DRDO tests tech for stealthier submarines

10 Mar 2021 Editorial Team

The Defence Research and Development Organisation (DRDO) conducted the final development test of Air Independent Propulsion (AIP) in Mumbai.

The AIP technology allows a submarine to be submerged for longer periods underwater and makes the sub surface platform more deadly by making it quieter than a nuclear submarine.

The Indian Navy is now planning to retrofit all its Kalvari class non nuclear attack submarines with AIP during their first upgrade, expected around 2023. The 1,615 tonne Kalvari class submarine is being built by Mazagon Dockyards Ltd (MDL) in collaboration with the French Naval Group and is based on Scorpene design.

India now has the AIP technology along with the US, France, China, the UK. The DRDO's AIP technology is based on a Phosphoric Acid Fuel Cell, and the last two Kalvari class submarines will be powered by it. The AIP design was tested on land in Mumbai.

The AIP or marine propulsion technology allows non nuclear submarines to operate without access to atmospheric oxygen (through snorkel or surfacing) and augments the diesel-electric propulsion system of attack submarines. This means that AIP fitted submarines do not have to surface for charging their batteries and remain underwater for long periods. The AIP is retrofitted into existing submarine hulls by adding an additional hull section. The AIP equipped submarines are identified as SSP, while classic diesel attack submarines carry the SSK classification.

While the nuclear submarine generates noise due to the ship's reactor constantly pumping coolant to maintain the engine's temperatures, the AIP equipped submarine maintains a lethal silence. The new technology will allow Indian submarines to take advantage of internal refraction in equatorial waters due to temperature differences on the surface and within the ocean.

Image Source

4th Indian Cement Review Conference 2021

17-18 March

Click for event info

The Defence Research and Development Organisation (DRDO) conducted the final development test of Air Independent Propulsion (AIP) in Mumbai. The AIP technology allows a submarine to be submerged for longer periods underwater and makes the sub surface platform more deadly by making it quieter than a nuclear submarine. The Indian Navy is now planning to retrofit all its Kalvari class non nuclear attack submarines with AIP during their first upgrade, expected around 2023. The 1,615 tonne Kalvari class submarine is being built by Mazagon Dockyards Ltd (MDL) in collaboration with the French Naval Group and is based on Scorpene design. India now has the AIP technology along with the US, France, China, the UK. The DRDO's AIP technology is based on a Phosphoric Acid Fuel Cell, and the last two Kalvari class submarines will be powered by it. The AIP design was tested on land in Mumbai. The AIP or marine propulsion technology allows non nuclear submarines to operate without access to atmospheric oxygen (through snorkel or surfacing) and augments the diesel-electric propulsion system of attack submarines. This means that AIP fitted submarines do not have to surface for charging their batteries and remain underwater for long periods. The AIP is retrofitted into existing submarine hulls by adding an additional hull section. The AIP equipped submarines are identified as SSP, while classic diesel attack submarines carry the SSK classification. While the nuclear submarine generates noise due to the ship's reactor constantly pumping coolant to maintain the engine's temperatures, the AIP equipped submarine maintains a lethal silence. The new technology will allow Indian submarines to take advantage of internal refraction in equatorial waters due to temperature differences on the surface and within the ocean. Image Source4th Indian Cement Review Conference 202117-18 March Click for event info

Infrastructure Transport

15 Sep 2025

Cabinet Approves Key Highway and Rail Projects in Bihar Region

The Union Cabinet on Wednesday approved the four-laning of the 84.2-km Mokama-Munger section of the Buxar-Bhagalpur high-speed corridor, a key industrial region in poll-bound Bihar. The Cabinet also sanctioned the doubling of the 177-km Bhagalpur-Dumka-Rampurhat railway line, which passes through Bihar, Jharkhand, and West Bengal, at a cost of Rs 31.7 billion.The Rs 44.5 billion highway project will be constructed under the hybrid annuity model, a variant of public-private partnership. The Mokama-Munger stretch was the only remaining two-lane section of the 363-km Buxar-Bhagalpur corridor. Fou..

Infrastructure Transport

15 Sep 2025

NGT Issues Notice on Bengaluru Twin Tunnel Project

The National Green Tribunal (NGT) on Wednesday issued notices in response to a petition filed by Bengaluru Praja Vedike and others, challenging the Bengaluru twin tunnel road project. Petitioners claim the project was “hastily announced” and bypassed mandatory environmental impact assessment procedures.Notices have been served to the Karnataka Government, Greater Bengaluru Authority, State Environment Impact Assessment Authority (SEIAA), Bengaluru Smart Infrastructure Ltd (B-SMILE), the Union Ministry of Environment, Forest and Climate Change, and project consultants.The 16.74-km twin-tube..

Real Estate

15 Sep 2025

India’s Residential Sales to Dip Slightly in FY26

Residential sales in India’s seven major cities are projected to decline by up to 3 per cent year-on-year in FY26 to 620–640 million square feet (msf), amid a moderation in sales velocity, according to ratings agency Icra.In FY25, sales stood at 643 msf, down 8 per cent YoY, following a sharp contraction in new launches and moderated demand in the affordable and mid-income segments. This slowdown came after the sector posted a robust compound annual growth rate of 26 per cent in area sales between FY22 and FY24.Icra noted: “Having seen a strong upcycle, the sector entered an equilibrium ..