"There has been so much testing done that our confidence has gone way up," said Air Force Col. Eileen Collins, commander of the mission aboard Discovery. She noted that she and her crew have been "very, very heavily involved" in the day-to-day flight preparations and decision-making.
"I am confident enough that we're not going to have a hole the size of what Columbia had" because of improvements to the fuel tank to prevent foam shedding, she said. "If that does happen, we will know it. In fact, if we have a very small hole or a very small crack, we'll know that, too, and if that happens, we have the potential repair techniques."
The seven astronauts will also have the international space station as a haven, if their shuttle is damaged beyond repair by fuel-tank debris.
Collins, the only woman to command a space shuttle flight, said: "It's time for us to go fly."
The astronauts traveled to Kennedy Space Center from Houston to view the redesigned external fuel tank that will propel them to orbit as early as May. They also got a look at the new inspection boom that they will use in space to scour their ship's belly and wings for any damage.
In their first news conference as a crew, the astronauts said considerable progress has been made in developing techniques for repairing shuttle cracks and small holes in orbit.
But NASA has all but given up, for now anyway, in trying to devise a patch for wing gashes exceeding 4 inches; the hole carved into Columbia's left wing by a chunk of foam insulation was between 6 inches and 10 inches.
During their space station delivery and repair mission, two of Discovery's crew will conduct a spacewalk to try out the repair methods. If there is small damage, astronaut Charles Camarda said, he believes the techniques would work and "we would have a very good chance of returning safely."
"I have the utmost confidence that this is going to be an extremely safe flight," Collins said.
Collins and her crew plan to take up mementos of the seven Columbia astronauts who were killed when their ship broke apart over Texas on Feb. 1, 2003.
"It's their legacy we're continuing," said astronaut Stephen Robinson.
By Marcia Dunn