Mastcam-Z is a multispectral, stereoscopic imaging investigation on the Mars 2020 mission’s
Perseverance
rover. Mastcam-Z consists of a pair of focusable, 4:1 zoomable cameras that provide broadband ...red/green/blue and narrowband 400-1000 nm color imaging with fields of view from 25.6° × 19.2° (26 mm focal length at 283 μrad/pixel) to 6.2° × 4.6° (110 mm focal length at 67.4 μrad/pixel). The cameras can resolve (≥ 5 pixels) ∼0.7 mm features at 2 m and ∼3.3 cm features at 100 m distance. Mastcam-Z shares significant heritage with the Mastcam instruments on the Mars Science Laboratory
Curiosity
rover. Each Mastcam-Z camera consists of zoom, focus, and filter wheel mechanisms and a 1648 × 1214 pixel charge-coupled device detector and electronics. The two Mastcam-Z cameras are mounted with a 24.4 cm stereo baseline and 2.3° total toe-in on a camera plate ∼2 m above the surface on the rover’s Remote Sensing Mast, which provides azimuth and elevation actuation. A separate digital electronics assembly inside the rover provides power, data processing and storage, and the interface to the rover computer. Primary and secondary Mastcam-Z calibration targets mounted on the rover top deck enable tactical reflectance calibration. Mastcam-Z multispectral, stereo, and panoramic images will be used to provide detailed morphology, topography, and geologic context along the rover’s traverse; constrain mineralogic, photometric, and physical properties of surface materials; monitor and characterize atmospheric and astronomical phenomena; and document the rover’s sample extraction and caching locations. Mastcam-Z images will also provide key engineering information to support sample selection and other rover driving and tool/instrument operations decisions.
The Mars 2020
Perseverance
rover is equipped with a next-generation engineering camera imaging system that represents an upgrade over previous Mars rover missions. These upgrades will improve the ...operational capabilities of the rover with an emphasis on drive planning, robotic arm operation, instrument operations, sample caching activities, and documentation of key events during entry, descent, and landing (EDL). There are a total of 16 cameras in the
Perseverance
engineering imaging system, including 9 cameras for surface operations and 7 cameras for EDL documentation. There are 3 types of cameras designed for surface operations: Navigation cameras (Navcams, quantity 2), Hazard Avoidance Cameras (Hazcams, quantity 6), and Cachecam (quantity 1). The Navcams will acquire color stereo images of the surface with a
96
∘
×
73
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field of view at 0.33 mrad/pixel. The Hazcams will acquire color stereo images of the surface with a
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102
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at 0.46 mrad/pixel. The Cachecam, a new camera type, will acquire images of Martian material inside the sample tubes during caching operations at a spatial scale of 12.5 microns/pixel. There are 5 types of EDL documentation cameras: The Parachute Uplook Cameras (PUCs, quantity 3), the Descent stage Downlook Camera (DDC, quantity 1), the Rover Uplook Camera (RUC, quantity 1), the Rover Descent Camera (RDC, quantity 1), and the Lander Vision System (LVS) Camera (LCAM, quantity 1). The PUCs are mounted on the parachute support structure and will acquire video of the parachute deployment event as part of a system to characterize parachute performance. The DDC is attached to the descent stage and pointed downward, it will characterize vehicle dynamics by capturing video of the rover as it descends from the skycrane. The rover-mounted RUC, attached to the rover and looking upward, will capture similar video of the skycrane from the vantage point of the rover and will also acquire video of the descent stage flyaway event. The RDC, attached to the rover and looking downward, will document plume dynamics by imaging the Martian surface before, during, and after rover touchdown. The LCAM, mounted to the bottom of the rover chassis and pointed downward, will acquire
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FOV images during the parachute descent phase of EDL as input to an onboard map localization by the Lander Vision System (LVS). The rover also carries a microphone, mounted externally on the rover chassis, to capture acoustic signatures during and after EDL. The
Perseverance
rover launched from Earth on July 30th, 2020, and touchdown on Mars is scheduled for February 18th, 2021.
