Shielded Microbes Could Spread Life Far Beyond Earth

Outer space might be the toughest environment for life, but some hardy microbes have been able to survive in it for surprising amounts of time. How long they can do so and why they are able to withstand the difficulties of space remains a topic of controversy.


Persistent strains of microbes have been discovered in spacecraft clean rooms. In 2014, Russian reports emerged of plankton surviving on the exterior of the International Space Station, a claim that NASA officials objected to for lack of evidence.

Still, understanding how well microbes can survive in space is of importance when sending out orbiters or landers around bodies that might present the right conditions for life, such as Mars. Scientists want to be careful to avoid contaminating other worlds with life from our own. And microbes' resilience to outer space enhances the prospects of panspermia, in which life can be seeded between planets via meteors and other traveling bodies.

This basis formed part of the rationale for a study led by Rocco Mancinelli, a senior research scientist at the Bay Area Environmental Research Institute, a nonprofit space and atmospheric science research group.

"Results from of this study are relevant to understanding the adaptation and evolution of life," Mancinelli wrote in an e-mail to Astrobiology Magazine.

His results were published in the January issue of the International Journal of Astrobiology in the article, "The affect of the space environment on the survival of Halorubrum chaoviator and Synechococcus (Nägeli): data from the Space Experiment OSMO on EXPOSE-R."

Finding the Limits

Part of Mancinelli's research focuses on microbe-environment interactions, specifically looking at the environmental limits in which organisms can live. One of his research interests includes the vacuum of space, which also is subject to extreme ultraviolet radiation from the sun, since there is no atmosphere to filter it out.

More broadly, the experiment is a demonstration of how important it is to keep spacecraft as clean and microbe-free as possible before they leave the lab. NASA, the European Space Agency and other entities have planetary protection guidelines that detail how best to accomplish this, and Manicelli said research in this area must continue.

"We realize that we cannot sterilize spacecraft completely, but we can decrease the bio-load significantly. The relevance here is that we must understand that the probability of potential contamination exists, and that we must reduce that probability as much as possible," he said.

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