High above the turning Earth, two human beings spent six hours suspended in vacuum, threading cables and fastening brackets to a structure that has circled the planet for nearly three decades. On Thursday morning, NASA astronauts Anil Menon and Jessica Meir completed the 281st spacewalk in support of the International Space Station, installing hardware that will receive new solar arrays — work that is both a quiet act of maintenance and a deliberate preparation for the station's eventual end. In the long arc of human presence in low Earth orbit, this moment sits at a threshold: sustaining what