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Thanks to the VIR spectrometer onboard NASA’s Dawn spacecraft, which orbited Vesta in 2011–2012, thousands of hyperspectral images of its surface have been collected. The mission confirmed the HED (Howardite–Eucrite–Diogenite) meteorite composition of Vesta. Moreover, the VIR spectrometer detected the 2.8 µm absorption band, due to the presence of the OH molecule. In this work, we took advantage of the newly calibrated data of the VIR spectrometer by characterizing new spectral features thanks to the improved signal-to-noise (S/N) ratio for these spectra. The main goals of this work are as follows: (1) to characterize Vesta’s surface in the visible range and (2) to confirm, reinforce and characterize the OH distribution on Vesta by studying the 2.8 µm band and looking for OH combination bands around 2.2–2.4 µm. A possible relation between the 1.9 µm absorption band due to the presence of pyroxenes and the one at 0.5 µm was analyzed. Finally, the analysis of hydroxyl absorption bands evidenced an anti-correlation between the abundance of hydroxyl-bearing molecules and the surface reflectance. This confirms that the hydroxyl presence is linked to the dark units on Vesta.

Suspended particulate matter (PMx) is one of the most important environmental pollutants. Miniaturized sensors capable of measuring and analyzing PMx are crucial in environmental research fields. The quartz crystal microbalance (QCM) is one of the most well-known sensors that could be used to monitor PMx. In general, in environmental pollution science, PMx is divided into two main categories correlated to particle diameter (e.g., PM < 2.5 µm and PM < 10 µm). QCM-based systems are capable of measuring this range of particles, but there is an important issue that limits the application. In fact, if particles with different diameters are collected on QCM electrodes, the response will be a result of the total mass of particles; there are no simple methods to discriminate the mass of the two categories without the use of a filter or manipulation during sampling. The QCM response depends on particle dimensions, fundamental resonant frequency, the amplitude of oscillation, and system dissipation properties. In this paper, we study the effects of oscillation amplitude variations and fundamental frequency (10, 5, and 2.5 MHz) values on the response, when particle matter with different sizes (2 µm and 10 µm) is deposited on the electrodes. The results showed that the 10 MHz QCM was not capable of detecting the 10 µm particles, and its response was not influenced by oscillation amplitude. On the other hand, the 2.5 MHz QCM detected the diameters of both particles, but only if a low amplitude value was used.

Introduction: Quartz Crystals Microbalances (QCMs) are widely used sensors for monitoring and characterizing dust and particles deposition processes in different planetary environments and measuring material contamination coming from outgassing sources in space, in support to other instruments (e.g. spectrometers). Furthermore, they are capable of detecting and measuring the presence of volatile com-pounds of astrobiological interest such as water and organics. These measurements can be particularly relevant when performed on primitive asteroids or comets, or on targets of potential astrobiological interests, e.g. Mars [1]. These sensors convert mass changes into fundamental resonance frequency variations, according to Sauerbrey equation [2]. The VISTA (Volatile In Situ Thermogravimetry Analyser) instrument is a QCM-based device able to perform measurements of abundance of volatiles and dust particles in planetary and asteroidal environments. The instrument can characterize the planetary regolith from 5-10 µm to sub-µm particles and monitor the contamination processes on board satellites (cubesat, etc.) caused by molecular outgassing. VISTA is one of the two scientific payloads of MILANI CubeSat, developed by Tyvak International that leads a consortium composed by entities and institutions from Italy, Czech Republic and Finland, in the framework