Video: Change of command aboard International Space Station

Now in the home stretch of a complex, multi-year upgrade, two space station astronauts floated outside the lab complex Thursday and pressed ahead with the third of four spacewalks the current crew is carrying out to complete the replacement of aging batteries in the station’s solar power system.

A Russian cosmonaut, his Canadian co-pilot and a NASA flight engineer packed their Soyuz spacecraft for departure from the International Space Station Monday night, targeting a landing on the steppe of Kazakhstan to close out an action-packed 204-day mission.

SpaceX called off the planned launch of a Falcon 9 rocket Saturday less than 15 seconds before liftoff to investigate the “slightly odd” behavior of the vehicle’s upper stage engine steering system, company chief Elon Musk said.