During Martian solar days 57–100, the Mars Science Laboratory Curiosity rover acquired and processed a solid (sediment) sample and analyzed its mineralogy and geochemistry with the Chemistry and ...Mineralogy and Sample Analysis at Mars instruments. An aeolian deposit—herein referred to as the Rocknest sand shadow—was inferred to represent a global average soil composition and selected for study to facilitate integration of analytical results with observations from earlier missions. During first‐time activities, the Mars Hand Lens Imager (MAHLI) was used to support both science and engineering activities related to sample assessment, collection, and delivery. Here we report on MAHLI activities that directly supported sample analysis and provide MAHLI observations regarding the grain‐scale characteristics of the Rocknest sand shadow. MAHLI imaging confirms that the Rocknest sand shadow is one of a family of bimodal aeolian accumulations on Mars—similar to the coarse‐grained ripples interrogated by the Mars Exploration Rovers Spirit and Opportunity—in which a surface veneer of coarse‐grained sediment stabilizes predominantly fine‐grained sediment of the deposit interior. The similarity in grain size distribution of these geographically disparate deposits support the widespread occurrence of bimodal aeolian transport on Mars. We suggest that preservation of bimodal aeolian deposits may be characteristic of regions of active deflation, where winnowing of the fine‐sediment fraction results in a relatively low sediment load and a preferential increase in the coarse‐grained fraction of the sediment load. The compositional similarity of Martian aeolian deposits supports the potential for global redistribution of fine‐grained components, combined with potential local contributions.
Key Points
Curiosity acquired and examined its first solid sample at the Rocknest sand shadow
MAHLI images were critical in the science investigation of Rocknest materials
MAHLI images played a critical role supporting first‐time engineering activities
•We describe various imaging experiments made by ChemCam’s Remote Microscopic Imager.•RMI gives the LIBS geological context and serves for long distance reconnaissance.•RMI provides clues regarding ...the origin of rocks and their diagenetic evolution.
The Mars Science Laboratory rover, “Curiosity” landed near the base of a 5km-high mound of layered material in Gale crater. Mounted on the rover mast, the ChemCam instrument is designed to remotely determine the composition of soils and rocks located a few meters from the rover, using a Laser-Induced Breakdown Spectrometer (LIBS) coupled to a Remote Micro-Imager (RMI). We provide an overview of the diverse imaging investigations that were carried out by ChemCam’s RMI during the first year of operation on Mars. 1182 individual panchromatic RMI images were acquired from Sol 10 to Sol 360 to document the ChemCam LIBS measurements and to characterize soils, rocks and rover hardware. We show several types of derived imaging products, including mosaics of images taken before and after laser shots, difference images to enhance the most subtle laser pits, merges with color Mastcam-100 images, micro-topography using the Z-stack technique, and time lapse movies. The very high spatial resolution of RMI is able to resolve rock textures at sub-mm scales, which provides clues regarding the origin (igneous versus sedimentary) of rocks, and to reveal information about their diagenetic and weathering evolution. In addition to its scientific value over the range accessible by LIBS (1–7m), we also show that RMI can also serve as a powerful long distance reconnaissance tool to characterize the landscape at distances up to several kilometers from the rover.
We have assessed the characteristics of clasts along Curiosity's traverse to shed light on the processes important in the genesis, modification, and transportation of surface materials. Pebble‐ to ...cobble‐sized clasts at Bradbury Landing, and subsequently along Curiosity's traverse to Yellowknife Bay, reflect a mixing of two end‐member transport mechanisms. The general clast population likely represents material deposited via impact processes, including meteorite fragments, ejecta from distant craters, and impactites consisting of shocked and shock‐melted materials from within Gale Crater, which resulted predominantly in larger, angular clasts. A subset of rounded pebble‐sized clasts has likely been modified by intermittent alluvial or fluvial processes. The morphology of this rounded clast population indicates that water was a more important transporting agent here than at other Mars sites that have been studied in situ. Finally, we identified populations of basalt clasts and porphyritic clasts of undetermined composition by their morphologic and textural characteristics; basalts are confirmed by geochemical data provided by ChemCam.
Key Points
We examined Curiosity clasts to assess modification and transport processes
Pebble‐ to cobble‐sized clasts reflect a mix of two transport mechanisms
Water was an important transporting agent at the Curiosity landing site
Hydroxyapatite (HA) powders were synthesized by the wet precipitation method, with and without surfactant, under identical processing parameters. These powders were then heat treated at 900°C for 3h ...in air. The detailed characterization of the powders was done by using SEM, dynamic light scattering, nitrogen adsorption, XRD, Raman spectroscopy, and FTIR techniques. The HA phase, identified by well defined PO43− and OH− ion peaks in Raman and FTIR spectra, was observed in all the powder samples. The addition of surfactant changed the morphology of the particles from spherical to needle/rod-like structure and increased the surface area up to three times (from 33 to 96m2/g). Also, suppression in the evolution of β-TCP phase was observed along with decrease in the crystal size and crystallinity of the powder due to the addition of surfactant. Synthesized nano-HA crystals were found to have diameters and lengths in the range 10–25nm and 75–150nm, respectively. The heat treatment changed the architecture of the particles, increased the crystallinity and reduced the surface area to ≈7m2/g. However, the relative increase in crystallinity was much higher for the powder synthesized with surfactant. The ratio of the average crystallite size to the crystallinity degree was about 0.53±0.07 for all the powders. The particle size distribution was bimodal and coarser for the powder synthesized without surfactant. The pore size analysis showed transformation of a predominantly mesoporous structure into a meso- plus macroporous one on heat treatment. The intensity of OH− group peak in Raman spectra was found to be highly sensitive to the crystalline state of the HA powder and may be used to assess crystallinity.
