2016 — a long but not unusual gestation period for a complex underwater weapon requiring extensive validation of its guidance, propulsion, and warhead systems against realistic submarine threat profiles.[2] Development and qualification trials were extensive: in the 2015-16 financial year alone, the torpedo underwent 130 technical trials, alongside 14 dedicated user trials conducted by the Navy between January and March 2015, reflecting the rigorous test regime applied before the weapon was cleared for service use.[3]
The torpedo is electrically propelled using a Silver Oxide-Zinc (AgOZn) battery system, which offers a good balance of underwater endurance, low acoustic signature, and reliable performance compared to older thermal or combustion-based torpedo propulsion systems. It measures 7.78 metres in length and weighs approximately 1,500 kg, carrying a 250 kg high-explosive warhead.[1]
Varunastra uses a combination of fibre-optic wire guidance for precise mid-course control from the launching ship, plus autonomous active-passive acoustic homing and multi-constellation GNSS (satellite navigation) assistance for terminal targeting, giving it strong resistance to enemy acoustic countermeasures and decoys designed to spoof simpler torpedo guidance systems.[1] These features were specifically validated during development trials against simulated quiet, low-noise submarine targets, reflecting the weapon’s design intent of countering modern, acoustically quiet diesel-electric and nuclear submarines.[2]
The torpedo has an operational range of roughly 40–50 km, a maximum operating depth of 600 metres, and a top speed in the range of 40–50 knots (roughly 70+ km/h submerged), giving Indian Navy surface ships a credible long-range engagement capability against submarines well beyond visual or short-range sonar detection distances.[1]
On 5 June 2023, the Indian Navy and DRDO conducted the first “combat” configuration test-firing of Varunastra, successfully hitting a target at a range of 40 km after being fired — a significant validation milestone confirming the weapon’s real-world engagement performance under conditions closely simulating operational use rather than purely instrumented trial conditions.[4]
Varunastra has over 95 percent indigenous content, making it one of DRDO’s most self-reliant major naval weapons programmes. In March 2025, India’s Defence Acquisition Council approved additional orders for more Varunastra torpedoes, underscoring continued Navy confidence in the weapon nearly a decade after its initial induction, while NSTL has separately been developing a submarine-launched variant intended to extend the design’s reach beyond 50 km range.[5]
India’s government has signalled openness to exporting Varunastra to friendly nations, with Vietnam specifically identified as a potential customer since around 2016; the weapon’s high indigenous content and demonstrated performance have been cited as factors that could make Indian-origin torpedoes more broadly attractive to countries seeking to diversify away from traditional Western or Russian suppliers.[5]
Alongside Varunastra, NSTL has continued developing lighter torpedo designs for aircraft and helicopter-based anti-submarine warfare, aiming to give the Navy a fully indigenous family of both heavyweight ship-launched and lightweight air-launched torpedoes, reducing reliance on imported systems across the broader underwater-weapons portfolio.[6]
As India’s standard heavyweight anti-submarine torpedo, Varunastra equips the Navy’s principal destroyer and frigate classes, providing a credible, largely indigenous means of engaging hostile submarines at range — a capability considered increasingly important given the growth of submarine forces operated by regional competitors in the Indian Ocean Region.[1]
| Type | Ship-Launched Heavyweight Anti-Submarine Torpedo |
| Length | 7.78 m |
| Weight | ~1,500 kg |
| Warhead | 250 kg HE |
| Range | 40–50 km |
| Speed | 40–50 knots |
| Max Depth | 600 m |
| Propulsion | Electric (Silver Oxide-Zinc battery) |
| Guidance | Fibre-optic wire guidance, active-passive acoustic homing, GNSS |
| Inducted | 26 June 2016 |
| Developer | DRDO (NSTL) / Bharat Dynamics Limited |