An International Space Station crew including NASA astronaut Christina Koch, who has spent more time in space on a single mission than any other woman, has landed safely in Kazakhstan.

Two NASA astronauts have ventured out on a second all-female spacewalk to finish upgrading the International Space Station's power grid.

NASA astronauts Christina Koch and Jessica Meir exited the International Space Station on Friday, the first time in a half-century of spacewalking that a woman floated out without a male crewmate.