Assessment of Microbial Habitability Across Solar System Targets

TL;DR

This paper develops a new index to evaluate the habitability of solar system bodies for microbes, prioritizing targets like Europa, Mars, and Enceladus based on environmental suitability.

Contribution

It introduces the Microbial Habitability Index (MHI), a novel qualitative method for ranking planetary bodies by their potential to support microbial life.

Findings

Europa, Mars, and Enceladus identified as top candidates for microbial habitability.

A planetary environmental database was created to support habitability assessment.

The MHI provides a comparative metric based on environmental factors and Earth analogues.

Abstract

With a fleet of exploratory space missions on the horizon, the study of target specific biospheres is crucial for accurately determining the probability of the existence of microbial life on various planetary bodies and prioritising targets accordingly. Although previous studies have compared the potential habitability of objects in our solar system by bulk characteristics, it is less common that precise qualitative methods are developed for ranking candidates hospitable to microbial life on a local environment basis. In this review we create a planetary environmental database and use it to motivate a list of primary habitability candidates and essential criteria for microbial survival. We then propose a new method, the Microbial Habitability Index (MHI) which uses a metric of microbial survival factor values in target environments compared with appropriate Earth analogues to assess their potential for life. We arrive at a selection of eight primary candidates and from this set conclude that Europa, Mars, and Enceladus have the highest potential for facilitating microbial survival.