NASA’s strategic objective in planetary science is to “ascertain the content, origin, and evolution of the solar system and the potential for life elsewhere”. Much of our scientific research and many of our spacecraft are geared toward understanding the conditions that allow life to emerge and persist in the solar system. We will look at life in extreme environments on Earth, and use it as a guide to understanding the potential for life beyond Earth. Of special interest as possible locations where life may exist (or may have existed in the past) are Mars and the icy satellites of the giant planets Jupiter and Saturn. NASA is currently developing missions to Mars and Europa (a moon of Jupiter), with the goal of seeking signs of life. In this presentation, we will focus on the Mars 2020 rover, which will seek signs of ancient life on the martian surface with a suite of instruments optimised for detecting potential biosignatures. The rover will also collect samples for possible future return to Earth.