 By SUE VORENBERG Scripps Howard News Service April 13, 2005
Scientists at Sandia National Laboratories are helping NASA prepare a new network of sensors embedded inside the shuttle's wing. They will detect anything that strikes the wing and let astronauts know if they should worry, said Ken Gwinn, a Sandia engineer. "If they did detect a significant hit they could take safe haven at the International Space Station and figure out what to do and how to fix the damage," Gwinn said. "On the Columbia shuttle, they didn't even know they had a problem, much less have time to fix it." If astronauts on the space shuttle Columbia had known that a briefcase-sized piece of foam had damaged their wing, they might have prevented the re-entry explosion that took their lives on Feb. 1, 2003, Gwinn said. After the crash, Sandia helped NASA and other agencies determine the cause by developing computer models and structural analyses. That information is now being used to make the other shuttles, like Discovery, safer, Gwinn said. "These sensors and the information we get from them will give everyone a much better understanding of what's happening with the whole system," Gwinn said. "I think this is a big advance in their safety and knowledge of what's going on." Each of the Discovery's wings now has 88 sensors embedded under the hardened tiles. Those sensors detect heat, acceleration and vibrations, according to NASA's Web site. The agency has also added a network of video cameras and improved the tiles and foam so nothing that big can break off again, Gwinn said. Sandia's part of the much bigger plan has been to calibrate and create software that ties all the vibration sensors into a network that will tell astronauts and NASA agents on the ground if something is amiss. "If there's an impact on the wing of any material, it will send vibrations through the structure that the sensors can see," said David Crawford, a Sandia scientist. "If we see a certain magnitude of vibrations at several locations, that will tell us we need to look more closely." Sandia scientists are also trying to tweak the system so it can see what sort of material has hit the wing, although that's a difficult task, Crawford said. "We're trying to see if that's possible right now, but the most important thing we're doing is corresponding a signal with a level of damage," Crawford said. "It's not so much what it was that is important, as how big it was and how fast it was moving, which is what we can see." The Sandia models have taken about a year and a half to develop, and scientists have run hundreds of calculations so far to calibrate the new sensor network. They will probably continue to run even more scenarios up until the actual launch date, Gwinn said. Helping NASA get its shuttle program back off the ground has been fun for Sandia's scientists, Gwinn added. "It's fantastic, really," he said. "For us to work on a system like the shuttle is really as good as it gets. It felt good to help NASA determine what went wrong with Columbia, and now we get to help them fix part of that problem. That's the best part of all of this."
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