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

Evaluation of a generic unidirectional header compression protocol

Header Compression techniques are now widely used in wireless and satellite communications. The main drawback of these techniques is to weaken the transmission against bit error or packet losses. Indeed, a corrupted or missing header can lead to a non-decompression of consecutive packets and then to a disconnection until the reception of a non-compressed packet. The parameters of the header compression system should then be carefully determined. In this paper, we first review the main header compression protocols standardized for a unidirectional link. This analysis allows us to build a simple generic header compression model depending on few parameters characterizing a header compression protocol. The evaluation of this model in cases corresponding to particular applications allows us to draw some first lessons for the use of header compression in Satellite communications

En cas de panne

Les pannes font parler, donnent à penser et mettent au travail. Malgré les efforts pour les contrôler, les anticiper et les prévenir, les pannes constituent toujours des moments de rupture, de suspens, qui menacent des ordres productifs, techniques, symboliques et sociaux de plus en plus hybridés. Les pannes dont il est question dans ce numéro ouvrent de vastes horizons géographiques, historiques, sensoriels et pratiques. Elles offrent un point de vue nouveau sur nombre de situations limites actuelles, où des algues proliférantes côtoient de trop près des téléviseurs, où des haies à comptabiliser constituent une épreuve pour les nouveaux salariés du clic, et où la reprise en main en mode manuel s’éloigne à mesure que l’hybridation entre l’être humain et la machine devient manifeste. Non, la panne n’a pas disparu de nos sociétés, elle continue de s’y lover, faisant feu de tout bois, humains et non-humains éternellement intriqués

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

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 ofthe 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-ResolvedRaman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), highresolution 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 reporton SuperCam’s science objectives in the context of the Mars 2020 mission goals and waysthe 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 providedby the United States; the calibration target holder is contributed by Spain, and the targetsthemselves 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 workis 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 itwill serve as the foundation for Mars operations and future processing of the dat

Isotope ratios of H, C, and O in CO2 and H2O of the Martian atmosphere

Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and O-18/O-16 in water and C-13/C-12, O-18/O-16, O-17/O-16, and (CO)-C-13-O-18/(CO)-C-12-O-16 in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established similar to 4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing