Posted: Wed, Apr 14, 2010, 9:11 AM ET (1311 GMT)
Two astronauts completed the third and final spacewalk of the STS-131 mission on Tuesday, completing the installation of a new ammonia tank. Rick Mastracchio and Clayton Anderson spend 6 hours and 24 minutes outside the station on an EVA that started at 2:14 am EDT (0614 GMT). The two completed the installation of fluid lines on a new tank of ammonia coolant added to the station during the previous two spacewalks, moving ta depleted tank to the shuttle's cargo bay for return to Earth, and also performed several other miscellaneous tasks. After the spacewalk astronauts reported problems trying to active the new tank because of a stuck valve in one of the nitrogen pressurization lines. Engineers on the ground are troubleshooting the problem, which could require an EVA by station astronauts to resolve.
