To ask if you could live outside the International Space Station (ISS) is rhetorical at best — but could any living organism on Earth manage it?
One unassuming toughie did, and provided at least rough proof of concept that life could exist on Mars.
Lichen from Antarctica’s McMurdo Dry Valleys survived 18 months on a platform attached to the outside of the ISS’s Columbus module, Futurism reported. Though they emerged in worse shape than temperate lichens tested separately in “Mars-like conditions,” many still survived.
The International Space Station. Photo: NASA
Damaged but not destroyed
The study authors focused on the success of the species in the Martian simulation.
“The most relevant outcome was that more than 60% of the cells…remained intact after ‘exposure to Mars,’ ” said Rosa de la Torre Noetzel of Spain’s National Institute of Aerospace Technology (INTA) and co-researcher on the project.
Survival in outer space itself was lower. Only around 35% of these lichen’s cells retained their membranes throughout the experiment.
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Nevertheless, this is strong evidence that lichen is tougher than anything alive by many orders of magnitude.
For carbon-based life forms, outer space is — in a word — unsurvivable. In no particular order, space is:
- Hundreds of degrees below freezing. Or thousands of degrees above, depending on your location.
- Radiative. Astronauts on a six-month mission receive up to 2,000 millisieverts of radiation, per NASA. For comparison, personnel tasked with the Chernobyl cleanup received about 120.
- A shooting gallery with very high-velocity ammo. A .50 caliber bullet travels about .86 kilometers per second. Meteorites can cover 40km in a second.
No fluke
However, repeated experiments have proven lichen’s resistance to these conditions.
In 2005, researchers placed lichens aboard a rocket and then attached them to a European Space Agency module outside a Russian satellite. They left them for 16 days, then brought them back home.
“All exposed lichens, regardless of the optical filters used, showed nearly the same photosynthetic activity after the flight,” the study said. “These findings indicate that [most lichen cells] can survive in space after full exposure to massive UV and cosmic radiation, conditions proven to be lethal to bacteria and other microorganisms.”
