ChemCam

ChemCam
NASA/JPL-Caltech/LANL · Public domain · source
Name	ChemCam
Type	Laser-induced breakdown spectroscopy instrument
Mission	Mars Science Laboratory (Curiosity)
Operator	NASA / Jet Propulsion Laboratory
Launch	November 26, 2011
Deployed	August 2012 (Mars surface)
Mass	11.9 kg
Power	~17 W (average)

ChemCam

ChemCam is a remote geochemical analysis instrument flown on the Mars Science Laboratory rover Curiosity. Developed by a consortium led by the Los Alamos National Laboratory and the Institut de recherche en astrophysique et planétologie, the instrument couples a pulsed laser with a spectrometer and a remote camera to perform laser-induced breakdown spectroscopy on Martian rocks and soils from distances of several meters. ChemCam has provided compositional context that complements the sample collection and in situ analysis of the rover's Sample Analysis at Mars and Alpha Particle X-Ray Spectrometer investigations.

Overview

ChemCam was selected as part of the payload for the Mars Science Laboratory mission during the 2003–2004 development cycle of planetary instruments alongside instruments such as Mastcam and APXS. The instrument's primary capability is to vaporize microscopic material with a high-energy pulsed laser and analyze the resulting plasma emission across ultraviolet, visible, and near-infrared wavelengths. The ChemCam team includes contributors from Los Alamos National Laboratory, French National Centre for Scientific Research, University of Hawaii, University of Nantes, and ISMRA, integrating expertise drawn from laboratories with histories in planetary spectroscopy, combustion physics, and optical engineering. ChemCam's operations were coordinated with mission planning teams at Jet Propulsion Laboratory and science teams based at academic institutions including Brown University and Cornell University.

Instrument Design and Components

ChemCam's architecture comprises three primary subsystems: a pulsed Nd:YAG laser head, a remote micro-imager, and a suite of spectrometers housed in an electronics box on the rover deck. The laser subsystem, engineered by teams at Los Alamos National Laboratory and industrial partners such as THALES, emits 1067 nm pulses frequency-doubled for target ablation and is mounted on the rover's Mast Unit assembly alongside the Mastcam optics. The remote micro-imager, derived from heritage from instruments developed at Institut de Recherche en Astrophysique et Planétologie, provides context imaging and focus capability. Spectral channels covering ~240–850 nm were designed with gratings and detectors supplied by collaborations including CEA and CNRS laboratories. Control electronics and data handling use flight processors and software developed in coordination with NASA and contractor teams at Ames Research Center and Ball Aerospace.

Operation and Data Acquisition

ChemCam operates by firing a sequence of laser pulses at a selected target, typically acquiring tens to hundreds of pulses per observation to remove dust and sample fresh material. Each pulse produces a short-lived plasma whose optical emission is collected by the telescope, fed into three spectrometers, and recorded as spectra; a co-aligned micro-imager documents the pre- and post-shot surface morphology. Flight operations are planned in day-to-day tactical sequences by Jet Propulsion Laboratory mission planners and uplinked using the Deep Space Network relay via orbiters like Mars Reconnaissance Orbiter and Mars Odyssey. Data are returned as raw spectra and processed products to science teams at institutions such as University of Toulouse, University of California, Los Angeles, and Imperial College London for interpretation. ChemCam observations have been integrated with remote sensing datasets from CRISM and imaging from HiRISE to place local composition in regional context.

Scientific Objectives and Key Findings

ChemCam was tasked to determine elemental composition of Martian rocks and soils to assist in selecting samples and understanding past aqueous and volcanic processes. Key achievements include identification of diverse basaltic compositions across Gale Crater and detection of high-silica materials in the Pahrump Hills and Murray Formation exposures, evidence supporting silica enrichment linked to hydrothermal or diagenetic processes. ChemCam analyses revealed unexpected concentrations of hydrogen-bearing phases by correlating LIBS results with observations by Dynamic Albedo of Neutrons and SAM organics experiments. The instrument detected variations in trace elements such as lithium, boron, and manganese that informed hypotheses about past redox conditions, linking findings to sedimentary contexts in areas like Yellowknife Bay and Aeolis Palus. Cross-comparison with the Alpha Particle X-Ray Spectrometer and CheMin mineralogy results helped constrain alteration histories and identify targets for drilling by Curiosity.

Calibration and Data Processing

Calibration of ChemCam relied on pre-flight laboratory spectra of rock standards at institutions including Los Alamos National Laboratory and Centre Nationale d'Etudes Spatiales facilities, supplemented by on-Mars calibration targets mounted on the rover, and vicarious calibration using known Martian surfaces imaged by Mastcam. Data processing pipelines developed by teams at Washington University in St. Louis and Johns Hopkins University Applied Physics Laboratory convert raw counts to calibrated radiance and elemental abundances using multivariate techniques like partial least squares regression and univariate analysis. The calibration approach accounts for matrix effects, atmospheric attenuation modeled with inputs from Mars Climate Sounder and rover environmental sensors, and instrument drift characterized through periodic observations of onboard standards. Processed data products are archived and disseminated to the community via science data systems maintained by NASA and partner institutions.

Mission Integration and History

ChemCam has been active from Curiosity's landing in 2012 and has contributed to long-term exploration of Gale Crater, enabling tactical decision making for traverse planning and drill targeting. The instrument's development involved international partnerships spanning France, United States, and European research centers, with principal investigators and co-investigators drawn from universities and national laboratories including Los Alamos National Laboratory and Institut de recherche en astrophysique et planétologie. ChemCam operations adapted over the mission to prioritize energy-efficient campaigns and to integrate lessons from earlier Mars missions such as Viking and Mars Exploration Rover missions. Its dataset continues to support comparative studies with sample-return planning efforts and informs design considerations for future instruments on missions like Mars 2020 and proposed rover concepts by agencies including NASA and ESA.

Category:Mars Science Laboratory instruments