Looking for life on Mars is a complicated problem. We worry that if we rove up to any life on Mars, we’ll accidentally kill it with germs on our rovers. We worry that life may exist in places other than where we happen to be looking, so even if we don’t see life that doesn’t mean there isn’t life.

Ideally, we want a way to look for life in as many different places as possible, and we want to look for life in a way that doesn’t potentially contaminate life in a way that causes a Martian genocide.

If this seems like an impossible task, it just might be if you confine yourself to looking for Martian life on Mars. In a new paper in Science, researchers Ryuki Hyodo and Tomohiro Usui describe how the regular impact of asteroids into Mars’ surface has launched martian rocks into space. 

We periodically get these rocks crashing into Earth, and Mars’ moons Phobos and Deimos should have been regularly hit over and over. They suggest that if we can send missions to these moons, they will be able to study the Mars rocks that have impacted the moons and look for life in those rocks. This allows a rover to sample rocks from all over Mars on one small moon, and we shouldn’t have to worry about killing off any present-day life since we’re not going to be anywhere near that life.  

Unfortunately, we won’t immediately be able to sort out where on Mars any life-containing meteorites may have originated, but if we find life from Mars in rocks on one of these moons, we know we have to search Mars far and wide.

More Information

The search for life on Mars expands to studying its moons (Phys.org)

“Searching for life on Mars and its moons,” Ryuki Hyodo and Tomohiro Usui, 2021 August 13, Science