of the Hera program of the European Space Agency (ESA). Hera, due to launch in 2024, is the ESA part of the Asteroid Impact & Deflection Assessment (AIDA) international collaboration with NASA, who is responsible for the Double Asteroid Redirection Test (DART) kinetic impactor spacecraft. The main objective of MILANI is the study of the binary asteroid system Didymos-Dimorphos, characterizing the asteroid with a dust sensor (VISTA) and a spectrometer (ASPECT). In this work, the calibration operations and the performance tests, to assess VISTA capability of characterizing volatile compounds and simulant contaminations in vacuum chamber at low temperatures. The sensor has been developed by an Italian Consortium composed by three Research Institutes: INAF-IAPS (National Institute of Astrophysics - Institute for Space Astro-physics and Planetology), CNR-IIA (National Council of Research – Institute of Atmospheric Pollution) and Politecnico di Milano and led by INAF-IAPS. Figure 1. VISTA EQM developed for ESA Hera space mission. Working Principle: The instrument core is a QCM whose frequency variations directly depends on the deposited sample mass on the crystal surface during sublimation, condensation and absorption/desorption processes. The instrument consists of: 1) two quartz crystals mounted in a sandwich-like configuration; 2) a Thermal Control System (TCS), composed by two integrated heaters and a Thermoelectric Cooler (TEC); 3) a Proximity Electronics (PE). VISTA is also capable of performing Thermo-Gravimetric Analysis, which is a technique used to monitor thermal processes involving volatile compounds, e.g. deposition/sublimation and absorption/desorption. It can also monitor particles lower than 5-10 µm and sub-µm particles [1]. Calibration: The QCM frequency can change not only due to the mass deposition/release, but also due to the variation of environmental parameters, such as temperature and pressure. In order to disentangle frequency variations due to mass deposition and environmental parameters, the sensor is calibrated by measuring the frequency as a function of temperature. According to literature [3], the frequency-temperature curve follows a third-degree polynomial (Figure 2). Figure 2. QCM frequency as a function of temperature in vacuum. Performance tests: VISTA capability to detect contaminant depositions and to monitor the accumulation and desorption processes is verified by placing an effusion cell containing an organic compound, used as a contamination source, placed in the Field Of View (FOV) of the sensing crystal and heated up to 100°C. The experimental setup is shown in Figure 3. Figure 3. VISTA EQM experimental setup for contamination simulation. The QCM is connected with four screws with a copper U shape and in contact with a cold sink set to -10°C to help the molecules condensation on the crystal surface. The frequency is monitored during the tests and the deposited flux can be retrieved (Figure 4) at each temperature set point. Figure 4. Deposition test from +50°C to +100°C. Two methods can be used to retrieve the enthalpy of sublimation ΔHsub by using the deposition rates, i.e. the Van’t Hoff relation [4] or Langmuir relation [5]. Thus, by measuring two different deposition rates, k1 and k2, at two different close temperatures T1 and T2, it is possible to obtain the compound ΔHsub by means of Van’t Hoff relation or throughout the temperature range by using Langmuir relation. TGA cycles are then performed by heating the crystals by means of the built-in heaters. After the heating cycles, the frequency returns to its initial value, thus indicating that all the deposited mass desorbed during the test (Figure 5). Figure 5. TGA cycles from +15°C to +50°C and from +40°C to +70°C. The desorption rates from crystals surface can be used as well to calculate the ΔHsub and compare it with the ΔHsub results obtained during the depositions/contamination processes. References: [1] E. Palomba et al (2016), OLEB, 46(2-3; [2] G. Sauerbrey (1959), Z. Phys., 155, 206-222; [3] D. Salt (1987); [4] S.W. Benson et al., 1968; [5] I. Langmuir, 1913.

