CHEMICAL AND MAGNETIC PROPERTIES OF PROPOSED MARTIAN REGOLITH SIMULANT

Production of materials that simulate the chemical and physical properties of planetary surfaces (such as Mars and the moon) plays an important role in the design and calibration of surface exploration missions. These materials are also generally made available for educational and outreach activities. Detailed testing of these candidate stimulants is important; here we present results of tests conducted on Hawaiian palagonite material that is proposed as a Mars simulant.

In order to determine the validity of Mars-1A, a proposed Martian regolith simulant, the magnetic properties, chemistry and mineralogy of this stimulant were analyzed in order to determine if these characteristics are dependent on the particle-size. The magnetic properties of the bulk material have also been analyzed and compared to published data on the magnetic properties of Martian dust particles. In order to determine these characteristics, the simulant has undergone XRF, XRD, magnetic hysteresis, and Mossbauer spectroscopy

During XRF analysis, the simulant experienced mass depletion, indicating high wt% of volatile elements. This depletion was at higher rates in smaller grains, with wt% loss up to 44.83%. The smaller grains also show depleted levels wt% SiO2, FeO, Cr, and Ni. This suggests compositional differentiation between the larger and smaller grains. Hysteresis analysis yielded saturation magnetizations in a range from 0.15 – 0.57emu/g, which indicate between .1 and .5wt% magnetite. Here again there is a trend in magnetic mineral composition as a function of Mars-1A sieve size. The course fractions contain .4 to .5wt% magnetite; the finer sizes contain less magnetite. The smaller grains show an affinity to more efficient volatile loss, less SiO2, depleted FeO, Cr, Ni, and less magnetite.

Overall, the data shows that the Mars-1A simulant material shows a very similar composition to prior simulant like the JSC Mars-1 (Allen et al, 1996). The Mars-1A is also similar in SiO2, FeO, CaO to regolith samples collected by the Viking Pathfinder missions. The Mars-1A is enriched in MgO and TiO2, and highly enriched in Al2O3 compared to the regolith from these missions (McSween and Keil, 2000).

Works Cited

McSween, H.Y., Keil, K., 2000, Mixing relationships in the Martian regolith and the composition of globally homogenous dust: Geochemica et Cosmochimica Acta, v. 64, no. 12, p. 2166-2166.