A rock-zapping laser instrument on NASA’s next Mars rover has roots in a demonstration that Roger Wiens saw 13 years ago in a colleague’s room at Los Alamos National Laboratory in New Mexico.The Chemistry and Camera (ChemCam) instrument on the rover Curiosity can hit rocks with a laser powerful enough to excite a pinhead-size spot into a glowing, ionized gas. ChemCam then observes the flash through a telescope and analyzes the spectrum of light to identify the chemical elements in the target.

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