Analysts on the ground were studying the images and expected to make a decision on Saturday. Earlier in the week, they noticed a half-inch ding on a window but they didn't think it would pose any danger.
The shuttle is due back on Earth on Sunday, ending a 16-day mission during which Endeavour delivered equipment allowing the international space station to double in size to six residents next year. The shuttle crew also performed four spacewalks to unjam a giant joint which rotates solar wings to track the sun and generate power for the space station.
"This has been a highly successful mission," flight director Mike Sarafin said Friday.
Besides making preparations to land Saturday, shuttle astronauts had a round of television interviews and also were releasing a tiny satellite to test solar cell technology for the Department of Defense.
Endeavour's astronauts have enough supplies to last until Tuesday if the weather isn't cooperative at the Kennedy Space Center in Florida or the two backup landing sites in California and New Mexico.
Hours before the final inspection Friday, Endeavour undocked from the space station after spending 12 days there. Endeavour's astronauts were forced to delay for several hours a third and final rocket-firing away from the station to avoid a piece of an old, broken-up Russian satellite. The firing would have put the shuttle within about 6 1/2 miles of the debris.
"Per the flight rules, it was the safe course of action," Sarafin said. "The piece we're talking about was smaller than a breadbox but big enough to do damage."
While at the space station, the shuttle dropped off an extra bathroom, kitchen and bedrooms, and a new recycling system designed to turn astronauts' urine and sweat into drinking water. The processor needed some work before it finally started spewing out recycled urine.
