The space shuttle Endeavour's astronauts uncovered no noticeable flaws in the thermal shielding of their ship Wednesday following an in-depth inspection with lasers and cameras.
Flight director Tony Ceccacci said a preliminary look at the images beamed down found nothing amiss, and everything was on track for Friday's planned landing. But he cautioned that 20 hours usually are needed to analyze all the data.
The survey of the wings and nose, which took almost all morning, is standard before a shuttle returns to Earth. Endeavour's successful space station construction mission is due to end Friday morning.
NASA wants to make sure the most vulnerable parts of Endeavour's heat shield were not pierced by micrometeorites or space junk during the past two weeks in orbit.
The astronauts used a laser-tipped boom to check for damage. It's the same tool used to check for launch damage early in the flight; nothing serious was detected back then despite an unusual loss of insulating foam from the fuel tank.
NASA added all these extra safety checks when shuttle flights resumed two years after the 2003 Columbia disaster. A hole in Columbia's left wing, caused by flying foam, led to its destruction during re-entry.
Wednesday's job wrapped up work, once and for all, with the shuttle's robot arm, which held the inspection boom and all the laser and camera sensors.
"It's been a long one," shuttle commander Mark Polansky said, referring to the 16-day mission. "I think we're happy to be done."
Endeavour and its crew of seven left the international space station Tuesday after delivering and installing fresh batteries, big spare parts and a porch for Japan's science lab to hold outdoor experiments. Five spacewalks were carried out.
As the inspection was under way, an unmanned Russian vessel carrying more than 2.75 tons of water, oxygen and other supplies docked at the station, despite a last-minute problem.
The craft wasn't lined up right for the linkup, so the automatic approach was nixed and commander Gennady Padalka had to manually guide it in. NASA officials said their Russian counterparts would investigate what went wrong.
Mission Control praised Padalka for his "tremendous" effort.