Tuesday, August 18, 2009

New Technology: An Inflatable Heat Shield

A successful NASA flight test has shown that a spacecraft returning to Earth can use an inflatable heat shield to slow and protect itself as it enters the atmosphere at hypersonic speeds. This was the first time anyone has successfully flown an inflatable reentry capsule, according to engineers at NASA's Langley Research Center.

The Inflatable Re-entry Vehicle Experiment, or IRVE, was vacuum-packed into a 15-inch diameter payload "shroud" and launched on a small sounding rocket from NASA's Wallops Flight Facility on Wallops Island, Va. Nitrogen inflated the 10-foot (3 m) diameter heat shield, made of several layers of silicone-coated industrial fabric, to a mushroom shape in space several minutes after liftoff.

"This was a huge success," said Mary Beth Wusk, IRVE project manager, based at Langley. "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."

The Black Brant 9 rocket took about four minutes to lift the experiment to an altitude of 131 miles (211 km). Less than a minute later it was released from its cover and started inflating on schedule at 124 miles (199.5 km) up. The inflation of the shield took less than 90 seconds.

"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."

Inflatable heat shields hold promise for future planetary missions, according to researchers. 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.

No comments: