Research indicates that the space station is excessively clean.

      Recent research suggests that the International Space Station (ISS) might benefit from a bit more dirt. While a pristine environment seems ideal for astronauts spending six months there, excessively clean conditions may negatively impact their health.

      Astronauts have long dealt with immunity problems, skin rashes, and other inflammatory issues while on the ISS, and new findings indicate that these issues could be linked to the station's overemphasis on sterility.

      Published this week in the journal Cell, the study revealed that the ISS has a significantly lower diversity of microbes than human-made environments on Earth, with most organisms introduced by astronauts themselves. The researchers suggest that astronauts' health could improve by incorporating more Earth-based microbes into the station.

      "Future constructed environments, including space stations, could benefit from intentionally promoting diverse microbial communities that more closely resemble the natural microbial exposures found on Earth, rather than depending on highly sanitized areas," stated Rodolfo Salido from the University of California, San Diego, who co-authored the study.

      The research involved ISS astronauts swabbing 803 surfaces on the station. The samples were then analyzed in Earth-based laboratories, allowing scientists to identify the bacterial species and chemicals present on the ISS.

      The study found that human skin was the primary source of microbes on the station, while traces of cleaning products and disinfectants were also widespread. Interestingly, different microbial communities and chemical compositions were discovered in various modules of the station, often reflecting the module's usage. For instance, dining areas had more food-related microbes, while bathrooms showed higher levels of urine- and fecal-associated microbes and their metabolites.

      However, the researchers noted a scarcity of free-living microbes typically found in soil and water. Introducing these microbes to the ISS could potentially enhance astronaut health without compromising cleanliness.

      "There’s a significant difference between exposure to healthy soil from gardening versus being surrounded by our own waste, which can happen in a completely enclosed environment lacking healthy microbial sources from outside," remarked Professor Rob Knight, a microbiologist at the University of California, San Diego, and a senior author of the study.

      Salido added, "If we truly want life to thrive beyond Earth, we cannot merely take a tiny branch of the tree of life and send it into space, hoping it will succeed. We must consider what other beneficial companions we should accompany astronauts with to cultivate sustainable and advantageous ecosystems."

      The findings may also have relevance for individuals working and living in similarly sterile conditions on Earth, according to the researchers. The ISS is maintained in a meticulous condition through various methods, including regular vacuuming, which in microgravity can appear quite entertaining.