NASA Mulls Possible One-Day Extension to STS-114 Mission

HOUSTON- While NASA hopes to solve its external tank foam woes in time to launchanother space shuttle in the near future, discussions are underway on how to getthe most out of the Discovery's current presence at the International SpaceStation (ISS) should mission managers opt to extend its flight by one day.

Bynot running a booster fan typically used to circulate air between the shuttleand station, and implementing other conservation techniques, flight controllershave built up 21 hours in available time the shuttle can remain on orbit ifneeded, said Phil Engelauf, mission operationsrepresentative for Discovery's STS-114 spaceflight, during a mission statusbriefing here at NASA's Johnson Space Center (JSC).

Themeasures have allowed Discovery's crew to save on the valuable cryogenicreactants used to power the shuttle's fuel cells, and will hope full reach thefull-day mark soon, he added.

"We'reoptimistic that we'll get enough cryo margin to insert that day," Engelaufsaid, adding that should mission managers decide to go with the one-day flightextension, it would most likely occur between Aug. 3-4.

Discovery'ssuccessful launch and, so far, nearly flawless spaceflight has been somewhatovershadowed by a foam debris problem that resurfaced with its external tank.During its July 26 launch, the tank unexpectedly shed chunks of foam insulationmuch too large to meet NASA's standards. A similar foam shedding eventcritically wounded the space shuttle Columbiaduring launch in 2003, punching through the heat shield on the orbiters leftwing. Hot atmospheric gases entered the damaged area as Columbia returned to Earth on Feb. 1, 2003,destroying the vehicle and killing its astronaut crew.

Shuttleprogram managers said this week they do not plan to launch another shuttleuntil they understand and fix the new foam issue. The Atlantis orbiter wasslated to launch the STS-121 mission during a flight window stretching between Sept. 9-24. That shuttle's Aug. 3 rollout to thelaunch pad, and other processing operations, have not been changed as of today,said John Shannon, NASA's manager of flight operations and integration for theshuttle program, during the briefing.

Thepotential of another long gap in shuttle flights to the ISS - Discovery'sSTS-114 flight is the first in two and a half years - has led to somediscussion of how to utilize Discovery's resources and crew if mission managersdecide to do so, shuttle officials said.

Theaddition of even a single, unscheduled day in Discovery's timeline could be aboon for the ISS crew, they added.

Withseven extra hands on board, ISS Expedition 11 commander SergeiKrikalev and flight engineer John Phillips couldcatch up on maintenance tasks that may have fallen by the wayside as theastronauts prepared for Discovery's arrival, Engelaufsaid, adding that any unique tools, spare laptop computers or other materialthat could be useful to the station now or in the future could be transferredto the ISS.

"Thecrew of Discovery and on the current space station assignment are looking atwhat, if anything, we can do while Discovery is there to pre-position thestation for a longer gap between flights should there be one," NASAadministrator Michael Griffin told reporters via teleconference, stressing thatit is much too soon to assume NASA's next shuttle flight is beyond 2005.

Earliertoday, a NASA spokesman said the Discovery astronauts are checking if they canpack up any additional water - produced by reactions in the orbiter's fuelcells - to leave with the ISS crew.

Bybeing smart and working hard to address the unexpected foam shedding issuesseen during Discovery's Tuesday launch, NASA could loft the Atlantis orbiter inone of two flight windows this year, Griffinsaid.

"Ifwe can do those things and are successful, then we'll catch one of those flightopportunities, and if not the date will move," Griffin said. "We don't start out by assumingwe can't succeed."

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