ISRO Missions and Discoveries

ISRO tests system recoverable rocket ‘Inflatable Aerodynamic Decelerator (IAD)’


From UPSC perspective, the following things are important :

Prelims level: Inflatable Aerodynamic Decelerator (IAD)

Mains level: Not Much

The Indian Space Research Organisation (ISRO) has successfully tested a technology that could aid the cost-effective recovery of spent rocket stages and safely land payloads on other planets.

What is IAD?

  • IAD is a technique used for an atmospheric entry payload.
  • An inflatable envelope and an inflatant (anything that inflates the envelope, like air or helium) make up the inflatable aerodynamic decelerator.
  • While entering the atmosphere, it inflates like a balloon and decelerates the lander.
  • The inflatant is designed to fill the inflatable envelope to a condition such that it surrounds the payload meant to enter the atmosphere of a planet or satellite and causes aerodynamic forces to slow it down.
  • In simpler words, IAD is designed to increase drag upon entering the atmosphere of any planetary body, like Earth, Mars, or even Moon.
  • Its shape is maintained by a closed, gas-pressured body and the inflatant gas is also generated internally. Some versions also use ram air or both.

How significant is this IAD?

  • Some space agencies, including NASA, have already successfully tested advanced versions of the technology, including the supersonic and hypersonic variants.
  • However, for near future missions of ISRO, the current version that it tested is perfect.
  • Its use was first proposed by NASA more than 50 years ago for planetary entries.

Minuscule of ISRO’s IAD

  • The IAD tested by ISRO was inflated at an altitude of around 84 km and the sounding rocket’s cargo dropped through the atmosphere on it.
  • It is fitted with a booster motor. It also has a spin rocket that is ejectable.
  • The inflatable structure is made out of Kevlar fabric, which is a very strong synthetic fibre and also heat resistant to withstand atmospheric pressure and temperature changes.
  • On top of it, it’s coated with polychloroprene, an oil and wax resistant rubber, to withstand extreme temperatures.
  • In the inflation system, it uses compressed nitrogen stored in a bottle.
  • It has consistently decreased the payload’s velocity through aerodynamic drag while maintaining the expected trajectory during the test flight.

Where does ISRO intend to use it?

  • The IAD will help ISRO in performing many space tasks effectively including recovery of spent stages of rockets, for landing payloads on missions to other planetary bodies.
  • This is the first instance where an IAD has been specially created for spent stage recovery.
  • So inter-planetary missions are certainly one aspect that ISRO wishes to explore.


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