“It is impossible to predict how disruptive microbial contamination could be without knowing the traits of both the invading species and the receiving environment,” said Ricciardi.
For now, Ricciardi has thoughts on how to prevent spreading Earth microbes. Upcoming missions to Europa, Titan, and possibly Enceladus are riskier because those moons are thought to have greater habitability potential. It seems unlikely that anything is still alive on the Red Planet, but there could be hypothetical life-forms that somehow eluded the killer radiation everything else is exposed to and burrowed deep beneath the surface. “Early detection could be aided by DNA sequencing technologies and thorough databases on organisms found in the ‘clean rooms’ in which spacecraft are assembled.” Back contamination will become more of a problem to face when the samples that Perseverance is collecting on Mars right now are returned to Earth. “Early detection and rapid response are keys to biosecurity,” he said. “Early detection and rapid response measures developed to manage the risks of invasive species on Earth could be applied to planetary biosecurity,” he said. Prevention is the most effective weapon we have against forward or back contamination. Invasive species can cause extinction of endemic species even if the invaders aren’t pathogenic (like cane toads). By the time the alien thing starts wreaking havoc on an ecosystem, it could be too late. Life as we don’t know it, which evolved somewhere far from here, could have adaptations and genetic structures so different from anything on Earth that nobody sees it for what it is. The problem is that we might not recognize life from elsewhere as something alive. Ricciardi and his colleagues believe that planets and moons where life may be hiding should be treated like insular ecosystems, so both forward and back contamination are prevented. Cane toads devastated Australia when they were introduced. Something we do know is that ecosystems considered insular, such as Hawaii, Australia, Madagascar, and Antarctica, evolved in isolation and are particularly vulnerable to invasive species. Microorganisms like e.coli and black mold have survived the punishing conditions of outer space while crawling on the ISS, so they might be able to make it through a mission to the Moon or even Mars. This is why all spacecraft and payloads have to be sterile before taking off. Forward contamination is a current concern for NASA and other space agencies. Back contamination would involve unwanted organisms landing and breeding on Earth, while forward contamination means Earth organisms could populate another planet. “The concern is not only about alien pathogens, but about organisms that could colonize and proliferate Earth environments.” “Unprecedented risks are posed by a new era of space exploration aimed at targeting areas most likely to contain life,” Ricciardi told SYFY WIRE. He coauthored a study recently published in BioScience.
Now that there is so much discussion around humans eventually going (boldly or otherwise) where none of our species have gone before, invasion ecologist Anthony Ricciardi of McGill University in Montreal, Canada, is nervous. Pathogens that keep mutating have done worse. Invasive species that spawned right here have done enough damage where they don’t belong.