(C)NASA/KSC
Astronauts Piers Sellers and Mike Fossum went outside
Discovery on Saturday for the mission's first spacewalk,
performing station maintenance and testing the shuttle's
robotic arm and boom as a work platform.
Managers have extended the mission by a day, paving the
way for a third spacewalk.
http://www.nasa.gov/externalflash/sts-121_front/index.html