HOUSTON (AP) - Shuttle astronauts spotted three more pieces of debris floating in space outside Atlantis early Wednesday, but officials said it didn't seem their appearance would prevent a landing attempt Thursday. The objects were sighted during stepped-up inspections a day after the discovery of two other mysterious objects forced a postponement of the planned Wednesday landing.
NASA downplayed the discovery of Wednesday's objects, saying the important question was whether an in-depth inspection of the shuttle showed no damage to Atlantis' heat shield. An initial examination had turned up nothing of concern, NASA officials said.
"It's not uncommon to see little bits of pieces of things floating by," said flight director Paul Dye.
Atlantis commander Brent Jett described the objects as two rings and a piece of foil. He told Mission Control the first object, about 100 feet from the shuttle, was "a reflective cloth or a mechanic looking- cloth. ... It's not a solid metal structure."
NASA officials thought the debris may have come from the shuttle's cargo bay.
"Typically, when we open the payload doors on the first day of flight, we will see objects," landing flight director Steve Stich said. "It's a little bit unusual to see objects maybe this late in the mission."
Before the postponement Tuesday, Atlantis had been scheduled to touch down just before daybreak Wednesday, when the weather forecast wasn't favorable for landing anyway. The landing time was reset for early Thursday, with a good weather forecast, but could be put off until Friday.
NASA managers didn't see anything that concerned them during the initial inspection using the shuttle's robotic arm. But they decided to go ahead with another inspection using a boom as an extra safety precaution. That inspection was continuing late Wednesday morning.
The boom, which is attached to the shuttle's 50-foot robotic arm and has cameras and sensors at its end, can look at hard-to-reach places.
The first object sighted Tuesday morning appeared to drift away when landing systems were put through a normal but bumpy trial run.
Worry about whether it came from a crucial part of Atlantis was enough to make NASA postpone the landing. NASA officials said their best guess was that the object was a plastic filler placed in between thermal tiles which protect the shuttle from blasting heat.
But after being unable to determine what the object was Tuesday, NASA managers opted to spend early Wednesday making sure the shuttle was in good shape instead of concentrating on solving the mystery.
The engineers' main concern was the status of the all-important heat shield, because a damaged shuttle skin led to the 2003 demise of the shuttle Columbia.
"We are going to verify that our critical heat shield is in good shape for entry to the best of our ability," shuttle program manager Wayne Hale said.
A second mystery object was spotted midday Tuesday and photographed by astronaut Dan Burbank. Jett said the object looked like a picture hanging clip. But it may be a garbage bag, which would unlikely be a damage risk, but the issue will be moot if the heat shield looks good, Hale said.
"So far we do not know the identity of the two things that floated away yesterday," Houston spacecraft communicator Hans Schlegel told Atlantis Tuesday night. "Today we want you to survey the vehicle to make sure it's ready for entry. Last night we already surveyed from ground."
Mission controllers also used cameras at the end of the robot arm to take pictures around the payload bay while astronauts slept on Tuesday.
If astronauts are too tired from the shield inspection process Wednesday, NASA could postpone landing until Friday, Hale had said.
NASA has not worked on a contingency plan of parking the shuttle at the international space station for astronauts' safe haven, but has not ruled that out if serious damage was found.
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