NASA Mulls Its Shuttle Landing Options
NASA's ability to deal with adversity in its space operations is
legendary -- STS-116 has been no exception. Despite a balky solar
panel and tools lost in space, the shuttle and ISS crews have
managed to execute all STS-116 mission objectives except one so
far, meeting launch and landing schedules.
NASA slipped Thursday's originally scheduled landing to
accommodate an additional spacewalk to fully retract that balky
solar panel. Now, it looks as though Mother Nature will have
another say in NASA's schedule as the forecast at Kennedy Space
Center calls for low clouds and rain showers for Friday's
rescheduled landing.
As if that weren't bad enough, NASA's backup landing site of
Edwards Air Force Base in California is calling for crosswinds of
20 mph -- just 3 mph in excess of the agency's 17 mph safety
limit.
The agency's tertiary landing site at White Sands, NM might
prove to be the only option left. Although good weather is forecast
there, it's the poorest choice logistically -- NASA would have to
reposition a tremendous amount of equipment to support the
orbiter's return to Florida.
NASA's chief of its flight directors’ office Phil Engelauf
told the Associated Press, "More than likely, we will evaluate the
conditions on a case-by-case basis on Friday and pick the lesser of
evils."
Discovery's crew will continue with landing preparations today
including tests of the shuttle's flight control system, stowing
loose items and deploying a small satellite. Ground controllers are
expected to give a thumbs-up after studying pictures of the
shuttle's heat shielding the crew transmitted earthward on
Wednesday.
There is a note of urgency in NASA's landing site dilemma. In
the past the agency hasn't been shy about delaying a shuttle's
landing to wait for better weather at its landing site of choice.
This time, NASA wants the shuttle down no later than Saturday --
that's when the fuel cells providing Discovery's primary power run
dry.
A landing in New Mexico poses some concerns for the space
agency, but none that would interfere with getting Discovery on the
ground safely. The last time a shuttle landed at White Sands in
1982, fine sand on the runway contaminated the shuttle's exterior
and damaged its brakes.
Engineers are also worried freezing weather over the
weekend there might damage the shuttle's thrusters and freeze water
and fuel lines.
Additionally, complicated logistics issues mean a landing at
White Sands will delay the shuttle's return to Florida by a month,
and flying the orbiter back there piggy-back on the agency's
special-purpose 747 is expensive.
It's unclear how a delay in returning Discovery to Florida might
interfere with NASA's launch schedule for 2007. Three shuttle
launches have already been pushed back for next year.
NASA says it has seven chances for a landing at any of its three
landing sites Friday and Saturday.