WASHINGTON, Oct. 5 (Xinhua) -- Two U.S. astronauts floated outside the International Space Station on Thursday on a spacewalk to repair the orbiting laboratory's robotic arm.
The spacewalk, conducted by Randy Bresnik and Mark Vande Hei of the U.S. space agency NASA, started at 8:05 a.m. EDT (1205 GMT) and was expected to last about 6.5 hours.
The pair's main task was to replace one of two Latching End Effectors on the station's robotic arm, Canadarm2, which experienced a stall recently.
Canadarm2 has two identical Latching End Effectors used to grapple visiting cargo vehicles and payloads, provide data and telemetry to the rest of the Canadian-built Mobile Base System and the unique capability to "walk" from one location on the station's truss to another, NASA said.
It's the third spacewalk of Bresnik's career and the first for Vande Hei.
Three spacewalks has been planned for October. Bresnik will lead all three, with Vande Hei joining him again Oct. 10 and Joe Acaba of NASA joining him Oct. 18.
The second and third spacewalks will concentrate on the lubrication of the newly installed Latching End Effector and the installation of a pair of external cameras.