The damaged section of blanket, about 4 inches by 6 inches, isn't in an area that's affected too much by heat during re-entry, but NASA's John Ira Petty says that doesn't mean officials aren't worried.
"We're looking very closely at it. We're analyzing photos and other information that's been sent down from the station. A decision will be made based on that, whether we want to try to take some measures to replace that or just go ahead and land with it as is."
Petty says astronauts have several options for how to deal with the tear and will decide within the next few days how to procede.
"The crew is equiped to take some measures. They could range everywhere from just going out and tucking it back in under these tiles that are just ahead of it or perhaps just repairing some of the stitching."
This is the first shuttle mission of 2007. Atlantis is delivering components of the Internation Space Station and is expected to return to earth next Tuesday.