What if the Space Shuttle, traveling at 500 miles per hour, slammed into, say ... an ice cube? What kind of damage would result? Does the density of the ice make a difference? What about the size or orientation of the ice crystals?
NASA is looking for answers to these and other questions about potential debris hazards as part of its Space Shuttle Return-to-Flight Program. Because debris from Space Shuttle Columbia's external tank resulted in the loss of the orbiter, scientists and engineers in the Ballistic Impact Lab at NASA Glenn Research Center want to know if ice debris falling off the super-cooled external tank could cause significant damage during launch.
But ice impact analysis is a new area for NASA. So to jump start the investigation they asked for help from Erland Schulson, Director of the Ice Research Laboratory at Thayer School of Engineering. Schulson is also the George Austin Culligan Distinguished Professor of Engineering.
"They did a literature search on the mechanical behavior of ice and they called me because, they said, 'Your name kept popping up,'" said Schulson. At first, NASA invited him just to give a talk at the Kennedy Space Center last April on the basics of ice mechanics. But soon after that, they decided to bring him on as a consultant to the Shuttle program.
"This is one series of many tests that are being performed throughout the country to ready the external tank for a safe return to flight. Facilities at NASA centers, as well as many Defense Department and university facilities, are being utilized to obtain timely and cost-effective results," said Sandy Coleman, External Tank Project Manager at NASA's Marshall Space Flight Center in Huntsville, Ala., in a Dec. 17 interview with the Mississippi Sun Herald.
Schulson receives ice samples at his lab in Cummings Hall, assesses their strength and structure in his multi-axial loading system, a unique device which measures the force required to crush the ice, and then sends them on to NASA for ballistic impact testing. Said Schulson, "I'm providing NASA with quantifiable data on the ice they're testing as a starting point for answering the question, Does the strength and structure of the ice that forms on the external tank affect its potential to do damage to the Space Shuttle?"
After testing the first set of ice samples, Schulson realized it was a learning opportunity for him as well. "To conduct the sort of testing NASA was looking for, we didn't have to modify our system at all," he said. "But the project has definitely gotten me thinking about questions I haven't thought about before, such as the physics of fracture at very high speeds."
Thayer School doctoral candidate Andrew Fortt and engineering research associate Daniel Iliescu are also assisting with the project.
"It's been a great experience for them. They've learned a lot," Schulson said. "I am also a sounding board for NASA. I've spent a lot of time thinking about the structure and behavior of ice, and I'm helping them to learn very quickly."
Schulson expects the project to run until the next Shuttle launch later this year.
By CATHARINE LAMM
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Last Updated: 12/17/08