NASA Mulls Landing Options for Shuttle Discovery
As seen through windows on the aft flight deck of Space Shuttle Discovery, the payload bay is featured in this image photographed by a STS-116 crewmember flight day two activities.
CAPE CANAVERAL, Fla. -- NASA mission managers are eyeing the weather for Friday’s planned landing of the space shuttle Discovery while awaiting the results from a second look at the orbiter’s heat shield.
“We’re assuming the vehicle is in a go condition for landing unless somebody illuminates an issue out of that data,” Phil Engelauf, NASA’s mission operations representative for Discovery’s STS-116 flight, said of today’s heat shield inspection during an afternoon status briefing. “But the assumption is everything is fine and we have no reason to suspect anything other than that for the vehicle as of this time.”
Meanwhile, mission managers and flight controllers are going over options for Discovery’s return to Earth, currently set for no earlier than 3:56 p.m. EST (1856 GMT) on Friday.
Discovery’s STS-116 astronaut crew, commanded by veteran spaceflyer Mark Polansky, is due to land here at NASA’s Kennedy Space Center to conclude a successful 13-day mission that continued assembly of the International Space Station (ISS), but only if the weather cooperates.
“If we have ‘Go’ weather at Kennedy, than we’ll certainly try to get into Kennedy,” Engelauf said. “If we have questionable weather at Kennedy and better weather at one of the other sites, then we’ll probably end up going to one of the other sites.”
Current weather forecasts for NASA’s Shuttle Landing Facility here predict low clouds and a hint of rain that could prevent Discovery’s planned touchdown at KSC, NASA officials said.
KSC is NASA’s preferred orbiter landing strip since it allows shuttle engineers to turn the vehicle around for its next flight at the space agency’s launch site more quickly.
The space agency is also tracking weather at the shuttle’s alternate landing sites at Edwards Air Force Base in California’s Mojave Desert, where high cross winds are expected, and the White Sands Space Harbor in New Mexico.
“Our intent will be to land somewhere on Friday,” Engelauf said.
If a KSC landing is unavailable, NASA mission managers will shift to either Edwards or White Sands depending on the weather at each site. In the past, the White Sands site has been viewed as last resort due to a dearth of orbiter turnaround facilities at the New Mexico installation.
A landing at Edwards, which like KSC contains the required infrastructure to land an orbiter and ferry it back to NASA’s Florida spaceport, typically adds one extra week and added cost of about $1.7 million to once more ready a NASA shuttle for flight.
With a White Sands landing at Northrup Strip, returning Discovery back to KSC for turnaround processing could take up to 45 days, NASA officials said.
“It will be longer coming back from there,” Engelauf said.
NASA landed a space shuttle once at the White Sands facility in 1982 during the STS-3 mission aboard Columbia, but the orbiter suffered contamination from the landing strip's gypsum surface, the space agency said.
Engelauf added that some initial infrastructure to handle Discovery’s post-landing power and purging needs will be flown out to the White Sands site in preparation for the site’s potential use.
Discovery’s landing schedule woes stem from the loss of one of two extra days NASA traditionally adds to each shuttle flight to ensure the orbiter has enough supplies to maintain its crew until landing.
Discovery launched Dec. 9 on a planned 12-day mission with two days in reserve in case of a systems glitch or poor landing weather. But mission managers sacrificed one of those spare days Monday to stage an unplanned spacewalk by STS-116 astronauts Robert Curbeam and Christer Fuglesang to wrangle an unruly ISS solar array into its storage boxes.
NASA flight rules stipulate that the space agency land somewhere Friday if possible to protect its remaining flight day in the event of an unforeseen systems glitch, though the orbiter’s supplies will only last through Saturday, Engelauf said.
Polansky and his STS-116 crewmates are wrapping up successful flight to the ISS, where they installed a new piece of the orbital laboratory, rewired its power grid and performed an astronaut swap for the outpost’s Expedition 14 crew.
The astronauts are due to launch a pair of microsatellites from Discovery’s payload bay, along with a third set on Thursday, before returning to Earth on Dec. 22.
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