NASA astronaut Christina Koch works while tethered near the Port 6 truss

iss061e005311 (Oct. 11, 2019) --- NASA astronaut Christina Koch works while tethered near the Port 6 truss segment of the International Space Station to replace older hydrogen-nickel batteries with newer, more powerful lithium-ion batteries. Fellow NASA astronaut Andrew Morgan (out of frame) assisted Koch during the six-hour and 45-minute spacewalk.