Fungal Spores From NASA Cleanrooms Survive Simulated Mars and Space Travel Conditions

by Clarence Oxford
Los Angeles CA (SPX) Apr 23, 2026
Scientists have long recognized the resilience of fungi, but a new study demonstrates that certain strains may be capable of surviving every stage of a mission to Mars - from spacecraft assembly through the journey to the Martian surface.

Researchers isolated fungal microbes from NASA cleanrooms, the controlled facilities used for the assembly, testing, and launch of spacecraft. These fungi had persisted in the cleanrooms despite standard decontamination procedures. When the researchers subjected asexual reproductive spores called conidia - grown from those fungal strains - to simulated conditions of space travel and Mars, including low temperature, ultraviolet and ionizing radiation, low atmospheric pressure, and exposure to simulated Martian regolith, the conidia of the fungus Aspergillus calidoustus survived. Only the combination of extreme low temperature and high radiation together proved lethal.

The study, published in Applied and Environmental Microbiology, is the first to show that microbial eukaryotes - organisms with a nucleus, such as fungi - could potentially persist through every phase of a Mars mission. "This does not mean contamination of Mars is likely, but it helps us better quantify potential microbial survival risks," said study leader Kasthuri Venkateswaran, Ph.D., a former Senior Scientist in the Biotechnology and Planetary Protection Group at NASA's Jet Propulsion Laboratory. "Microorganisms can possess extraordinary resilience to environmental stresses."

Current planetary protection decontamination strategies focus largely on bacteria. The study points out a significant gap: fungi isolated from spacecraft-associated environments have only recently been identified as a concern, and germicidal techniques are not routinely assessed against them. "Microbial survival is not determined by a single environmental stress but rather by combinations of stress tolerance mechanisms," Venkateswaran said.

For the experiments, the team generated conidia from 27 fungal strains isolated from assembly facilities used in NASA's Mars 2020 program, which delivered the Perseverance rover to Mars. They also included two reference organisms - bacterial and fungal - known for high radiation tolerance. The conidia were then subjected to each of the harsh environmental stressors individually and in combination.

A. calidoustus, isolated directly from NASA cleanrooms, emerged as the standout survivor across the test conditions. Its ability to tolerate the extreme clean environments of spacecraft facilities, endure spaceflight, and persist on robotic systems operating on the Martian surface makes it, the researchers conclude, a strong candidate for a microbe capable of inadvertent planetary transfer.

The findings build on earlier work identifying bacteria and fungi on spacecraft surfaces after decontamination. "Together, these investigations help refine NASA's planetary protection strategies and microbial risk assessment approaches for current and future space exploration missions," Venkateswaran said.

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