CAPE CANAVERAL, Fla. -- Space shuttle Discovery could return home today to an unusual sort of white Christmas that NASA managers want to avoid.
Only once in 114 previous landings has the shuttle touched down at the White Sands Missile Range in southern New Mexico, a blanched desert of gypsum sand so desolate that the first atomic bomb was detonated there. White Sands' Northrup Strip traditionally has been viewed by NASA as a shuttle runway of last resort, available in case circumstances prevented a return to primary landing sites at the Kennedy Space Center or Southern California's Edwards Air Force Base.
That could be the situation facing shuttle managers today. Dwindling supplies aboard Discovery, along with iffy weather in Florida and California, make a White Sands landing more likely than at any time since the third shuttle flight returned there almost a quarter-century ago in March 1982.
If Discovery heads to New Mexico, the meager facilities at White Sands would add weeks to the time needed to return the orbiter to Florida and could expose the ship to harsher conditions than those at Kennedy Space Center and Edwards.
"From a crew landing standpoint, it is a great place to land," said John Shannon, chairman of the shuttle's mission management team. "But the turnaround is going to take a little bit longer."
NASA typically makes sure the shuttle has enough onboard supplies to allow two or more additional days at the end of each mission to ensure good landing weather and permit troubleshooting of any technical issues. However, mission managers traded one of those days Monday for a fourth spacewalk to retract a balky solar array.
The shuttle has enough fuel left to generate electricity until tomorrow. In order to safeguard against possible technical problems that could take time to fix, flight rules dictate that Discovery must land somewhere today if weather conditions permit.
NASA managers will be watching those conditions closely at all three sites. Ideally, they would like to bring Discovery home for a 3:56 p.m. landing at Kennedy Space Center. However, thick clouds and a chance of showers are forecast at Cape Canaveral for that opportunity and another at 5:32 p.m.
Edwards is expecting mostly clear skies with no rain in the forecast for landing opportunities at 5:27 p.m., 7 p.m., and 8:36 p.m. However, crosswinds are expected to gust between 17 and 26 mph. The maximum crosswind allowable for day landings at Edwards is 20 mph if there is little air turbulence.
At White Sands, partly cloudy skies and "go" conditions are forecast for landing opportunities at 5:27 p.m. and 7:02 p.m. Even so, shuttle officials don't want to go there.
After Columbia's landing in 1982, technicians spent months ridding the orbiter of gypsum sand that had blown inside. Procedures are in place to prevent that from happening again. However, it could take up to 60 days to prepare Discovery for a return to Florida. And snow showers and freezing temperatures are possible at White Sands this weekend.
NASA is flying in equipment to keep warm shuttle components that could be damaged by freezing. Engineers also would have to bring in machinery to hoist Discovery aboard its jumbo transport jet for the ride back to Florida.
NASA managers are hoping that won't be necessary.
Michael Cabbage writes for the Orlando Sentinel.