Examinando por Autor "Conrad, Pamela G."

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Photogeologic Map of the Perseverance Rover Field Site in Jezero Crater Constructed by the Mars 2020 Science Team
(Springer Link, 2020-11-03) Stack, K. M.; Williams, N. R.; Calef, F. J.; Sun, V. Z.; Williford, K. H.; Farley, K. A.; Eide, S.; Flannery, D.; Hughes, C.; Jacob, S. R.; Kah, L. C.; Meyen, F.; Molina, A.; Quantin Nataf, C.; Rice, M.; Russel, P.; Scheller, E.; Seeger, C. H.; Abbey, W. J.; Adler, J. B.; Amudsen, H.; Anderson, R. B.; Ángel, S. M.; Arana, G.; Atkins, J.; Barrington, M.; Berger, T.; Borden, R.; Boring, B.; Brown, A.; Carrier, B. L.; Conrad, Pamela G.; Dypvik, H.; Fagents, S. A.; Gallegos, Z. E.; Garczynski, B.; Golder, K.; Gómez, F.; Goreva, Y.; Gupta, S.; Hamran, S. E.; Hicks, T.; Hinterman, E. D.; Horgan, B. N.; Hurowitz, J.; Johnson, J. R.; Lasue, J.; Kronyak, R. E.; Liu, Y.; Madariaga, J. M.; Mangold, N.; McClean, J.; Miklusicak, N.; Nunes, D.; Rojas, C.; Runyon, K.; Schmitz, N.; Scudder, N.; Shaver, E.; SooHoo, J.; Spaulding, R.; Stanish, E.; Tamppari, L. K.; Tice, M. M.; Turenne, N.; Willis, P. A.; Aileen Yingst, R.; European Research Council (ERC); National Aeronautics and Space Administration (NASA); Molina, A. [0000-0002-5038-2022]; Hughes, C. [0000-0002-7061-1443]; Jacob, S. [0000-0001-9950-1486]; Arana, Gorka [0000-0001-7854-855X]; Sun, V. Z. [0000-0003-1480-7369]; Stack, K. [0000-0003-3444-6695]; Williford, K. [0000-0003-0633-408X]; Flannery, D. [0000-0001-8982-496X]; Gupta, S. [0000-0001-6415-1332]; Williams, N. [0000-0003-0602-484X]; Unidad de Excelencia Científica Centro de Astrobiología María de Maeztu del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Mars 2020 Perseverance rover landing site is located within Jezero crater, a similar to 50 km diameter impact crater interpreted to be a Noachian-aged lake basin inside the western edge of the Isidis impact structure. Jezero hosts remnants of a fluvial delta, inlet and outlet valleys, and infill deposits containing diverse carbonate, mafic, and hydrated minerals. Prior to the launch of the Mars 2020 mission, members of the Science Team collaborated to produce a photogeologic map of the Perseverance landing site in Jezero crater. Mapping was performed at a 1:5000 digital map scale using a 25 cm/pixel High Resolution Imaging Science Experiment (HiRISE) orthoimage mosaic base map and a 1 m/pixel HiRISE stereo digital terrain model. Mapped bedrock and surficial units were distinguished by differences in relative brightness, tone, topography, surface texture, and apparent roughness. Mapped bedrock units are generally consistent with those identified in previously published mapping efforts, but this study's map includes the distribution of surficial deposits and sub-units of the Jezero delta at a higher level of detail than previous studies. This study considers four possible unit correlations to explain the relative age relationships of major units within the map area. Unit correlations include previously published interpretations as well as those that consider more complex interfingering relationships and alternative relative age relationships. The photogeologic map presented here is the foundation for scientific hypothesis development and strategic planning for Perseverance's exploration of Jezero crater.
Acceso Abierto
Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars
(American Geophysical Union: Advancing Earth and Space Science, 2019-11-12) Trainer, M. G.; Wong, M. H.; McConnochie, T. H.; Franz, H. B.; Atreya, S. K.; Conrad, Pamela G.; Lefèvre, F.; Mahaffy, Paul R.; Malespin, C. A.; Manning, H. L. K.; Martín Torres, Javier; Martínez, G. M.; McKay, C. P.; Navarro González, R.; Vicente Retortillo, Á.; Webster, C. R.; Zorzano, María Paz; Universidad Nacional Autónoma de México (UNAM); Zorzano, M. P. [0000-0002-4492-9650]; Navarro González, R. [0000-0002-6078-7621]; Martín Torres, J. [0000-0001-6479-2236]; Vicente Retortillo, A. [0000-0002-4553-7624]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Sample Analysis at Mars (SAM) instrument onboard the Mars Science Laboratory Curiosity rover measures the chemical composition of major atmospheric species (CO2, N2, 40Ar, O2, and CO) through a dedicated atmospheric inlet. We report here measurements of volume mixing ratios in Gale Crater using the SAM quadrupole mass spectrometer, obtained over a period of nearly 5 years (3 Mars years) from landing. The observation period spans the northern summer of MY 31 and solar longitude (LS) of 175° through spring of MY 34, LS = 12°. This work expands upon prior reports of the mixing ratios measured by SAM QMS in the first 105 sols of the mission. The SAM QMS atmospheric measurements were taken periodically, with a cumulative coverage of four or five experiments per season on Mars. Major observations include the seasonal cycle of CO2, N2, and Ar, which lags approximately 20–40° of LS behind the pressure cycle driven by CO2 condensation and sublimation from the winter poles. This seasonal cycle indicates that transport occurs on faster timescales than mixing. The mixing ratio of O2 shows significant seasonal and interannual variability, suggesting an unknown atmospheric or surface process at work. The O2 measurements are compared to several parameters, including dust optical depth and trace CH4 measurements by Curiosity. We derive annual mean volume mixing ratios for the atmosphere in Gale Crater: CO2 = 0.951 (±0.003), N2 = 0.0259 (±0.0006), 40Ar = 0.0194 (±0.0004), O2 = 1.61 (±0.09) x 10‐3, and CO = 5.8 (±0.8) x 10‐4.