Overview of the magnetic properties experiments on the Mars Exploration Rovers

Abstract

[1] The Mars Exploration Rovers have accumulated airborne dust on different types of permanent magnets. Images of these magnets document the dynamics of dust capture and removal over time. The strongly magnetic subset of airborne dust appears dark brown to black in Panoramic Camera (Pancam) images, while the weakly magnetic one is bright red. Images returned by the Microscopic Imager reveal the formation of magnetic chains diagnostic of magnetite-rich grains with substantial magnetization (>8 Am 2 kg À1 ). On the basis of Mössbauer spectra the dust contains magnetite, olivine, pyroxene, and nanophase oxides in varying proportions, depending on wind regime and landing site. The dust contains a larger amount of ferric iron (Fe 3+ /Fe tot $ 0.6) than rocks in the Gusev plains ($0.1-0.2) or average Gusev soil ($0.3). Alpha Particle X-Ray Spectrometer data of the dust show that some of the iron in magnetite is substituted by titanium and chromium. The good correlation of the amount of calcium and sulfur in the dust may be caused by the presence of a calcium sulfate related phase. The overall mineralogical composition points to a basaltic origin of the airborne dust, although some alteration has taken place as indicated by the large degree of oxidation.

Geochemical properties of rocks and soils in Gusev Crater, Mars: Results of the Alpha Particle X‐Ray Spectrometer from Cumberland Ridge to Home Plate

“…However, the APXS spectra are consistent with a Ti‐bearing phase, implying an igneous origin (titanomagnetite and/or its oxidized equivalent titanomaghemite). Mössbauer spectra of surface targets (rock and soil) and the capture magnet [ Morris et al , 2006, 2008a; Madsen et al , 2008] together with the Ti and Cr from APXS firmly establish Ti‐bearing magnetite as the strongly magnetic phase at Gusev Crater. The other elements (i.e., Si, Ca, P, Cl, and S) shown in Figure 12 are associated together as suggested by the similar enrichment trends over the course of the mission.…”

Spirit Mars Rover Mission to the Columbia Hills, Gusev Crater: Mission overview and selected results from the Cumberland Ridge to Home Plate

“…Long duration measurements were made on these materials (Berkner Island). Finally, long duration magnet measurements were also made during the winter campaign [ Madsen et al , 2008].…”

Sands at Gusev Crater, Mars

“…MI images include disturbed soils (scuffed, brushed, contact impressions with the Mössbauer (MB) plate), and rock surveys [ Herkenhoff et al ., ; Golombek et al ., ; Farrand et al ., ; Yingst et al ., , ]. These images supported primary science objectives, placements of the Instrument Deployment Device (IDD) and remote sensing experiments, the monitoring of dust accumulations on the rover's magnets [ Madsen et al ., ], and various engineering activities. They also included multiple frames of the same targets taken at different depths of field, out of focus images, and overlapping image fields for constructing focal section merges, mosaics, and anaglyphs.…”