Discovery's astronauts take final spacewalk

Discovery's astronauts have taken one final spacewalk outside the International Space Station before the shuttle goes into retirement.

Spacewalkers Alvin Drew and Stephen Bowen have been doing relatively minor jobs that will leave the orbiting lab in the best possible condition, once the space shuttles stops flying.

Drew and his colleague Stephen Bowen whittled down the entire to-do list, including installing a rail car light and an outdoor robot's camera.

Discovery will remain at the space station until Sunday.

The shuttle astronauts are staying an extra day to help fit the new storage room.

There is a possibility that yet another bonus day might be added, which would stretch the mission to 13 days.