LOS ANGELES, July 30 (Xinhuanet) -- Shuttle Discovery was set to stay docked with the International Space Station for one more day, US space agency NASA said Saturday.

    Shortly after astronauts Soichi Noguchi and Steve Robinson completed their first spacewalk, NASA mission managers decided to keep the crew in the space for an extra day to deliver more supplies for the Space Station, while future shuttle launch date is still unknown.

    NASA grounded future shuttle flights after finding Discovery's fuel-tank foam loss during lift-off on July 26. Engineers warned the disaster of shuttle Columbia would recur unless they could thoroughly solve the foam insulation problem.

    Soichi Noguchi and Steve Robinson completed the first of their three spacewalks at the International Space Station at 3:36 p.m. PDT. They began the excursion at 8:46 a.m. PDT.

    The spacewalk, not only the first of Discovery mission but alsoa first for Noguchi and Robinson, was performed over expectation, according to NASA.

    "I'm happy to welcome Steve and Soichi in the EVA hall of fame," said NASA space walk manager Cindy Begley in an early afternoon briefing after the spacewalk. "I'm just more than happy with the performance today."

    After setting up tools, the spacewalkers conducted tests of shuttle heat shield repair techniques inside Discovery's payload bay.

    Then, they completed several assembly and repair tasks on the International Space Station. They replaced an antenna and swapped out connectors to supply power a gyroscope. They also prepared theSpace Station for their upcoming spacewalks slated for Monday and Wednesday.

    Mission operations manager Phil Engelauf said the two-man spacewalk crew worked so efficiently they were able to add a few tasks to their time outside. Noguchi used a new digital camera to take more images of the shuttle's exterior.

    But NASA also acknowledged that none of the repair kits flying on Discovery could mend a hole the size of the one responsible for Columbia's catastrophic re-entry, estimated up to 25 centimeters across.

    It could be years before engineers come up with such a big patch, NASA said. For now, the largest hole that any of the repair methods aboard Discovery could tackle would be no large than 10 centimeters.

    During the past day, Space Station and shuttle crewmembers alsounloaded equipment and supplies from the Raffaello Multi-Purpose Logistics Module and transferred them to the Station. These supplies included water, paper, pens, and laptop computers, NASA said. Enditem