Was Mars once capable of supporting life? This is the fundamental question the Curiosity rover seeks to answer as it makes its way across the Red Planet. Successfully landing on Mars in the summer of 2012 as part of NASA’s Mars Exploration Program, Curiosity is a roving, robotic laboratory studying the planet’s habitability.

To carry out its mission, Curiosity relies on the most advanced suite of instruments ever sent to the Martian surface — among them, a laser-firing tool called the ChemCam. A concept originally developed at the Energy Department’s Los Alamos National Laboratory, ChemCam serves two key purposes: determine whether rocks and soil on Mars contain chemicals necessary for life, and identify rocks and soil for analysis by other instruments aboard the rover. ChemCam is a multi-partnership effort between Los Alamos; the French national space agency, Centre National d’Etudes Spatiales; and French research agency Centre National de la Recherche Scientifique.

So how exactly does ChemCam work? At the instrument’s heart is a high-powered laser, capable of focusing more than 1 million watts of power onto a pinhead-sized area for five-billionths of a second. The process works in a straightforward manner: First, ChemCam fires its short laser pulses at a target (Martian rocks or soil) with pinpoint accuracy. Then, once hit by the laser, electrons within the target become excited, emitting light. Next, ChemCam uses a built-in telescope to capture this light, sending it down an optical fiber to the body of the rover. Finally, a spectrometer on board the rover “reads” the light — identifying the types of atoms within the target. By revealing which atoms are present, ChemCam accomplishes the vital task of informing scientists of a target’s composition. Beyond its laser, ChemCam also makes use of a high-resolution camera — powerful enough to view a human hair from seven feet away — providing scientists with extremely detailed images throughout the Mars exploration.

Since its arrival on Mars, ChemCam has achieved exciting milestones. In December,ChemCam’s laser surpassed 100,000 zaps — providing scientists with a plethora of data to help inform the overall mission. And, this past January, ChemCam documented a trail of minerals that point to the prior presence of water on Mars.

ChemCam’s work is far from over. The instrument is designed to fire 1 million shots over the course of Curiosity’s Martian odyssey. View the slideshow above to learn more about what ChemCam reveals about the Red Planet.