The NASA Curiosity rover Mast Camera (Mastcam) system is a pair of fixed-focal length, multispectral, color CCD imagers mounted approximately 2 m above the surface on the rover's remote sensing mast, ...along with associated electronics and an onboard calibration target. The left Mastcam (M-34) has a 34 mm focal length, an instantaneous field of view (IFOV) of 0.22 mrad, and a FOV of 20 deg × 15 deg over the full 1648 × 1200 pixel span of its Kodak KAI-2020 CCD. The right Mastcam (M-100) has a 100 mm focal length, an IFOV of 0.074 mrad, and a FOV of 6.8 deg × 5.1 deg using the same detector. The cameras are separated by 24.2 cm on the mast, allowing stereo images to be obtained at the resolution of the M-34 camera. Each camera has an eight-position filter wheel, enabling it to take Bayer pattern red, green, and blue (RGB) 'true color' images, multispectral images in nine additional bands spanning approximately 400-1100 nm, and images of the Sun in two colors through neutral density-coated filters. An associated Digital Electronics Assembly provides command and data interfaces to the rover, 8 Gb of image storage per camera, 11 bit to 8 bit companding, JPEG compression, and acquisition of high-definition video. Here we describe the preflight and in-flight calibration of Mastcam images, the ways that they are being archived in the NASA Planetary Data System, and the ways that calibration refinements are being developed as the investigation progresses on Mars. We also provide some examples of data sets and analyses that help to validate the accuracy and precision of the calibration.
•MER Pancam photometric data for both rovers collected from 1900 images and modeled.•El Dorado low albedo ripple sands among most forward-scattering materials modeled.•Silica-rich materials near Home ...Plate exhibited wavelength-dependent scattering.•Soil albedo outside Victoria Crater wind streak ∼16% higher than inside streak.•Opportunity outcrop rocks and soils homogeneous over 12km of rover traverse path.
The Panoramic Camera (Pancam) on the Mars Exploration Rovers Spirit and Opportunity acquired visible/near-infrared (432–1009nm) multispectral observations of soils and rocks under varying viewing and illumination geometries. Data retrieved from these images were modeled using radiative transfer theory to study the microphysical and surface scattering nature of materials at both sites. Nearly 57,000 individual measurements from 1900 images were collected of rock and soil units identified by their color and morphologic properties over a wide range of phase angles (0–150°). Images were acquired between Sols 500 and 1525 in the Columbia Hills and regions around Home Plate in Gusev Crater and in the plains and craters between Erebus and Victoria Craters in Meridiani Planum. Corrections for diffuse skylight incorporated sky models based on observations of atmospheric opacity throughout the mission. Disparity maps created from Pancam stereo images allowed estimates of local facet orientations. For Spirit, soils at lower elevations near Home Plate were modeled with lower single scattering albedo (w) values than those on the summit of Husband Hill, but otherwise soils exhibited similar scattering properties to previous Gusev soils. Dark ripple sands at the El Dorado dunes were among the most forward-scattering materials modeled. Silica-rich soils and nodules near Home Plate were analyzed for the first time, and exhibited increased forward scattering behavior with increasing wavelength, consistent with microporosity inferred from previous high resolution images and thermal infrared spectroscopy. For Opportunity, the opposition effect width parameter for sandstone outcrop rocks was modeled for the first time, and demonstrated average values consistent with surfaces of intermediate porosity and/or grain size distribution between those modeled for spherule-rich soils and darker, clast-poor soils. Soils outside a wind streak emanating from the northern rim of Victoria Crater exhibited w values ∼16% higher than soils inside the streak. Overall, w values and scattering properties for outcrop rocks, spherule-rich soils, and rover tracks were similar to previous Meridiani Planum analyses, emphasizing the homogeneity of these materials across nearly 12km of rover odometry.
