57 research outputs found
Characterization and mapping of surface physical properties of Mars from CRISM multi-angular data: application to Gusev Crater and Meridiani Planum
The analysis of the surface texture from the particle (grain size, shape and
internal structure) to its organization (surface roughness) provides
information on the geological processes. CRISM multi-angular observations
(varied emission angles) allow to characterize the surface scattering behavior
which depends on the composition but also the material physical properties
(e.g., grain size, shape, internal structure, the surface roughness). After an
atmospheric correction by the Multi-angle Approach for Retrieval of the Surface
Reflectance from CRISM Observations, the surface reflectances at different
geometries are analyzed by inverting the Hapke photometric model depending on
the single scattering albedo, the 2-term phase function, the macroscopic
roughness and the 2-term opposition effects. Surface photometric maps are
created to observe the spatial variations of surface scattering properties as a
function of geological units at the CRISM spatial resolution (200m/pixel). An
application at the Mars Exploration Rover (MER) landing sites located at Gusev
Crater and Meridiani Planum where orbital and in situ observations are
available, is presented. Complementary orbital observations (e.g. CRISM
spectra, THermal EMission Imaging System, High Resolution Imaging Science
Experiment images) are used for interpreting the estimated Hapke photometric
parameters in terms of physical properties. The in situ observations are used
as ground truth to validate the interpretations. Varied scattering properties
are observed inside a CRISM observation (5x10km) suggesting that the surfaces
are controlled by local geological processes (e.g. volcanic resurfacing,
aeolian and impact processes) rather than regional or global. Consistent
results with the in situ observations are observed thus validating the approach
and the use of photometry for the characterization of Martian surface physical
properties
Surface reflectance of Mars observed by CRISM/MRO: 2. Estimation of surface photometric properties in Gusev Crater and Meridiani Planum
The present article proposes an approach to analyze the photometric
properties of the surface materials from multi-angle observations acquired by
the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on-board the
Mars Reconnaissance Orbiter. We estimate photometric parameters using Hapke
model in a Bayesian inversion framework. This work also represents a validation
of the atmospheric correction provided by the Multi-angle Approach for
Retrieval of Surface Reflectance from CRISM Observations (MARS-ReCO) proposed
in the companion article.The latter algorithm retrieves photometric curves of
surface materials in reflectance units after removing the aerosol contribution.
This validation is done by comparing the estimated photometric parameters to
those obtained from in situ measurements by Panoramic Camera instrument at the
Mars Exploration Rover (MER)-Spirit and MER-Opportunity landing sites.
Consistent photometric parameters with those from in situ measurements are
found, demonstrating that MARS-ReCO gives access to accurate surface
reflectance. Moreover the assumption of a non-Lambertian surface as included in
MARS-ReCO is shown to be significantly more precise to estimate surface
photometric properties from space in comparison to methods based on a
Lambertian surface assumption. In the future, the presented method will allow
us to map from orbit the surface bidirectional reflectance and the related
photometric parameters in order to characterize the Martian surface
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
OLIVINE COMPOSITION AND REFLECTANCE SPECTROSCOPY RELATIONSHIP REVISITED
International audienc
Asystematic intercalibration tool between multiband imaging and spot spectra datasets
International audienc
Asystematic intercalibration tool between multiband imaging and spot spectra datasets
International audienc
The Aristarchus Plateau on the Moon : Mineralogical and structural study from integrated Clementine UV-Vis-NIR spectral data
International audienc
The Aristarchus Plateau on the Moon : Mineralogical and structural study from integrated Clementine UV-Vis-NIR spectra data
International audienc
A Systematic Testing Approach Using the Modified Gaussian Model (MGM) for Mafic Mineralogy Mapping in Natural Conditions (Earth, Mars)
International audienc
OMEGA mapping the recent volcanotectonic activity at Cerberus, Mars from HRSC and OMEGA observations
International audienc
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