Shuttle Astronauts On Second EVA

ANN REAL TIME NEWS: 0600 EDT -- Discovery astronauts Soichi Noguchi and Steve Robinson crawled across the outside of the International Space Station Monday, tackling a problem that has plagued the ISS for months. They were replacing a troublesome gyroscope -- one of four that control the attitude of the station itself.

The Control Moment Gyro weighs more than 650 pounds and is the size of a washing machine. Noguchi, an exchange astronaut from Japan, and Robinson, are lifting the old CMG out of its fitting and loading it into the shuttle's payload bay. They'll then fit the station with a brand-new CMG in an EVA expected to last almost seven hours.

There is still talk about whether to send the spacewalking duo out for another EVA to deal with a problem on the underside of the shuttle itself. There, gap-filler is protruding from between rows of thermal tiles in not one, but two places.

"We have a team of folks working aggressively to go and make that gap filler safe if we decide it's an issue. We have a separate team looking at the effects of leaving that gap filler protruding," mission flight director Paul Hill said Sunday.

If Hill and company decide the gap-filler problem should indeed be addressed, Robinson and Noguchi will do so Wednesday, during their third and final EVA.

Discovery will spend an extra day at the station, helping the two-man crew there perform tasks that require extra hands, because at this point, there's no telling when another shuttle mission will get off the ground. NASA ordered the entire surviving fleet of orbiters grounded once again, after a chunk of foam fell from the external tank last Tuesday during the boost phase of Discovery's launch. In an incident remarkably familiar to the one that caused Columbia's destruction two years ago, that chunk of foam impacted the orbiter's left wing. There was no immediate indication of serious damage to Discovery.

"The Columbia accident made us realize we had been playing Russian roulette with the shuttle crews," said deputy shuttle program manager Wayne Hale, quoted by the BBC.

FMI: www.nasa.gov