The light-scattering properties of surface materials on Mars are typically modeled using in situ spectrophotometric imaging sequences taken at multiple times of day to provide sufficient phase ...coverage. Herein, we report analyses of observations acquired at one time of day but under varying emission angles using the Mars Hand Lens Imager (MAHLI) on the robotic arm of the Mars Science Laboratory (MSL) rover as a goniometer. A multiple-viewpoint data set was acquired on Sol 544 by manipulating the arm to provide MAHLI images from 20 arm positions, all centered at the same location and from a near-constant distance of 1 m from the surface, permitting a phase angle coverage from ∼8 to 100°. From these images, we constructed a digital terrain model of the scene, and used it in combination with atmospheric scattering models to remove the diffuse components of radiance from surface units. Radiative transfer models using Hapke theory were conducted using the direct radiance components from specific rock and soil units. Despite the relatively limited number of observations, our modeled Hapke parameters were well-constrained for terrain types such as soils and certain types of rocks that were common within the scene, but the errors increased for rock types with fewer observations. Results from one-term and two-term Henyey-Greenstein phase functions show the soil units to be more backscattering than rocks, consistent with previous photometric studies of martian landing sites. Overall, we find that the MAHLI goniometer sequences can produce reasonable and consistent photometric results, providing a new and efficient means of acquiring spectrophotometric data by arm cameras on rovers such as MSL.
•Demonstrated first use of a Mars rover arm-mounted camera (MAHLI) as a goniometer•Obtained color images at 20 arm positions, covering phase angles of 8–100 °•Ran Hapke scattering models of atmosphere-removed direct radiance of rocks and soil•Modeled single scattering albedo and phase function well, similar to past Mars work•Method holds promise for quick, efficient means to characterize surface photometry.
The last sets of Panoramic Camera (Pancam) visible/near-infrared (432–1009 nm) multispectral observations made under varying viewing and illumination geometries by the Mars Exploration Rovers Spirit ...and Opportunity were examined using radiative transfer models to study the surface scattering and microphysical nature of rock and soil units at both sites. Nearly 12,000 individual measurements were collected for this study of soil, dust, and rock units over phase angles of ~0° to ~150°. Images were acquired on sols 1944–1946 (June 2009) at Troy, the final resting place of Spirit on the western side of Home Plate in Gusev crater, and by Opportunity at three locations on the western rim of Endeavour crater in Meridiani Planum between sols 2785 (November 2011) and 3867 (December 2014). Sky models were developed from observations of atmospheric opacity, which enabled corrections for diffuse skylight when combined with surface facet orientations determined from stereo images. Model results were improved by removing data affected by scattered light evident in some high phase angle images (resulting from minor dust contamination on the camera windows). At Troy, relatively dust-free “gray” rock units exhibited narrow, forward scattering behaviors akin to previous analyses of similar gray rock units at Gusev crater. Soils and “red” rocks coated with greater amounts of dust were more backscattering. Red rocks exhibited higher single scattering albedo (w), macroscopic roughness (θ), and opposition effect width (h) parameters, indicative of rough, low-porosity surfaces perhaps with more uniform grain size distributions. At Meridiani Planum, rubbly soils near São Gabriel crater and Cape Tribulation exhibited w values typical of previous soil analyses. However, the large drift “dust” deposits found in depressions on the northern tip of Cape York near Turkey Haven demonstrated elevated w values with a downturn toward 1009 nm, consistent with minor hydration of these materials. The dust deposits were modeled with the lowest θ values and highest h values of all soil units analyzed during the Opportunity mission, indicative of a smooth surface with homogeneous grain size distribution and/or lower porosity than other units. The dust unit scattering function was dissimilar to those for atmospheric and airfall-deposited dusts, however, suggesting that the originally deposited materials had been modified, perhaps by hydration and ongoing aeolian effects. Analyses of phase curve ratios among the units studied here and from laboratory data of analog soils suggested that surface scattering is a major control on the peak phase angle position of the “arch” in phase curve ratios, alongside the effects of particle-scale roughness.
•Surface scattering studied using final Pancam visible/near-infrared photometry data.•Dust deposits showed single-scattering albedo values consistent with minor hydration.•Dust exhibited smoothest surface with uniform grain size &/or low relative porosity.•Dust scattering function was dissimilar to atmospheric and airfall-deposited dust.•Phase curve ratios suggested surface scattering controls peak phase angle of “arch”.
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