NASA Mars Science Lab Mission: SAM

The SAM instrument is the largest of the 10 science instruments for NASA's Mars Science Laboratory mission. 

It will examine samples of Martian rocks, soil and atmosphere for information about chemicals that are important to life and other chemical indicators about past and present environments. Credit: NASA

The Mars Science Laboratory is on its way to the red planet, and its rover Curiosity should touch down next summer. If the mission hits paydirt and comes across organic material, then one instrument in particular has the chemical tools for studying these building blocks of life.

The instrument is called Sample Analysis at Mars, or SAM (or "Samantha" to those who built her). As the name makes clear, SAM is there to analyze samples taken from the surface and from the atmosphere. It uses sophisticated chemical lab equipment packed into the size of a microwave oven.

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.

"Life on Earth means water, energy and the complexity of carbon chemistry," says Paul Mahaffy from NASA Goddard Space Flight Center and the PI of the SAM instrument. "We'll be looking for all of the above, but with a special emphasis on the complexity."

Curiosity's predecessors, the Mars Exploration Rovers Spirit and Opportunity, had a mantra of "follow the water." Now, the paradigm is shifting towards "follow the carbon," Mahaffy says.

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.