Lunar missions may contaminate the moon with hardy Earth microbes

New research indicates that the moon may harbor conditions that are more favorable for microbial life than previously assumed. This revelation heightens the potential for contamination during future lunar missions, which aim to reinforce our understanding of the moon’s geological and possibly biological history.

Planetary protection measures are critical for safeguarding other celestial bodies against contamination by terrestrial microorganisms. Such contamination could distort our knowledge of life elsewhere in the solar system.

The absence of Earth-like protections, such as an atmosphere and magnetic field, means the lunar surface experiences harsh conditions, including high-energy cosmic radiation, extreme temperature variations, and intense ultraviolet radiation. Historically, these factors led scientists to believe the moon is effectively devoid of life.

Consequently, lunar exploration missions are classified under low-risk categories of planetary protection, similar to lunar bodies such as comets and Venus.

However, recent findings from researchers, including Stefano Bertone at NASA’s Goddard Space Flight Center, suggest that certain extremophiles could endure several days—potentially even longer—on the moon’s surface. Their findings raise serious concerns about contamination of lunar regions, particularly the poles, earmarked for exploration by NASA’s Artemis missions.

“As we prepare for our return to the moon, it’s imperative that we analyze the impact of our presence there,” Bertone stated at the Europlanet Science Congress (EPSC) held in Helsinki, Finland, on September 12.

In their study, Bertone and his colleagues tested five resilient microbial species, including black mould (Aspergillus niger) and bacteria such as Staphylococcus aureus and Bacillus subtilis, to determine their resistance to UV radiation. They then synthesized environmental data based on UV intensity, sunlight exposure, and temperature shifts from lunar surface conditions to create a survival map for these organisms.

All specimens were shown to endure in illuminated regions of the moon, standing in stark contrast to the permanently shadowed areas. Notably, black mould demonstrated the longest viability, remaining active for up to seven days in suitable conditions, thereby highlighting the regions at risk for contamination from Earth-based microorganisms.

“This study is pivotal. If there is potential for contamination, decisive actions must be taken, though such measures could have significant economic implications,” remarked Stas Barabash from the Swedish Institute of Space Physics. For instance, enhanced sterilization protocols for equipment may raise operational costs for upcoming missions.