Video: Expedition 50 spacewalk highlights

Two astronauts floated outside the International Space Station early Friday for the first of four planned spacewalks to wrap up a complex multi-year job to replace 48 aging batteries in the lab’s solar power system with 24 more powerful lithium-ion units.

Former astronaut Bruce McCandless II, a retired Navy captain and son of a Medal of Honor winner who joined NASA during the buildup to the Apollo program, served as capsule communicator when Neil Armstrong took his historic first step on the moon and later flew in space twice during the shuttle program, died Thursday. He was 80.

Two Russian cosmonauts stepped outside the International Space Station Wednesday, sent birthday greetings to former cosmonaut Alexey Leonov, the first man to walk in space, and then carried out a full slate of maintenance work.