Call Comes As Crew Prepares For Unrehearsed Spacewalk

It's the kind of call that makes an astronaut's heart swell with national pride. Docked with the International Space Station some 370 miles above the Earth, the crew of the space shuttle Discovery Tuesday took a call from President George W. Bush.

"I want to thank you for being risk takers for the sake of exploration," Bush said during the brief radio hookup. "And I wish you Godspeed on your mission. Obviously, as you prepare to come back, a lot of Americans will be praying for a safe return," the president added.

The call came as STS-114's Stephen Robinson prepared conduct a seven-hour long EVA to go where no spaceborne shuttle crew has ever gone before -- beneath the orbiter to trim filler material between thermal tiles.

The gap-filler is now dangling from the bottom of the shuttle. Mission managers are worried it could heat up and cause another Columbia-like disaster if not repaired.

"When we first heard about it, I think a number of us did have misgivings," astronaut Andrew Thomas said. "We were concerned about it. We were concerned about the implications of it." Thomas was quoted by the Associated Press.

"The bottom line is there is large uncertainty because nobody has a very good handle on the aerodynamics at those altitudes and at those speeds," Deputy Shuttle Program Manager Wayne Hale told AP. "Given that large degree of uncertainty, life could be normal during entry or some bad things could happen."

Robinson will be perched on the end of the 58-foot long, Canadian-made robotic arm as he works with improvised tools to trim the dangling filler, which is made of ceramic-covered fabric. Robinson will first try to remove the fabric by hand. If that doesn't work, he'll use a makeshift hacksaw to cut it away. If that doesn't work, he'll use a pair of scissors -- but that's considered a last-ditch option because he won't be able to make as clean a cut as he might otherwise.

The filler material is protruding from the shuttle's belly about a single inch in two places, according to NASA. As astronauts worked on improvising the hacksaw, NASA engineers worked to figure ways to trim the filler without harming the orbiter itself (above).

"I am pretty comfortable with using tools very carefully," Robinson told reporters in a space-based news conference early Tuesday. "But no doubt about it, this is going to be a very delicate task. But as I say, a simple one.... There won't be any yanking going on at all. It will be a gentle pull with my hand. If that doesn't work, I have some forceps. I will give it a slightly more than gentle pull. If that doesn't work, I saw it off with a hacksaw."

FMI: www.nasa.gov/returntoflight/main/index.html