Microbes might get freeze-dried on the moon’s south pole

Certain hardy microbes could survive on the moon.

Previous lunar missions explored the moon’s equator, where high ultraviolet radiation and daily temperature swings make the surface inhospitable to life. But Artemis IV, set to launch in 2028, will land a crewed mission on the moon’s south pole. The pole’s unique topography could sustain some bacteria and fungi, meaning future missions should carefully consider the risk of contamination in the region, researchers report August 19 in Science Advances.   

At the poles, sunlight hits the moon’s surface at a much lower angle than at the equator. This creates permanently shadowed regions with temperatures as low as -200° Celsius and little UV radiation. The conditions aren’t too different from those needed to freeze-dry microbes like baker’s yeast, says Heather Graham, an organic geochemist the NASA’s Goddard Space Flight Center in Greenbelt, Md.

Graham and her colleagues at NASA investigated three types of bacteria and two types of fungi commonly associated with humans. These microbes have previously hitched a ride on spacesuits, inside payload capsules and even on the outside of the International Space Station. The team found that all five microbes could survive for at least 24 hours in certain areas of the moon’s southern pole.

The hardiest microbe was Aspergillus niger, a fungus commonly found in showers and water heaters. The fungus has thick cell walls and the ability to repair DNA even in a dormant state. In some areas, the researchers estimate Aspergillus could survive for more than a week.

But surviving is not the same as thriving. It’s unlikely that these microbes could reproduce or grow in these conditions. But even dead or dormant microbes could pose a threat to lunar research. Their proteins and other chemical signatures would still show up in samples of the moon’s surface and throw off measurements.

The study’s insights will inform decontamination protocols for Artemis IV and other crewed missions. Mars provides a more hospitable environment for microbes than the moon, Graham says, so the risk of life transfer there will be much higher. “The better we get at clean exploration on the moon, the much better position we’ll be in on a place like Mars.”