U.S. astronaut Sunita Williams and Japanese astronaut Akihiko Hoshide are conducting a more than six-hour space walk to conduct maintenance work outside the International Space Station.
Among the tasks they are performing while in space, the astronauts will replace a faulty power relay, rig power cables for a Russian laboratory module due next year and replace a failing robotic arm camera.
This is the fifth space walk for Williams, a NASA flight engineer. Hoshide is conducting his first spacewalk and is the third Japanese astronaut in history to do so.
The spacewalk is the 164th in support of station assembly and maintenance. This is the first U.S.-based spacewalk since July 2011.
This is the second spacewalk of the current space station mission. The first was conducted 10 days ago by Commander Gennady Padalka and Flight Engineer Yuri Malenchenko.