Twoastronauts will float outside the International Space Station Saturday on the last spacewalk of their mission, one aimed at performing some last few maintenance chores on the orbiting laboratory.
Clad inbulky NASA spacesuits, Discoveryshuttle astronauts Danny Olivas and Christer Fuglesang plan spend 6 1/2hours working outside the space station to prepare the orbital outpost forfuture missions.
The spacewalkis slated to begin at 4:49 p.m. EDT (2049 GMT). It is the third and lastspacewalk of Discovery?s 13-day mission to the space station to boost thespace station?s supplies and science gear.
?I thinkthe challenge is really to not lose eyes on the goal, and that is basically toconduct three safe and successful EVAs,? Olivas said in a news conference lateFriday using NASA?s term for spacewalks. ?We have two under our belts ? but twobehind us doesn?t mean that the third one is going to be as much or even more of achallenge.?
Saturday?sspacewalk includes a hodgepodge of maintenance tasks to replace broken componentsand prepare thespace station for the arrival of spare parts and a new room over the nextyear. The astronauts plan to replace a broken part of the station?s attitudecontrol system and an old circuit breaker, as well as install new navigationantennas and deploy a vital spare parts attachment point.
Olivas andFuglesang also plan to string a set of 60-foot (18-meter) power and data cablesalong the space station?s hull to support a new module slated to arrive earlynext year. The cables can be stiff in space and hard to handle, missionmanagers said.
?They canget to be like a bundle of snakes so we have a good plan in place on how toroute these and how to secure them,? said Zeb Scoville, NASA?s lead spacewalkofficer for Discovery?s mission.
Saturday?sspacewalk will mark the fifth career excursion for both Olivas and Fuglesang. Fuglesang,whois Swedish and represents the European Space Agency, has already performed morespacewalks than any other European astronaut and expected Saturday?s excursionto be his last.
?It willalso feel a little bit sad because there won?t be any more chances,? saidFuglesang, who is making his second spaceflight, in a news conference lateFriday. ?But I?ll try to enjoy the moment as much as I can and focus on thework I have to do.?
The currentspacewalk record is held by Russian cosmonaut Anatoly Solovyov with 16spacewalks and more than 80 hours of orbital work.
Discoverylaunched toward the space station last week to deliver newscience gear, supplies and a treadmill named after comedian StephenColbert. The shuttle also ferried a new crewmember for the station?s six-personcrew.
Discoveryis due to undock from the space station on Tuesday and return to Earth onThursday.
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SPACE.comis providing complete coverage of Discovery's STS-128 mission to theInternational Space Station with Managing Editor Tariq Malik and Staff WriterClara Moskowitz in New York. Clickhere for shuttle mission updates and a link to NASA TV. Live spacewalkcoverage begins at 3:50 p.m. EDT.