- The Washington Times - Thursday, August 4, 2005

HOUSTON — After much analysis, NASA cleared Discovery to return to Earth next week, concluding yesterday that there was no need to send the astronauts on another spacewalk to repair a torn thermal blanket near a cockpit window.

Mission managers could not guarantee that a piece of the blanket won’t rip off during re-entry and slam into the spacecraft, but they said the chance of that happening was remote and that it would be riskier to try to fix the problem.

“The lowest risk, the best choice and the unanimous decision of the engineers in the management team is that we should re-enter as is,” deputy shuttle program manager Wayne Hale said at a press conference.

NASA had been considering sending out the astronauts to snip away part of the blanket for fear a 13-inch section weighing less than 1 ounce could tear away during the latter stages of descent and strike the shuttle, perhaps causing grave danger.

Wind tunnel tests hurriedly conducted in California on thermal blanket samples showed that tiny pieces of the fabric might shred off, Mr. Hale said. In the worst situation, he noted, there is a 1.5 percent chance that the entire 13-inch section would come off and hit the shuttle.

Under that remote circumstance, the cloth could strike the rudder speed brake and create a hole and 6-foot-long crack, but even that would not be enough to endanger Discovery and its crew of seven, Mr. Hale said.

“I am not here to tell you that we are 100 percent confident that there is no risk during re-entry. That would be untrue and foolish to even try to make that case,” he said. “But I am here to tell you that we’ve assessed this risk to the very best of our engineering knowledge and we believe that it is remote, small, whatever adjective you want to put with that.”

Discovery is scheduled to undock from the International Space Station tomorrow and land back at Cape Canaveral, Fla., before dawn Monday.

Had the astronauts been asked to repair the blanket, it would have been the fourth spacewalk of the 13-day mission. It also would have been the second time during the flight that the astronauts had to step outside to repair the shuttle’s thermal protection and reduce the risk of another Columbia-type disaster during the trip home, when the spacecraft passes through the blowtorch heat of re-entry.

Mission Control radioed the “good news” to the astronauts before they went to sleep.

Mr. Hale pointed out that there is a “profound” difference in the way NASA is handling such problems now, compared with the way it did before and during Columbia’s doomed flight in 2003. Many of the safeguards put into place for this flight — such as photographing the shuttle from every angle and using lasers to hunt for any cracks in its thermal shielding — were the result of the disaster.

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