Space shuttle crew scans again for damage

The shuttle Discovery crew yesterday used a boom with laser scanners to take another look at minor damage on their ship's heat shield while Nasa's chief said he expects engineers will quickly fix the fuel tank problems that have again grounded the fleet.

"We don't expect this to be a long drawn-out affair," Nasa Administrator Michael Griffin said in a teleconference with reporters.

During Discovery's launch on Tuesday on Nasa's first manned mission since the 2003 Columbia disaster, a chunk of foam nearly as large as the one responsible for downing Columbia fell off Discovery's fuel tank. Nasa said a smaller chunk of foam also broke off and appeared to have hit Discovery's wing but did not appear to have caused any damage.

Columbia was destroyed because a 0.75-kilogramme chunk of falling insulating foam damaged heat panels on the ship's left wing, allowing superheated gases to blast into the structure as the shuttle flew through the atmosphere for landing on February 1, 2003. Seven astronauts died when Columbia broke up over Texas.

"We were actually quite surprised to hear we had some large pieces of debris fall off the external tank," Discovery commander Eileen Collins said during the crew's first in-flight interview. "It wasn't what we had expected.

"I don't think we should fly again unless we do something to prevent this from happening again."

Discovery was flying with the International Space Station 352 kilometres above earth after they linked up on Thursday. Yesterday, the crew used the space station's robotic arm to position a 15-metre boom outfitted with laser imagers to look at six damaged areas on the heat shield on Discovery's underside.

Engineers believe the shuttle is in good shape to return to earth on August 7 but want additional information about the size and depth of six damage sites, shuttle operations manager Phil Engelauf said.

The Discovery crew also prepared for the first of three spacewalks planned during the flight.

Astronauts Steve Robinson and Soichi Noguchi are scheduled for a six-hour spacewalk today at 4:44 a.m. EDT (0844 GMT) to test heat shield repair techniques and to begin installing a new gyroscope.