To prevent a Martian lab, NASA needs to build a very special lab

With such concerns in mind, NASA must act as if samples from Mars could spawn the next pandemic. “Because it is not a zero-percent chance, we are doing our due diligence to make sure that there’s no possibility of contamination,” said Andrea Harrington, the Mars sample curator for NASA. Thus, the agency plans to handle the returned samples similarly to how the Centers for Disease Control and Prevention handles ebola: carefully.

“Carefully,” in this case, means that once the Mars samples drop to Earth, they must be initially held in a structure called the Sample Receiving Facility. The mission’s planners say the structure should meet a standard known as “Biosafety Level 4,” or BSL-4, which means it is capable of safely containing the most dangerous pathogens known to science. But it also has to be pristine: functionally, a giant, cleanroom that prevents substances on Earth from contaminating the samples from Mars.

The agency has little time to waste: If the sample return mission occurs on time — admittedly a big “if” — Mars rocks could land on Earth by the mid 2030s. It could take about as much time to build a facility that can safely contain the Martian materials, and that is if it is built on schedule, without disruption from political or public challenges.