CAPECANAVERAL, Fla. - The weather outlook for NASA?s Tuesday launch of the shuttleDiscovery has dipped slightly, with an increased risk of rain showers and thickclouds preventing the planned space shot.
?We areconcerned about the weather for tomorrow?s launch,? said Kathy Winters, NASA?sshuttle weather officer, during a morning briefing here at the Kennedy Space Center.
Discoverynow has a 40 percent chance of good weather, down from 60 percent, for its planned11:38 a.m. EDT (1538 GMT) launch toward the International Space Station(ISS). Weather forecasts improve for subsequent launch opportunities onWednesday and Thursday, Winters said.
Commandedby veteranshuttle flyer Pamela Melroy, Discovery?s seven-astronaut STS-120 crew willdeliver a vital connecting node to the ISS, swap one station crewmember andrelocate an old U.S. solar array during a 14-daymission.
So far,poor weather at Discovery?s Pad 39A launch site has only had a limited impacton liftoff preparations, said NASA test director Steve Payne.
Rain showersdelayed efforts to load Discovery with the super-chilled liquid hydrogen andliquid oxygen that will power the orbiter?s three fuel cells during flight byabout one hour on Sunday, but shuttle workers were able to make up the losttime once the weather subsided, Payne said.
?That wasn?ta big deal,? he added. ?We had contingency time built in just for that.?
Payne saidlaunch preparations are back on schedule with plans to roll back the shroud-likeRotating Service Structure, which protects Discovery from weather, at 3:00 p.m.EDT (1900 GMT) today.
Shuttleworkers will also load final cargo items inside Discovery?s middeck latertoday. They are slated to begin fueling the orbiter?s 15-story external tankwith the 520,000 gallons of liquid hydrogen and liquid oxygen propellant thatwill feed Discovery?s three main engines during the nine-minute launch to spaceat about 2:13 a.m. EDT (0613 GMT), Payne said.
Engineers haveadded some modifications to Discovery?s fuel tank, including tweaking the designof plumbing line mounts and stripping cork-like insulation from some brackets,to avoid the type of debris-shedding that dinged the belly-mounted heatshield of the shuttle Endeavour during NASA?s STS-118 launchon Aug. 8.
Flightcontrollers have also cut about an hour from the launch countdown to decreasethe amount of time in which ice can form on Discovery?s cryogenic propellant-filledfuel tank, mission managers have said.
Discovery?sSTS-120 mission will mark NASA?s third of four shuttle flights dedicated tospace station construction this year.
NASAwill begin broadcasting Discovery?s STS-120 launch and mission operations liveon NASA TV at 6:30 a.m. EDT (1030 GMT) on Tuesday. Click here for SPACE.com?s live launchcoverage, mission updates and NASA TV feed.
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