Cosmonauts discover bacteria on ISS exterior

Earthly origin is almost impossible to rule out.
By Laurel Kornfeld | Dec 01, 2017
Russian cosmonauts on the International Space Station (ISS) discovered living bacteria in samples taken from the exterior of their module during recent spacewalks.

Anton Shkaplerov, a cosmonaut who served on two previous ISS missions and is set to embark on a third, which he will head, in December, told the Russian news agency TASS that living bacteria "from outer space" were found in materials collected on the outside of the Russian module via cotton swabs.

The swabs were subsequently sent back to Earth for analysis.

"And now, it turns out that somehow these swabs reveal bacteria that were absent during the launch of the ISS module. That is, they have come from outer space and settled along the external surface. They are being studied so far, and it seems they pose no danger, Shkaplerov told the news agency.

This is not the first time cosmonauts have found bacteria during ISS spacewalks. In 2014, cosmonaut Vladimir Solovyov reported finding several microorganisms, including sea plankton, in samples from the space station's exterior.

NASA does not have access to data from either finding and has therefore issued no comments in response to either one.

The bacteria likely came from Earth, possibly via tablet PCs and other materials delivered and put on the outside of the space station for long periods time so scientists can study their behavior in space.

They could also be microorganisms that live in Earth's upper atmosphere and have yet to be discovered. During its years orbiting the Earth, the ISS could have picked some of them up.

Various microorganisms, such as tardigrades, are known to be capable of surviving in extreme conditions.

Temperatures on the outside of the ISS range from minus 150 degrees Celsius to plus 150 degrees Celsius.

According to a recent study, some microorganisms can even be transported from one world to another via space dust. They can also be brought by asteroids and comets.

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