1. Introduction Hayabusa2 – Japanese Aerospace Exploration Agency Mission investigated the asteroid (162173) Ryugu and on 06 December 2020 successfully returned to the Earth ~5.4 g of collected materials. Indeed, the first touch-down operation (TD1) sampled surface material on 21st February 2019; after the formation of a 15 m artificial crater with the SCI operation (Saiki et al., 2013), the TD2 occurred on 11st July 2019 and collected samples in the vicinity of crater, probably also subsurface material excavated by the impact. Ryugu appears to be a rubble-pile asteroid due to the low density (about 1.2 g/cm3) which suggests a formation by re-accumulation of fragments generated by the catastrophic destruction of the parent body (Watanabe et al., 2019). NIRS3 spectra of Ryugu surface acquired during Hayabusa2 mission show a strong features at 2.7 μm (indicating a OH-rich content ascribed to Mg-rich phyllosilicates) (Kitazato et al., 2019) and a secondary absorption at about 2.8 μm, strongly correlated with the 2.7 μm band (Galiano et al., 2020). This work includes the Carbonaceous Chondrite meteorites (CCs) identification and selection in grains from ~1 to 4mm to simulate the Ryugu surface and analogue mixtures production by using different end-members: a dark component (graphite, carbon, etc.), Mg-rich phyllosilicates (i.e. Antigorite for OH stretching band at 2.7 μm) and Fe-rich dark component (e.g. Cronstedtite) to reproduce the 0.7 and 2.8 μm bands of Fe-bearing phyllosilicates. Four analogue mixtures have been sieved in the grain size 100-200 μm and 200-300 μm and named: Mixture#3, Mixture#4, Mixture#5 and Mixture#6. The spectra of the samples have been acquired by means of Bruker Vertex 80 FT-IR Spectrometer (incidence angle of 30° and emission angle of 0°) in the spectral range 2-4 μm (spectral resolution of 4 cm-1) and then compared with average Ryugu spectrum. The spectral slope (in the 2.0-2.5 μm range), Band Depth and Band Center of the feature at 2.7μm and reflectance at 2.1μm have been analysed. 2. CCs meteorites analysis The acquired meteorites spectra (fragments) compared with Ryugu ones are reported in Figure 1. The results show as the reflectance (at 2.1μm) values of meteorites (0.042 Murray, 0.032 Nagoya and 0.030 Nagoya) can be comparable with Ryugu reflectance level, i.e. 0.0296 as well as the BC (2.731 Murray, 2.749 Nagoya and 2.716 Nagoya and 2.719 of Ryugu spectra). Differently, the meteorites BD is from four to eight times more intense than Ryugu one. Figure 1. Meteorites spectra and comparison with Ryugu (smoothed with 61 channels). 3. Analogue mixtures analysis The analogue mixtures (about 0.1g) have been produced by considering the grain size of 100-200 µm and 200-300 µm (Figure 2). Each end-member has been analysed in the spectral range of interest, for example the Antigorite shows the bands at 2.3 µm (due to combination of Mg-O-H bending and O-H stretching) and at 2.7 µm (O-H stretching). Figure 2. Percentage composition of Ryugu analogue mixtures. The Figure 3 at left shows the spectra of Mixture #3 and #4 while at right the Mixture #5 and #6 compared with the mean spectrum of Ryugu (obtained by NIRS3 data) multiplied by 7 for a better comparison. The Mixture#3 does not show the contribution of OH bands due to high percentage of dark component, i.e. 42.5%. Thus, the Mixture#4 has been produced by increasing the Mg-rich phyllosilicates, reducing the dark component and introduce the Cronstedtite (Fe- bearing phyllosilicate). So that, it is important to introduce an additional dark component, i.e. the Cronstedtite (Fe- bearing phyllosilicate) which can help to decrease the reflectance level and to contribute to shallow 2.7 µm band due to OH. Figure 3. Analogue mixtures compared with average Ryugu spectrum. 