VIR-IAS-TN-32 - VIRTIS ROSETTA EGSE SW Version 7.5 - Functional Validation

The report describes the validation of the maintenance activity carried out by Techno System Developments on the VIRTIS Rosetta EGSE Software CIG Z571056CC1

VIR-IAS-TN-33 VIRTIS ROSETTA EGSE SW Version 7.6 Functional Validation

The report describes the validation of the maintenance activity carried out by Techno System Developments on the VIRTIS Rosetta EGSE Software CIG Z571056CC1 for the Software version 7.

VNIR spectroscopy of rock forming minerals mixtures: a tool to interpret planetary igneous compositions

Visible and Near Infrared (VNIR) spectroscopy is a powerful technique to investigate and map the mineralogical composition of a Solar System body. Laboratory activities, measuring and analyzing minerals and their mixtures, rock powders and slabs, varying the particle and grain sizes, permit to improve the confidence on the spectra.s interpretation. Here we summarized a set of activity on spectral mixtures between plagioclases and mafic materials at 63-125 and 125-250 µm: illustrating the spectral variations due to the different intensity of the plagioclase absorption varying it Fe2+ content once mixed with orthopyroxene - clinopyroxene, orthopyroxene - olivine poor and - olivine rich materials (Serventi et al., 2013); an IMSA (Hapke, 1993) application to retrieve the endmember.s optical constants and to model the relative mineral abundances in intimate mixtures (Ciarniello et al., 2011) highlighting the influence of the mineral distributions (Carli et al., 2014); a spectra deconvolution with Modified Gaussians (MGM, Sunshine et al., 1990) to define spectral parameters (Band Center, Depth and Width) trends respect to the mineralogical composition of endmembers (mineral chemistry) and mixtures (mineral abundances). Also discussing the influence of the sizes (Serventi et al., 2015)

BC-SIM-TR-032 HRIC ICO4 REPORT

The present document has been issued to describe the Instrument Check Out Phase (ICO#4) Tests of HRIC, channel of the Spectrometers and Imagers for MPO BepiColombo Integrated Observatory SYStem (SIMBIO-SYS)

Spectral characterization of volcanic rocks in the VIS-NIR for martian exploration

Igneous effusive rocks cover much of the surface of Mars [1,2,3]. Initially only two types of lithologies were thought to constitute the Martian crust, i.e. a basaltic one and a more andesitic one [1,2], while more evolved lithologies were ruled out.Nevertheless a more complex situation is appearing in the last years. Recently several observations have highlighted the presence of evolved, acidic rocks. High-silica dacite units were identified in Syrtis Major caldera by thermal IR data [4]. Outcrops in Noachis Terra were interpreted as constituted of felsic (i.e. feldspar-rich) rocks essentially by the observation of a 1.3-µm spectral feature in CRISM data, attributed to Fe2+ in feldspars [5]. However different interpretations exist, invoking plagioclase-enriched basalts [6] rather than felsic products.The increasing of high-resolution and in-situ rover-based observations datasets and the changing of the initial paradigm justify a new systematic spectral study of igneous effusive rocks. In this work we focus on the spectral characterization of volcanic effusive rocks in the 0.35-2.5-µm range. We are carrying out measurements and spectral analyses on a wide ensemble of effusive samples, from mafic to sialic, with variable alkali contents, following the classification in the Total-Alkali-Silica diagram, and discussing the influence on spectral characteristics of different mineral assemblages and/or texture ([7], [8]). [1] Bandfield J.L., et al., Science, 287, 1626, 2000; [2] Christensen P.R., et al., J. Geophys. Res., 105, N.E4, 9609-9621, 2000; [3] Ehlmann B.L. & Edwards C.S., Annu. Rev. Earth Planet. Sci., 42, 291-315, 2014; [4] Christensen P.R., et al., Nature, 436, 504-509, 2005; [5] Wray J.J., et al., 44th LPSC, abs. n.3065, 2013; [6] Rogers A.D. & Nekvasil H., Geophys. Res. Lett., 42, 2619-2626, 2015; [7] Carli C. and Sgavetti M.,Icarus, 211, 1034-1048, 2011; [7] Carli C. et al., SGL, doi 10.1144/SP401.19, 2015. <P /

Northwest Africa 6232: Visible-near infrared reflectance spectra variability of an olivine diogenite

Visible and near-infrared (VNIR) reflectance is an important spectroscopic technique to identify minerals, and their associations, on planetary body surfaces. Howardites, eucrites, and diogenites (HED) are a class of igneous-like meteorites whose genetic connection with asteroid 4 Vesta has since long been inferred and recently confirmed by Dawn mission results. Pyroxene and olivine are the two major mafic minerals present in HED which can be identified with VNIR reflectance measurements. Thus, studying the compositional variability of those phases and their mixtures by means of laboratory spectroscopic measurements on different diogenitic or eucritic samples is one of the prime methods to better understand the evolution of 4 Vesta's crust. Here, we report the VNIR reflectance spectral analysis of a harzburgitic olivine diogenite, Northwest Africa 6232 (probably paired with Northwest Africa 5480), containing variable amounts of olivine as small grains or aggregates. We found that the olivine diogenite spectral parameters (e.g., band position) of powdered samples and polished slabs are in agreement. Moreover, the olivine diogenite band position shifts from synthetic orthopyroxene in accordance with the presence of olivine and chromite. In particular, the presence of a large olivine clast permits us to determine a linear variation of the band position from synthetic orthopyroxene and olivine, but underestimates the presence of olivine in the olivine diogenite spot

BC-SIM-TR-003 - STC NECP Report

The present document has been issued with the aim of describing the NECP (Near Earth Commissioning Phase) Tests of STC the Stereo Camera part of SIMBIO-SYS instrument, payload of the BepiColombo mission

Gas emission investigation in small bodies: case of P67/Churyumov-Gerasimenko and Ceres

In the first close up to the comet P67/Churyumov-Gerasimenko at a heliocentric distance of about 3 AU, the Visible and Infrared Thermal Imaging spectrometer (VIRTIS) on board Rosetta observed the first jet emissions from the comet's surface. The emission intensity was quite weak, as the comet was still far from the Sun. However, we expect the comet's activity to increase very fast in the incoming months. Some images of the comet's nucleus show activity, which could be ascribed to volatiles sublimation, dust upwarding or instrumental stray light. We focused on those data showing possible jet emissions from the comet's nucleus, observed both in limb and nadir viewing geometries. In this work, we propose a method to correct for the stray light, and investigate the possible emission intensity radially distributed from the point of emission. We focus in particular on the gas wavelength regions where water vapor, hydroxyl and carbon monoxide species are expected. Data are also discussed in comparison with a simple model, able to describe how the hydroxyl emission intensities vary with the heliocentric distance. A lower limit to the hydroxyl detection with VIRTIS can be inferred at the moment, while a deeper analysis is expected on the data acquired when the comet will be closer to the Sun. Similarly, Ceres has showed hydroxyl emissions in the thermal IR observed from space. The present analysis can be extended to the case of this peculiar body, which is one of the targets of the Dawn mission. The research is supported by ASI (contract ASI-INAF I/062/08/0)