Localization and Physical Properties Experiments Conducted by Spirit at Gusev Crater

Abstract

dark parts of the two-toned rocks, the height of the largest of the bright (light-toned) rocks, and the perched rocks would suggest local deflation of 5 to 60 cm. Thus, there must have been previous deposition on this order. The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundleadjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, cohesive soil-like deposits in plains and hollows, bright and dark rock coatings, and relatively weak volcanic rocks of basaltic composition. Volcanic, impact, aeolian, and water-related processes produced the encountered landforms and materials. References and NotesDuring the first few Mars solar days (sols) (1) of operations, we determined the landed location in inertial coordinates by analyzing Spiritto-Earth two-way X-band Doppler transmissions and two passes of ultrahigh-frequency two-way Doppler between Spirit and the Mars Odyssey orbiter. The equivalent location in the International Astronomical Union (IAU) 2000 body-centered reference frame is 14.571892°S, 175.47848°E. The location with respect to surface features was derived by the correlation of hills and craters observed in images taken by the Pancam, the Entry Descent and Landing (EDL) Camera, and the Mars Orbital Camera.On the basis of these analyses, the landing site is located at 14.5692°S, 175.4729°E in IAU 2000 coordinates, ϳ300 m north-northwest of the radiometric solution. This offset is consistent with the map tie errors between inertially derived coordinate systems and those derived from image-based coverage of the planet. Localization experiments during traverses focused on systematic acquisition of forwardand backward-looking overlapping images, onboard inertial measurement unit (IMU) observations to derive rover tilt, and tracking the number of wheel turns to provide wheel-based odometry. These observations were employed in a least-squares bundle adjustment to solve for the position and orientation of Spirit in local Cartesian coordinates at discrete locations during traverses (Fig. 1 and Plate 14). In addition, measurements of differential rocker and bogie angles in the suspension system, together with IMU data, were used to reconstruct the elevation of each wheel at a 2-to 8-Hz sample rate relative to the start of each traverse (Fig. 1).Localization results were extracted for 33 traverse segments from the Columbia Memori-

Mars Exploration Rover Geologic traverse by the Spirit rover in the Plains of Gusev Crater, Mars

“…, ... , , , J rr sr » » ' Ine terrain characteristics, morphology, chemisface analyses, and trenching operations documented the lateral variations in landforms, try mineralogy and near-infrared spectra of geologic materials, and chemistry of the surface throughout the traverse, demonstrating rocks at the landing site are instead consistent the ability to apply the techniques of field geology by remote rover operations. Textures with basaltic lava flows ; and shapes of rocks within the plains are consistent with derivation from impact exca- Arvidson et al, 2004;Christensen et al, 2004a;vation , 2004), locally overlain by young ejecta indurated and more altered rock types at a time-stratigraphic contact between the plains deposits of recent origin and mixed with poorly and Columbia Hills that occurs over a distance of one to two meters. This implies that sorted aeolian sands composed of basaltic maregional geologic contacts are well preserved and that Earth-like field geologic mapping terial and air fall dust in will be possible on Mars despite eons of overturn by small impacts.…”

“…vial sediments in the upper tens of meters of the regolith Arvidson et al, 2004;. Geologic mapping of orbital image data ( Fig.…”

Lunar soil strength estimation based on Chang’E-3 images

“…Through these tracks, the wheel sinkage can be retrieved using photoclinometry or shape from shading (Gao et al, 2013;Spiteri et al, 2015). Similar approaches have been investigated by (Arvidson et al , 2003(Arvidson et al , , 2004Herkenhoff et al , 2008;Richter et al , 2006), however these methods mostly require the use of stereo images. Such methods are typically associated with high computational costs and hence, are unable to operate in Real-Time (Gao et al, 2013).…”

Water on Mars: Evidence from MER Mission Results

“…Figure 11 shows a trench in the soil [16] cut by the Spirit rover's wheel, with the crusty top layer quite visible. A hypothesis to explain the mechanisms by which these surface materials become cemented is that the soil is cemented by salts [17].…”

“…Figure 12 shows a microscopic-imager view [21] of cemented soil from the Gusev site. Duricrust textures [16,21] revealed by the Microscopic imager show features including the presence of fine sand-sized grains, some of which may be aggregates of fine silt and clay, surrounded by a pervasive light colored material that is associated with microtubular structures and networks of microfractures. Stereo views of undisturbed duricrust surfaces reveal rugged microrelief between 2-3 mm and minimal loose material.…”