If our tenure on Earth is anything to judge by, humans are not very good planetary tenants. Now, with a (nearly) clean slate on Mars, the National Aeronautics and Space Administration (NASA) is already trying to prevent us from destroying a second planet.

According to The New York Times, Catharine A. Conley earned the first-ever title of “planetary protection officer” for Mars, a position that puts the weight of preventing the humans from putrefying yet another world squarely on her shoulders.

Here on Earth, invasive species (including humans) often travel thousands of miles to get from home to a new country and then set up colonies where they leech resources and outcompete all other life. Though Mars is 33.9 million miles away, this same problem presents itself. Tiny bacteria, sealed inside the confines of spacecraft, can cling for dear life for millions of miles, and be dumped into the thin Martian atmosphere. In fact, they’ve already been doing it: since the Soviet Mars 2 probe landed in the dust with a crash, microbes have been repeatedly introduced to Mars.

NASA’s Opportunity and Curiosity, already lumbering around the Red Planet, have been banned from “special regions” where scientists think they might proliferate. Conley told The Times that Earth’s tiniest residents have already left a footprint:

She said that at launch, there were probably 20,000 to 40,000 heat-resistant bacterial spores on Curiosity, and perhaps 100 or 1,000 times more microbes not counted. Many of them would have since perished in the vacuum of space. Intense ultraviolet radiation on the Martian surface would have killed many more — but not all, and some drop in the soil as Curiosity trundles by and performs its science work.

If the bacteria were to grow uncontrollably, any potential life on Mars could foreseeably be wiped out in one fell swoop. Humans: 2, Planets: 0.

Image via NASA/JPL-Caltech