Launch Manager Confident Discovery Safe To Fly, Despite Lingering Wing Issue
Sunday, October 21st 2007, 8:03 pm
News On 6
CAPE CANAVERAL, Fla. (AP) _ The NASA official who presided over Columbia's doomed re-entry _ and who will make the final call about whether Discovery should launch Tuesday _ said he is confident this will be a safe flight despite lingering questions about wing imperfections.
Shuttle launch manager LeRoy Cain said Sunday he would delay the space station construction mission if he thought Discovery's wings would not hold up during its return from orbit. A hole in one of Columbia's wings led to its destruction 4 1/2 years ago; Cain was the flight director on duty at Mission Control.
``We have not cut any corners here. We've reviewed the data in detail,'' Cain said at a news conference.
Meteorologists said rain and possibly thunderstorms could delay the launch. The odds of acceptable weather for the late morning launch was 60 percent.
Half of the engineers who participated in Discovery's flight readiness review this past week favored a launch delay to allow further tests and possible replacement of three suspect wing panels. Senior managers opted to press ahead, saying they were not convinced repairs were needed.
A new inspection method uncovered what could be cracks just beneath the protective coating on these three wing panels. It's unknown whether the cracks, if they're there, might worsen and cause the coating to chip off, making the area more vulnerable to the 3,000-degree heat of re-entry. No one knows what could be causing cracks.
Cain said all 44 of the reinforced carbon panels that form the leading edge of Discovery's wings may have some similar flaw, along with the wing panels on NASA's two other shuttles. The as-yet-unanswered question, he said, is how bad the degradation needs to be in order to take action.
``We believe, to the best of our ability to know today, that this risk is certainly lower than some of the more significant risks that we take because of the inherent nature of this vehicle when we go fly,'' he said.
Discovery's astronauts will use an inspection boom in orbit to check each wing panel, especially the three in question. The equipment can detect whether any coating is missing, but is not sensitive enough to spot underlying cracks, Cain said.
As has been the case since the Columbia disaster, NASA would be poised to launch a rescue shuttle if Discovery could not re-enter safely because of damage.
During the last shuttle launch in August, a piece of foam insulation, possibly with ice attached, broke off a fuel tank bracket and smacked into Endeavour's belly, gouging tiles. No repairs were conducted in orbit, and the shuttle re-entered just fine.
To prevent foam from coming off these brackets again, NASA removed some of the denser underlying insulation, which is made of cork. Other modifications also were made to other parts of the external fuel tank.
Discovery's tank was used in extensive testing following the Columbia accident and recertified to fly in space.
Discovery will spend 1 1/2 weeks at the space station. It will carry up a pressurized module that will serve as the docking port for European and Japanese laboratories.