(C)NASA/KSC
Astronauts Piers Sellers and Mike Fossum will go outside Saturday
for the mission's first spacewalk, performing station maintenance
and testing the shuttle's robotic arm and boom as a work platform.
Discovery astronauts spent Friday inspecting the orbiter and
transferring supplies to the space station. 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