CAPE CANAVERAL - The countdown is on for the space shuttle Discoveryand seven astronauts who, if all goes well, will be NASA's first shuttleastronauts to reach space in since January 2003.
Atprecisely 6:00 p.m. EDT (2200 GMT) Sunday, NASA began counting the days,minutes and seconds remaining before Discovery's STS-114 mission is expected tolaunch into space. The spaceflight is currently scheduled to liftoff on July 13at 3:51 p.m. EDT (1951 GMT) from Launch Pad 39B here at NASA's Kennedy SpaceCenter (KSC) in Cape Canaveral, Florida.
"We'regetting excited about the upcoming flight," said STS-114 commander Eileen Collinsafter arrivinghere Saturday. "We're anticipating about what it's going to be like getting theshuttle back in space again."
Collins andher STS-114 crewmates are the first shuttle astronauts set to ride a NASAorbiter spaceward since the ill-fated flight of STS-107 aboard Columbia.
Columbia's mission,which launched on Jan. 16, 2003, ended in tragedy when the orbiter broke apartduring reentry, leaving no survivors. Wing damage, caused at liftoff by achunk of loose external tank foam, breached Columbia's protective thermal protectionsystem and allowed hot gases into the orbiter's left wing, destroying thespacecraft.
Discovery'sexternal tank has been modifiednot only to prevent the type of foam debris that struck Columbia, but also to reduce the formation ofice on the tank's exterior. NASA has added heaters to replace foam insulationon the external tank's bipod fitting - where the chunk that doomed Columbia originated - andalong a bellows unit that flexes in response to the tank's supercoldpropellant.
"We arefinally here, we're ready to go," said Sandy Coleman, NASA's external tankproject manager, during a press briefing today. "The external tank iscertified."
Discovery'sSTS-114 mission is a 12-day test flight bound for the International Space Station(ISS), where the shuttle crew will deliver a cargo module full of supplies andconduct three spacewalks. The shuttle astronauts will also test a new orbitalboom to scan Discovery for damage and test repair techniques for fixingheat-resistant tiles and reinforced carbon carbon panels.
"Sheer excitementis the best way to explain it," Stephanie Stilson, Discovery's vehicle manager toldSPACE.com. "It's seems like it's a littleunreal, I want to pinch myself to see if we really are as close [to launch] aswe are now."
WhileStilson and her entire vehicle team are excited for Discovery's spaceflight,they will keep a close eye on the orbiter's systems as launch day nears.
"We'll bewatching things very closely," Stilson said. "I don't think we've ever had a launchcountdown that didn't have something that you had to go in and fix or check outor take a second look at."
Over thenext several days, launch officials will take a series of critical steps toprepare Discovery for flight.
On July 11 at about 2:00 p.m. EDT (1800 GMT), padengineers will begin loading the hypergolic reactants Discovery will use duringits spaceflight. The protective rotating service structure covering the orbiteris set to be swung back on July 12 at 7:00 p.m. EDT (2300 GMT). Technicians areexpected to begin loading Discovery's external tank with the liquid hydrogenand liquid oxygen propellant at 6:00 a.m. EDT (1200 GMT) on July 13.
"Currentlywe're tracking no issues at all as far as preparations go," NASA test directorJeff Spaulding said during a morning countdown update.
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