Two hundred fifty miles above Earth, on a Thursday in early August, NASA astronauts Jessica Meir and Anil Menon spent six and a half hours in the void completing the final piece of infrastructure that will allow the International Space Station to generate significantly more power. It was the seventh and last of its kind — a quiet, methodical act of preparation that connects a laboratory already decades beyond its designed lifespan to the ambitions of missions not yet flown. In the long arc of human spaceflight, such moments rarely announce themselves as historic, yet they are the hinges on whi