TY - JOUR
T1 - Spectrophotometric properties of materials from the Mars Science Laboratory at Gale crater
T2 - 1. Bradbury Landing to Cooperstown
AU - Johnson, Jeffrey R.
AU - Grundy, William M.
AU - Lemmon, Mark T.
AU - Liang, W.
AU - Bell, James F.
AU - Hayes, A. G.
AU - Deen, R. G.
N1 - Publisher Copyright:
© 2022 The Authors
PY - 2022/11/1
Y1 - 2022/11/1
N2 - During the first 443 martian days (sols) of the Mars Science Laboratory (MSL) Curiosity rover mission, visible/near-infrared (445–1012 nm) multispectral observations were acquired at different times of sol by the Mast Camera (Mastcam) and Navigation Camera (Navcam) at five locations along the traverse. Measurements of soil, dust, and rock units spanned sufficient incidence, emission, and phase angles to enable radiative transfer models to constrain the surface scattering functions, single-scattering albedo (w), and microphysical properties of the units at each site. Although the model results were mainly consistent with previous results from other landing sites, there were some notable exceptions. For example, the less dusty “Blue rocks” units were modeled as more backscattering compared to ostensibly dustier “Red rocks” units, which was opposite to results from other landed missions. Relations between the peak phase angle of phase curve ratios, w values, and macroscopic roughness (θ¯) suggested that unlike most of the materials observed by the Spirit and Opportunity rovers, the effects of particle-scale roughness and internal scattering were a greater influence on MSL units than surface scattering. Also noteworthy were unique photometric signatures modeled from data acquired at the landing site on Sol 20 as part of the first in situ spectrophotometric analyses of materials subjected to erosion and/or surface dust removal from spacecraft descent engines. Modeled w spectra were relatively flat and dark for the Sol 20 Blue rocks unit and were positively correlated with average θ¯ values, similar to some laboratory studies of coarse-grained and/or glassy mafic materials. While low w values and backscattering behaviors were modeled for the Sol 20 “Regolith” unit, the more heavily scoured, lighter-toned regions included soils with extremely forward scattering behaviors, large w values, and that lacked ferric absorption features. The absence of phase reddening effects in all the Sol 20 units likely also was caused by surface disruptions during the landing. Future analyses of additional spectrophotometric data sets from both Curiosity and the Mars 2020 Perseverance rover will continue to yield important comparisons among the variable scattering properties of martian geologic units.
AB - During the first 443 martian days (sols) of the Mars Science Laboratory (MSL) Curiosity rover mission, visible/near-infrared (445–1012 nm) multispectral observations were acquired at different times of sol by the Mast Camera (Mastcam) and Navigation Camera (Navcam) at five locations along the traverse. Measurements of soil, dust, and rock units spanned sufficient incidence, emission, and phase angles to enable radiative transfer models to constrain the surface scattering functions, single-scattering albedo (w), and microphysical properties of the units at each site. Although the model results were mainly consistent with previous results from other landing sites, there were some notable exceptions. For example, the less dusty “Blue rocks” units were modeled as more backscattering compared to ostensibly dustier “Red rocks” units, which was opposite to results from other landed missions. Relations between the peak phase angle of phase curve ratios, w values, and macroscopic roughness (θ¯) suggested that unlike most of the materials observed by the Spirit and Opportunity rovers, the effects of particle-scale roughness and internal scattering were a greater influence on MSL units than surface scattering. Also noteworthy were unique photometric signatures modeled from data acquired at the landing site on Sol 20 as part of the first in situ spectrophotometric analyses of materials subjected to erosion and/or surface dust removal from spacecraft descent engines. Modeled w spectra were relatively flat and dark for the Sol 20 Blue rocks unit and were positively correlated with average θ¯ values, similar to some laboratory studies of coarse-grained and/or glassy mafic materials. While low w values and backscattering behaviors were modeled for the Sol 20 “Regolith” unit, the more heavily scoured, lighter-toned regions included soils with extremely forward scattering behaviors, large w values, and that lacked ferric absorption features. The absence of phase reddening effects in all the Sol 20 units likely also was caused by surface disruptions during the landing. Future analyses of additional spectrophotometric data sets from both Curiosity and the Mars 2020 Perseverance rover will continue to yield important comparisons among the variable scattering properties of martian geologic units.
KW - Curiosity
KW - Mars
KW - Multispectral
KW - Photometry
KW - Spectroscopy
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U2 - 10.1016/j.pss.2022.105563
DO - 10.1016/j.pss.2022.105563
M3 - Article
AN - SCOPUS:85137672065
SN - 0032-0633
VL - 222
JO - Planetary and Space Science
JF - Planetary and Space Science
M1 - 105563
ER -