Cape Canaveral, Fla. ? Discovery astronaut Steve Robinson made the delicate repair he’s been assigned to carry out this morning sound easy – mundane, even.

“The main tools I plan to use are right here,” Robinson said Tuesday, smiling and making a pinching motion with his index finger and thumb. “I plan to reach out with my right hand and grab the little piece of material and pull it from between the tiles in the belly of the orbiter.”

He will be doing this, of course, in the zero-gravity of space, with a helmet, suit and bulky gloves consisting of 13 layers of material, while fastened to a robotic arm beneath the orbiting shuttle and positioned, at times, within a foot of areas that are among the most sensitive to the vehicle’s heat shield.

“It’ll be a gentle pull with my hand, and if that doesn’t work I have some forceps,” Robinson said. “I’ll give a slightly more than gentle pull; if that doesn’t work I saw it off with a hacksaw, no yanking.”

President Bush waves to crews of the space shuttle Discovery and the International Space Station in the Roosevelt Room of the White House. President Bush phoned the astronauts on Tuesday, thanking them for being risk

Today’s repair during Robinson’s third spacewalk was required, officials said, because they knew too little about the consequences the two protrusions of synthetic fabric, called gap fillers, might inflict upon the spacecraft’s re-entry into the earth’s atmosphere.

“We came to the conclusion that we don’t know enough to feel confident with this,” said Wayne Hale, deputy shuttle program manager. “… The remedy is easy, so we should go and exercise that remedy.”

But that was not always the conventional wisdom. Astronauts Andrew Thomas and Charles Camarda acknowledged Tuesday that the crew had initial misgivings. And Paul Hill, the lead flight director, also said that most engineers’ gut reaction was to stay away from such a delicate and critical area of the shuttle. They feared further damage could be done with an inadvertent kick or bump, or from the variety of sharp instruments Robinson will have.

“I think in this particular case it was a very close call,” said Camarda, who is also an aerospace engineer. But the uncertainty of the heating effects of these two small pieces made NASA choose the option of pulling the fabric out, he said.