Fungal spores survive simulated Mars mission conditions

Aspergillus calidoustus is a drug-resistant pathogen that can cause severe infections in immunocompromised individuals. Researchers warned that the fungus could potentially hitch a ride to Mars and become an invasive species. Earth microbes on Mars could be mistaken for alien lifeforms, throwing off research, according to the study's implications.

The researchers collected fungal microbes from NASA's cleanrooms used for the Mars 2020 program. They generated conidia from 27 fungal strains isolated from assembly facilities of the Mars 2020 program. Only the combination of extreme low temperature and high radiation killed the fungus, the researchers said.

Kasthuri Venkateswaran, study leader at NASA's Jet Propulsion Laboratory, said in a press conference: "This does not mean contamination of Mars is likely, but it helps us better quantify potential microbial survival risks." He added: "Microorganisms can possess extraordinary resilience to environmental stresses." Venkateswaran noted that "microbial survival is not determined by a single environmental stress but rather by combinations of stress tolerance mechanisms." He concluded: "Together, these investigations help refine NASA's planetary protection strategies and microbial risk assessment approaches for current and future space exploration missions."

The study was published in the journal Applied and Environmental Microbiology. It remains unclear how likely it is that Aspergillus calidoustus actually contaminates Mars, and what specific mechanisms allow the fungus to survive extreme conditions.