English: http://mars.jpl.nasa.gov/m2020/mission/science/
Connection to Mars Exploration Program Science Strategy: Seek Signs of Life
The Mars 2020 mission would explore a site likely to have been habitable, seek signs of past life, fill a returnable cache with the most compelling samples, and demonstrate technology needed for the future human and robotic exploration of Mars.
Exploration Timeline
NASA's Mars Exploration Program has a long-term, systematic exploration plan for the Red Planet. Mars missions build on each other, with discoveries and innovations made by prior missions guiding what comes next. Mars missions are guided by evolving, discovery-driven science strategies that provide continuity in Mars science exploration themes.
The first framing theme was "Follow the Water," as water is essential to life as we know it. Finding past and present signs of water help define environments with conditions for past or present microbial life.
With past orbiters, landers, and rovers finding evidence of water, the theme "Explore Habitability" emerged to look for additional conditions necessary to life, including chemical elements and compounds necessary for life as we know it. Mars Science Laboratory's Curiosity rover marks a transition to the current science theme: "Seek Signs of Life."
While Curiosity is seeking evidence of habitable conditions (both past water and the chemistry needed for life), under the science definition team's vision, Mars 2020 would potentially seek signs of past life itself in the geologic record. It would also potentially include experiments that would prepare for human exploration