FILE - This May 23, 2010 image provided by NASA shows the International Space Station with the Earth in the background. The image was photographed by an STS-132 crew member on space shuttle Atlantis after the station and shuttle began their post-undocking relative separation. On Tuesday, Dec. 17, 2013, NASA decided to schedule a series of urgent spacewalks to fix a broken cooling line at the International Space Station. The first is scheduled for Saturday, Dec. 21, 2013. (AP Photo/NASA)