In situ detection of boron by ChemCam on Mars

We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

Metal Enrichment of Wave-Rippled Sediments on Ancient Mars

International audienceThe Curiosity rover is ascending a sedimentary-rock mountain, Mount Sharp, testing hypotheses about how and why Mars' surface dried out. Within the past year, Curiosity has investigated an apparently Mount-Sharp-spanning feature - the Marker Band, which frequently forms a topographic bench. The Marker Band is distinctive in its lateral extent, stratigraphic confinement, and nontrivial thickness. The Marker Band also shows a distinct metal-rich geochemistry unlike any other materials previously analyzed by the rover, and its lower part exhibits wave ripples extending across hundreds of meters (possibly kilometers). Thus, the Marker Band is a marker of a change in the environment within Gale crater from drier conditions that formed underlying sulfates to wetter conditions that formed wave ripples (Gupta et al. this conference). Wave ripples do not persist above the rippled Marker Band, but further clues regarding the evolution of Mars' carbon cycle and atmosphere are obtained from carbonate in drilled samples immediately above the rippled Marker Band (Tutolo et al., this conference), which is strongly elevated in δ13C (Burtt et al., this conference). APXS data for drill fines from ~1 cm depth within the rippled layers show >40 wt% FeO, ~2 wt% Zn, and >1 wt% MnO (Thompson et al., LPSC 2023); metal enrichment is also seen in ChemCam data, which also show highly variable MnO. Tentative, but reasonable extrapolation of these data to parts of the Marker Band not visited by the rover suggests an excess Fe mass of 0.2 Gton. Potential processes capable of transporting the metals include transport by chloride-rich brines, or (via interaction with CO) as metal carbonyls. Although post-lithification mechanisms for metal emplacement have not been ruled out, a possible pre-lithification mechanism involves Mn and Fe deposition in a shallow lake in oxidizing conditions. In this scenario, Fe and Mn oxide nodules form and scavenge trace metals (e.g. Zn) by adsorption. We will conclude by discussing remaining open questions about the formation and metal enrichment of the rippled Marker Band. For example, possible sources of water for metal transport include (but are not limited to) compaction water, or alternatively groundwater derived from precipitation inside the crater rim

Metal Enrichment of Wave-Rippled Sediments on Ancient Mars

International audienceThe Curiosity rover is ascending a sedimentary-rock mountain, Mount Sharp, testing hypotheses about how and why Mars' surface dried out. Within the past year, Curiosity has investigated an apparently Mount-Sharp-spanning feature - the Marker Band, which frequently forms a topographic bench. The Marker Band is distinctive in its lateral extent, stratigraphic confinement, and nontrivial thickness. The Marker Band also shows a distinct metal-rich geochemistry unlike any other materials previously analyzed by the rover, and its lower part exhibits wave ripples extending across hundreds of meters (possibly kilometers). Thus, the Marker Band is a marker of a change in the environment within Gale crater from drier conditions that formed underlying sulfates to wetter conditions that formed wave ripples (Gupta et al. this conference). Wave ripples do not persist above the rippled Marker Band, but further clues regarding the evolution of Mars' carbon cycle and atmosphere are obtained from carbonate in drilled samples immediately above the rippled Marker Band (Tutolo et al., this conference), which is strongly elevated in δ13C (Burtt et al., this conference). APXS data for drill fines from ~1 cm depth within the rippled layers show >40 wt% FeO, ~2 wt% Zn, and >1 wt% MnO (Thompson et al., LPSC 2023); metal enrichment is also seen in ChemCam data, which also show highly variable MnO. Tentative, but reasonable extrapolation of these data to parts of the Marker Band not visited by the rover suggests an excess Fe mass of 0.2 Gton. Potential processes capable of transporting the metals include transport by chloride-rich brines, or (via interaction with CO) as metal carbonyls. Although post-lithification mechanisms for metal emplacement have not been ruled out, a possible pre-lithification mechanism involves Mn and Fe deposition in a shallow lake in oxidizing conditions. In this scenario, Fe and Mn oxide nodules form and scavenge trace metals (e.g. Zn) by adsorption. We will conclude by discussing remaining open questions about the formation and metal enrichment of the rippled Marker Band. For example, possible sources of water for metal transport include (but are not limited to) compaction water, or alternatively groundwater derived from precipitation inside the crater rim

Metal Enrichment of Wave-Rippled Sediments on Ancient Mars

International audienceThe Curiosity rover is ascending a sedimentary-rock mountain, Mount Sharp, testing hypotheses about how and why Mars' surface dried out. Within the past year, Curiosity has investigated an apparently Mount-Sharp-spanning feature - the Marker Band, which frequently forms a topographic bench. The Marker Band is distinctive in its lateral extent, stratigraphic confinement, and nontrivial thickness. The Marker Band also shows a distinct metal-rich geochemistry unlike any other materials previously analyzed by the rover, and its lower part exhibits wave ripples extending across hundreds of meters (possibly kilometers). Thus, the Marker Band is a marker of a change in the environment within Gale crater from drier conditions that formed underlying sulfates to wetter conditions that formed wave ripples (Gupta et al. this conference). Wave ripples do not persist above the rippled Marker Band, but further clues regarding the evolution of Mars' carbon cycle and atmosphere are obtained from carbonate in drilled samples immediately above the rippled Marker Band (Tutolo et al., this conference), which is strongly elevated in δ13C (Burtt et al., this conference). APXS data for drill fines from ~1 cm depth within the rippled layers show >40 wt% FeO, ~2 wt% Zn, and >1 wt% MnO (Thompson et al., LPSC 2023); metal enrichment is also seen in ChemCam data, which also show highly variable MnO. Tentative, but reasonable extrapolation of these data to parts of the Marker Band not visited by the rover suggests an excess Fe mass of 0.2 Gton. Potential processes capable of transporting the metals include transport by chloride-rich brines, or (via interaction with CO) as metal carbonyls. Although post-lithification mechanisms for metal emplacement have not been ruled out, a possible pre-lithification mechanism involves Mn and Fe deposition in a shallow lake in oxidizing conditions. In this scenario, Fe and Mn oxide nodules form and scavenge trace metals (e.g. Zn) by adsorption. We will conclude by discussing remaining open questions about the formation and metal enrichment of the rippled Marker Band. For example, possible sources of water for metal transport include (but are not limited to) compaction water, or alternatively groundwater derived from precipitation inside the crater rim

