The International Space Station may lack the microbial diversity needed for optimal astronaut health, according to a recent study, suggesting it could benefit from being “dirtier.”

Astronauts stationed on the ISS often face issues with their immune systems, skin health, and other ailments.

This could be attributed to the station’s limited variety of microbes compared to Earth, as indicated by new research.

The microbes present are primarily those introduced by humans, leading researchers to propose that introducing more environmental microbes to the space station could be beneficial for astronaut health.

This situation is likened to the positive effects of gardening, which has been shown to enhance people’s immune responses.

“There’s a significant distinction between being exposed to beneficial soil through gardening and existing in a confined space with no new contributions of healthy microbes from the environment,” explained Rob Knight from UC San Diego.

During the study, scientists collaborated with astronauts to collect samples from 803 surfaces aboard the ISS—approximately 100 times more than in previous surveys.

3D maps were created to illustrate the sampling locations, the variety of microbes identified, and their potential interactions with the station’s chemical composition.

The majority of microbes isolated were from human skin, with various cleaning agents also present throughout the facility.

The analysis revealed that the microbial diversity aboard the ISS is significantly lower than what is found on Earth, resembling other extremely sterile environments such as hospitals.

This research is detailed in the paper, ‘The International Space Station Has a Unique and Extreme Microbial and Chemical Environment Driven by Use Patterns,’ published in the journal Cell.