Foam May Have Hit Discovery's Wing

Shortly after Tuesday's launch, NASA officials said that camera footage shot of the external fuel tank showed a large piece of foam, believed to be 24 to 33 inches long, 10 to 14 inches wide and 2.5 to 8 inches thick, sheared away from the tank. But NASA says an even smaller chunk of foam may have hit a wing during liftoff .

The debris was only slightly smaller than the chunk of foam that left a crack in Columbia's wing, causing it to disintegrate during the heat of re-entry in February 2003, killing seven astronauts. Though the piece of foam fell away into space and didn't strike the orbiter, NASA decided to suspend future shuttle missions and take another look at why foam was continuing to fall off the tank, a problem engineers thought they had solved after the Columbia disaster.

This morning, Discovery's astronauts are unloading 15 tons of supplies onto the space station and they also plan to check the shuttle for damage . Deputy Shuttle Program Manager Wayne Hale says the agency wants to make sure they didn't miss anything. Officials say Discovery still looks safe to fly home in a week.

Astronauts are also preparing tools for the mission's first spacewalk tomorrow. During the spacewalks, astronauts will try out new repair techniques for the shuttle's tiles and delicate carbon panels; replace a gyroscope, which helps steer the space station; and install a storage platform on the station.

NASA also says it's trying to come up with ways to leave more water and oxygen aboard the space station than initially planned.