NASA says Discovery and crew are ready to fly on Wednesday

CAPE CANAVERAL, Fla. -- NASA resolved the last few technical concerns about Discovery on Tuesday and pronounced it ready for launch on the first space shuttle flight since the Columbia disaster 2 1/2 years ago.

"We're go for launch tomorrow, pending the weather," NASA Administrator Michael Griffin said after one final meeting of NASA's managers on whether to go ahead with liftoff.

Discovery and its crew of seven were set to blast off Wednesday afternoon on a flight to the international space station. The biggest worry was thunderstorms in the forecast; NASA put the chances of acceptable weather at launch time at 60 percent, down from 70 percent a day earlier.

Griffin said that the remaining technical concerns "had been put to bed" and that NASA managers had engaged in a free and open exchange of ideas before giving the go-ahead.

He said that given the complexities of spaceflight, something unforeseen could come back and "bite us." But he added: "Everything we know about has been covered."

Investigators in the Columbia accident blamed the tragedy in part on the space agency's "broken safety culture," or a tendency to downplay risks and discourage engineers from speaking up. Since the disaster, NASA has worked to increase openness and respect dissenting opinions.

"Obviously, it is utterly crucial for NASA, for the nation, for our space program to fly a safe mission," said Griffith, who is overseeing his first launch as NASA chief. He added, "We have done everything that we know to do."

Some of the last, remaining concerns for NASA involved fuel tank sensors that didn't read properly during a recent test and a balloon monitor that gathers data on upper-level wind speed.

Columbia was hit by a suitcase-size piece of insulating foam that fell off its external tank during liftoff. The crack allowed fiery gases to penetrate the wing during re-entry on Feb. 1, 2003, destroying the spacecraft and killing all seven astronauts aboard.

Discovery is outfitted with a redesigned fuel tank and has dozens of motion and temperature sensors embedded in the wings to detect any blows from debris.

Also, more than 100 cameras on the ground and aboard two planes will focus on Discovery as it climbs toward orbit, and spy satellites as well as astronauts on both the shuttle and the international space station will take their own pictures to help determine whether the orbiter was damaged by debris on liftoff.

The shuttle will spend more than a week at the space station, replenishing its cupboards and repairing broken equipment both inside and out. The astronauts will also test techniques for inspecting and patching the spaceship's thermal skin in orbit.

Discovery holds a brand-new laser-tipped 50-foot boom that the astronauts will operate via remote control to inspect the shuttle for any cracks or holes.