Overview of the Spirit Mars Exploration Rover Mission to Gusev Crater: Landing site to Backstay Rock in the Columbia Hills

Abstract

[1] Spirit landed on the floor of Gusev Crater and conducted initial operations on soilcovered, rock-strewn cratered plains underlain by olivine-bearing basalts. Plains surface rocks are covered by wind-blown dust and show evidence for surface enrichment of soluble species as vein and void-filling materials and coatings. The surface enrichment is the result of a minor amount of transport and deposition by aqueous processes. Layered granular deposits were discovered in the Columbia Hills, with outcrops that tend to dip conformably with the topography. The granular rocks are interpreted to be volcanic ash and/or impact ejecta deposits that have been modified by aqueous fluids during and/or after emplacement. Soils consist of basaltic deposits that are weakly cohesive, relatively poorly sorted, and covered by a veneer of wind-blown dust. The soils have been homogenized by wind transport over at least the several kilometer length scale traversed by the rover. Mobilization of soluble species has occurred within at least two soil deposits examined. The presence of monolayers of coarse sand on wind-blown bedforms, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, E02S01,

Microbialites at Gusev Crater, Mars.

“…From the landing site to "Pot of Gold" site (on sol 200 about), extensive/destroyed volcanic outcroppings, often covered by weathering coatings and/or floating on eolic sands, as crater ejecta were found. The Rover then reached the inner basin of Columbia Hills, the images showed here layered sequences, containing sulfate and other soluble elements, due to ancient large process of aqueous alteration [1][2][3]. At Home Plate, where are the most evident geologic feature investigated in the Inner Basin, these layered sequences appeared formed by erosion of basaltic rocks and pyroclastic rocks, deposited as alluvial fans and/or as eolian sand sheets [4][5][6][7].…”

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

“…Another example of a morphologic indicator of composition is the identification of what appeared to be much softer, more friable, and platy or layered rocks (e.g., Bell et al, 2004a;Arvidson et al, 2006a). The first of these were seen in the West Spur of Husband Hill, where many rocks were found to be softer based on RAT grinding energies.…”

“…The traverse began in the Gusev cratered plains and included a visit to the rim and ejecta blanket of Bonneville crater, a ~3 km drive across the basaltic plains to the base of the Columbia Hills, a winter ascent of the West Spur and northwestern slopes of ~100 m high Husband Hill and a summertime descent down the southeast slope into the Southern Basin, leading finally to the exploration of a layered, roughly circular, 80-m wide feature known as Home Plate not far from the basin's topographic low point. Details about much of this traverse and its geologic goals can be found in Squyres et al (2004a) and Arvidson et al (2006a). Starting in April 2006, Spirit spent most of the rest of the year parked on a small ridge near Home Plate with her solar panels tilted towards the north in order to get enough solar power to survive her second martian winter.…”

“…A number of detailed studies of the geology and geomorphology of rocks and rocky materials the Gusev cratered plains and the Columbia Hills have been published (e.g., Grant et al, 2004;Squyres et al, 2004aCrumpler et al, 2005;Arvidson et al, 2006a;Golombek et al, 2006). While the details of the geology of the landing site presented in those papers are beyond the scope of this chapter, several kinds of morphologic features and properties have been observed during Spirit's traverse that can help to provide constraints on the composition and physical properties of Gusev crater rocky materials (Figure 13.2).…”

Science Priorities for Mars Sample Return

“…ND-SAG expects that a minimum of 6-12 months of surface operation would be required in order to reconnoiter a site and identify, characterize and collect a set of samples that captures its compositional diversity. To place this in context, the Opportunity rover did not complete the stratigraphic characterization in Endurance crater until Sol 315 and Spirit did not identify significant indicators of aqueous processes until it reached the Columbia Hills (roughly Sol 180; Arvidson et al, 2006). Sending MSR to a previously visited site (either of the two MER sites, the MSL or ExoMars site, or potential future sites) might substantially reduce the time needed for reconnaissance, but revisiting a site might also compromise samples intended for organic analyses by increasing the risk of terrestrial contamination.…”