Discovery has two opportunities to land at the Kennedy Space Center in Florida.
Mission Control told the shuttle crew early Saturday morning the initial weather forecast for the first opportunity called for light winds and no rain, ideal conditions for Discovery to land.
The second chance did have a slight chance of rain showers.
"Right now it looks pretty good," Mission Control said.
Since Discovery has enough supplies to allow it to stay in orbit until Tuesday, NASA will only aim on Saturday to bring home the shuttle in Florida, the primary landing site.
Florida would remain the only choice on Sunday as well, if Saturday's opportunities don't pan out, said flight director Richard Jones.
The backup site of Edwards Air Force Base in the California desert would not be considered until Monday.
NASA engineers said a metal clip that broke off Discovery's rudder on Friday poses no threat to the shuttle's landing.
The clip broke loose during a routine checkout of the flight systems needed for Saturday's descent.
Space shuttles have returned to Earth in the past with clips missing from the rudder, which opens like a book to serve as a speed brake. The V-shaped spring tabs, just 2 1/2 inches by 1 inch, protect that area from the intense heat of liftoff by providing a seamless barrier down the back edge of the rudder, or tail, panels.
Engineers suspect this clip, or tab, came loose during the vibrations of launch on May 31, and it wasn't until the speed brake panels were opened for checkout Friday, that it floated away.
