The Ma_MISS (Mars Multispectral Imager for Subsurface Studies) experiment is the visible and near infrared (VNIR) miniaturized spectrometer hosted by the drill system of the ExoMars 2020 rover. Ma_MISS will perform IR spectral reflectance investigations in the 0.4–2.2 μm range to characterize the mineralogy of excavated borehole walls at different depths (between 0 and 2 m). The spectral sampling is about 20 nm, whereas the spatial resolution over the target is 120 μm. Making use of the drill's movement, the instrument slit can scan a ring and build up hyperspectral images of a borehole. The main goal of the Ma_MISS instrument is to study the martian subsurface environment. Access to the martian subsurface is crucial to our ability to constrain the nature, timing, and duration of alteration and sedimentation processes on Mars, as well as habitability conditions. Subsurface deposits likely host and preserve H₂O ice and hydrated materials that will contribute to our understanding of the H₂O geochemical environment (both in the liquid and in the solid state) at the ExoMars 2020 landing site. The Ma_MISS spectral range and sampling capabilities have been carefully selected to allow the study of minerals and ices in situ before the collection of samples. Ma_MISS will be implemented to accomplish the following scientific objectives: (1) determine the composition of subsurface materials, (2) map the distribution of subsurface H₂O and volatiles, (3) characterize important optical and physical properties of materials (e.g., grain size), and (4) produce a stratigraphic column that will inform with regard to subsurface geological processes. The Ma_MISS findings will help to refine essential criteria that will aid in our selection of the most interesting subsurface formations from which to collect samples. Key Words: Mars—Subsurface—Spectroscopy—Mineralogy. Astrobiology 17, 612–620.

Ceres is the largest object in the main belt and is a wet body with a complex geological and chemical history. Its surface is composed of opaque materials, phyllosilicates, ammoniated-bearing minerals, carbonates, water ice and salts. Recently, aliphatic organics, whose origin is still uncertain, have been also detected on the Ceres surface by the imaging spectrometer Visible and Infrared Spectrometer (VIR) on board Dawn. Here, using VIR spectra, acquired with a high spatial resolution (< 100 m), we analyze the organic-rich areas, their spectral characteristics, and the associated mineralogy. The new VIR spectra in the 3.2–3.6 μm spectral range have been compared to organic standard compounds measured in the laboratory, to investigate more deeply the nature of the organic matter on Ceres. The mineralogy appears quite complex, and the organic matter is often associated with a larger amount of ammoniated phases and carbonates. The detailed spectral analysis, as well as the laboratory comparison, reveals the presence of a band at 2.99–3 μm, likely associated with organic or inorganic NH-compounds (amine or salts), and the organic matter may be characterized by a rather low abundance in oxygen atoms. Spectral models of the organic material indicate that hundreds of meters-size areas can be very rich in aliphatic organics, with an estimated organic amount larger than the quantity normally found in CC meteorites. The mineralogical context and the retrieved amounts suggest that the aliphatic organic is likely a Ceres’ endogenous product, and we formulate a hypothesis for the formation and evolution of the organic matter inside Ceres.

The NASA/Dawn mission has acquired unprecedented measurements of the surface of the dwarf planet Ceres, the composition of which is a mixture of ultra-carbonaceous material, phyllosilicates, carbonates, organics, Fe-oxides, and volatiles as determined by remote sensing instruments including the VIR imaging spectrometer. We performed a refined analysis merging visible and infrared observations of Ceres’ surface for the first time. The overall shape of the combined spectrum suggests another type of silicate not previously considered, and we confirmed a large abundance of carbon material. More importantly, by analyzing the local spectra of the organic-rich region of the Ernutet crater, we identified a reddening in the visible range, strongly correlated to the aliphatic signature at 3.4 µm. Similar reddening was found in the bright material making up Cerealia Facula in the Occator crater. This implies that organic material might be present in the source of the faculae, where brines and organics are mixed in an environment that may be favorable for prebiotic chemistry.