DRDO to make sun-powered UAVs (Drones) that can fly for 15 days

After launching development of stealth UCAVs (unmanned combat aerial vehicles), India is now also looking at designing solar-powered spy drones which can cruise in the sky for several days at a time.

The high-altitude, long endurance (HALE) solar-powered UAV will not just reduce Indian military's carbon footprint but more importantly provide a cost-effective and flexible 24x7 ISTAR (intelligence, surveillance, target acquisition and reconnaissance) platform akin to "a pseudo-satellite" orbiting closer to the ground.

"Yes, Army and IAF have asked us to develop the solar-powered HALE UAV. Initial work is in progress for such a drone which can undertake a 15-day continuous flight over 30,000-feet,'' DRDO's chief controller R&D (aeronautics) Dr Prahlada told TOI.

The drone will harvest solar energy during the day, storing it in fuel cells to provide power for electric motors for night flying. "Solar efficiency is low but we are looking at a payload of around 50kg (sensors, cameras etc). We will seek some collaboration from either US or European companies,'' said Dr Prahlada.

This comes at a time when several international aviation majors are doing cutting-edge research on solar UAVs . Boeing , for instance, is developing a UAV with a 400-feet wingspan, called Solar Eagle, which can operate continuously for an astonishing five years. It is being described as a "zero-maintenance, launch-and leave UAV''.

With remotely-piloted spy as well as combat drones being seen as major force-multipliers or game-changers in modern-day warfare, DRDO has launched a series of UAV programmes for Indian armed forces, which have largely depended on Israeli drones like Searchers and Herons till now.

As was first reported by TOI recently, this includes the secretive AURA (autonomous unmanned research aircraft) programme to develop UCAVs capable of firing missiles, bombs and PGMs (precision guided munitions).

The Cabinet Committee on Security has also now cleared a Rs 1,500 crore DRDO project to develop the Rustom-H MALE (medium-altitude, long-endurance) drone, capable of operating for 24 hours with a 350-kg payload. "Its first flight will take place in two years,'' said Dr Prahlada.

Then, of course, there is the smaller Rustom-I drone, with 8-12 hour endurance and a 100-kg payload, as well as the already-developed Nishant UAV, which has a 4.5 hour endurance level.

Army, in fact, has projected a requirement of seven "troops" (akin to squadrons) of Rustom drones. As for Nishants, Dr Prahlada said, "Army has already inducted four such drones, which can be launched from hydro-pneumatic launchers without the need of runways, while eight more are being manufactured.''

"Nishants can carry electro-optical, electronic intelligence and communication intelligence payloads so the home ministry is also interested,'' added.