Mars Exploration Rover Pancam multispectral imaging of rocks, soils, and dust at Gusev crater and Meridiani Planum

Abstract

Multispectral imaging from the Panoramic Camera (Pancam) instruments on the Mars Exploration Rovers Spirit and Opportunity has provided important new insights about the geology and geologic history of the rover landing sites and traverse locations in Gusev crater and Meridiani Planum. Pancam observations from near-UV to near-IR wavelengths provide limited compositional and mineralogic constraints on the presence abundance, and physical properties of ferric-and ferrous-iron bearing minerals in rocks, soils, and dust at both sites. High resolution and stereo morphologic observations have also helped to infer some aspects of the composition of these materials at both sites. Perhaps most importantly, Pancam observations were often efficiently and effectively used to discover and select the relatively small number of places where in situ measurements were performed by the rover instruments, thus supporting and enabling the much more quantitative mineralogic discoveries made using elemental chemistry and mineralogy data. This chapter summarizes the major compositionally-and mineralogicallyrelevant results at Gusev and Meridiani derived from Pancam observations. Classes of materials encountered in Gusev crater include outcrop rocks, float rocks, cobbles, clasts, soils, dust, rock grindings, rock coatings, windblown drift deposits, and exhumed whitish/yellowish salty soils. Materials studied in Meridiani Planum include sedimentary outcrop rocks, rock rinds, fracture fills, hematite spherules, cobbles, rock fragments, meteorites, soils, and windblown drift deposits. This chapter also previews the results of a number of coordinated observations between Pancam and other rover-based and Mars-orbital instruments that were designed to provide complementary new information and constraints on the mineralogy and physical properties of martian surface materials. 13

Mineralogy of the Paso Robles soils on Mars

“…The Phase 1 spectra exhibit diagnostic and very unusual spectral characteristics for geologic materials associated with Mars to date, as mentioned above (e.g., a convex-upward feature near 480 nm, a reflectance maximum at ~670 nm, and a minimum near 800-850 nm). These spectra contrast with most Pancam spectra of Mars that have a concaveupward shape near 400-600 nm, a reflectance maximum near 700-800 nm, and a reflectance minimum near 900 nm or longer (e.g., Bell et al 2007). These Phase 1 bright-soil Pancam spectra ( Fig.…”

Aeolian saltation on Mars at low wind speeds

“…This is true even for the rover traverse at Gale crater that included exploration of the Bagnold dune field [Ehlmann et al, 2017]. Instead, rovers have traversed landscapes that generally are mixtures of rock and lightly crusted, cohesive regolith [e.g., Arvidson et al, 2004aArvidson et al, , 2004bArvidson et al, , 2006Bell et al, 2008;Herkenhoff et al, 2008;Arvidson et al, 2010;Sullivan et al, 2011;Arvidson et al, 2014]. Close inspection of these terrains using hand lens-quality images nonetheless commonly reveals scattered, isolated sand grains perched on rock surfaces ( Figure 5).…”

An Alternative Approach to Mapping Thermophysical Units from Martian Thermal Inertia and Albedo Data Using a Combination of Unsupervised Classification Techniques

“…For example, in Gale crater both a fine-grained soil of mafic composition and a coarse-grained soil of felsic composition were detected along a Curiosity transect, with the latter appearing to be locally derived [39], and the former akin to global Mars mafic dust [39,41]. Mafic soils similar in composition to Martian dust were also observed by Spirit and Opportunity (e.g., [42,43]). …”