HOUSTON (AP) _ NASA delayed the planned landing of space shuttle Atlantis by at least a day Tuesday after engineers spotted an object that may have accidentally flown out of its cargo bay.
Landing had been scheduled for Wednesday morning. But a poor weather forecast and concerns that something crucial floated out of the craft prompted the delay, space shuttle communicator Terry Virts told the crew.
``Big interest in whether we're going to be doing any robotics tomorrow,'' responded Atlantis commander Brent Jett, referring to using the shuttle's robotic arm to inspect the spacecraft.
NASA engineers think the object may have shook loose from the shuttle during the firing of jets in preparation for landing. NASA managers may order Atlantis' robotic arm to be taken out again for an inspection, and the space agency hasn't ruled out the possibility of having the crew return to the space station.
Sensors on the shuttle's right wing detected some kind of impact about the same time the object was first spotted, but NASA officials said it was more likely the sensors were triggered by the spacecraft shaking during the jet firings.
A Russian Soyuz TMA-9 capsule with an Iranian-American telecommunications entrepreneur, an astronaut and a cosmonaut was heading to the space station for a docking set for early Wednesday.
Engineers are concerned because they don't know what the object is or whether it's a crucial piece of the shuttle.
``The question is what is it? Is it something benign? Or is it something more critical we should pay attention to,'' said Wayne Hale, space shuttle program manager. ``We want to make sure we're safe before committing to that critical journey through the atmosphere.''
NASA wanted an extra day to do a detailed photographic analysis of the shuttle and its cargo bay area, NASA spokesman Doug Peterson had said earlier. Already NASA had been using cameras to scan the cargo area.
Astronauts aboard the shuttle were able to take photos of the object and describe it to Mission Control.
``It's fairly small. ... It was departing away from us, maybe 1 or 2 feet per second,'' Jett radioed. ``It wasn't rising or falling. ... It was definitely moving away fairly quickly.''
Mission control spotted the baffling object _ the size of which was not immediately determined _ with a video camera in the shuttle's cargo bay. The object, which circled the Earth in the same orbit as the shuttle, probably came out of the cargo bay around 2:45 a.m. EDT Tuesday because some jets had just been fired on Atlantis, Peterson said.
``It's something that we didn't expect, but it's something that we're taking a real close look at,'' Peterson said. NASA ordered Atlantis to keep the camera running all night instead of stowing it ahead of the planned landing attempt as usual.
Even before the problem with the unexplained object surfaced, NASA had said weather could affect Wednesday's scheduled landing. A storm front moving through Florida could delay landing from 5:59 a.m., when the sky would still be dark, until 7:34 a.m. or until Thursday or Friday. Weather requirements are more stringent for dark sky landings because they are more difficult.
In preparation for the landing, the Atlantis crew had packed, checked flight controls _ similar to those on an airplane _ and test fired small jets that are used to guide the shuttle. The commander and pilot used simulations to practice their landing skills.
During their mission, the Atlantis astronauts officially resumed construction of the international space station after a four-year hiatus. The 115-foot-long solar wings they added will generate power for the space station once it's rewired during the next mission, slated for December.
Progress on the orbiting lab halted after the Columbia disaster in 2003, when the space shuttle disintegrated while re-entering the Earth's atmosphere, killing all seven astronauts aboard.
Since then, NASA has implemented several safety procedures, including Monday's inspection of the shuttle using a robotic arm with a TV camera and laser imagery system attached on the end.