When Neil Armstrong, Buzz Aldrin, and Michael Collins returned from the Moon in the summer of 1969, they spent three weeks isolated in quarantine to make sure that they hadn’t brought back any microbial lifeforms from the Moon, which could prove harmful to Earth life. Later, once the Moon had been unequivocally proved to be a dead world, future Apollo missions were allowed to skip quarantine. Elsewhere in the solar system, however, NASA still has to take planetary biosecurity seriously, because life could be out there. If we bring it back to Earth, it could be a danger to us and our ecosystems. Conversely, microbial Earth life could invade a fragile alien ecosystem, destroying a newly discovered lifeform before we have the chance to study it. Imagine discovering life on Mars, only to realize that it was life we had brought there with us.
To prevent these scenarios, planetary protection strategies are employed by NASA and other space agencies worldwide to minimize the risk of interplanetary cross-contamination. Mars rovers, for example, are all meticulously decontaminated before launch, ensuring that no Earth life makes its way to the surface of Mars.
For the moment, these practices are a safeguard against a purely hypothetical risk – no one knows if life exists beyond Earth. But if it does, we need to be ready for the consequences.
How do you prepare for something that might not exist? By examining something that does. Invasive species are a major problem worldwide. Human trade and travel imports species – often by accident – from one corner of the world to another. The effects can be devastating, wiping out local flora and fauna, reducing biodiversity, and forever altering ecosystems. What lessons can we learn from these very real challenges, to help us prepare for the possibility of an interplanetary equivalent?
A paper published in BioScience on November 17th by Anthony Ricciardi, Phillip Cassey, Stefan Leuko, and Andrew Woolnough examines this question and lays out several takeaways from the battle against invasive species here on Earth that apply to space exploration. Three highlights from the paper stand out:
It’s clear that we need to take planetary protection seriously, but how worried about this problem should we be, especially as more and more missions travel to potentially habitable places in the Solar System in the coming years? Are interplanetary invasions likely?
Luckily, the answer is ‘not likely’. But that doesn’t mean we can let our guard down, because if it does happen, the outcome could be devastating. As the paper’s authors put it, “at present, these are considered to be highly improbable events…However, we suggest that these biological invasion scenarios are analogous to extreme natural or technological disasters (e.g., major earthquakes, nuclear meltdowns) that, although typically rare, have potential consequences that are unacceptable and therefore merit unique safeguards.”
If battling invasive species on Earth has taught us anything, its that transporting organisms to new ecosystems can have enormous unintended consequences. But by taking precautions and working together, we can minimize the risk, exploring the Solar System while keeping both ourselves, and any potential alien lifeforms, safe from each other.
Learn more: Anthony Ricciardi, Phillip Cassey, Stefan Leuko, Andrew P Woolnough. “Planetary Biosecurity: Applying Invasion Science to Prevent Biological Contamination from Space Travel.” BioScience.
Featured Image: Beavers are an invasive species in Tierra del Fuego, where they have a substantial impact on the landscape and local ecology through their dams. Credit: User:IlyaHaykinson (Wikimedia Commons)
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