When the Mars Science Laboratory rover ‘Curiosity” lands on Mars in August 2012, its Sample Analysis at Mars (SAM) instrument will “follow the carbon” to better understand the past and present habitability of our planetary neighbor. SAM sits in the belly of the rover and will be fed solid samples by the robotic arm. It is one of 10 science instruments on Curiosity that all work together to study the past and present habitability of Mars.

SAM will have the sensitivity for measuring organic molecules at a level of a few parts per billion, but there’s no guarantee that any organics will be found. A more sure-fire bet is that the mission will better characterize whether Mars was ever friendly to organic compounds and the life that depends on them.