July 24, 2012
Credit: Credit: NASA
Engineers from NASA’s Langley Research Center say they collected good data from the third Inflatable Reentry Vehicle Experiment (IRVE-3) in an early morning flight test from Wallops Island, Va., July 23, and hope to use it to develop lightweight hardware that can bring robots and eventually humans down on the surface of Mars.
Nearer term, the inflatable concept may be used to retrieve scientific samples and hardware from the International Space Station, and to recover reusable launch-vehicle hardware after missions.
“Potential applications include recovering launch vehicle assets,” says Langley’s Neil Cheatwood, the IRVE-3 principal investigator. “We have actually had conversations with more than one of the vendors about looking at whether this could help there.”
The 680-lb. flight demonstration payload lifted off at 7:01 a.m. EDT from Wallops Flight Facility atop a three-stage Black Brant sounding rocket that carried it to an altitude of 253 nm, where its onboard control system flipped it over and inflated its concentric-ring structure with nitrogen into a 10-ft.-dia. aeroshell covered with a four-layer thermal blanket.
The blanket — an outer layer of ceramic-fiber Nextel, two layers of silica Pyrogel and a gas barrier to prevent burnthrough — protected the inflated structure as it re-entered the atmosphere at speeds on the order of Mach 10, which generated outer temperatures of about 1000F and mechanical loading of about 20 gs.
“We saw actually a more energetic entry than we were expecting,” Cheatwood said in a post-flight press conference. “We saw about 15 watts per centimeter squared of heating. But our thermocouples actually showed a little bit lower temperatures than we would expect in response to that.”
The testbed splashed down about 20 min. after launch off the North Carolina coast, where it was spotted from the air floating on the surface. A U.S. Navy high-speed Stiletto boat was dispatched to locate and retrieve the experiment for analysis.
So far there have been no formal expressions of interest in the technology for scientific probes or recovery of samples and hardware from the ISS, although Cheatwood said NASA may offer it in future announcements of competitions for New Frontiers and Discovery missions. Meanwhile, the IRVE team will continue working on the ground to find better thermal-protection materials in an effort to raise the amount of heat-shielding while lowering the payload weight.
Cheatwood said that while there are no more flight demonstrations funded for now, one concept would involve using space station garbage as ballast for a test of an inflatable heat shield returning from the ISS.