NASA-led researchers simulating conditions at the Moon’s South Pole have found that five common Earth microbes could survive for weeks to months in permanently shadowed craters. The findings raise contamination concerns for upcoming missions, while offering a natural laboratory to study extreme survival.
Surviving the Lunar South Pole: Which Microbes Can Endure
The Moon is typically characterized as a hostile, barren environment plagued by intense ultraviolet radiation, a natural vacuum, and extreme temperature swings. However, new research published in Science Advances reveals that certain sheltered areas near the lunar south pole may offer conditions where microorganisms could survive, at least for days or weeks. The study analyzed five common species of fungi and bacteria that frequently hitchhike aboard crewed spacecraft and space stations.
The tested organisms included three bacterial species — Bacillus subtilis, Staphylococcus aureus, and Deinococcus radiodurans — alongside two fungi, Aspergillus niger and several species of Fusarium. Planetary scientists modeled how these organisms would fare across three specific landing candidate regions: Nobile Rim, Connecting Ridge, and de Gerlache Rim. The simulations factored in elevation data and surface temperatures collected by the Lunar Reconnaissance Orbiter alongside radiation maps.
The results showed clear distinctions in hardiness. The two fungal species proved significantly tougher than the bacteria. Aspergillus niger emerged as the most resilient organism tested, capable of surviving in areas with partial sunlight exposure. Meanwhile, the bacteria brought up the rear because ultraviolet radiation rapidly degraded them, though Deinococcus radiodurans outperformed Staphylococcus and Bacillus.
“The bacteria we examined were less resilient to ultraviolet radiation and consequently had less survival, with Deinococcus leading the way and Staphylococcus and Bacillus bringing up the rear.”
Prabal Saxena, NASA Goddard Space Flight Center planetary scientist
Shadowed Craters and Micro-Niches That Protect Life
The survival of these organisms hinges directly on how sunlight interacts with the lunar poles. Because the Moon features a very small axial tilt, the Sun hovers just above the horizon, skimming the surface like a flashlight resting on a table. This geometry casts deep, permanent shadows across crater floors, mountains, and ridges, effectively blocking both lethal UV radiation and intense daytime heat.
While lunar daytime temperatures can reach a scorching 260 degrees Fahrenheit (127 degrees Celsius) on sunlit surfaces, permanently shadowed regions stay bitterly cold, plunging to –330 degrees Fahrenheit (about –201 degrees Celsius). In these cold pockets, microorganisms enter a dormant sleep state rather than dying instantly. Furthermore, researchers noted that human exploration itself creates unexpected shelters.
“Because the sun never gets that high in the sky in these polar regions, because the moon is not tilted like the Earth is, you can have an astronaut footprint create a mini PSR.”
Prabal Saxena, NASA Goddard Space Flight Center planetary scientist, via Reuters
The researchers emphasized that the study evaluated cellular persistence rather than growth or reproduction. None of the tested microbes grew actively in the simulations. However, organic geochemist Heather Graham pointed out that subsurface burial could keep cells warm and protected from radiation, while potential pockets of liquid water might eventually enable active biological processes.
Contamination Stakes for Artemis and Beyond
As space agencies plan crewed returns to the Moon for the first time since 1972, these findings complicate planetary protection protocols. Carrying microbes is biologically unavoidable, as human skin hosts roughly 1 million bacteria on an area the size of a pencil eraser. These organisms inevitably vent from spacesuits and habitats during surface operations.
This accidental hitchhiking creates a dual challenge for scientists preparing for the upcoming Artemis III mission. First, introduced microorganisms could corrupt ancient lunar chemistry, making it difficult to distinguish native materials from human contamination. Second, if astronauts intend to utilize local resources such as subsurface water ice or establish long-term bases, understanding imported organic matter becomes critical.
“A lot of what we’re trying to do with Artemis is to understand the moon, its history, its connections to the Earth,”
Heather Graham, NASA Goddard Space Flight Center organic geochemist
Yet researchers also see a silver lining. By acknowledging that human-related microbes can persist in these polar environments, scientists gain a unique natural laboratory to test the extreme limits of biology. Whether this microbial resilience will interfere with future scientific discoveries or serve as an unexpected baseline for astrobiology remains an open question as launch dates draw closer.
