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Astronauts step out for final spacewalk of mission
2008-11-24
CAPE CANAVERAL, Fla. - Astronauts carried out one last spacewalk Monday to finish an unprecedented clean and lube job that they began a week ago at the international space station. Spacewalkers Stephen Bowen and Shane Kimbrough hoped to wrap up work on a jammed solar-wing rotary joint and, as a precaution, squirt some extra grease on another joint that works fine. Just before Monday's spacewalk began, NASA added a 16th day to space shuttle Endeavour's mission. Managers wanted to give the astronauts more time to fix a machine that's supposed to turn urine into drinking water and more repair work was on tap Monday for the fifth day in a row. The $154 million recycling equipment was delivered by Endeavour, along with other home makeover items needed to expand the space station crew to six next year. Monday's spacewalk was the fourth for Endeavour's astronauts. Not everything got done during the last one -- one more bearing needed to be replaced in the clogged joint -- so Bowen and Kimbrough have to take care of that, too. The rotary joint on the right side of the space station hasn't worked properly for more than a year, preventing the solar wings on that side from pointing automatically toward the sun. Grinding parts left the joint full of metal grit. Almost all the greasy mess was cleaned up during the first three spacewalks and new bearings were put in. Bowen and Kimbrough planned to finish the job Monday. If that goes well, the first test of the newly repaired joint would be Tuesday. An identical joint on the left side of the orbiting complex has worked perfectly, but NASA wanted the spacewalkers to grease it up to ensure its longevity. As they have before, the spacewalkers had to share grease guns 225 miles up. There was one less tool kit after a sack full of grease guns and other items floated away on the first spacewalk last Tuesday. Inside the space station, meanwhile, skipper Mike Fincke faced more repair work on the new urine processor. It has shut down after limited use; its longest test run ended after almost three hours. NASA was hoping for a full four-hour test run Monday, after a little more tinkering by Fincke. When informed more urine might be needed, Fincke said, "Well, we've got a very adequate supply of yesterday's coffee to help." Mission Control then joked: "We'll see if we need to add some Diet Coke to the plan." For the record, there is no Diet Coke -- or any other soda -- up there. The astronauts have managed to collect samples of the recycled water for return to Earth aboard Endeavour, relying mostly on converted condensation. NASA would prefer more urine in the mix; that's the way the system was designed. No one can drink the recycled water until tests show it's safe. Additional samples will be returned on the next space shuttle flight in February, to confirm everything is working properly. NASA's goal is to have six people living on the space station by June. The extra day in space for Endeavour now means that the two crews -- eight men and two women -- will celebrate Thanksgiving together and not part company until Friday. Endeavour's touchdown is now scheduled for Sunday. ___ On the Net: NASA: http://spaceflight.nasa.gov
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