Four volunteers have spent a full year inside a 1,700-square-foot 3D-printed habitat in Houston, living as if they were on Mars — and on October 31, they finally get to come home from a planet they never left. The most important Mars mission of the past year did not launch. It did not need to. On October 19, 2025, four volunteers walked into Mars Dune Alpha, NASA's 3D-printed simulated Mars habitat at Johnson Space Center in Houston, and closed the door. On October 19, 2026,