Special Purpose Coating Can avert rentry issues, Indian scientists use to increase missile range

BANGALORE: Indian scientists have developed path-breaking technology that has the potential to increase the range of missiles and satellite launch vehicles by at least 40%, a member of the team which achieved the technological breakthrough said. 

India’s longest-range missile, Agni III, is capable of hitting targets 3,500 km away and the new technology could boost its range to 4,900 km. The enhanced range is made possible by adding a special-purpose coating of chromium metal to the blunt nose cone of missiles and launch vehicles, G Jagadeesh, an assistant professor at the Indian Institute of Science (IISc) here said. 

IISc, which is in celebrating its centenary this year, has applied for an international patent for the technology. 

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

The findings of the team—which also includes Vinayak Kulkarni of IIT-Guwahati and G M Hegde, E Arunan and K P J Reddy of IISc—have been reported in the latest issue of the Physics of Fluids journal published by the American Institute of Physics. 

The breakthrough also has potential to help avert problems of the type which led to break up in 2003 of the American space shuttle Columbia when it was re-entering the earth’s atmosphere. The disaster was caused by damage to the shuttle’s thermal protection system, killing seven crew members, including astronaut of Indian origin Kalpana Chawla. 

The special-purpose coating in place of the tiles and panels which now protect orbiters against extreme heat during re-entry into the atmosphere is seen as distinct possibility. 

“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,” he said.