Orlando, Fla. ? The crew of the shuttle Discovery is getting an extra day in space.

With future shuttle flights grounded indefinitely, NASA decided Saturday to extend the mission so Discovery’s astronauts can do more maintenance work on the international space station and transfer over surplus supplies such as paper, pens and laptop computers.

“We’ll sure appreciate getting that extra day,” said Bill Gerstenmeier, space station program manager.

Earlier, astronauts Stephen Robinson and Soichi Noguchi, armed with a high-tech caulking gun and putty knives, went for a space walk, spending nearly seven hours testing shuttle repair techniques and working on the space station.

“There are just no words to describe how cool this is,” Robinson said.

NASA finished analysis of Discovery’s heat-protective tiles and thermal blankets on Saturday and declared them in good shape for the eventual ride home.

In this image from NASA TV, space shuttle Discovery mission specialist Steve Robinson can be seen suspended from Discovery's robotic arm during a space walk Saturday. The shuttle crew will stay an extra day at the International Space Station for additional maintenance and payload transfer.

But the ship is not officially cleared for its landing – now targeted for Aug. 8 – because engineers still are examining imagery and other data on the condition of the wings and two regions where filler material between tiles might be sticking out a bit.

“In terms of surface area, we’ve probably cleared 90 percent” of the shuttle’s exterior for landing, said Wayne Hale, deputy shuttle program manager.

The flight is the first since shuttle Columbia broke apart over Texas on its return home in 2003 after a piece of foam came off the ship’s external tank during launch and damaged its wing. Seven astronauts were killed.

Cameras on Discovery captured footage of foam also breaking free from its external tank, but NASA has concluded that the biggest – and therefore most dangerous – chunk of insulation did not hit the orbiter.

Hale said Discovery has operated flawlessly in space and showered kudos on the crew’s performance.

Robinson and Noguchi took center stage Saturday, emerging from Discovery’s airlock shortly before 6 a.m. At the time, the ship was soaring more than 200 miles over central Asia.

Their first task involved patching up cracks and gouges in deliberately damaged samples of shuttle tiles and the carbon panels that cover the wing edges.

They used the caulking gun and putty knives to cover damaged areas with a paintlike substance or a gooey material that Robinson described as “pizza dough.” The materials bubbled a bit as the astronauts layered them.

In addition to the repair tests, the astronauts took digital pictures of an insulating blanket that might be out of place near Discovery’s cockpit window and rerouted wiring to a gyroscope on the station. The station has four gyroscopes that maintain the laboratory’s orientation in space, and the wiring restored power to one that had turned off earlier this year.

Robinson and Noguchi are scheduled to make two more walks before Discovery leaves the outpost.