Spacewalk delayed a day

Endeavour's crew was told tonight to get ready to repair a thermal tile gouged during launch, even though a final decision on the tricky maneuver has not been made.

"We had a long discussion about whether we could make the situation worse," said deputy shuttle program manager John Shannon, also chairman of the Mission Management Team.

Engineers have studied models of the damage with computer analysis and with testing in the superheated flow of an arc-jet that mimics re-entry.

"I think most of the data is in place," said Shannon. "I wanted the team to go off and think about it overnight."















Arc-jet tests on a sample of damaged tile showed that the 3-inch gouge would pose no danger to the crew or the shuttle.

A Friday spacewalk was moved to Saturday, which would allow the crew to prepare for the repair. Spacewalker Rick Mastracchio, who has practiced the repair in a vacuum, has been chosen to fix the 3-inch gouge caused by falling foam about a minute after launch.

If the repair is ordered, NASA might add two days and a fifth spacewalk to the mission. Again, no decision has been made.

"It's really too early to talk about a fifth (spacewalk)," said lead space station flight director Joel Montalbano.

The shuttle's aluminum skin would melt at about 1,200 degrees, and the adhesive holding the tiles could be weakened at 650 degrees. However, in arc-jet tests, aluminum behind a section of damaged tile reached some 340 degrees, only 40 degrees warmer than arc-jet tests with undamaged tile.

"I'm cautiously optimistic that repairs won't be needed," said Shannon. "This is not a catastrophic case."