Experts are hoping to collect microbiological samples to study how microbes behave, and possibly thrive, in harsh environments—but the harsh environment in question isn’t anywhere near where you’d expect.
Astronauts aboard the International Space Station (ISS) will attempt to collect microbiological samples from the outside of the space station during an upcoming spacewalk. Surface samples will be collected near life support system vents, as detailed in a NASA statement published on Tuesday, and could shed light on how, or even if, the ISS releases microorganisms into space.
The extravehicular sample collection is taking place as part of the ISS External Microorganisms experiment, a NASA project that, as the name suggests, studies microorganisms on the outside of the space station. The samples will be analyzed back on Earth.
Though spacecraft and spacesuits are sterilized before missions, humans carry unique microbiomes filled with essential microbes that can’t—and shouldn’t—be removed. So when astronauts blast off into the black void that is space, they also bring trillions of microorganisms along for the ride.
“We can’t sterilize everything we send into space, and don’t want to, but we do a lot to limit potential pathogens from making their way to the station,” NASA microbiologist Sarah Wallace said in a statement. “At launch, the cargo, food, vehicles, and crew members each have their own microbiome, or suite of microbes. When everything gets to the station, these microbiomes become part of the space station microbiome.”
The space station microbiome is unlike any on Earth, with hitchhiking microbes facing harsh conditions like radiation and microgravity. Some of these organisms survive, adapt, and even reproduce. The unique environmental pressures even trigger microbial mutations that don’t exist on Earth, which is another story entirely.
Scientists are very interested in these extremophiles—forms of life that can withstand extreme conditions—because their attributes could have implications for industries on Earth and shed light on how these hardy microbes might survive on other extraterrestrial destinations, like the Moon or Mars.
As a consequence, astronauts frequently swab the ISS interior to monitor its unique microbiome. The upcoming sample collection from the ISS exterior is happening because the station is likely expelling some of these microbes into space through its ventilation exhaust.
Additionally, the results of the external swabs could inform the concept of Panspermia, a hypothesis suggesting that life originated elsewhere in the galaxy before reaching and colonizing Earth. For this to be plausible, some microbial ancestor would need to have survived the harsh conditions of outer space—like those outside the ISS—before eventually reaching Earth.
Panspermia remains a hypothesis, but scientists have previously tested how earthly extremophiles might fare in the vacuum of space, with algae and tardigrades both faring surprisingly well.
In addition to building on previous experiments about how microorganisms behave beyond Earth, the newly scheduled sample collection could shed light on how humans might be contaminating space. After all, we wouldn’t want to one day discover microbes on Mars just to wonder whether they’re truly Martians, or simply hitchhikers.