NASA has successfully flight tested an inflatable heat shield to slow and protect a spacecraft as it enters the atmosphere at hypersonic speeds. The IRVE (Inflatable Re-entry Vehicle Experiment) launched from Wallops, Island, Va., Aug. 17, marking the first time anyone has successfully flown an inflatable re-entry capsule, according to engineers at NASA's Langley Research Center.
The IRVE was launched on a small sounding rocket, vacuum-packed into a 15-inch payload shroud. The Black Brant 9 rocket took about four minutes to lift the payload to an altitude of 131 miles. Less than a minute later, the IRVE was released from its cover and started inflating on schedule at 124 miles up. Nitrogen inflated the 10-foot diameter heat shield, made of several layers of silicone-coated industrial fabric, in less than 90 seconds to a mushroom shape in space.
"This was a huge success," Mary Beth Wusk, IRVE project manager, said in a statement. "IRVE was a small-scale demonstrator. Now that we've proven the concept, we'd like to build more advanced aeroshells capable of handling higher heat rates."
According to NASA, inflatable heat shields hold promise for future planetary missions. To land more mass on Mars at higher surface elevations, for instance, mission planners need to maximize the drag area of the entry system. The larger the diameter of the aeroshell, the bigger the payload can be.
"Everything performed well even into the subsonic range where we weren't sure what to expect," said Neil Cheatwood, IRVE principal investigator and chief scientist for the Hypersonics Project of NASA's Aeronautics Research Mission Directorate's Fundamental Aeronautics Program. "The telemetry looks good. The inflatable bladder held up well."
According to Cheatwood, the idea of inflatable decelerators has been around for 40 years, but technical issues plagued the project, including concerns about whether materials could withstand the heat of re-entry. Since then, however, materials have advanced and because of NASA's numerous Mars missions -- including rovers, landers and orbiters -- there's more understanding of the Martian atmosphere.
After its brief flight, IRVE fell into the Atlantic Ocean about 90 miles down range from Wallops. No efforts were made to retrieve the experiment or the sounding rocket, although cameras and sensors on board documented the inflation and high-speed free fall and sent the information to researchers on the ground.