Video: Expedition 50 spacewalk highlights

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.

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.

Three new residents completed the final leg of their pursuit of the International Space Station, with docking to the complex at 2158 GMT (4:58 p.m. EST) Saturday, two days after blastoff from the Baikonur Cosmodrome in Kazakhstan. The Soyuz capsule carrying the U.S.-Russian-French crew linked up with the research lab’s Rassvet module.