For as long as we’ve been sending people to space, there has been the worry of bringing back some kind of as-yet-undiscovered pathogen from beyond Earth. So far, thankfully, nothing has come of the fear. But according to a new paper published in the journal Ambio, researchers argue that NASA’s long-term plans for a permanent lunar colony should include a quarantine facility for space germs on the Moon.

The proposal comes via Frederick Moxley, a former Pentagon adviser and biodefense specialist, and Anthony Ricciardi, an invasive-species expert at McGill University. The pair argues that since we are going to be bringing so many samples from the moon and Mars back to Earth, along with potentially other worlds down the line, and since we currently have no way to guarantee that there aren’t any potentially unknown microorganisms all over them, we should probably keep them as far away from Earth as possible just in case.

They think a lunar bio-containment facility is the perfect buffer between space and the potentially dangerous spread of space germs. Instead of bringing samples directly home, they would first get dropped off on the moon, where they would be studied in highly secure, fully automated laboratories, so the research team’s theory goes. The materials would then be sterilized before anything is considered safe to travel home.

It’s a space truck stop where rocks can get a quick shower before the final leg of the journey.

What If Space Is Littered With Nasty Space Germs That Kill Us All?

The authors argue that invasive species have time and time again shown how seemingly harmless little organisms introduced to a new environment can cause enormous damage to ecosystems. If it can happen between earthly ecosystems, it can definitely happen between planets.

As evidence of potential contamination of our planet, the researchers point to previous findings about how bacteria on the International Space Station developed drug-resistant traits while in space, which raises the concern over future missions potentially bringing back altered microorganisms that have whole new characteristics that weren’t there at first.

Moxley and Ricciardi admit that a pandemic caused by some kind of alien microbe is impossible to predict, but it’s better to be safe than sorry, especially as governments and private companies make space exploration more commonplace, which will provide plenty of opportunities for a pathogen to sneak in.