Video: Narrated preview of Jan. 13 spacewalk

Astronauts Randy Bresnik and Mark Vande Hei headed outside the International Space Station Thursday on a spacewalk to replace one end of the lab’s Canadian-built robotic arm, a changeout that engineers say will restore the device to full capability.

Clad in pressurized spacesuits, two Russian cosmonauts headed outside the International Space Station on Wednesday and hand-released four tiny CubeSats and installed hardware for a German experiment to track animal migration.

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.