Discovery's countdown rolls on amid final troubleshooting
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: December 6, 2006
NASA and contractor engineers are wrapping up around-the-clock work to resolve two last-minute technical issues that cropped up Tuesday during shuttle Discovery's countdown. While engineers are optimistic Discovery will be cleared for launch as planned Thursday, NASA's Mission Management Team will meet this afternoon to assess the data reviews.
Of more pressing concern, perhaps, forecasters now expect a 60 percent chance of low clouds that would prevent a launch attempt Thursday. In addition, conditions at all three of NASA's emergency runways in Spain and France are predicted to be no-go due to high winds, showers or both. At least one emergency trans-Atlantic landing site is required for launch, regardless of the weather in Florida.
"We're having a nice day here today at Kennedy Space Center, but tomorrow we are expecting a frontal system to come into the area and that is going to bring in a lot of cloud cover for the launch window," said shuttle weather officer Kathy Winters.
Winters said the outlook for Friday is 70 percent no-go because of high winds, clouds and isolated showers, improving slightly to 60 percent no-go Saturday. Conditions in Spain and France improve, however, and at least one landing site should be available both days if conditions in Florida permit a launch.
Conditions should improve early next week but additional fronts are expected to move through Central Florida by the middle of the week, bringing more clouds and high winds.
"It does look like we're going to persist with this easterly flow through mid next week," Winters said. "But it does get a little more southeasterly on Tuesday and the winds come down some. ... So we're thinking weather starts getting more promising as we go into Sunday evening, Monday evening, but particularly Tuesday evening.
"We still are going to be concerned about crosswinds (at the shuttle landing strip), but we think Tuesday out of those three days is probably the best day. After that, we start being concerned about the next front that's going to be moving into the area. On Wednesday, we expect the weather to start deteriorating due to that front."
Discovery's mission to re-wire the international space station is scheduled to run 12 days. The shuttle needs to get off the ground by Tuesday to avoid being in orbit or landing on Christmas day.
Otherwise, the countdown is proceeding smoothly as engineers wrap up troubleshooting on two technical issues.
In one case, a large 800-pound launch pad power supply malfunctioned overnight Monday, sending a brief surge through the shuttle's electrical system. The power supply was replaced and engineers are reviewing data to make sure the spike didn't damage any orbiter systems. That review is almost complete and no problems have been found.
The other issue involves test data that has raised questions about the strength of a specific lot of adhesive used to secure insulation in joints between solid-fuel booster segments. Engineers are trying to determine if the adhesive is, in fact, suspect, if it is in place in Discovery's boosters and if so, does it represent a concern.
The insulation in question cannot be inspected at the pad. At least some engineers believe the adhesive isn't even needed because of how the joint operates when the motor is ignited. But the Mission Management Team ordered a review to make sure Discovery's boosters are good to go.