NASA reports that a test of an inflatable heat shield was successfully conducted on July 23, Monday morning. The test was the latest in a series of technology demonstrators conducted by the space agency.
The inflatable heat shield
The Hypersonic Inflatable Aerodynamic Decelerator or HIAD consists of a series of rings that form a protective cone when fully inflated, according to NASA. The HIAD consists of heat resistant kevlar that will allow a spacecraft that deploys it to enter land on any planet with an atmosphere -- Earth and Mars come to mind -- in safety. NASA suggests that an operational HIAD would permit the deployment of larger spacecraft with more instruments with which to conduct planetary exploration. It provides this service with a large volume and reduced weight. The HIAD also provides some control for a re-entering spacecraft by allowing it to be shifted from side to side within the protective cone.
The test flight
NASA reports that the prototype HIAD was launched aboard a sounding rocket from NASA's Wallops Island facility in Virginia. The Inflatable Reentry Vehicle Experiment (IRVE-3) reentered the Earth's atmosphere at hypersonic speeds and impacted into the Atlantic Ocean. NASA engineers determined that the HIAD, which was inflated with nitrogen, maintained its shape throughout the descent. NASA will study temperature and heat data from onboard sensors to determine how the inflatable heat shield performed as a protective barrier to the friction of reentry.
Traditional heat shields
Hitherto, heat shields have been made of heat resistant materials placed either on the underside of a capsule, such as Mercury, Gemini, and Apollo, or else in the form of tiles on the skin of the space shuttle, which reentered the atmosphere nose first. NASA will use a material called Avcoat, used on both the Apollo spacecraft and on some parts of the space shuttle, for the Orion Multi Purpose Crew Vehicle.
The future of inflatable heat shields
Laboratory and wind tunnel testing of the HIAD inflatable heat shield continues, according to NASA. In the future, NASA envisions the HIAD for two types of missions. An inflatable heat shield could serve as an easy way to deliver cargo back to Earth from the International Space Station or some other space-based facility. Also, a future HIAD could be used to land on worlds with an atmosphere, Mars, Venus, and Titan, a moon of Saturn, come to mind. Inflatable heat shields can be used for both robotic and crewed missions.
Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times, and The Weekly Standard.