Video: Expedition 50 spacewalk highlights

In a complex bit of orbital surgery, two spacewalking astronauts cut into a $2 billion cosmic ray detector Friday, venting away life-sustaining carbon dioxide refrigerant and then snipping eight coolant lines the size of soda straws to prepare the high-tech “patient” for a coolant pump transplant.

For the second time in less than a week, astronauts will leave their quarters inside the International Space Station on Thursday to outfit a relocated docking adapter to eventually receive Boeing and SpaceX commercial crew capsules.

Staging NASA’s third spacewalk in 15 days, two astronauts floated outside the International Space Station Friday and installed a new high definition camera, replaced a degraded camera on a recently attached robot arm grapple fixture, finished lubricating the mechanism and carried out a variety of other “get-ahead” tasks.