NASA says the International Space Station is 'too clean'

Astronauts have long dealt with rashes and immune hiccups while circling above Earth. Certain studies have implicated changes in their immune system when they leave our planet’s usual air, water, and soil behind.

Recent research work, published in the journal Cell, suggests that a super-sanitized spaceship may be one reason for these issues.

After carefully sampling the International Space Station (ISS), co-first authors Rodolfo A. Salido and Haoqi Nina Zhao from the University of California, San Diego (UC San Diego), and their team, found that the station lacks many natural microbes that people regularly encounter on Earth.

Space and Earth’s microbes

Many scientists think that a broad range of tiny organisms keeps our bodies well-tuned. If people spend months in a place with only human-associated germs, they might miss out on some beneficial exposure.

Soil-based microbes, for example, have been linked to healthy immune responses in children who grow up around farmland.

“We noticed that the abundance of disinfectant on the surface of the International Space Station is highly correlated with the microbiome diversity at different locations on the space station,” said Zhao.

When the station is scrubbed and disinfected often, fewer natural bacteria remain. 

Space microbes and immunity

Researchers involved in human spaceflight have explored how microgravity can affect the immune system.

The finding that the ISS carries fewer types of microbes than typical Earth buildings caught people’s attention. 

“Future built environments, including space stations, could benefit from intentionally fostering diverse microbial communities that better mimic the natural microbial exposures experienced on Earth, rather than relying on highly sanitized spaces,” said Salido.

The authors pointed out that this goes beyond just avoiding harsh cleaning products.

They suggest that introducing certain environmental organisms might help astronauts fight off skin irritations and general inflammation.

Over-sanitized space stations

Those involved in the study note that the ISS samples had very few outdoor microbes. This could resemble hospitals on Earth or isolated labs, where constant sanitizing also leads to microbial simplicity.

Fewer types of organisms in these spaces may be one factor behind increased inflammatory problems.

Although more data is needed, it sparks new conversations about designing cleaner areas without wiping out helpful microbial players.

Implications beyond orbit

This approach might be valuable on Earth too. Buildings and hospitals could theoretically benefit from thoughtfully boosting their microbial variety.

That might mean adding plants, soils, or materials that bring in carefully chosen germs, as long as safety is not compromised.

Some public health experts think that being exposed to wider microbial communities can keep immune systems from going into overdrive and causing allergic or inflammatory symptoms.

Although not everyone agrees on the best approach, researchers see an interesting path forward in bringing carefully selected microbes into sterile settings.

Future space stations and microbes

It is not enough to shovel in random dirt, of course. Scientists are careful to emphasize that it should be done safely.

They are working on better ways to track how different bacterial strains could help or harm people in closed environments.

Future spacecraft might feature “green zones” or living walls that deliver healthy microbes while staying free of pathogens.

Some labs are also working on specialized disinfectants that target harmful microbes while leaving neutral or beneficial ones alone.

It is a big shift from the traditional “kill everything” mentality, but it shows promise in places that need a delicate balance.

Connections to astronaut well-being

Space agencies have monitored astronaut health in orbit for decades. More subtle aspects, including changes in crew immune responses, continue to draw attention.

If steering the microbial environment helps reduce rashes or other troublesome symptoms, that might improve quality of life in cramped cabins.

The growing discussion around how “dirty” or “clean” a craft should be will likely influence spacecraft design as humans consider longer missions.

For those headed to the Moon or Mars, a more natural microbial environment might be worth trying.

The study is published in Cell.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–