[<< wikinews] Astronauts replace ISS nitrogen tank in spacewalk
Wednesday, February 13, 2008 

Two astronauts have performed a spacewalk, or EVA, to replace a depleted nitrogen tank in the Integrated Truss Structure of the International Space Station. The Space Station's Nitrogen Tank Assembly (NTA), was successfully replaced with a new one, launched aboard Space Shuttle Atlantis, which is currently visiting the station, on mission STS-122. The old tank will be returned to Earth aboard the Shuttle. The NTA forms part of the Space Station's cooling system.
The spacewalk was successful, and the primary task of changing the tank was completed ahead of schedule, allowing the astronauts to perform several secondary tasks, which included the installation of thermal covers on the newly installed Columbus module, and inspection of micrometeoroid shields on the Destiny module.
American astronaut Rex Walheim and German astronaut Hans Schlegel, both of the STS-122 crew, left the ISS Quest airlock at 14:27 GMT, and re-entered it at 21:12, after six hours and 45 minutes of extra-vehicular activity. This is the 103rd spacewalk to be made as part of the International Space Station programme, and the second of three planned for the STS-122 mission.
Meanwhile, NASA have announced that the STS-122 mission has been extended by one day. Landing is now scheduled for next Wednesday, at 13:59 GMT. The extension will give the astronauts extra time to finish activating the Columbus module, a process which has been delayed due to computer problems aboard the module. 

== Sources ==
 "STS-122 Spacewalkers Complete Second Outing, Mission Extended" — NASA, February 13, 2008
Chris Bergin. "Extra docked day confirmed for STS-122 - EVA-2/Columbus problem" — NASASpaceflight.com, February 13, 2008
William Harwood. "Spacewalkers to swap out depleted tank in station truss" — Spaceflight Now, February 13, 2008
William Harwood. "Spacewalk ends; mission extended one day" — Spaceflight Now, February 13, 2008
 "STS-122 Spacewalkers Complete Second Outing As Mission Extended" — Space-Travel.com, February 13, 2008