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The Mastcam-Z Radiometric Calibration Targets on NASA’s Perseverance Rover: Derived Irradiance Time-Series, Dust Deposition, and Performance over the First 350 Sols on Mars.
  • +17
  • Marco Merusi,
  • Kjartan Münster Kinch,
  • Morten Bo Madsen,
  • James F. Bell III,
  • Justin N. Maki,
  • Alexander G. Hayes,
  • Jonathan Joseph,
  • Jeffrey R. Johnson,
  • Meiissa Rice,
  • Edward Cloutis,
  • Daniel Applin,
  • Mark T Lemmon,
  • Alicia Fallacaro Vaughan,
  • Jorge I. Núñez,
  • Elsa Jensen,
  • Jessica Z. Kristensen,
  • Kristen Paris,
  • Ernest Cisneros,
  • Megan R Kennedy,
  • Olivier Gasnault
Marco Merusi
University of Copenhagen, University of Copenhagen

Corresponding Author:[email protected]

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Kjartan Münster Kinch
University of Copenhagen, University of Copenhagen
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Morten Bo Madsen
Niels Bohr Institute, University of Copenhagen, Denmark, Niels Bohr Institute, University of Copenhagen, Denmark
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James F. Bell III
Arizona State University, Arizona State University
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Justin N. Maki
Jet Propulsion Laboratory, California Institute of Technology, Jet Propulsion Laboratory, California Institute of Technology
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Alexander G. Hayes
Cornell University, Cornell University
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Jonathan Joseph
Cornell University, Cornell University
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Jeffrey R. Johnson
Johns Hopkins University Applied Physics Laboratory, Johns Hopkins University Applied Physics Laboratory
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Meiissa Rice
Western Washington University, Western Washington University
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Edward Cloutis
University of Winnepeg, University of Winnepeg
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Daniel Applin
UW, UW
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Mark T Lemmon
Space Science Institute, Space Science Institute
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Alicia Fallacaro Vaughan
Apogee Engineering, LLC, Apogee Engineering, LLC
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Jorge I. Núñez
Johns Hopkins University Applied Physics Laboratory, Johns Hopkins University Applied Physics Laboratory
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Elsa Jensen
Malin Space Science Systems, Inc., Malin Space Science Systems, Inc.
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Jessica Z. Kristensen
Niels Bohr Institute, University of Copenhagen, Niels Bohr Institute, University of Copenhagen
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Kristen Paris
Arizona State University, Arizona State University
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Ernest Cisneros
Arizona State University, Arizona State University
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Megan R Kennedy
Malin Space Science Systems, Malin Space Science Systems
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Olivier Gasnault
Institut de Recherche en Astrophysique et Planétologie (IRAP), Institut de Recherche en Astrophysique et Planétologie (IRAP)
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Abstract

The Mastcam-Z radiometric calibration targets mounted on the NASA’s Perseverance rover proved to be effective in the calibration of Mastcam-Z images to reflectance (I/F) over the first 350 sols on Mars. Mastcam-Z imaged the calibration targets regularly to perform reflectance calibration on multispectral image sets of targets on the Martian surface. For each calibration target image, mean radiance values were extracted for 41 distinct regions of the targets, including patches of color and grayscale materials. Eight strong permanent magnets, placed under the primary target, attracted magnetic dust and repelled it from central surfaces, allowing the extraction of radiance values from eight regions relatively clean from dust. These radiances were combined with reflectances obtained from laboratory measurements, a one-term linear fit model was applied, and the slopes of the fits were retrieved as estimates of the solar irradiance and used to convert Mastcam-Z images from radiance to reflectance. Derived irradiance time series are smoothly varying in line with expectations based on the changing Mars-Sun distance, being only perturbed by a few significant dust events. The deposition of dust on the calibration targets was largely concentrated on the magnets, ensuring a minimal influence of dust on the calibration process. The fraction of sunlight directly hitting the calibration targets was negatively correlated with the atmospheric optical depth, as expected. Further investigation will aim at explaining the origin of a small offset observed in the fit model employed for calibration, and the causes of a yellowing effect affecting one of the calibration targets materials.