4. Preliminary results and future aims The mixtures #4, #5, #6 showed a negative spectral slope due to the high percentage of Antigorite (up to 60%) responsible of the 2.7 μm band while 3 μm spectral band has been ascribed to the adsorbed atmospheric water. Furthermore, the Cronstedtite included in the Mixture#6 gave a contribution to the dark component equal to 32.5% by avoiding negative effects on 2.7 μm spectral band that remains to be well defined. Preliminary analysis exhibit a good comparison between Ryugu BC and analogue mixtures BC (due to the presence of Mg-phyllosilicate) whereas the BD in spectra of analogue mixtures is deeper than the Ryugu one. The Ryugu reflectance is two-three times lower than the mixtures reflectance and characterized by a positive spectral slope, contrarily to the mixtures’ spectra which have a negative spectral slope. Starting from Mixture#6, next step will aim at reducing the reflectance level and decrease the OH band contribution, as well as producing a positive spectral slope. By using thermal controlled setup in vacuum chamber at different temperatures (e.g. 100, 200, 300, 400°C), a thermal metamorphism can be simulated and new spectra will be acquired. In the future, laser and ion irradiations can be considered to simulate the micrometeorite impacts and solar wind processes which help to decrease the spectral level and increase the spectral slope, as well as to reduce the analogue mixtures spectral bands. References: Galiano A., et. al. 2020, Icarus, v. 351, 113959; Kitazato, K. et al. 2019, Science 364, 6437: 272-275; Saiki, T., et al. 2013, Acta Astronautica, v. 84, 227-236; Tatsumi, E. et. al., 2021, Nat Commun 12, 5837; Watanabe, S. et al., 2019, Science 364, 6437: 268-272

Introduction: V-type asteroids are those whose spectra is similar to Vesta [1].Vesta underwent two huge impact events [2], that could have formed objects of this taxonomic class [3,4] and have eventually supplied the Vesta meteorites (HEDs) escaped from the Main Belt.In this work, we look for statistically significant differences among the modal mineralogy of V-type asteroids belonging to different dynamical subclasses through a combination of spectroscopic analysis and Hapke Radiative Transfer Model (RTM).Data and Methods: 76 Vis-NIR V-type asteroid spectra were downloaded from the Planetary Data System (PDS). In this work, we considered four dynamical families of V-type as follows:(i) Vestoid: V-type members of the Vesta dynamical family, as defined by [4] using the hierarchical clustering method (HCM).(ii) Fugitive: following the definition of [4], they are V-type asteroids with a < 2.3 au and comparable e and i with the Vesta family.(iii) Low-I: according to [4], they are V-type asteroids having i < 6◦ and 2.3 < a < 2.5 au.(iv) IOs (Inner Others): the remaining V-type asteroids in the inner main belt.VNIR spectra of Vesta’s, V-type asteroids surface and HED show absorption bands centred at approximately 0.9 and 1.9μm, confirming the pyroxenes presence [5]. Through scatterplot analysis of spectral parameters (in particular, band depth and half width half maximum) of V-type asteroids and of HED, these two bands give evidence of the grain size range of each asteroid. The obtained information is used as constrain in the Hapke’s RTM (to prevent possible degeneration in the creation of synthetic spectra) to retrieve modal composition for each V-type asteroid. To simulate asteroids spectra in the Hapke RTM, we used the main endmembers of HED and we also added a darkening agent (Murchison spectrum) to find possible correlations between V-type asteroids and dark regions on Vesta [6].Spectral fits of the asteroid’s dataset are robust with a global R mean square of 0.98, while the retrieved particle sizes are small with a mean value of 20 µm.Results and Discussion: Comparing the modal mineralogy obtained from Hapke RTM and the [7] studies, it is possible to assign a lithology to each dynamical subclass. In particular, we can distinguish diogenites (approximately 100 % of pyroxene), noritic diogenites (2-42 % plagioclase, 52-97 pyroxene), cumulate eucrite (30-64 % plagioclase and 36-70 % pyroxene) and basaltic eucrite (39-46% plagioclase, 46-60 % pyroxene).Then, in Figure 1, we report the mean and the standard deviation of sample of the four subclasses (Fugitive, Vestoids, Inner Others and Low-i). It seems that Vestoids and Fugitive are diogenitic (diogenitic and noritic diogenites respectively), while Low-I and Inner Other (IOs) are eucritic (Figure 2).Figure 1: Results of mean mineralogy for each subclass from Hapke retrivalFigure 2: Probability density function of Pyroxene (up) and of Plagioclase (bottom) for each subclass The most ‘ancient’ family, that is Low-i asteroids (they may date back to the LHB epoch or