Microbial contamination within spacecraft poses a threat to crew health and operational integrity. Currently, microbial reduction within the International Space Station (ISS) relies on rigorous cleaning, which is time-consuming for astronauts.

In this study, we analyze the ISS microbiome and apply a new antimicrobial polymer coating to evaluate its effectiveness in reducing microbial contamination. The polymer was coated on five different materials representing common objects manipulated by crew members. Six coupons for each substance were placed on six placards at different locations on the ISS, while five placards were left on Earth to accumulate microorganisms through passive and direct transfer.

The study lasted six months and utilized microbial cell culture and genomic analysis to assess bacterial and fungal communities and identify species. Lower than expected microbial loads on ISS surfaces were observed, indicating a reduced need for extensive cleaning.

The polymer coating reduced the surface load of culturable bacteria by 3.16 log10 compared to the uncoated surface. Coated surfaces had less genetic material and lower microbial species richness. Additionally, the polymer coating was proven to be durable and lasted on the surface of the ISS for six months.

This study demonstrates that antimicrobial polymer coatings effectively inactivate microorganisms and remain on surfaces even in zero gravity environments. Its applications could be beneficial in preventing viral and bacterial contamination, and could be used to enhance crew health and maintain spacecraft integrity on long-duration spaceflights. It also produced data that suggests an audit of current ISS cleaning practices may be warranted.

Next-generation space antimicrobials: Assessing microbial activity and decline across the ISSbiorxiv.org

astrobiology, microbiology,