NASA Study: Earth Microbes Could Survive Near the Moon's Shadowed South Pole

NASA scientists say some Earth microbes carried by astronauts could survive for at least one Earth day in the Moon's shadowed polar regions, according to a study published Aug. 19, 2026, in Science Advances. As humans settle the Moon, separating ancient lunar chemistry from contamination matters — a challenge that also applies when missions search Mars for signs of life, researchers said.

The team, led by planetary scientist Prabal Saxena of NASA's Goddard Space Flight Center, first mapped why shadows form near the lunar poles. Because the Moon's axial tilt is slight, sunlight sweeps across the surface nearly level with the horizon, so crater rims, ridges and even small bumps block light from reaching nearby ground, creating pockets that stay extremely cold and shielded from radiation.

Researchers tested five microbes found in spaceflight or on humans — Aspergillus niger, Bacillus subtilis, Staphylococcus aureus, Deinococcus radiodurans and several Fusarium species — for their tolerance to heat and ultraviolet (UV) radiation. They then modeled conditions at three South Pole sites — Nobile Rim, Connecting Ridge and De Gerlache Rim — using elevation and temperature data from NASA's Lunar Reconnaissance Orbiter.

The resulting maps showed "survivable niches" ranging from crater floors several miles wide to spots no larger than an astronaut's boot print. Aspergillus niger, a fungus found aboard the International Space Station, proved the most UV-tolerant of the five — even though it is not usually classified as an extremophile, an organism built to survive extreme conditions — and could persist in some sunlit spots, the study found.

Humans carry roughly 1 million bacteria on every skin patch the size of a pencil eraser, and some escape spacesuits and habitats. NASA sterilizes robotic spacecraft by heating them above 400 degrees Fahrenheit, a method not possible on crewed missions. Co-author Andrew Needham of NASA Goddard said establishing this baseline will help future Mars missions confirm signs of life are not contamination astronauts brought.