Scientists at NASA’s Jet Propulsion Laboratory have found that a fungus commonly found in spacecraft cleanrooms can survive the combined stresses of space travel to Mars, challenging assumptions about planetary protection.
How the fungus withstands Mars-like conditions
Researchers tested 27 strains of Aspergillus calidoustus, a filamentous fungus known as a conidial fungus, isolated from cleanrooms during preparations for the Perseverance rover mission after decontamination procedures. They exposed the fungal spores, or conidia, to low temperatures, ultraviolet and ionizing radiation, low pressure, and Martian regolith. The spores withstood these individual extremes, with survival depending on the combination of factors rather than any single stressor. Only the combination of very low temperature and high radiation proved lethal to the fungus.
Why this matters for planetary protection
The findings suggest that current spacecraft decontamination protocols may not eliminate all microbial threats, as even complex eukaryotic organisms with nucleus-enclosed cells can persist through all stages of a Mars mission—from preparation to surface exploration. This connects to prior research showing moss spores surviving nine months on the International Space Station’s exterior, indicating that compact life forms possess exceptional resilience in space environments. Planetary protection efforts aim to prevent forward contamination of Mars with Earth microbes, which could interfere with the search for native Martian life.
What does this mean for future Mars missions?
Future missions may need to reassess sterilization techniques to ensure they effectively target resilient fungal spores, as current methods might not eliminate organisms capable of surviving transit and surface conditions on Mars.
How does this relate to previous space microbiology research?
This study builds on earlier findings, such as moss spores surviving space exposure, demonstrating that eukaryotic microorganisms can endure spaceflight stresses, which has implications for understanding life’s limits in extreme environments and the robustness of planetary protection measures.