The survival of organisms in the vacuum of space may support the theory that life did not originate on Earth, but somewhere in the galaxy. Experts hope to collect microbiological samples to study how microbes behave and possibly thrive in harsh environments, but the harsh conditions are not at all where expected.
During an upcoming spacewalk, astronauts aboard the
International Space Station (ISS) will attempt to collect microbiological samples from the outside of the space station. According to a NASA statement released Tuesday, Jan. 21, samples from the surface will be collected near life support system vents and could shed light on how the ISS ejects microorganisms into space and whether it does so at all.
The extravehicular sample collection is being conducted as part of the ISS External Microorganisms experiment, a NASA project that, as the name suggests, is studying microorganisms on the outside of the space station. The samples will be analyzed on Earth.
Although spaceships and spacesuits are sterilized before flights, humans carry a unique microbiome filled with essential microorganisms that cannot - and should not - be removed. So when astronauts go into the black void of space, they also take trillions of microorganisms with them.
"We can't sterilize everything we send into space, nor do we want to, but we do a lot to keep potential pathogens off the station," says NASA microbiologist Sarah Wallace. "On launch, cargo, food, vehicles and crew members have their own microbiome, or set of microbes. When everything gets to the station, those microbiomes become part of the space station microbiome."
The space station microbiome is not like Earth's: hitchhiking microbes face harsh conditions such as radiation and microgravity, some of these organisms survive, adapt and even reproduce.
The unique environmental pressures even cause mutations in microorganisms that don't exist on Earth, which is another story.
Scientists are very interested in these extremophiles - life forms that can withstand extreme conditions - because their properties could have implications for industry on Earth and shed light on how these hardy microbes could survive on other extraterrestrial objects such as
Moon or
Mars.
Because of this, astronauts often swab the interior of the ISS to monitor the unique microbiome. The upcoming collection of samples from the outside of the ISS is being done because the station is likely ejecting some of these microbes into space through a ventilation hood.
In addition, the results of the external swabs may help develop the concept of panspermia, a hypothesis suggesting that life originated somewhere in the galaxy before reaching and colonizing Earth. For this to be plausible, some microbial ancestor must have survived in the harsh conditions of outer space, such as those outside the ISS, before reaching Earth.
Panspermia remains a hypothesis, but scientists have already tested how terrestrial extremophiles might behave in the vacuum of space, and algae and quietwalkers have performed surprisingly well.
In addition to previous experiments to study the behavior of microorganisms beyond Earth, a new planned collection of samples may shed light on how humans can pollute space. After all, people don't want to discover microbes on Mars one day and wonder if they're really Martians or just travelers.