Tuesday's spacewalk was the fourth for Bresnik's career and the second for Vande Hei.
Next spacewalk is planned for 18th October this year.
Two astronauts aboard the International Space Station (ISS) have completed a spacewalk lasting about 6.5 hours to lubricate components of the new latching end effector they installed in the previous spacewalk on the Canadarm2 robotic arm.
Bresnik and Vande Hei are slated to exit the Quest airlock around 8 a.m. EDT (1200 GMT). NASA astronaut Joe Acaba and European Space Agency astronaut Paolo Nespoli will help the spacewalkers get suited up and out the door. "I have a little bit of adrenaline going on right now", Mr. Vande Hei said as he got to work more than 400 km above Rio de Janeiro.More news: Researchers Wonder Why a Giant Hole Keeps Opening Up in Antarctica
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After lubricating the robotic arm, the two United States astronauts replaced the camera present on the station's truss. And on Tuesday, they lubricated the replaced latching end effectors.
While conducting a spacewalk during shuttle mission STS-123 in 2008, NASA astronaut Rick Linnehan is anchored to the end of Canadarm2. Also, on October 18, during the last and final spacewalk of the series, another camera named the "Old Yeller" present at the Destiny Laboratory, will be replaced with a new HD camera. Bresnik and Vande Hei moved later to secondary tasks like tightening a latch on an external oxygen tank, preparing ammonia pump module to permit venting before planned relocating, removal of two handrails to prepare space for installation of wireless antennas in future, changing camera lens cover.
A third spacewalk in the series is scheduled October 18 by Bresnik and station flight engineer Joe Acaba.