HOUSTON - As space shuttle Atlantis crew members continued their return trip to Earth on Wednesday, they waited for results of a final inspection of the spacecraft to make sure its heat shield was in good shape.
A camera attached to a robotic arm and boom surveyed the wings and nose cap of the shuttle after it undocked from the international space station Tuesday.
Engineers on earth want to study the images to make sure the shuttle can withstand the intense heat of re-entering Earth's atmosphere before they give final approval for it to land Thursday at Cape Canaveral, Fla.
"I don't anticipate any problems," said flight director Cathy Koerner.
Such inspections became a part of all shuttle missions after the Columbia accident in 2003 killed seven astronauts.
During their nearly 10 days at the space station, Atlantis' astronauts helped install a new truss segment, unfurled a new pair of power-generating solar arrays, repaired a peeled-back thermal blanket near Atlantis' tail, and activated a rotating joint that allows the new solar arrays to track the sun.
Their 11-day mission was extended to 13 days so astronauts could repair the thermal blanket.
Atlantis' astronauts were scheduled Wednesday to check the shuttle's engine and thermal control systems.
But even if the shuttle's heat shield is cleared for landing, the weather might not cooperate.
A front in the Florida panhandle was expected to send showers to the Kennedy Space Center on Thursday and Friday.
"Get us some good weather for Thursday if you can. It doesn't have to be good. It just has to be good enough," shuttle commander Rick Sturckow told Mission Control.
Atlantis has conserved enough fuel to orbit until Sunday, but managers want the shuttle to land by Saturday. The flight would only be extended to Sunday if there were technical problems that needed to be fixed.
More than an hour after the shuttle undocked, a piece of debris that looked like a blanket and at least five tiny flashing particles floated past the space station. Engineers were still reviewing video and photographs to identify the debris.
"It's not a big concern," said Mike Suffredini, NASA's space station program manager.
Atlantis wasn't cleared to leave the station until the Russian computers passed a test Monday to take control of the station's thrusters. Computers controlling the outpost's positioning crashed last week but were revived last weekend.
Astronauts on Atlantis had turned off lights and computers to conserve fuel in case the shuttle needed to stay at the station an extra day.
The shuttle is bringing back U.S. astronaut and former space station resident Sunita Williams, whose more than six months in space set a record for the longest spaceflight by a woman. U.S. astronaut Clay Anderson, her replacement, was taken to the station aboard Atlantis.
NASA said the space station and the space shuttle would be visible Wednesday night from the United States. Cities with the best chances of getting a view were Denver, Detroit, San Francisco and Washington, said NASA spokeswoman Kylie Clem.
