Earth Microbes Could Survive in the Moon's Shadowed South Pole, NASA Study Finds

Microbes carried to the Moon with astronauts could stay alive in cold, shadowed pockets of its south pole region, NASA scientists report in Science Advances on August 19, 2026. The team, led by planetary scientist Prabal Saxena of NASA's Goddard Space Flight Center, warns that as humans build a permanent presence on the Moon, contamination from visiting crews may become hard to distinguish from ancient lunar chemistry — a concern that extends to Mars.

Bringing microbes is unavoidable: humans host about a million bacteria on every patch of skin the size of a pencil eraser, and these vent from spacesuits and habitats. Robotic spacecraft can be baked at over 400 degrees Fahrenheit to reduce organisms, but astronauts cannot. The team picked five microbes known to endure spaceflight — the fungus Aspergillus niger, Bacillus subtilis, Staphylococcus aureus, Deinococcus radiodurans, and several Fusarium species. Aspergillus niger has been sampled inside the International Space Station and can survive outside it.

The Moon barely tilts, so the Sun at its poles hovers just above the horizon, and elevated terrain casts shadows that stay cold, preserve water and block lethal radiation. Using elevation and temperature data from NASA's Lunar Reconnaissance Orbiter and radiation models, the team simulated three south pole sites — Nobile Rim, Connecting Ridge and De Gerlache Rim — and mapped "survivable niches" ranging from a miles-wide crater floor to an astronaut's boot print. Survival meant staying alive for at least one Earth day, not growing. Aspergillus niger, the most resistant to ultraviolet (UV) radiation, survived even in partly sunlit spots.

"We need to understand what was there before us, because when we go to Mars to search for signs of life beyond our planet, we will want to make sure it's not stuff we brought," said co-author Andrew Needham, an Artemis contamination-control scientist at Goddard. The authors stress there is no evidence the Moon has the ingredients to sustain microbial growth.