Post-landing major element quantification using SuperCam laser induced breakdown spectroscopy

International audienceThe SuperCam instrument on the Perseverance Mars 2020 rover uses a pulsed 1064 nm laser to ablate targets at a distance and conduct laser induced breakdown spectroscopy (LIBS) by analyzing the light from the resulting plasma. SuperCam LIBS spectra are preprocessed to remove ambient light, noise, and the continuum signal present in LIBS observations. Prior to quantification, spectra are masked to remove noisier spectrometer regions and spectra are normalized to minimize signal fluctuations and effects of target distance. In some cases, the spectra are also standardized or binned prior to quantification. To determine quantitative elemental compositions of diverse geologic materials at Jezero crater, Mars, we use a suite of 1198 laboratory spectra of 334 well-characterized reference samples. The samples were selected to span a wide range of compositions and include typical silicate rocks, pure minerals (e.g., silicates, sulfates, carbonates, oxides), more unusual compositions (e.g., Mn ore and sodalite), and replicates of the sintered SuperCam calibration targets (SCCTs) onboard the rover. For each major element (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O), the database was subdivided into five "folds" with similar distributions of the element of interest. One fold was held out as an independent test set, and the remaining four folds were used to optimize multivariate regression models relating the spectrum to the composition. We considered a variety of models, and selected several for further investigation for each element, based primarily on the root mean squared error of prediction (RMSEP) on the test set, when analyzed at 3 m. In cases with several models of comparable performance at 3 m, we incorporated the SCCT performance at different distances to choose the preferred model. Shortly after landing on Mars and collecting initial spectra of geologic targets, we selected one model per element. Subsequently, with additional data from geologic targets, some models were revised to ensure results that are more consistent with geochemical constraints. The calibration discussed here is a snapshot of an ongoing effort to deliver the most accurate chemical compositions with SuperCam LIBS

The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests

The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover Curiosity provides remote compositional information using the first laser-induced breakdown spectrometer (LIBS) on a planetary mission, and provides sample texture and morphology data using a remote micro-imager (RMI). Overall, ChemCam supports MSL with five capabilities: remote classification of rock and soil characteristics; quantitative elemental compositions including light elements like hydrogen and some elements to which LIBS is uniquely sensitive (e.g., Li, Be, Rb, Sr, Ba); remote removal of surface dust and depth profiling through surface coatings; context imaging; and passive spectroscopy over the 240-905 nm range. ChemCam is built in two sections: The mast unit, consisting of a laser, telescope, RMI, and associated electronics, resides on the rover's mast, and is described in a companion paper. ChemCam's body unit, which is mounted in the body of the rover, comprises an optical demultiplexer, three spectrometers, detectors, their coolers, and associated electronics and data handling logic. Additional instrument components include a 6 m optical fiber which transfers the LIBS light from the telescope to the body unit, and a set of onboard calibration targets. ChemCam was integrated and tested at Los Alamos National Laboratory where it also underwent LIBS calibration with 69 geological standards prior to integration with the rover. Post-integration testing used coordinated mast and instrument commands, including LIBS line scans on rock targets during system-level thermal-vacuum tests. In this paper we describe the body unit, optical fiber, and calibration targets, and the assembly, testing, and verification of the instrument prior to launch

The SuperCam Instrument Suite on the NASA Mars 2020 Rover: Body Unit and Combined System Tests

TheSuperCaminstrumentsuiteprovidestheMars2020rover,Perseverance,with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and in- frared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: The mast unit (MU), consisting of the laser, telescope, RMI, IR spectrometer, and associated electronics, is described in a companion paper. The on-board calibration targets are described in another companion paper. Here we describe SuperCam’s body unit (BU) and testing of the integrated instrument.The BU, mounted inside the rover body, receives light from the MU via a 5.8 m opti- cal fiber. The light is split into three wavelength bands by a demultiplexer, and is routed via fiber bundles to three optical spectrometers, two of which (UV and violet; 245–340 and 385–465 nm) are crossed Czerny-Turner reflection spectrometers, nearly identical to their counterparts on ChemCam. The third is a high-efficiency transmission spectrometer contain- ing an optical intensifier capable of gating exposures to 100 ns or longer, with variable delay times relative to the laser pulse. This spectrometer covers 535–853 nm (105–7070 cm−1 Ra- man shift relative to the 532 nm green laser beam) with 12 cm−1 full-width at half-maximum peak resolution in the Raman fingerprint region. The BU electronics boards interface with the rover and control the instrument, returning data to the rover. Thermal systems maintain a warm temperature during cruise to Mars to avoid contamination on the optics, and cool the detectors during operations on Mars.Results obtained with the integrated instrument demonstrate its capabilities for LIBS, for which a library of 332 standards was developed. Examples of Raman and VISIR spec- troscopy are shown, demonstrating clear mineral identification with both techniques. Lumi- nescence spectra demonstrate the utility of having both spectral and temporal dimensions. Finally, RMI and microphone tests on the rover demonstrate the capabilities of these sub- systems as well