Microbes May Thrive in the Moon’s Shadow: Unveiling the Secrets of Lunar Survival

Lunar Shadows and Microbial Survival Niches in the South Polar Region

Planetary scientist Prabal Saxena led a team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, using elevation maps and temperature data from the Lunar Reconnaissance Orbiter to simulate conditions at potential Artemis III landing sites. The computer models identified several potentially survivable niches in the Moon’s shadowed polar regions. According to the study, all five tested microbes could remain dormant for at least 24 hours under these conditions. The study defines survival as an organism staying alive for at least one Earth day, though it does not mean the microbes can grow or reproduce.

Sunlight behaves uniquely at the lunar poles due to the Moon’s very small axial tilt. When viewed from the poles, the Sun appears to hover just above the horizon, skimming the surface like a flashlight lying on a table. Elevated parts of the surface, such as crater ridges, mountains, and small bumps, block light from reaching low-lying terrain. This produces pockets of shadowed areas that remain extremely cold, preserve water, and shield fragile molecules.

Microbial Hitchhikers and Artemis Contamination Risks

Bringing microbes along on space missions is unavoidable, as humans have an average of one million bacteria living on each patch of skin the size of a pencil eraser, which vent from spacesuits and habitats. Andrew Needham, an Artemis contamination-control scientist for lunar samples at NASA Goddard and a co-author of the paper, noted that researchers need to establish a baseline measurement of what contaminants humans bring. “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,” Needham said.

Even dead or dormant microorganisms could complicate the study of lunar soil by contaminating samples and making it difficult to distinguish natural lunar chemistry from material introduced by humans. While NASA often reduces biological contamination on robotic spacecraft by baking them to temperatures above 400 degrees Fahrenheit, that approach is not possible with crewed missions. As a result, microbial contamination takes on new meaning as human activity on the Moon increases.

Unexpected Resilience of Spaceflight Fungi and Bacteria

The research examined five common spaceflight microbes, including the human skin bacterium Staphylococcus aureus and the fungus Aspergillus niger. According to the findings, Aspergillus niger could potentially survive in lunar polar conditions for up to a week. The fungus commonly grows in warm, humid places like bathrooms and HVAC systems, and astronauts have sampled it inside the International Space Station, with experiments showing it can survive outside the station as well.

Aaron Regberg, a geomicrobiologist at NASA’s Johnson Space Center in Houston and a co-author of the study, expressed surprise that such microbes could endure exposure on the exterior of the space station. These species are typically not considered extremophiles capable of withstanding harsh conditions like the vacuum of space. “I would have expected these microbes to have dried out,” Regberg said. Despite the challenges, the researchers suggest the Moon could serve as a valuable natural laboratory to test the real-life limits of microbial survival in an environment that cannot easily be reproduced on Earth.

Frequently Asked Questions

Can Earth microbes grow and reproduce on the Moon?

No. The study defines survival as staying alive in a dormant state for at least 24 hours to a week, but the extreme conditions do not allow these organisms to grow or reproduce.

Which microbes were tested in the NASA study?

Researchers examined five common spaceflight microbes, including the human skin bacterium Staphylococcus aureus and the fungus Aspergillus niger.

Why are scientists concerned about lunar contamination?

Microbial material carried by astronauts can persist in shadowed polar regions, complicating the study of lunar soil and making it harder to distinguish natural lunar chemistry from human-introduced material.

How does sunlight reach the Moon’s South Pole?

Due to the Moon’s small axial tilt, the Sun hovers just above the horizon, allowing elevated terrain to cast shadows over low-lying pockets that remain permanently dark and cold.