A new study conducted by an astrobiologist has discovered just how filthy the International Space Station truly is, and some of the findings are highly unusual.
Many people may have wondered just how sanitary conditions are within a confined space station, that doesn’t get fresh air for months or years.
Back in June, astronaut Scott Kelly has compared the smell in this sealed environment with that of antiseptic mixed with garbage, but still insisted that it didn’t actually smell bad. In comparison, he revealed that space had its own particular scent, like that of burning metal.
Despite these quaint pieces of information, little was known about the bacteria that live on the International Space Station: if it’s less prevalent than on Earth, if it’s more dangerous, if it’s thriving or barely surviving etc.
Therefore, it felt imperative to carry out such an analysis, especially in preparation of NASA’s journey to Mars, and a team led by astrobiologist Kasthuri Venkateswaran decided to take the plunge.
Researchers at NASA’s Jet Propulsion Laboratory, in Pasadena, California performed a DNA analysis on a HEPA filter that had been employed on the ISS for 40 months, in order to identify bacteria in recycled air.
Furthermore, they conducted similar molecular tests on 2 bags of dust collected by the spacecraft’s vacuum cleaner, to detect potential pathogens from the ISS surfaces.
Afterwards, the scientists focused on investigating NASA cleanrooms on Earth, which are used in order to prevent bringing germs and other contaminants to space.
The results were eventually published in the journal Microbiome. Unsurprisingly, it was discovered that there were much more numerous germ populations associated with human skin on the ISS than in NASA cleanrooms, since the spacecraft is much more extensively used.
However, the researchers believe that the ISS is actually much more hygienic than regular individuals might expect.
“The ISS is a unique built environment. People assume it’s filthy, but it’s not. It’s many, many times cleaner than your bathroom at home”, explained Venkateswaran.
For example, researchers detected the presence of Actinobacteria, which is the most prevalent phylum on the skin microbiota.
In the vacuum bag samples, astrobiologists identified Staphyloccocus, another Gram-positive bacteria, found on the skin and mucous membranes.
Unlike Actinobacteria however, Staphyloccocus is much more dangerous, being one of the main causes of food poisoning, toxic shock syndrome, conjunctivitis and community-acquired meningitis.
It was determined that in fact the filters had collected a bacterial population that was 75 smaller than the one encountered in vacuum cleaners, which suggests that the air within the International Space Station is much more hygienic than the surfaces.
When comparing the prevalence of germs in ISS vacuum dust with that of microbes found in carefully controlled cleanrooms, it was discovered that aboard the spacecraft the bacteria population is twice is numerous.
Therefore, it appears that when ranking these environments based on cleanliness, HEPA filters allow air on ISIS to be the most sanitary, NASA cleanrooms are half as salubrious, whereas spacecraft surfaces are the most contaminated.
Researchers also discovered microbial populations on board which weren’t found in cleanroom facilities. Those were Propionibacterium, common skin-asociated bacteria found in sweat glands, sebaceous glands and other portions of the skin.
Now, the aim is to analyze if these microbes could damage equipment or pose any health risks to astronauts as a result of being in an confined environment, given that zero gravity might influence their prevalence and virulence.
This is especially important since spacecraft crew might be more immuno-compromised due to their unusual living conditions, which include higher levels of carbon dioxide and space radiation.
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