Future manned space exploration will require astronauts to live in self-sustaining habitats like bioregenerative life support systems (BLSSs). BLSSs are artificial ecosystems that maintain their own air, food, and water supplies with the help of plants, animals, and high-tech recycling. Health and safety, including protection of food from mold, will be critical in these enclosed environments, but the potential dynamics of fungal communities and fungal toxins in BLSSs aren’t clear. To learn more, a new study analyzed the fungal microbiome (mycobiome) in a crewed BLSS test station in China over 375 days. DNA testing revealed that the BLSS, called Lunar Palace 1, had a unique fungal community that was more diverse than those in plant-less space habitats like the International Space Station. Overall, most of the surface fungi originated from plants, not people. The mycobiomes in the plant growth rooms remained stable, but the surface mycobiome in the living area changed when the crew was switched. In addition, some mycotoxin genes were detected, but their levels didn’t increase over time or with crew shifts. Although risk assessments are needed, this study reveals that plants form and stabilize the BLSS mycobiome, while people disrupt it and provides data to help plan space missions involving these habitats.