NASA officials say they will decide Thursday whether to attempt risky spacewalk repairs on a gouge in some heat tiles on the belly of the shuttle Endeavour.
Shuttle commander Scott Kelly asked Mission Control what was going on.
"Unfortunately, we have no idea which way the wind is blowing at the moment," he was told Wednesday night.
If the patching job is ordered, it will likely happen on Saturday to give engineers more time to plan the operation. That could delay Endeavour's departure by a day.
Preliminary tests indicate no need to fix the gouge, but mission managers want to wait until heat-blasting tests have been completed.
"At the moment, they don't have all the data they would like to make their decision," Mission Control told the shuttle astronauts.
The worry isn't a Columbia-type disaster that could kill all seven astronauts. Instead, they are worried that if too much heat gets to the frame, it could damage the aluminum structure and require lengthy post-flight repairs.
The damage occurred about a minute after liftoff on Aug. 8. A piece of debris struck Endeavour.
Astronauts can use goo, similar to caulking, to fill the hole, or they can use a type of blackening substance that can be used to add extra heat protection to the white tiles.
If possible, NASA wants to avoid a major repair.
"When you've got a small leak in your kitchen and you go to fix it and suddenly you've banged a few things and you've got water all over your floor -- it's the same sort of thing. You don't want to introduce risk if you don't have to," NASA spokesman Allard Beutel told Â鶹´«Ã½net.
The spacewalk
Shuttle astronaut Rick Mastracchio and International Space Station resident Clay Anderson spent 5.5 hours on a spacewalk.
The spacewalk for Mastracchio ended early after he noticed a cut to his glove.
NASA said Wednesday the move was a precaution and that astronaut Rick Mastracchio was in no immediate danger, even though he was told to return immediately to the International Space Station's airlock.
"The gloves were good. I don't know where that little hole came from,'' Mastracchio radioed.
Mastracchio and Clay Anderson were working on the relocation of a solar array on the space station.
Most of their major scheduled activities were completed, NASA said, adding the cut was discovered about four hours into the walk.
Astronauts are required to check their gloves every 30 minutes. There are several layers to the gloves.
With files from The Associated Press
