https://phys.org/news/2018-05-scientists-chemistry-lab-evidence-life.html

Although the surface of Mars is inhospitable to known forms of life today, there is evidence that in the distant past, the Martian climate allowed the presence of liquid water—an essential ingredient for life—at the surface. This evidence includes features that resemble dry riverbeds and mineral deposits that only form in the presence of liquid water. NASA has sent rovers to Mars that have found additional signs of past habitable environments, such as the Opportunity and Curiosity rovers both currently exploring the Martian terrain.

The MOMA instrument will be capable of detecting a wide variety of organic molecules. Organic compounds are commonly associated with life, although they can be created by non-biological processes as well. Organic molecules contain carbon and hydrogen, and can include oxygen, nitrogen, and other elements. To find these molecules on Mars, the MOMA team had to take instruments that would normally occupy a couple of workbenches in a chemistry lab and shrink them down to roughly the size of a toaster oven so they would be practical to install on a rover.