even to the 4.48-Ga impact on Vesta), seems to have an eucritic composition. In the most recent models of the structure of Vesta, it has a massive eucritic crust. Moreover, [2] found that the density of craters increases from the Rheasilvia rim to northern latitudes. This dichotomy in terms of crater density indicates that heavily cratered terrains (centered at about 348°E, 17°N and 110°E, 17°N) are much older than Rheasilvia basin, whose most probable age is estimated to be 1.0 ± 0.2 Ga [2]. Thus, it is compatible with the mineralogy of the Low-I asteroids that ‘swept out’, in the past, the outermost layer of Vesta.Fugitive better match with a diogenitic composition. For this subclass, the probable age of formation is at least 1 Ga so that they could migrate away from Vesta [4], then it is possible that they were ejected in an older (2 Ga) cratering event that produced the Veneneia basin that underlies Rheasilvia [8].Furthermore, [9] found from Dawn data that Rheasilvia basin (probable age is estimated to be 1.0 ± 0.2 Ga [9]) is consistent with a larger abundance of diogenite on the surface, while spectra from the equatorial regions are consistent with a larger eucrite amount. Thus, there is a possible chronologic link between impact events on Rheasilvia crater and the Vestoids, which, from our work, have a mineralogy associated to Diogenites.In any family, there is no signature of dark material as carbonaceous chondrites (here we used Murchison spectra to simulate it). This could be explained by the fact that it has an exogenous origin [6,10], and it could have impacted on Vesta after the V-type family formation.From this work, a possible chronologic link between impact events on Vesta and the V-type family is possible. We plan to augment the database of V-type asteroids to improve the statistical analysis. References: [1] De Meo,F. E. et al. (2009), Icarus, n. 202,p.160–180; [2] Marchi, S. et al. (2012), SCIENCE, Vol 336, Issue 6082, pp. 690-694; [3] Carruba, V. et al. (2007), A&A 465, 315-330;[4] Nesvorny, D. et al. (2008), Icarus, vol 183, 85–95; [5] De Sanctis,M.C. et al. (2013), Meteorit. Planet. Sci, vol. 48, n. 11, p. 2166–2184; [6] Palomba,E et al. (2014), Ica-rus, n. 240, pp. 58-72; [7] Mittlefehldt,D.W. et al. (2015), Chemie der Erde, vol. 75, pp. 155-183 ; [8] McSween, H.Y.J. et al. (2013), Meteorit. Planet. Sci, vol. 48, n. 11, p. 2090–2104; [9] De Sanctis, M.C. et al. (2012), SCIENCE ,VOL 336; [10] Turrini, D. et al. (2014), Icarus, 240, 86-102

Introduction: The Solar System dust is the smallest Solar System building block, and therefore its study allows understanding the early stages of the Solar System formation. The comprehension of the Solar System formation and evolution processes is also constrained by the inventory and spatial distribution of volatiles in our System. In particular, the delivery process of volatiles of astrobiological interest (water and organics) to the Earth is a key issue to understand the life formation in our planet. Asteroids and comets may have been the source of these volatiles to the terrestrial planets’ atmospheres and to the Earth’s oceans. The boundary between asteroids and comets is not well defined, and many main-belt asteroids are probably volatile-rich and would become cometary if they were moved to the inner Solar System. Piezoelectric Crystal Microbalances (PCMs) are widely used sensors to monitor dust and particles deposition processes in space and to characterize material outgassing in vacuum. This kind of sensors converts mass changes into fundamental resonance frequency variations, according to Sauerbrey equation [1]. In this work we present VISTA (Volatile in-Situ Thermogravimeter Analyser), one of the two scientific payloads on board MILANI Cubesat, as part of the ESA Hera Program. The MILANI Cubesat development is led by Tyvak International, prime contractor of a consortium composed by entities and institutions from Italy, Czech Republic and Finland. The main MILANI objective is executing a scientific mission aiming at studying the binary asteroid system Didymos-Dimorphos, characterizing the asteroid with a dust sensor, i.e. VISTA, and a spectrometer, i.e. ASPECT. VISTA is developed by an Italian Consortium composed by three Research Institutes: INAF-IAPS (National