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The International Space Station is Cleaner Than Your Home
등록일 : 2017-06-29 14:08 | 최종 승인 : 2017-06-29 14:08
Anne Taylors

[리서치페이퍼=Anne Taylors 기자]

Photo by NASA / Wikimedia Commons

If there are humans there are microorganisms, especially bacteria.  The International Space Station (ISS) is not omitted from this fact either.

However, the space station is cleaner than most places on earth, so the bacteria doesn't present much of an issue.  Astronauts have regular scheduled cleaning duties along with their other daily tasks.  Any cargo or vehicles carrying cargo are put through a ringer of sanitizing procedures before the scheduled launch, while the crew spends the 10 days leading up to blast off in quarantine.   

Mark Ott, a microbiologist at Johnson Space Center says "Once every three months, we sample from two locations in each module of the U.S.segment of the station."  The Russian space agency Roscosmos which shares the station with the U.S.heavily monitors its segments.What happens is they collect air and surface samples and culture them on plates that have a growth medium, one for bacteria and one for fungi.  Then they return these plates to the ground and when organisms grow from them scientists can identify what it is. 

Basically, the same system is used to handle or prepare drinking water on the station as back on Earth to kill and stop microorganisms from growing.  They also closely monitor the drinking water system regularly.  The monitoring used to be done once a month, but the water always tested so clean scientists decided it was only needed every three months.  Ott says, microbiologically speaking, astronaut's drinking water is essentially cleaner than most anything they drink will drink in the earth's atmosphere.

The ISS has medical requirements for the monitoring of its environment.  The station shows to contain the same microorganisms found in any home or office on the earth.  Scientists maintain that microorganisms are everywhere, however only a few are pertinent medically and only when in the right situation will make a person sick.  The medical staff combats those events by keeping a keen eye out for any issues that may pop up and if so the station gets and extra scrubbing.  The small presence of any organisms is typically not much risk to the astronaut's health, adding "It may be something typically found in a bathroom, for example, but that you wouldn't want in an office space." 

Photo by NASA / Wikimedia Commons

Sometimes they find a microorganism that looks harmful, but then after some scientific DNA testing they realize it is just slightly different and of no worry, however, it is still a difficult task to distinguish these when they are of a closely related species

This happened recently when investigation verified 11 strains of bacterium.  The bacterium was of the Bacillus anthracis, cereus, thuringiensis group, or the Bacillus cereus group which had been found previously in 2014.  This huge family of bacteria is known to have bad bugs, and is very common around humans on earth, which meant the findings on the space station are not out of the ordinary.  Researchers were able to identify the individual species of the samples and had found some of them to be a very close match to Bacillus Anthracis, using DNA hybridization.  However, none of them displayed the physical traits or more importantly the toxin-producing plasmids that would deem them a potential risk.  The space station is continually being researched to find any type of organisms growing there.

Bacillus anthracis by CDC / Wikimedia Commons

Several different studies with differing techniques have been conducted as far as microbial environment goes on the space station.  The studies have a different agenda compared to NASA's regular monitoring, although they can at times support the goals of the program in general.

Ott says "We should be investigating new and different ways of monitoring spacecraft for microorganisms, but we must be careful when we interpret the results.NASA has and continues to closely monitor the International Space Station to ensure it provides a safe and healthy environment for our astronauts."

An ongoing study of the Impact of Long-Term Space Travel on the Astronauts' Microbiome, Microbiome for short was started in 2013 which investigates the effects on the immune system of humans, and also their microbiome.  Microbiome is the whole collection of microbes living inside a human body at any time.  Periodic samples are retrieved off of different areas of astronauts' bodies, also they get samples from around the space station which are sent back to a lab on Earth for analysis.

NASA and the Sloan Foundation have become partners for a program supporting microbiome research of a built environment and or the microbial ecosystem of man-made environments and their main subject is the space station.  Five post-doctoral fellowships have been awarded to run experiments with NASA's archive containing over a decade's worth of collected microbes from NASA's space station modules.  The fellowship experiments are aimed at better understanding how microbial communities colonize, adapt, and evolve on the space station, which is necessary because where humans go microorganisms go.

ISS Configuration by NASA / Wikimedia Commons

[리서치페이퍼=Anne Taylors 기자]
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