NASA rover Curiosity prepares to zap a Martian rock in first laser target practice

Mounted to Curiosity’s "head" just above its camera "eyes," ChemCam combines a powerful laser with a telescope and spectrometer that can analyze the light emitted by zapped materials, thereby determining the chemistry of Mars rocks with unprecedented precision.
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ChemCam’s telescope will observe the process, while its spectrometer — which is sensitive to light from every element on the periodic table — will analyze emissions from the resulting plasma, telling scientists what lies within.

"ChemCam is designed to look for lighter elements such as carbon, nitrogen and oxygen, all of which are crucial for life," said Los Alamos' Roger Wiens, ChemCam principal investigator. "The system can provide immediate, unambiguous detection of water from frost or other sources on the surface, as well as carbon — a basic building block of life as well as a possible byproduct of life. This makes the ChemCam a vital component of Curiosity’s mission."