Spacewalkers complete 4 years of power upgrades for station

A pair of spacewalking astronauts completed a four-year effort to modernize the International Space Station's power grid on Monday, installing one last battery. Over the weekend, flight controllers in Houston used the space station's big robot arm to replace the last pair of old-style batteries with a single better-quality one. NASA's Mike Hopkins and Victor Glover put the finishing touches on this newest lithium-ion battery to complete a series of spacewalks that began in 2017. Although the spacewalk got started late, Hopkins and Glover hustled through the battery work in under an hour. They also made quick work of camera installations and squeezed in some extra chores.