Indian-developed technology to boost range of missiles and protect re-entry vehicles

Bangalore: Agni III, which is India's longest-range missile with a capability of striking targets 3,500 km away, may now have an extended range of around 5,000 km thanks to a unique solution discovered by Indian scientists at the prestigious Indian Institute of Science (IISc) here. The technology will increase the range of not just missiles but also other satellite launch vehicles.

The technology also has the exciting possibility of reducing the risk of occurrence of a Columbia space shuttle-type of tragic accident.

The enhanced range of an Indian re-entry vehicle or missile will now be due to a special-purpose coating of chromium metal applied to the blunt nose cone of missiles and launch vehicles, for which international patents have been sought for by the team of IISc scientists (See: Indigenous technology to increase range of Indian missiles by a third)

The prestigious IISc is celebrating its centenary this year.

''Objects such as missiles fly at hypersonic velocities which are more than five times the speed of sound and encounter atmospheric drag because of friction. The chromium coating works by adding temporary heat and pushing the stagnating gas away to create an easier path,'' G Jagadeesh, an assistant professor at the IISc here said.

The findings of the IISc team, which also includes Vinayak Kulkarni of IIT (Guwahati) and GM Hegde, E Arunan and KPJ Reddy, have been reported in the latest issue of the Physics of Fluids journal published by the American Institute of Physics.

Laboratory experiments have shown that atmospheric drag because of the coating fell by 47% and Jagadeesh said a ''conservative estimate'' was that this would result in range going up by at least 40%.

''The measurements show about 47% reduction in the drag coefficient for a 60° apex angle blunt cone in a Mach 8 flow of 3.4  MJ/kg specific enthalpy,'' reads an extract from the article in the journal.

Scientists say the breakthrough also has potential to avert disasters of the type that struck space shuttle Columbia in 2003, which resulted in the death of seven astronauts, including Indian-born astronaut Kalpana Chawla. The shuttle burned out as it was re-entering the earth's atmosphere as there were problems it's thermal protection system.

The special-purpose coating developed at the IISc could likely replace the tiles and panels which currently protect orbiters against extreme heat during re-entry into the atmosphere.

''The coating evaporates once the object has re-entered the atmosphere. This novel method is path-breaking because additional energy is not required to reduce drag; objects which travel into space need to carry a much lower fuel load,'' Jagadeesh said.