HOUSTON--Following a hecticweek docked at the International Space Station (ISS) where a few historic"firsts" were performed in space, the shuttle Discovery is being prepared tocome home.
"We're ready to go," said Paul Hill,Discovery's lead STS-114 flight director, during a briefing here at NASA'sJohnson Space Center.
The only major concern, aside fromthe typical risks associated with flying the shuttle--effectively a 100-tonglider during reentry--back to Earth, is weather at Kennedy Space Center whereit will land at 4:46 a.m. EDT ( 0846 GMT) Aug. 8, Hill said.
"We are highly confident in thisentry," veteran astronaut Eileen Collins, Discovery's STS-114 commander, saidearlier this week. "I think we're going to have a clean entry."
Discovery is set to undock from theISS Saturday at 3:44 a.m. EDT (0744 GMT) then back about 400 feet away, whereit will slowly circle the orbital laboratory with the station with shuttlepilot James Kelly at the helm.
"The only reason we're doing it isto take pictures of the space station," Hill said. "There's no technical reasonother than the fact that we can see all the way around. We're going to take thetime to snap some pictures from some angles we haven't seen since the lastorbiter was there."
Discovery is the first shuttle tovisit the space station since 2002, and NASA's first orbiter to fly since theColumbia disaster. Columbia's STS-107 mission, commanded by astronaut RickHusband, ended in tragedy about 16 minutes before landing when the orbiterbroke apart during reentry on Feb. 1, 2003 while flying over Texas.Investigators pinned the accident on wing damaged cause during Columbia'slaunch, when a piece of foam debris fell form the orbiter's external tank andpierced its heat shield.
Many of the new tools and methodsused by Discovery's crew are a direct result of the Columbia accident.
The astronauts repeatedlyused a laser camera-tipped inspection boom extension for the shuttle's roboticarm to scan their ship's thermal protection system, and ISS crewmembersphotographed the orbiter's heat tile-covered belly during a backflipmaneuver prior to dockingon July 28.
The shuttle is now fit forlanding after an in-flight repair to pluck two protruding strips of fillermaterial from its belly tiles during a first-ever spacewalkand conclusions that a damaged thermal blanket should not pose a hazard duringlanding, the shuttle is fit for landing, mission managers said.
"But there is no such thing as no concern,"Hill said. "Just making it past the milestone where we lost STS-107 is notenough."
Hill said that the lost Columbiaastronauts have been a constant presence in his mind and those of his flightteam, even as mission controllers focused on returning Discovery and itsSTS-114 crew home safely.
"During the crew commemorationyesterday, they were on our minds a lot," Hill said. "During de-orbit I'm sureI'll have a thought or two about Rick Husband and his crew. At wheel stop, Ithink a lot of us are going to think a lot about the STS-107 crew as well asthe STS-114 crew at landing."
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