NASA is considering whether the space shuttle Discovery needs to dodge a piece of space junk before heading for a scheduled landing back on Earth.
Mission Control says the debris apparently came off the linked shuttle and international space station during a spacewalk Saturday. Eperts do not know what the piece is.
The shuttle is scheduled to land Thursday evening but thunderstorms could keep it in orbit an etra day or two.
If Discovery skips Florida on Thursday, NASA will consider the backup touchdown site in California as early as Friday.
Discovery spent more than a week at the space station. Returning astronaut Timothy Kopra lived there nearly two months.