(AP) -- NASA has moved the shuttle Discovery out of the way of a mystery piece of orbiting junk and is hoping for a scheduled landing on Earth.
The astronauts fired shuttle thrusters around noon Thursday to avoid what Mission Control is calling a "mystery object."
Officials say the debris apparently came off the linked shuttle and international space station during a spacewalk Saturday. Experts do not know what the piece is.
The shuttle is scheduled to land Thursday evening in Florida but thunderstorms could keep it in orbit an extra day or two.
If Discovery skips Florida on Thursday, NASA will consider the backup touchdown site in California as early as Friday.
Discovery delivered supplies and spent more than a week at the space station.
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