(Phys.org) --The ChemCam laser instrument aboard NASA's Curiosity rover fired its 100,000th shot recently, chronicling its adventures on Mars with a coffee-table-book's worth of spectral data that might rival snapshots gathered during a long and satisfying family vacation here on Earth. ChemCam zaps rocks with a high-powered laser to determine their composition and carries a camera that can survey the Martian landscape.