CAPE CANAVERAL, Fla. - With electrical supplies dwindling on the space shuttle Discovery, NASA officials say they are determined to bring it down safely early today despite unpredictable weather at the primary landing site in Florida.
If weather prevents the shuttle from touching down at Kennedy Space Center for a second day, the National Aeronautics and Space Administration is considering landing in New Mexico or at the shuttle's primary backup site in California.
"We're going to land [today] one way or another, one place or another, and all we're talking about is where," NASA Administrator Michael Griffin said yesterday at the Florida landing strip. All three of the shuttle program's landing sites have been placed on standby.
NASA officials say Discovery must land by tomorrow, when its electricity-generating hydrogen could begin to run out.
Besides Cape Canaveral landing plans have been readied for Edwards Air Force Base in California or - in a worst-case scenario - White Sands Space Harbor in New Mexico.
A complicated series of decisions and orbital calculations will factor into Discovery's final approach. As with launches, orbital mechanics mean there are windows during which the shuttle crew can bring the orbiter into a safe descent ending at one of the three U.S. airfields.
Seasonal weather patterns also affect when the shuttle can land. Afternoon or evening landings would be out of the question in Florida because of the prevalence of heat-spawned thunderstorms.
This morning, two landing times are available for each site.
Florida remains the landing site of choice, as a touchdown in California or New Mexico would add $1 million to the mission price tag, for transporting the shuttle back to Florida by jet.
Much of the immediate future of the shuttle program remains in question, however.
As with the Columbia, which disintegrated on re-entry in 2003 after falling insulation damaged heat-resistant tiles during liftoff, Discovery's launch was tainted when foam detached from its external fuel tank.
NASA grounded its shuttle fleet after the Columbia disaster and spent $1.4 billion to fix the launch system before Discovery's launch July 26. Though the foam that fell off Discovery's tank did not appear to strike the orbiter, shuttle launches are on hold until those problems and others can be fixed.
As the shuttle passed over the South Pacific and later Iran, clouds less than 1,000 feet over Cape Canaveral ended any hope of an on-time landing yesterday.
In the last 111 landings, shuttles touched down 61 times at Kennedy, 49 times at Edwards and only once at White Sands, in 1982. That was NASA's third shuttle flight, and the Columbia landed in a sandstorm. For years afterward, workers found sand in the ship's crevices.
Though NASA officials said they would not make a final decision until the last moment, chances appeared good for a landing at Edwards.
Weather conditions in Florida today were expected to be similar to those of the morning before, NASA said. Edwards was expected to have acceptable conditions for landing; White Sands' forecast included showers.
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