Common Earth microbes hitchhiking on spacesuits and equipment could survive for weeks or months in shadowed niches near the lunar South Pole, raising contamination concerns for future crewed bases, according to a study led by NASA scientists published in Science Advances.
Survival Potential in Lunar Polar Regions
Planetary scientist Prabal Saxena of NASA’s Goddard Space Flight Center led modeling simulations examining five microbial species near three lunar South Pole regions: Nobile Rim, Connecting Ridge, and de Gerlache Rim. According to NASA’s Lunar Reconnaissance Orbiter data and radiation exposure metrics, the models indicate that certain microbes could endure for weeks to months in permanently shadowed craters, particularly during autumn and winter seasons.
Aspergillus niger, a common black mold prevalent in warmer climates and indoor HVAC systems, proved to be the most resilient fungus tested. Astronauts have previously discovered Aspergillus niger inside the International Space Station, and experiments show it can survive outside the station in orbit, according to Aaron Regberg, a geomicrobiologist at NASA’s Johnson Space Center in Houston. The research also evaluated Fusarium, a soil-borne fungus, which showed resilience though not matching Aspergillus.
Did you know? Humans carry an average of 1 million bacteria on each patch of skin the size of a pencil eraser, making crewed contamination of celestial bodies an unavoidable challenge for space agencies.
Bacteria Resilience and Radiation Exposure
Three bacteria species were subjected to the simulated lunar conditions: Deinococcus radiodurans, Staphylococcus aureus, and Bacillus subtilis. According to Saxena, these bacterial strains proved less resilient to ultraviolet radiation than the fungi. Deinococcus radiodurans led the group in endurance, while Staphylococcus aureus and Bacillus subtilis brought up the rear.
While the survival models mapped "survivable niches" as large as crater floors miles wide, organic geochemist and study co-author Heather Graham of NASA Goddard noted that the study focused strictly on cellular persistence rather than growth or reproduction. However, buried cells could potentially remain warm and shielded from radiation, while pockets of liquid water might theoretically support future growth.
Impact on Scientific Operations and Exploration
Both NASA and China are pursuing initiatives to return astronauts to the lunar surface for the first time since 1972, with NASA’s Artemis program specifically targeting the South Pole. Artemis contamination-control scientist for lunar samples Andrew Needham emphasizes that researchers must establish a baseline measurement of terrestrial contaminants before surface science begins.
Contamination threatens to skew scientific analysis of the regolith’s chemical makeup and organic molecules, making it difficult to distinguish ancient lunar geology from Earth-borne hitchhikers. Researchers argue that understanding these microbial limits on the Moon will also inform planetary protection protocols for crewed missions to Mars.
Frequently Asked Questions
Can Earth microbes reproduce on the moon? The study assessed cellular persistence rather than growth or reproduction, though researchers noted that buried cells or potential liquid water pockets could theoretically support organisms under specific scenarios.
Which microbes are most resilient in space environments? Fungi such as Aspergillus niger demonstrated the highest resilience, surviving both in space station exterior experiments and lunar South Pole simulations.
How do microbes reach the lunar surface? Microbes are unintentionally transferred by astronauts via spacesuits, tools, and machines during surface operations.
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