Two members of the U.S. space shuttle Discovery have embarked on their second spacewalk of their current mission to begin rewiring the International Space Station.
The astronauts are rerouting connectors from the station's temporary power source to a new set of solar panels that were installed during a shuttle flight in September.
The wiring change will allow new laboratories to be added to the station beginning next year. The rewiring job is scheduled to be completed during a third spacewalk Sunday.
The space station and shuttle crews spent Wednesday partially retracting one of the two solar panels that have provided electricity to the station for the past six years. The 35-meter-long panel became stuck in one place despite dozens of radio commands. Ground controllers decided it was retracted enough to allow the new solar wings to rotate and track the sun.
Officials with the U.S. space agency, NASA, may schedule a fourth spacewalk for next week so astronauts can manually retract the old solar panel.