Potential Survivable Niches for Microbial Life at the Lunar Poles

Environmental conditions on most of the lunar surface are incredibly harsh for the survival of most microbial life, due to a combination of high doses of ultraviolet (UV) radiation, energetic particle radiation, high temperatures and desiccation. This is true in equatorial regions, where all previous crewed exploration of the Moon has taken place. However, the extent of these conditions at high latitude regions has not been examined. This study includes shielding by topography to understand the interplay between surface roughness and exposure to harmful radiation. This is particularly relevant at the lunar poles, where maximum Sun elevation is limited to a few degrees above the horizon. We will discuss recent analyses that consider data describing the resilience of common microorganisms and remote sensing data of the lunar surface from the Lunar Reconnaissance Orbiter (LRO), to determine potential survivability niches for several microbial cells at the lunar poles.

Ultraviolet radiation turns out to be the main “microbe killer” at the lunar poles for the set of specific common and extremophilic microbes under consideration. We used recent models of solar fluxes at UV wavelengths to assess the existence of favorable locations in the lunar southern polar regions. First, we modeled regional UV fluences at the surface based on available fractional solar visibility maps. Then, we used available altimetry-based Digital Elevation Models (DEM) along with ray-tracing techniques to carefully model ground conditions at specific locations. Combined with LRO’s Diviner temperature measurements, our results suggest that the lunar south pole possesses significant regions of lower temperatures and ultraviolet light flux.

By comparing these surface conditions to survivability data of specific microorganisms, we find that certain regions of the lunar poles may be less hostile to survival of microbial life than previously assumed. We find significant areas in the lunar south pole that likely possess surface conditions amenable to the survival of several common microbial cells over time-scales relevant to future lunar exploration. We will discuss the implications of this potential survivability given the numerous plans for manned exploration of the lunar south pole in the near future.