NASA recently launched its Inflatable Re-entry Vehicle Experiment, a subscale version of an inflatable heat shield or aeroshell, atop a Black Brant 9 rocket from its launching pad on Wallops Island, Va. An inflatable heat shield could protect future spacecraft from the heat of hypersonic reentry for landing on Mars, the Earth, or any other planet.
The 1,400-lb IRVE consists of inflatable bladders made of Kevlar and silicone. Kevlar gives the bladders strength while the silicone coating lets them hold pressurized nitrogen. The bladders, in turn, are covered with three Kevlar layers and three Kapton layers for support, and three layers of open-weave Nextel fabric, which will let the shield survive the heat.
For the test, the device was vacuum packed into a 22-in.-diameter nose cone with the inflatable bladders and fabric surrounding a central core. The core held the inflation system and test instrumentation that documented the experiment. Video signals, along with temperature and pressure data, were beamed to Earth stations as the IRVE splashed down in the Atlantic Ocean and was not recovered. NASA also checked whether it could track the inflated devices with radar as it plummeted to Earth.
Inflatable heat shields will give NASA more flexibility in the size of the payloads that can land on Mars. Current heat shields are limited in size to the diameter of the launch vehicle’s payload faring. Larger shields, which create more drag upon reentry, could make it possible to deliver larger payloads or land payloads on higher elevation sites.