CAPE CANAVERAL -- The seven astronauts set to crew NASA's first space shuttle flight since the Columbia accident are confident their orbiter and redesigned external tank will perform, but admit some details still need to be ironed out.

The crew of STS-114, NASA's first return to flight mission, is in the middle of a two-day inspection of the shuttle Discovery here at NASA's Kennedy Space Center.

"This is a test flight," astronaut Eileen Collins, the mission's commander, told reporters here Thursday. "I believe in what we are doing...I believe we are covered."

NASA is currently targeting a May 12 launch, but with three months left until NASA's current launch window opens, there are still issues - such as exactly what capability the STS-114 crew will have to repair Discovery's thermal protection tiles and reinforced carbon-carbon (RCC) panels - to be resolved.

Tile repair

Collins said she fully believes her crew expects to launch with at least some sort of thermal protection repair capability, though what that may be remains unclear.

"We are looking at five different types of repair techniques," Collins told reporters. "Of those five, we may fly with all of them or just a subset of them."

One of those methods includes a sort of caulking procedure to fill in cracks or holes in shuttle tiles using. It was a hole in Columbia's left wing, caused by a piece of foam insulation that broke of the orbiter's external tank during launch, that let in hot gases during its Feb. 1, 2003 reentry and destroyed the spacecraft.

"It comes down to a sort of artistic application of this pinkish-orange goo," said mission specialist Steve Robinson, who expects to spend one of the three planned STS-114 spacewalks testing tile repair methods. "I don't know if we're ready to do it in space yet or not."

Check out time

While the STS-114 mission's primary goal is to test several new technologies aimed at improving shuttle safety, Discovery will also be carrying vital spare parts, food and other supplies to the International Space Station (ISS).

During their inspection of Discovery, the STS-114 astronauts are looking over the payload bay, exterior thermal tiles and internal cabling in conjunction with their mission goals.

The orbiter sports new, wing-mounted sensors to track impacts and a 50-foot (15 meter) boom to scan Discovery's exterior for any damage while in orbit. A redesigned external tank - dubbed the safest ever constructed by its builders - will carry the fuel Discovery will burn to reach space.

"It's a very detailed analysis that this vehicle has been subjected too," mission specialist Andrew Thomas said. "

That analysis appears to satisfy Collins.

"Clearly I'm not going to go fly if it's unsafe. I'm a person who won't go on roller coasters because they scare me," Collins said. "We're really excited about flying and the crew will be ready."

        Fixing NASA: Continuing Coverage of the Space Shuttle Return to Flight