Microbes carried to space by human explorers could survive in shaded areas near the moon’s south pole, according to researchers from NASA and the University of Maryland.
Even on the moon, where extreme temperatures and intense ultraviolet (UV) radiation make the surface deeply hostile to life, some microbes from Earth may find temporary refuge. New modeling suggests that shaded pockets near the lunar south pole could allow certain bacteria and fungi to survive for as long as a week.
The NASA-led research, published in Science Advances, could matter as human exploration expands across the moon and eventually reaches Mars.
“When we created lunar maps with purple, red and blue representing different surviving microbe species, we were surprised at how colorfully they turned out,” said study co-author Stefano Bertone, an associate research scientist in the University of Maryland’s Department of Astronomy. “So much for ‘nothing can survive on the moon.’”
Human exploration raises contamination risks
The results underscore how differently microbes can respond to extreme lunar conditions and why their persistence matters for future exploration. As people establish a longer-term presence on the moon and eventually travel to Mars, biological material carried from Earth could make it harder to separate naturally occurring ancient chemistry from contamination introduced by astronauts.
Humans constantly shed microbes into their surroundings. A patch of skin about the size of a pinky nail, for example, can contain roughly a million bacteria. An astronaut’s footprint could therefore leave hundreds of millions of living bacteria behind on the lunar surface. Even with stringent sterilization procedures, “there’s potential for a lot of human contamination of the lunar landscape and, inevitably, the science we do there,” Bertone said.
Understanding and planning for that contamination will be important wherever human missions travel.
“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 Prabal Saxena, a planetary scientist at NASA’s Goddard Space Flight Center who led the new study.
Lunar shadows can shelter microbes
Determining where microbes could persist requires understanding how sunlight reaches the moon’s polar terrain. Because the moon has only a slight axial tilt, the sun remains very low above the horizon near the poles. Even modest rises in the landscape can therefore block sunlight from depressions and low-lying areas, creating cold shadows that can preserve water and reduce exposure to damaging radiation.
Earlier studies concluded that microbial survival was highly unlikely in the places humans have already visited on the moon, primarily near the equator. Those models, however, did not account for how local topography changes environmental conditions. That omission becomes especially important near the lunar poles, where craters, slopes, and other surface features create extensive shadows and where future human exploration is now focused.
“Incorporating the bumps and craters was a key to this study,” Bertone said. “The question was, how well can the moon’s surface topography shield some areas from UV, and is it enough to keep any of our study organisms alive?”
The researchers simulated microbes commonly associated with spaceflight environments and/or human skin in three areas near the lunar south pole that are candidate landing regions for the upcoming Artemis III mission. They constructed detailed environmental maps using elevation and temperature measurements from instruments aboard NASA’s Lunar Reconnaissance Orbiter, then combined those data with models describing how radiation reaches the lunar surface.
Bertone also applied ray tracing, a technique that follows the movement of light and can model effects such as reflection, refraction, soft shadows, and more. He combined it with measurements from the Lunar Orbiter Laser Altimeter—which provides precise topographical information including surface brightness, slopes, and roughness.
“We can trace the path of light from the sun to the moon considering the sun’s position and every bump and boulder that causes a ray to bounce and pivot before reaching the surface,” he explained. “Even what are called permanently shaded regions get light, and therefore UV, indirectly. It’s all extremely nuanced, and this method lets us account for small details.”
Some microbes could persist for days
The simulations revealed “survivable niches” of varying sizes where microbes might persist for as long as seven days. Aspergillus stood out for its resistance to UV radiation and could potentially survive across 15 to 30% of areas that receive at least some sunlight during lunar winter.
Every microbe examined had potentially survivable locations in all three modeled regions. Aspergillus could persist for at least seven days across 3% of the mapped terrain, while all five microbes could potentially survive in portions of the De Gerlache Rim’s permanently shaded regions even after scattered UV light was taken into account.
Survival, however, does not mean the microbes would be able to grow. Organisms persisting under these conditions would remain in a cryptobiotic state, with growth possible only if suitable conditions later developed. There is currently no evidence that the moon provides key requirements for microbial growth and reproduction, including liquid water, which typically requires an atmosphere and moderate temperatures.
Even so, survival has to occur before growth is possible, making microbial persistence an important consideration for both exploration and scientific research, Bertone said.
The moon could test microbial limits
The lunar south pole could also provide researchers with a natural laboratory for studying just how far microbial survival can be pushed. Carefully controlled experiments in shaded terrain could reveal how Earth organisms respond to environmental conditions that are difficult to reproduce accurately in laboratories on Earth.
The researchers next plan to develop more detailed illumination models, use higher-resolution topography, and expand microbial experiments. One approach, called shape from shading, can reconstruct 3D planetary terrain, craters and surface slopes from 2D photographs by analyzing light intensity, shadows and surface angles. Together, these efforts could provide a clearer picture of how human-associated microbes persist after reaching the moon.
“In planning human operations to the moon or elsewhere, we need to know everything we can about what’s been left behind,” Bertone said.
Reference: “Potential survivable niches for microbial life on the lunar south pole” by Prabal Saxena, Stefano Bertone, Heather V. Graham, Natalie M. Curran, Aaron B. Regberg, Andrew Needham, D. E. (Betsy) Pugel and Noah E. Petro, 19 August 2026, Science Advances.
DOI: 10.1126/sciadv.aec0811
This work was supported by NASA (Award Nos. 24-PPR24-0003, 80GSFC24M0006 and 820GSFCS), the NASA Goddard Science Task Group Program and the GSFC Sellers Exoplanet Environments Collaboration.
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