In this interview, Jennifer Stern explains how she went from studying methane emissions in landfills to searching for signs of life on Mars. Stern is a geochemist who is using Curiosity’s Sample Analysis at Mars (SAM) instrument to sort out geological signatures in the rock record from potential biological processes. SAM is a combination of three individual instruments that is roughly the size of a microwave oven, and will analyze samples taken by Curiosity’s robotic arm.