Analytical data on three Martian simulants

Abstract

The preparation of planetary missions as well as the analysis of their data require a wide use of planetary simulants. They are very important for both testing mission operations and payloads, and for interpreting remote sensing data. In this work, a detailed analysis of three commercially available simulants of Martian dust and regolith is presented. Indeed, up to date, a complete data set related to their chemical, mineralogical, granulometric and spectral characters is not fully provided by their distribution and sales companies. Our dataset regards the Mars Global (MGS-1) High-Fidelity Martian Dirt Simulant [1], the Mojave Mars Simulant MMS-1 [2] and the Enhanced Mars Simulant (MMS-2) [2]. Being essential for ensuring consistency and enabling data comparison, all the chosen Martian simulants underwent the same analytical process. Grainsize data were collected using a Laser Diffraction Particle Size Analyzer. Chemical analysis was performed by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Mineralogical analysis was carried out by X-Ray powder Diffractometry (XRD). Moreover, the largest particles of MGS-1 simulant were analyzed with the Scanning Electron Microscope (SEM-EDS) in order to confirm their chemical composition. Finally, the spectral acquisitions in the VNIR-SWIR range were taken by two Headwall Photonics hyperspectral imaging cameras. This complete series of data integrating pre-existing ones (e.g., Cannon et al. [1] and Karl et al. [2]) can in the future be used to allow a straightful choice of the right simulant for biological and life-support experiments and potential testing of mission instruments, to help inferring the composition of the Martian surface from remote sensing data, and to create new simulants or adjust the existing ones in order to get closer to the known Martian regolith variability and eventually new compositional information provided by future missions.

Keywords: Grainsize; Hyperspectral; MARS; Mass-spectrometer; SEM; SWIR; VNIR; XR-diffraction.

Fig. 1

Granulometric curves of the original MGS-1.

Fig. 2

a) XRD pattern related to qualitative analysis of the simulant MGS-1; b) XRD pattern related to quantitative analysis of the simulant MGS-1: minerals detected are shown in different colors. The gray curve at the bottom represents the differences, in terms of intensities, between the measured (black) pattern and the fitted (red) pattern, it shows effectively the goodness of the fit.

Fig. 3

Mineralogical and chemical characterization of the coarser grains of the MGS-1 simulant. a) Pyroxene and gypsum/Al-oxides crystals, corresponding to dark and red samples respectively; b) Secondary Electrons (SE) pictures of the crystal and the sites where the data were collected; c) Back Scattered Electrons (BSE) pictures of the crystal and the sites where data were collected; d) spectrum acquired on the black crystal and related elemental ratio from the energy-dispersive spectroscopy analysis expressed in oxide percentage.

Fig. 4

Spectra of the original (i.e., bulk sample) and different grainsize fractions of MGS-1.