HOUSTON, Oct 29 (Reuters) NASA said today that it may add a day to shuttle Discovery's stay at the International Space Station so astronauts can inspect a balky joint that rotates solar power panels on the orbiting outpost.
The malfunctioning joint is a key part of the station's power system and could delay plans to complete it.
Space station programme manager Mike Suffredini said the circular mechanism, 10 feet (3 meters) in diameter, would get a long look during a Thursday spacewalk that originally was intended to test a shuttle heat shield repair technique.
An extra day would be added to Discovery's flight so that astronauts could rest before the fifth and final spacewalk of the mission on Saturday, he said. The schedule changes still must be approved by NASA senior managers, said Suffredini in a briefing at Johnson Space Center in Houston.
The joint, which was installed on the station in June, had been malfunctioning as it rotated to keep the solar panels pointed toward the sun. On yesterday spacewalk, astronaut Daniel Tani found metal shavings inside, indicating excessive wear on moving parts.
Suffredini said astronauts Scott Parazynski and Douglas Wheelock will closely document the damage to help NASA figure out what is causing it.
He said it was unlikely the joint could be repaired before Discovery's departure, which would now occur November 5. The shuttle's landing would be two days later.
Suffredini expressed confidence the problem could be fixed.
''I don't think it's anything we can't recover from,'' he said.
The joint problem shifted focus from a Tuesday spacewalk in which Parazynski and Wheelock are to help guide a 18-ton solar power truss into a new station location, in preparation for the addition of European and Japanese laboratories.
It will be installed on a separate rotating joint that already has one solar array and has been working well since its installation last year. The arrays, which look like giant golden wings, stretch out about 240 feet (73 metres).
With the new array in place, the station would have enough electricity for the December addition of Europe's Columbus lab, Suffredini said.
But until the repair of the bad joint, which has one solar array and is scheduled to get another, it was not clear if the station could also support Japan's Kibo lab, he said. Kibo is to be delivered in three segments starting in February.
Discovery arrived at the space station on Thursday, delivering the Italian-built Harmony module. Its installation on Friday added the first new room to the station in six years.
NASA hopes to finish the 0 billion space station by 2010 when the shuttle fleet is to be retired.
Reuters GT GC006