A sealed station gets no deliveries. Whatever you carried aboard is what stews in there, and from outside comes only radiation and cold.
Mikhail Vishnevsky, a mycologist, military doctor and author of more than twenty books on fungi, uses that picture to explain a worry. In a closed system with nothing coming in or out, a fungus that nobody learns to control will sooner or later clog everything. He calls fungi our greatest biological threat today. In the same breath he calls them potentially "our main salvation".
The second claim is the one that matters if you ever hope to see a human settlement off Earth. Every trait that makes fungi a nuisance on a station becomes a plus somewhere else. They are allies for settling extreme places and can break down any carbon-bearing material you hand them. Whoever plans a base on another planet is planning with fungi, whether they mean to or not.
Then comes the turn. Chernobyl blew up in 1986, and fungi have been found living there. Vishnevsky says their enzymes let them eat the reactor's carbon and uranium rods.
A biology textbook files fungi under heterotrophs: they live on ready-made organic matter that something else grew, and they take it apart. Plants are the other camp. They need only sunlight and carbon dioxide. At Chernobyl, Vishnevsky says, the textbook line stops holding. These fungi take nothing but radiation, the way a leaf takes light, and then "cook something for themselves, rummage around and eat it".
Fungi are now a little bit autotrophs, which shows their total, complete versatility and readiness to switch to the most varied forms and schemes of living.
Грибы теперь уже немножечко и автотрофы, что уже показывает их абсолютную полную универсальность и готовность переключиться на самые разные формы, схемы жизнедеятельности.
— Mikhail Vishnevsky, Gleb Solomin Podcast, 78:08
Note the word "little". Vishnevsky does not claim a mushroom has become a tree.
Orbit offers a check on how much weight that word carries. In 2022, Nils Averesch reported in Frontiers in Microbiology that the dark-pigmented fungus Cladosporium sphaerospermum grew about 1.21 times faster on the International Space Station than in ground controls. He stressed that real radiosynthesis, meaning carbon fixed with the help of ionizing radiation, has still to be shown. The fungus liked orbit. Whether it was eating the radiation is the open part.
Vishnevsky's bet is that the answer matters less than the habit it points to. A group that can swap its way of making a living can be sent ahead of us. Fungi already take open space in their stride: near-permanent freezing, vacuum, hard ultraviolet. He credits Paul Stamets, whose fringe claims about fungi he mostly doubts, with getting this one right.
The numbers come from Antarctica. Fungi that live inside bare rock there were put through simulated Martian days and nights, with heat, cold, ultraviolet and freezing. At least 60 percent of the colonies survived, grew and kept growing. In Vishnevsky's picture they would not go alone. They would travel with cyanobacteria, archaea and other pioneer organisms, but as the main component of a Mars colony's first steps.
NASA is working in the same direction. Its Mycotecture off Planet project, described in June 2024, studies growing structures off-planet from fungal mycelium. Its experiments and models include melanin-producing strains for radiation protection.
The host asked the obvious question: could our rovers already have seeded Mars by accident? Something is probably lying around up there, Vishnevsky says, though likely nothing serious. From here, he adds, nobody can see what is really happening on Mars.
