Libs on the Red Planet: Exploration of Another World Using Chemcam and Supercam

NASA’s Mars rovers Curiosity (landed 2012) and Perseverance (landed 2021) both use laser-induced breakdown spectroscopy (LIBS) to determine the elemental composition of rocks and soils within ~7 m of the rover. SuperCam on the Perseverance rover combines LIBS with remote Raman and visible+infrared reflectance spectroscopies to characterize a previously habitable environment in Jezero crater, which was once a lake; it contains a delta formation at the mouth of an ancient river. SuperCam’s LIBS uses a microphone to record the sound intensities of the plasma, providing information on the targets’ physical properties (hardness, weathering coatings). In addition to exploring the crater’s geochemistry, SuperCam will characterize compositions around locations of samples being collected and cached for return to Earth in a decade. SuperCam’s predecessor, ChemCam, has fired nearly 1 million laser pulses on > 20,000 observation points across Curiosity’s ~25 km traverse up Mt. Sharp in Gale crater to study compositional variations of lakebed sediments that were deposited > 3 billion years ago, and to probe chemistry of groundwater from materials precipitated in fractures in the rocks. The team regularly archives 1 abundances of 8 major elements and several trace elements. Overall, the ChemCam team has calibrated and published 2 compositions for 25 elements. I will describe the instruments, their calibration, and our exploration and discoveries.