Did you know that the United States is part of an international Outer Space Treaty? Formally (and wordily) called “Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies,” the treaty establishes the foundation of Space Law. Basically the idea is that no country can put nuclear weapons into orbit or establish a military base on the moon (Sorry Newt Gingrich!) Also everyone should maintain the integrity and cleanliness of Outer Space, since it is not owned by any one country, and must be preserved for Science.
With that goal in mind, NASA has a Planetary Protection Officer that consults with engineers to ensure that equipment sent from Earth is suitably decontaminated before launch. Capsules that are sent into the void of space have little risk of contaminating another heavenly body, and have more relaxed decon standards. Rovers have much more strict requirements.
Still, each type of machine has a certain allowable amount of organisms that tag along – kind of like the amount of spiders and dog hairs allowed in sausage. Total sterility is impossible, but the engineers try to keep the number of organisms to a minimum. Some parts can be autoclaved – put in a pressure cooker that kill organisms with heat and pressure. More delicate equipment is wiped down with alcohol.
The Mars Curiosity Rover was clean and all set to fly when engineers decided to tweak the packing on the drill bits that the rover will use to drill into the Martian terrain. Concerned that a rocky landing might damage the bit-grabbing mechanism, they pre-loaded one of the bits onto the drill to make sure that it would be ready to go, even if it couldn’t load the bit mechanically. Unfortunately, these engineers failed to tell the Planetary Protection Officer, and the drill was sealed up without being properly cleaned.
Since Curiosity is mainly traveling through dry, rocky areas, there may be little risk of contaminating Mars with our Earth bugs. After analyzing the exposure risk, the Planetary Protection Officer decided that the only real concern would be in Curiosity found water. Since liquid water in required for all Earth life forms, a bacteria that jumped ship in the Martian desert is probably a goner, but one that takes up residence in a pond just might survive.
The odds of Curiosity finding water in the cold, dry Gale Crater where it landed are pretty low. However, can you imagine being the engineer that would have to steer away from the water in the event that you did find it? I don’t know if I would have that kind of self-control.
Perhaps I’m being optimistic, but I would be shocked if organisms from the earth survived on the edges of this drill despite the harsh UV light, the dryness of the environment, the freezing temperatures and lack of air pressure. The bacteria that are tagging along are probably from humans – we are walking bacteria bags, after all – and are happier hanging around a warm, moist body than in the harsh rocky environment of Mars. As long as one of the NASA employees didn’t have a nasty case of Deinococcus radiodurans, I can’t imagine that the rover was contaminated with anything that would set up shop on Mars.
In the event that we did collect bacteria from Mars that we had previously planted there, then wouldn’t we be able to figure that out? Yes, it would be devastating to set up cultures from some precious Mars soil and realize that you had grown E. coli or even a common soil microorganism. But with genetic tests you could determine if the organisms are recently from Earth or if there really are similar microbes growing on Mars.
Of course, it’s never wise to bet against the bacteria. So far we’ve found organisms in almost every place we’ve looked, including ice cores in Antarctica and in boiling geysers. We’ve also found them in the
Atacama desert, which is the most Mars-like environment you can find without leaving earth. So it’s certainly smart to be as clean as possible. You never know what kind of organisms might survive an interplanetary round-trip.