Examinando por Autor "Bell, J. F."

Mostrando 1 - 3 de 3

Acceso Abierto
Dust, Sand, and Winds Within an Active Martian Storm in Jezero Crater
(AGU Advancing Earth and Space Science, 2022-11-16) Lemmon, M. T.; Smith, M. D.; Viúdez Moreiras, Daniel; De la Torre Juarez, M.; Vicente Retortillo, Á.; Munguira, A.; Sánchez Lavega, A.; Hueso, R.; Martínez, Germán; Chide, B.; Sullivan, R.; Toledo, D.; Tamppari, L. K.; Bertrand, T.; Bell, J. F.; Newman, C. E.; Baker, M.; Banfield, D.; Rodríguez Manfredi, J. A.; Maki, Justin N.; Apéstigue, Víctor; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN); Ministerio de Economía y Competitividad (MINECO); NASA Jet Propulsion Laboratory (JPL); Arizona State University (ASU); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Rovers and landers on Mars have experienced local, regional, and planetary-scale dust storms. However, in situ documentation of active lifting within storms has remained elusive. Over 5–11 January 2022 (LS 153°–156°), a dust storm passed over the Perseverance rover site. Peak visible optical depth was ∼2, and visibility across the crater was briefly reduced. Pressure amplitudes and temperatures responded to the storm. Winds up to 20 m s−1 rotated around the site before the wind sensor was damaged. The rover imaged 21 dust-lifting events—gusts and dust devils—in one 25-min period, and at least three events mobilized sediment near the rover. Rover tracks and drill cuttings were extensively modified, and debris was moved onto the rover deck. Migration of small ripples was seen, but there was no large-scale change in undisturbed areas. This work presents an overview of observations and initial results from the study of the storm.
Acceso Abierto
Hexagonal Prisms Form in Water-Ice Clouds on Mars, Producing Halo Displays Seen by Perseverance Rover
(AGU Advancing Earth and Space Science, 2022-10-03) Lemmon, M. T.; Toledo, D.; Arruego, I.; Wolff, M. J.; Patel, P.; Guzewich, S.; Colaprete, A.; Vicente Retortillo, Á.; Tamppari, L. K.; Montmessin, F.; De la Torre Juarez, M.; Maki, Justin N.; McConnochie, T.; Brown, Adrian Jon; Bell, J. F.; Apéstigue, Víctor; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN); NASA Jet Propulsion Laboratory (JPL); Arizona State University (ASU); Ministerio de Economía y Competitividad (MINECO); Gobierno Vasco; European Research Council (ERC); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Observations by several cameras on the Perseverance rover showed a 22° scattering halo around the Sun over several hours during northern midsummer (solar longitude 142°). Such a halo has not previously been seen beyond Earth. The halo occurred during the aphelion cloud belt season and the cloudiest time yet observed from the Perseverance site. The halo required crystalline water-ice cloud particles in the form of hexagonal columns large enough for refraction to be significant, at least 11 μm in diameter and length. From a possible 40–50 km altitude, and over the 3.3 hr duration of the halo, particles could have fallen 3–12 km, causing downward transport of water and dust. Halo-forming clouds are likely rare due to the high supersaturation of water that is required but may be more common in northern subtropical regions during northern midsummer.
Acceso Abierto
Radiometric Calibration Targets for the Mastcam-Z Camera on the Mars 2020 Rover Mission
(Springer Link, 2020-12-03) Kinch, K. M.; Madsen, M. B.; Bell, J. F.; Maki, Justin N.; Bailey, P.; Hayes, A. G.; Jensen, O. B.; Merusi, M.; Bernt, M. H.; Sorensen, A. N.; Hilverda, M.; Cloutis, E.; Applin, D.; Mateo Martí, Eva; Manrique, J. A.; López Reyes, G.; Bello Arufe, A.; Ehlmann, B. L.; Buz, J.; Pommerol, A.; Thomas, N.; Affolter, L.; Herkenhoff, K. E.; Johnson, J. R.; Rice, M.; Corlies, P.; Tate, C.; Caplinger, M. A.; Jensen, E.; Kubacki, T.; Cisneros, E.; Paris, K.; Winhold, A.; European Research Council (ERC); Kinch, K. [0000-0002-4629-8880]; López Reyes, G. [0000-0003-1005-1760]; Manrique, J. A. [0000-0002-2053-2819]; Affolter, L. [0000-0002-2869-8522]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Mastcam-Z Camera is a stereoscopic, multispectral camera with zoom capability on NASA’s Mars-2020 Perseverance rover. The Mastcam-Z relies on a set of two deck-mounted radiometric calibration targets to validate camera performance and to provide an instantaneous estimate of local irradiance and allow conversion of image data to units of reflectance (R∗ or I/F) on a tactical timescale. Here, we describe the heritage, design, and optical characterization of these targets and discuss their use during rover operations. The Mastcam-Z primary calibration target inherits features of camera calibration targets on the Mars Exploration Rovers, Phoenix and Mars Science Laboratory missions. This target will be regularly imaged during flight to accompany multispectral observations of the martian surface. The primary target consists of a gold-plated aluminum base, eight strong hollow-cylinder Sm2Co17 alloy permanent magnets mounted in the base, eight ceramic color and grayscale patches mounted over the magnets, four concentric, ceramic grayscale rings and a central aluminum shadow post (gnomon) painted with an IR-black paint. The magnets are expected to keep the central area of each patch relatively free of Martian aeolian dust. The Mastcam-Z secondary calibration target is a simple angled aluminum shelf carrying seven vertically mounted ceramic color and grayscale chips and seven identical, but horizontally mounted ceramic chips. The secondary target is intended to augment and validate the calibration-related information derived from the primary target. The Mastcam-Z radiometric calibration targets are critically important to achieving Mastcam-Z science objectives for spectroscopy and photometric properties.