Final Shuttle Spacewalk Underway

Even something as mundane sounding as removing a pump takes on special importance when it happens during the final shuttle mission.

Given that the last space shuttle mission is currently underway, the spacewalk that astronauts aboard the International Space Station have just begun will be the last of its kind, as well. For six-and-half hours, astronauts Ron Garan and Mike Fossum will work to remove an ammonia pump attached to the orbiting station and place it in the cargo bay of the space shuttle Atlantis. The pair will then try out a refuelling experiment funded by Canada and the U.S. to see if it's possible to fuel satellites from the space station. The spacewalk is the 160th to have been launched from the ISS, and the last of any shuttle mission, as NASA's shuttle program is to be retired once Atlantis returns to Earth on July 21.