Discovery ready for Friday return - WHITE SANDS???

[Spanky]

HOUSTON, Texas (AP) -- NASA managers cleared Discovery to return home Friday, planning for a possible touchdown in New Mexico for only the second time in space shuttle history because of bad weather on both coasts.

As the crew woke up to Christmas music Friday morning, they still didn't know where the spacecraft would touch down.

"I have a lot of things to worry about on this flight that I can control, and the weather is something I can't," Discovery commander Mark Polansky told reporters from space. "I'm ready to land at any of the three sites."

Discovery needs to be on the ground Saturday or it could run out of the fuel that powers its electrical system.

NASA normally has more time for the landing, but the astronauts spent an extra day at the international space station this week to work on a stubborn solar array.

Rain and clouds were forecast during the shuttle's first landing opportunity Friday afternoon at Kennedy Space Center in Florida, and crosswinds were expected at NASA's next-best option, Edwards Air Force Base in California's Mojave Desert.

The third option, White Sands Space Harbor in New Mexico, hasn't been used for a shuttle landing in 24 years, and in that landing, sand on the runway contaminated the orbiter, and the brakes were damaged. It isn't normally equipped to service the shuttles, either.

NASA managers hoped the weather would clear at one of the favored sites by the first landing opportunity, but they shipped a crane to White Sands anyway, along with equipment that purges gases and cools and heats the shuttle on the ground, thruster plugs and 60 workers from the Kennedy Space Center.

"As we get closer, we'll have much more certainty on what we're really faced with," said entry director Norm Knight, who will direct the landing.

The first landing opportunity was set for 3:56 p.m. EST at Kennedy Space Center. Other opportunities were 1 1/2 hours later at all three sites, followed by opportunities at Edwards and White Sands 1 1/2 hours after that. NASA managers were considering a last try at 8:36 p.m. ET at Edwards.

NASA has seven more opportunities to land the shuttle on Saturday.

Discovery originally had been scheduled to land on Thursday, but the flight was extended to allow a fourth spacewalk to fold up an accordion-like solar array on the space station.

Thursday afternoon, after another inspection and more analysis of the shuttle's heat shields, the space agency pronounced Discovery safe to return. Shuttles are routinely inspected in flight now for any debris damage of the sort that doomed Columbia in 2003.

During the 25 years of the shuttle program, there have been 63 landings at Kennedy, 50 at Edwards and just one at White Sands.

Even though the White Sands runway regularly is used for practice landings by astronauts, NASA does not like to use it for the real event. It could take as long as two months to get the shuttle back to Florida from New Mexico, compared to a week from Edwards, threatening NASA's ability to get Discovery ready to fly again next October.

Flight controllers in Houston, trying their hand at holiday songwriting, sent the Discovery crew in their daily messages lyrics to their version of the song, "Let it Snow."

"Oh, the weather at KSC is frightful. But at White Sands, it's so delightful. And since we have to land. Land White Sands. Land White Sands. Land White Sands," it said.

[Spanky]

STS-3 was planned as a 7 day flight. However, it was extended an extra day because of high winds at the backup landing site, Northrup Strip, White Sands, N.M., since the planned landing site at Edwards AFB was too wet for a safe landing.

Touchdown finally took place at 9:05 a.m. MST, March 30, 1982, at Northrup Strip (later renamed White Sands Space Harbor). STS-3 was the only shuttle mission to land at White Sands Missile Range. The landing demonstrated that the Shuttle could land in the desert, but sand damaged the orbiter.