Institute of Astrophysics - Institute for Space Astrophysics and Planetology), CNR-IIA (National Council of Research – Institute of Atmospheric Pollution) and Politecnico di Milano. HERA Mission goals: Hera is a planetary defence mission under development at the European Space Agency (ESA), launching in October 2024. Hera is the European contribution to the international Asteroid Impact Deflection Assessment (AIDA) cooperation, the first planetary defence mission, in collaboration with NASA, who is responsible for DART (Double Asteroid Redirection Test) kinetic impactor spacecraft. Hera will travel to a binary asteroid system, the Didymos-Dimorphos pair of near-Earth asteroids, and will study and characterize the asteroid system after the DART impact in September 2022. In the framework of Hera mission, VISTA will accomplish the following scientific goals: 1) detect the presence of dust particles smaller than 10 µm (residual dust particles from the impact and suspended dust in the binary system or coming from dust levitation process); 2) characterization of volatiles (e.g. water) and light organics (e.g. low carbon chain compounds) by using Thermo-Gravimetric Analysis (TGA) cycles (the desorption rates ad specific temperatures are used to characterize e volatiles and organics desorbed from the sensor surface); 3) molecular contamination monitoring in support to other Cubesat instruments and ASPECT spectrometer, coming from outgassing processes on-board the spacecraft, that usually happen in the first days or weeks in orbit. VISTA Heritage: The Consortium has a considerable heritage in the design, manufacturing and testing of PCM-based instrumentation both for laboratory and space applications coming from different ITT-Emits ESA Projects: 1) CAM (Contamination Assessment Microbalance), developed for “Evaluation of an in-situ Molecular Contamination Sensor for space use” (2014-2016) (Figure 1); 2) CAMLAB (Contamination Assessment Microbalance for LABoratory) developed for “Development of a European Quart Crystal Microbalance” (2017-2019) (Figure 2). Figure 1. PCM Engineering Model developed during CAM-ESA Project for space applications. Figure 2. PCM breadboard developed during CAMLAB-ESA Project for laboratory applications. Working principle: PCMs exploit the piezoelectric properties of quartz crystals, as mass deposition on the sensing area of the instrument induces variations of the crystal resonance frequency. The core of VISTA is composed of: 1) two quartz crystals mounted in a sandwich-like configuration (one sensing crystal and the other reference crystal); 2) a Thermal Control System (TCS), composed by two integrated heaters and a Thermoelectric Cooler (TEC); 3) a Proximity Electronics (PE). The instrument is also capable of performing Thermo-Gravimetric Analysis, a technique used to monitor thermal processes involving volatile compounds, e.g absorption/desorption and deposition/sublimation, by means of the built-in heaters. The TEC is used to cool down the sensor and enhance the condensation of particles on the microbalance. VISTA is capable of monitoring particles lower than 5-10 µm and sub-µm particles. VISTA technical characteristics are shown in Table 1. Table 1. VISTA technical characteristics. The sublimated compounds can be characterized by calculating the enthalpy of sublimation ΔHsub, which can be retrieved with two methods: 1) by considering the deposition rates and using Van’t Hoff relation [3]; 2) by using Langmuir relation [4]. Conclusions and future works: In this work, the VISTA instrument working principle and heritage were presented. Qualification activities are currently ongoing on the VISTA Engineering Qualification Model (EQM), shown in Figure 3, in order to qualify the sensor within the expected mechanical and thermal environment and evaluate the instrument performances in a representative environment, prior integration on the MILANI Cubesat. The next phase of the research activities will be the manufacturing, integration and testing of VISTA Flight Model (FM), that will launch in 2024. Figure 3. VISTA EQM developed for MILANI cubesat/HERA Space Mission. References: [1] G. Sauerbrey 1959, Z. Phys., 155, 206-222; [2] Palomba E. (2016), OLEB, 46 (2-3); [3] S.W. Benson et al. 1968; [4] I. Langmuir, 1913.

