Regolith as a Refuge: How Bacteriophage Qβ Survived on Mars

Viruses are among the simplest biological entities capable of replication. Their robustness and adaptability make them relevant not only to terrestrial ecosystems but also to astrobiological exploration. As durable entities, they may persist in environments far harsher than those tolerable to cellular life and are likely candidates for forward contamination. To assess their relevance in planetary protection and as potential biomarkers, we investigated the preservation of bacteriophage Qβ, an RNA virus, in Mars-analog environments using two commercial Martian regolith simulants: MGS-1 and MMS-2. MMS-2, enriched in iron oxides, exhibited higher oxidative potential than MGS-1, which is mainly composed of basaltic material. Viral survival was assessed across variables including time, temperature, concentration, and particle size. Our results show that inactivation in MGS-1 was primarily driven by adsorption, while in MMS-2 it was dominated by chemical oxidation. MGS-1 provided a more protective matrix, mitigating freeze-induced damage and shielding desiccated viral particles from UV-B and UV-C radiation. These findings highlight the importance of mineral composition in modulating viral persistence and suggest that regolith may act as both a barrier and a refuge. Understanding virus–mineral interactions is essential for assessing biosignature preservation, planetary protection, and the potential roles of viruses in the evolution and survival of life beyond Earth. Regolith as a Refuge: Differential Survival of Bacteriophage Qβ in Mars-Analog Environments, biorxiv.org Astrobiology,