Update: Forecast Iffy For KSC Landing

The threat of thunderstorms and gusting winds over Cape Canaveral could divert Endeavour's planned landing Sunday from Kennedy Space Center to Edwards Air Force Base in California, NASA officials said today.

A decision won't be made until weather conditions are assessed Sunday before landing opportunities at 1:19 p.m. and 2:54 p.m.

Bryan Lunney, the NASA flight director overseeing the shuttle's return, said neither time looked particularly good as of Saturday afternoon.

"It's a day that's setting up to be pretty windy," he said, adding that thunderstorms were expected to push anvil clouds across Central Florida. "We don't want to fly through those."

If KSC's forecast for Monday - now considered "borderline" - does not improve, NASA could choose to go ahead with a Sunday landing at Edwards, where the forecast is excellent for Sunday and Monday.

Sunday landings at Edwards could occur at 4:24 p.m. or 5:59 p.m. The shuttle would land on a temporary landing strip slightly shorter than KSC's, but officials said neither the strip nor staffing at Edwards posed any concern.

Although four total attempts are possible Sunday, Lunney said a maximum of three would be used to avoid consuming additional shuttle supplies.

A "go" or "no-go" decision is typically made about 90 minutes prior to the planned touchdown, before engines are fired to steer the orbiter's re-entry through Earth's atmosphere.

Shuttle program managers say a safe landing, not the location, is what's most important. But NASA prefers to land at KSC, the shuttle's home port, so processing of the vehicles for their next mission can begin immediately.

"It's simply a matter of ease," Lunney said.

Endeavour is currently targeted to return to the International Space Station in May, but that slot could be taken by the fifth and final mission to service the Hubble Space Telescope, to be flown by Atlantis.

If a shuttle lands at Edwards, it typically would take at least a week before it could be flown back to KSC on top of a 747, at a cost of about $1 million.

Though the shuttle has enough carbon dioxide-scrubbing air filters to fly until Tuesday, Lunney said he doesn't want to land later than Monday.

IMAGE NOTE: Click on the images above to enlarge them. The pictures show the tracks Endeavour would take for two landing attempts Sunday at Kennedy Space Center.