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NASA scientists have found that some microbes carried into space by human explorers may be capable of surviving in sheltered, shadowed areas near the Moon’s South Pole, raising concerns about contamination as human activity on the lunar surface expands.
The findings, published Aug. 19, 2026, in Science Advances, highlight the need to understand how long Earth-based microbes can persist in the Moon’s extreme environment. Researchers say contamination from astronauts could make it more difficult to distinguish the Moon’s ancient chemical signatures from material introduced by humans.
The issue will become even more important as future missions search for signs of life on Mars, scientists said.
“Humans are natural explorers, and with them come their voices, their memories … and their microbes,” said Prabal Saxena, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led the study.
Microbes can hitchhike into space
Humans inevitably carry microorganisms with them. On average, about 1 million bacteria live on an area of skin roughly the size of a pencil eraser. Some of these organisms can escape from spacesuits and habitats and enter the surrounding environment.
This presents a challenge for scientists studying the Moon’s ancient geology and searching for possible evidence of biology. However, researchers say the lunar environment could also provide a natural laboratory for studying the limits of microbial survival.
Carefully monitored, permanently or long-shadowed regions near the lunar South Pole could help scientists determine how Earth microbes respond to conditions that are extremely difficult to reproduce on Earth.
Before conducting such experiments, researchers say they need to establish a clear baseline of the biological and chemical material that humans introduce to the Moon.
“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 Andrew Needham, a NASA Goddard-based co-author and Artemis contamination-control scientist for lunar samples.
Some microbes are highly resilient
Even strict sterilization procedures cannot eliminate every hardy microorganism.
One example is Aspergillus niger, a fungus commonly found in warm, humid environments, including bathrooms and heating, ventilation and air-conditioning systems.
Astronauts have previously collected samples of the fungus aboard the International Space Station, while earlier experiments have shown that it can survive outside the station as well.
Aspergillus niger was among five microbes examined in the new study because of its demonstrated ability to withstand harsh spaceflight conditions.
The researchers say determining which organisms could survive on the Moon will be important for both planetary protection and future scientific research as humanity prepares for a more permanent presence beyond Earth.