Introduction The ESA Rosetta mission orbited the 67P/Churyumov-Gerasimenko comet (hereafter 67P) for two years and its results are providing important clues to understand activity processes on comets. The goal of the ISSI International Team “Characterization of 67P cometary activity” is two-fold: Retrieval of the activity of different regions of 67P’s surface during different time periods. Identification of the main drivers and the effects of cometary activity, via revealing the link between cometary activity and illumination/local time, dust morphology and composition, and surface geomorphology. Goal #1 has been reached by tracing the motion of dust particles detected in the coma back to the nucleus surface. Goal #2 accomplishment is in progress by means of data fusion of different instruments onboard the Rosetta spacecraft. Traceback The Grain Impact Analyser and Dust Accumulator (GIADA) [1] measured speed and momentum of fluffy and compact dust particles. We assumed radial motion, constant dust acceleration up to a 11 km altitude and constant speed above that height, to retrieve the source region of each dust particle detected in the coma [2]. We obtained that fluffy and compact dust distributions correlate on the surface, but not in the coma due to the different speeds of the two dust categories. Dust ejection is also correlated with solar illumination. Fluffy particles are more abundant in rough terrains [3], according to models which predict that they are embedded within pebbles [4]. Traceback is under study also with a different approach, based on retrieving ejection probability maps of detected dust particles [5]. Data Fusion GIADA vs VIRTIS. We related dust ejection rates of different surface regions, as retrieved by GIADA, and spectral indicators of water ice exposure measured by the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS) of Rosetta, such as the shortward shift of the 3.2 mm absorption band center and infrared spectral slope flattening [2]. The observed correlation between these parameters (Figure 1) indicates that ejection of dust comes from water ice-rich regions. Figure 1. Observed correlation between number of fluffy particles ejected from each 67P surface region and observed infrared slope flattening. Each symbol identifies a different geomorphological region of 67P. GIADA vs MIDAS. The Micro-Imaging Dust Analysis System (MIDAS) detected and measured physical properties of micron-sized particles. In principle, it provides complementary information with respect to GIADA, which detected mm-sized particles. We retrieved the number of parent particles hitting the MIDAS targets by applying two different methods [7,8]. Independently of the used approach, we obtained that the dust flux ratio between the two instruments is temporally constant. This suggests that the small particles detected by MIDAS are fragments of larger particles, as those detected by GIADA. The combination of MIDAS data and our traceback algorithm revealed that the physical properties (size, density, flatness) of compact dust are homogeneous across 67P’s surface (Figure 2). Indicators of dust pristinity were defined [8] and suggested that pristinity is correlated with size (being small particles more pristine) but not with the ejecting region evolution degree. Figure 2. Flatness distribution of dust particles detected on different MIDAS target (each target corresponds to a defined exposition period). Distributions are very similar. GIADA vs ROSINA. ROSINA-COPS (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis - COmetary Pressure Sensor) detected icy particles as pressure peaks [9]. The GIADA-ROSINA data fusion allows us to associate icy and dust particles and to retrieve the icy particle source regions. Currently, a moderate correlation between icy and dust fluffy dust particles was found. The work is in progress. Conclusions and future perspectives . We found that fluffy dust particles are more abundant on rough terrains, in agreement with their lower evolution degree and to comet formation models. Physical properties of compact dust are similar across the comet surface. The relation between dust and icy particles is under study. Future activities include: Analysis of the COSIMA mass spectrometer data [10], which observed dust composition variations. COSIMA-GIADA data fusion will allow understanding if they are related to different surface terrains. Analysis of OSIRIS images, which show bright patches on the comet surface, corresponding to frost enrichments and having different composition and morphology [11]. OSIRIS images combined with GIADA and ROSINA data will help in characterizing these peculiar regions. Laboratory activity aimed at simulating and interpreting the different photometric behavior of rough and smooth terrains [12] at the dust scale References [1] Della Corte, V. et al. (2014), Journal of Astronomical Instrumentation, 3, 1, 1350011-110; [2] Longobardo, A. et al. (2019), MNRAS, 483, 2, 2165-2176; [3] Longobardo, A. et al. (2020), MNRAS, 496, 1, 125-137; [4] Fulle, M. and Blum, J. (2017), MNRAS, 492, 2, S39-S44; [5] Ivanovski, S.L. et al. (2017), EPSC, 708; [6] Bentley, M.S. et al. (2016), Nature, 537, 7618, 73-75; [7] Longobardo, A. et al. (2020), EPSC, 1044; [8] Kim, M. et al. (2022), EGU abstract; [9] Pestoni, B. et al. (2022), EPSC, this session; [10] Hilchenback, M. et al. (2019), EPSC, 900; [11] Dehapriya, J.D.P. et al. (2018), EPSC, 1166; [12] Longobardo, A. et al. (2017), MNRAS, 469, 2, S346-S356. Acknowledgements This research was supported by the Italian Space Agency (ASI) within the ASI-INAF agreement I/032/05/0 and by the International Space Science Institute (ISSI) through the ISSI International Team “Characterization of cometary activity of 67P/Churyumov-Gerasimenko comet”. M.K. and T.M. acknowledge funding by ESA project "Primitiveness of cometary dust collected by MIDAS on-board Rosetta" (Contract No. 4000129476).

