Spirit Mars Rover Mission: Overview and selected results from the northern Home Plate Winter Haven to the side of Scamander crater

Abstract

[1] This paper summarizes Spirit Rover operations in the Columbia Hills, Gusev crater, from sol 1410 (start of the third winter campaign) to sol 2169 (when extrication attempts from Troy stopped to winterize the vehicle) and provides an overview of key scientific results. The third winter campaign took advantage of parking on the northern slope of Home Plate to tilt the vehicle to track the sun and thus survive the winter season. With the onset of the spring season, Spirit began circumnavigating Home Plate on the way to volcanic constructs located to the south. Silica-rich nodular rocks were discovered in the valley to the north of Home Plate. The inoperative right front wheel drive actuator made climbing soil-covered slopes problematical and led to high slip conditions and extensive excavation of subsurface soils. This situation led to embedding of Spirit on the side of a shallow, 8 m wide crater in Troy, located in the valley to the west of Home Plate. Examination of the materials exposed during embedding showed that Spirit broke through a thin sulfate-rich soil crust and became embedded in an underlying mix of sulfate and basaltic sands. The nature of the crust is consistent with dissolution and precipitation in the presence of soil water within a few centimeters of the surface. The observation that sulfate-rich deposits in Troy and elsewhere in the Columbia Hills are just beneath the surface implies that these processes have operated on a continuing basis on Mars as landforms have been shaped by erosion and deposition.

Seepage in Serpentinised Peridotites and on Mars

“…In the equatorial and mid-latitudes on the surface of Mars today, water is typically only stable in the vapour phase (Haberle et al 2001). However, near-surface salts and thin-film type weathering point to small amounts of liquid water on the surface within the geological recent past (Arvidson et al 2010). The availability of subsurface water remains a subject of active research, though it is generally believed that subsurface liquid water was available in the past, causing chemical alterations (Ehlmann et al 2010).…”

Surface mineral crusts: a potential strategy for sampling for evidence of life on Mars

“…Spirit encountered ferric sulfate-rich crusts in Gusev crater, which are likely to be associated with the hydrothermal activity (Arvidson et al 2010) and are evidently accessible by a rover. On Earth, hydrothermal activity is commonly associated with microbial life (Walter & Des Marais 1993).…”

Surface-based 3D measurements of small aeolian bedforms on Mars and implications for estimating ExoMars rover traversability hazards

“…Aeolian deposits consisting of loose unconsolidated material can constitute hazards to surface mobility of rovers: sinkage into the aeolian material and enhanced slippage can hamper traction and hence prevent forward progress, forcing the rover to backtrack (e.g., MER Opportunity, Arvidson et al, 2011) or, in the worst case, leading to permanent entrapment and end of mission (e.g., MER Spirit, Arvidson et al, 2010). Being able to estimate the depth of loose aeolian material (or the height of aeolian bedforms) before a rover drives over them is therefore clearly of great advantage.…”