The Hawai‘i Space Exploration Analog and Simulation (HI-SEAS) is a Poor Model for Studying International Space Station Microbiome

Abstract

The simulated space research station, HI-SEAS, serves as an experimental setting to replicate long duration space missions on Earth. However, its validity as a comparable Earth-based analog for the microbiota of space-mission environments remains unverified. In this study, the microbial landscape of HI-SEAS was compared with that of the International Space Station using diversity metrics, core microbiome analysis, and indicator species analysis. Two distinct datasets were employed for this purpose—one conducted by Sielaff et al. at the ISS, and the other carried out at the HI-SEAS model. Our findings revealed a significantly higher microbial diversity in the HI-SEAS model than in the International Space Station. Core microbiome analysis revealed no shared microbial species between HI-SEAS and the International Space Station. However, indicator species analysis identified two shared genera and potentially contaminating soil microbial genera in HI-SEAS, posing the question of whether or not HI-SEAS is a truly isolated environment. This study suggests that HI-SEAS is not an accurate Earth-bound model for the microbial landscape of the International Space Station. Future studies with more comparable sampling methods are needed to confirm the findings of this study.