Protecting earth from extraterrestrial contamination: The case for a lunar biocontainment facility

The advancement of space exploration into an era of sample return missions from Mars, asteroids, and icy moons raises the potential for biological contamination either to or from Earth. We consider the possibility that extraterrestrial organisms introduced to Earth could behave analogously to invasive species by destabilizing ecosystems or interacting unpredictably with their new environment. There are myriad cases of microbial organisms rapidly adapting to novel extreme conditions, undermining the notion that extraterrestrial life (e.g., indigenous to Mars) would be unable to survive on Earth. The plausibility of encountering extraterrestrial life warrants stringent planetary protection measures grounded in biosafety and biosecurity principles. Due to its proximity, natural isolation, and apparent lack of a biosphere, the Moon can serve as a secure site for biocontainment of extraterrestrial samples. Building upon historical lessons from biological invasions, we argue that a lunar quarantine infrastructure should form the cornerstone of modern astrobiological risk mitigation strategies.