Astronauts use robot arm for shuttle safety scan

By Ed Stoddard

DALLAS (Reuters) - Astronauts used a robot arm to scan the space shuttle Discovery's heat shield for damage on Wednesday as it headed for a Thursday rendezvous with the International Space Station.

"The mission is right on track ... We look forward to docking tomorrow," mission management chairman John Shannon told a press briefing at the Johnson Space Center in Houston.

The shuttle is due to dock with the ISS at 8:33 a.m. EDT on Thursday to kick off a 10-day construction mission at the outpost that will feature five spacewalks.

Astronauts spent the morning remotely maneuvering the arm to slowly inspect the shuttle wings and nose in a now mandatory post-launch routine begun after space shuttle Columbia broke apart on its return to Earth in 2003.

The scan with lasers and digital cameras looked for any damage to the heat shield that might have occurred when Discovery hurtled into space from Florida on Tuesday.

Data collected is beamed back to Earth for study by NASA engineers who will scrutinize it over the next few days. Preliminary analysis revealed nothing amiss.

Three suspect panels were given an especially close examination. Engineers using a new X-ray analysis technique warned managers ahead of the launch that three of the wing's 44 carbon-composite panels had tiny cracks in their silicon-carbide coatings.

After a lengthy debate, managers opted to proceed with the launch and assigned teams to monitor the situation.