Video: Highlights of second Expedition 50 spacewalk

Five days after work to replace the grapple fitting on one end of the space station’s robot arm, commander Randy Bresnik and flight engineer Mark Vande Hei ventured back outside the lab complex Tuesday to lubricate the new arm mechanism, to replace a degraded camera and to carry out a variety of lower-priority chores.

Astronauts Barry “Butch” Wilmore and Terry Virts floated outside the International Space Station Wednesday for the second of three spacewalks to help ready the complex for dockings by commercial crew capsules. Back inside the station’s airlock, Virts reported a small amount of water in his space helmet, but officials said he was not in any danger.

Two astronauts ventured outside the International Space Station early Thursday and performed what amounted to hand transplant surgery on the lab’s Canadian-built robot arm, removing a crippled grapple fixture on one end of the space crane and replacing it with an on-board spare.