The Moon’s south pole may contain small pockets where some Earth microbes could remain alive after being carried there by astronauts or spacecraft. A new Nasa study has mapped parts of the region where five types of bacteria and fungi may withstand lunar conditions for at least a day, with the hardiest organism potentially lasting for a week or more in certain locations. The finding does not mean the Moon can support microbial life as it does on Earth. Instead, it raises a practical problem for future exploration: organisms brought from Earth may persist in places scientists hope to study for their untouched chemical record. With Artemis missions targeting the lunar south pole, understanding where these microbial hitchhikers could survive is becoming increasingly important.
Why Earth microbes survive in some regions of the Moon’s south pole
The Moon is generally regarded as an extremely difficult environment for life. Its surface has no substantial atmosphere, receives intense ultraviolet radiation and experiences severe temperature changes. Yet conditions are not identical everywhere. Around the poles, the Sun stays very low on the horizon, while ridges, crater walls and other terrain can block sunlight from reaching nearby areas. According to the new study published in Science Advances, titled ‘Potential survivable niches for microbial life on the lunar south pole’, these topographical effects create regions with unusually low UV exposure and temperatures that may allow certain microbes to survive.Those differences are especially pronounced in permanently shadowed regions, or PSRs. Some never receive direct sunlight, although a small amount of scattered light can still reach their surfaces. The research team’s calculations found that such areas could be particularly favourable for microbial survival. In one detailed model of De Gerlache’s permanently shadowed region, all five microbes examined were capable of surviving in some locations for longer than a week when scattered ultraviolet light was taken into account.
Which five Earth microbes did researchers study for lunar survival
The researchers examined five types of microbes that are either commonly associated with humans and spacecraft or are already known for unusual resistance. They included Bacillus subtilis, Deinococcus radiodurans, Staphylococcus, Aspergillus and Fusarium. The selection was intended to represent organisms that could plausibly reach the lunar surface during human exploration, rather than an exhaustive survey of everything capable of surviving extreme conditions.The scientists concentrated mainly on ultraviolet radiation and temperature when estimating survival. They compared known microbial tolerance limits with detailed maps of the lunar surface. Data from Nasa’s Lunar Reconnaissance Orbiter were used to model temperatures and illumination, while higher-resolution terrain information helped researchers account for shadows cast by the Moon’s landscape. The study defined survival as remaining viable for at least one Earth day, not continuing to grow or reproduce.
How long could Aspergillus survive in the Moon’s south pole regions
Among the organisms included in the modelling, Aspergillus showed the widest potential survival range. At the Artemis III candidate regions examined around the south pole, the fungus could potentially survive in between 2% and 9% of mapped non-permanently-shadowed terrain during summer, rising to roughly 15% to 30% during winter. The study also found areas in all three examined regions where Aspergillus could potentially remain viable for at least seven days.The other organisms had considerably smaller predicted survival areas. Fusarium showed survival fractions roughly four to seven times lower than Aspergillus, while the corresponding areas for Deinococcus, Staphylococcus and Bacillus were smaller still. The results varied with season and location, with winter generally providing more favourable conditions. At Nobile Rim and Connecting Ridge, some of the most favourable spots could support several of the organisms at the same time.
Why does microbial survival on the Moon not mean the Moon can support life
The study does not suggest that fungi or bacteria are likely to establish growing populations on the Moon. Survival and habitability are very different things. A dormant cell can remain viable without actively reproducing, and the researchers say the present lunar surface lacks conditions thought to be necessary for sustained microbial growth, particularly readily available liquid water.As Nasa scientist Andrew Needham similarly warned, scientists need to establish what was already present before humans arrive, because material carried from Earth could complicate the search for evidence about the Moon’s chemistry or, eventually, life on Mars.The lunar south pole therefore provides an early test of how human exploration changes an extraterrestrial environment, and how carefully scientists will need to track those changes before interpreting what they find.
