NASA engineers are expected to decide today if Discovery astronauts need to perform another repair to the shuttle's exterior.
Of concern is whether a damaged thermal blanket under one of the cockpit windows would tear away during re-entry to Earth's atmosphere and strike the orbiter, especially when the shuttle slows from Mach 20 to less than Mach 6, deputy shuttle program manager Wayne Hale said.
Engineers estimate that any chunk of the blanket would weigh less than an ounce, Hale said. But NASA officials have to be concerned about "where might it go and what might it do."
The space agency has flown three samples of the material to its Ames Research Center in California to test them in a wind tunnel overnight.
Photos of the 20-inch-by-4-inch blanket show that it was punctured at one end - possibly by debris - and "poufed out" at the other, Hale said, reports CNN.
Managers are worried that a damaged piece of a thermal insulation blanket below the commander's window on the shuttle, which is docked at the International Space Station, may break off and strike the shuttle when it returns to Earth next week.
“We're waiting to hear the final answer from engineers,” Discovery Commander Eileen Collins said in an interview broadcast on NASA television.
The seven-member crew of Discovery are on “light duty” today after yesterday's repairs, NASA said. They're also remembering the crew of Columbia, which broke up on its return to Earth in February 2003, killing all seven people on board, and other astronauts who died in previous missions.
Discovery is the first shuttle mission to launch since the Columbia accident, which grounded the National Aeronautics and Space Administration's three remaining orbiters. The shuttle is scheduled to land at Kennedy Space Center in Cape Canaveral, Florida, at 4:46 a.m. local time on Aug. 8, reminds Bloomberg.