NASA Will Send Two Astronauts on a Spacewalk Outside the ISS to Search for Living Organisms

NASA astronauts Tracy Dyson and Matt Dominick have a unique mission. During their upcoming spacewalk scheduled for June 24, they’ll go into space to collect living organisms attached to the outside of the International Space Station (ISS).

Life in space? Outside the ISS, temperatures fluctuate between a scorching 250°F and a frigid -150°F. In addition, without the protection of the Earth’s atmosphere, radiation levels are extreme.

Despite sounding like science fiction, it’s a documented fact that multiple microorganisms are capable of surviving these extreme conditions. These organisms are known as extremophiles, and they can remain alive in a dormant state until environmental conditions become more favorable, at which point they resume their metabolic activity.

The fascinating world of extremophiles. One of the most well-known examples of extremophiles are tardigrades. These tiny eight-legged invertebrates have been the subject of numerous experiments and have shown incredible resilience in space.

There’s even a possibility that tardigrades could be living on the Moon. In 2019, the Israeli probe Beresheet crashed on the lunar surface while carrying dehydrated tardigrades as part of a “library” project. Although scientists don’t know if they survived the impact, they could still be there in a state of cryptobiosis, which is a form of dormancy that allows them to live without water and in extreme conditions.

Besides tardigrades, scientists are aware of bacteria and other even smaller microorganisms that are more resilient and can endure these harsh conditions for years.

Experiments on the exterior of the ISS. Over the years, astronauts have attached spore-forming bacteria and fungi on the outside of the space station, demonstrating that they can survive up to two years exposed to Earth orbit conditions.

A study published in January revealed that bacteria and fungi placed on absorbent cotton and attached to metal rods outside the ISS remained alive after two years in the vacuum of space. “The main factors for long-term survival could be the result of their dehydration and partial [freeze-drying] in the vacuum of near-Earth space,” the authors explained.

Additionally, back in 2020, a team of Japanese researchers found the bacterium deinococcus radiodurans was able to survive for three years in space.

Spacewalk. The spacewalk was initially scheduled for Thursday, June 20. However, it has now been postponed to June 24–just after Boeing’s Starliner will return to Earth–because one of the astronaut’s experienced discomfort in their suit.

During the spacewalk, astronauts Dyson and Dominick will collect samples from outside the ISS for analysis on Earth in order to determine if living organisms are still present. This experiment may help scientists answer the age-old question: Is there life beyond Earth?

Image | NASA

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