Astronauts step out on 1st spacewalk of mission

This image provided by NASA TV shows the Space Shuttle Atlantis with the shadow of the International Space station passing over it's cargo bay as the two pass over South America Wednesday Nov. 18, 2009. Atlantis arrived at the International Space Station on Wednesday for a weeklong stay, and the astronauts quickly unloaded a huge platform full of spare parts needed to keep the outpost running for another decade. (AP Photo/NASA)