WIKIARCHIVES.SPACE

NASA astronaut Christina Koch conducts her fourth spacewalk at the International Space Station. She and fellow NASA astronaut Jessica Meir (out of frame) ventured into the vacuum of space for seven hours and 17 minutes to swap a failed battery charge-discharge unit (BCDU) with a spare during the first all-woman spacewalk. The BCDU regulates the charge to the batteries that collect and distribute solar power to the orbiting lab’s systems.