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Microbes survive outside the International Space Station, might do same on Mars

The Biomex microbes in their ISS containers. ESA/ROSCOSMOS

Earth is home to some five million trillion trillion microbes. That’s not a typo. Five million trillion trillion live on Earth. At least half of the planet’s biomass comes from the microscopic organisms that inhabit the most extreme environments — from hot springs to the human gut.

A new study from researchers at the German Aerospace Center (DLR) shows that some microbes can inhabit an even more inhospitable environment: space outside the International Space Station (ISS). The research project, called Biomex (Biology and Mars Experiment), set out to see if some of the hardier kind of microbes could survive conditions on alien planets. The results suggest the answer is yes.

“The ISS is a unique platform to study the effect of extreme space and Mars-like conditions,” Jean-Pierre de Vera, an astrobiologist at DLR’s Institute of Planetary Research who led the study, told Digital Trends. “In particular, the question of Mars’s habitability and the detection of life under these extreme space conditions were the main drives to motivate me to test experimentally the hypothesis directly in space.”

Among the team’s questions were whether life could survive on Mars and which kind of biomolecules are stable enough to be detected.

Some of the microbes were placed in simulated Martian soil. DLR (CC BY 3.0))

Microbes have long been known to inhabit the ISS but to test their ability to survive outside of its climate-controlled walls, hundreds of samples, including bacteria, mosses, and algae, were placed in containers on the outside of the ISS’s Russian Zvezda module, where they were exposed to a vacuum and extreme ultraviolet radiation and temperature variations for 533 days. The samples were then sent back to Earth, where De Vera and his team studied them.

The results showed that some of the microbes seemed to thrive despite the conditions. To De Vera, the results indicate nothing less than a call to search for extraterrestrial life.

“Life could also originate on other worlds in the universe, if the conditions are approaching Mars-like and Earth-like conditions,” he said. “It even could exist as extremophilic lifeforms in some habitable niches, although the majority of the planet could be too extreme for life and evolution, as we know from our home planet Earth. It is therefore worth it to start missions for the search for life in our universe.”

Moving forward, De Vera and his colleagues will explore ways to identify life on other planes through a mission called Biosign (Bio-signatures and habitable niches).

A special issue dedicated to the Biomex project was published in February by the journal Astrobiology.

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