Introduction: The 4 Vesta asteroid is a differentiated asteroid, i.e. it has experienced melting and its structure is distinct layered: crust, mantle, nucleus. Hence, study of materials from different depths of Vesta would be helpful to understand its evolutionary history. Moreover, Vesta preserves information on the composition of primordial smaller asteroids that impacted on its surface. Vesta bright surface shows indeed dark units [1], that are supposed to be linked to exogenous material, and are therefore useful to understand the initial stages of the Solar System. The VIR spectrometer on board the NASA’s Dawn spacecraft [2], that orbited Vesta for approximately one year, collected thousands of hyperspectral images of its surface. Vesta spectra show the 2.7-2.8 μm absorption band, due to the presence of the OH molecule, whose distribution is inversely correlated with the reflectance of its surface [3]. In fact, it is included in carbonaceous chondrites, that are the darkening agents of the Vesta’s dark units [4]. Scientific Objectives: In this work we took advantage of the newly calibrated data of the VIR spectrometer, which are characterized by a better signal to noise (S/N) ratio, giving us the opportunity to search for spectral features that were never seen before, due to noise. Basing on this, the goals of this work were to: 1) confirm, reinforce and characterize the OH distribution on Vesta by studying the 2.7-2.8 µm band and by looking for OH combination bands that occur around 2.2-2.4 µm; 2) search for and characterize possible carbonates, that are supposed to be included in carbonaceous chondrites, i.e., the darkening agents of Vesta; 3) characterize the Vesta surface in the visible range. OH absorption band: The analysis on absorption bands related to the hydroxyl evidenced an anticorrelation between the abundance of hydroxyl and the reflectance of the surface (Figure 1). This confirms that the OH molecule is linked to the presence of the dark units on Vesta [3]. This is also a definitive proof that dark hydrated impactors (likely carbonaceous chondrites) are the darkening agents on Vesta, ruling out other interpretations suggested in literature (regolith grain size, impact shock and presence of opaque-rich eucrites and metals) [1]. Figure 1: Anti-correlation between the 2.8 µm band depth and the reflectance of the surface. We searched for the presence of possible combination bands centered around 2.2-2.4 µm. Weak features at 2.4 µm were found but no correlation with the 2.8 µm absorption band has been proved, so we can say that this feature is not related to the OH molecule and is likely a spectral artifact (Figure 2). Figure 2: This scatterplot shows that the 2.4 µm feature is not correlated to the 2.8 µm absorption band. Search for carbonates: We were not able to identify the 3.9 µm and the 3.4 µm absorption bands related to the presence of carbonates. This does not necessarily mean that carbonates are absent, but their abundance is not sufficient to observe an absorption band emerging from spectral noise. We compared VIR spectra with synthetic spectra of Vesta analogous mixtures (developed by applying a radiative transfer model) to calculate the upper limit of the abundance of carbonates on Vesta. The results show that carbonaceous chondrites that impacted on Vesta, contain no more than 0.5-2% of carbonates, in agreement with petrochemical analyses of typical Carbonaceous chondrites [5]. Caracterization in the visible range: The visible spectra showed an absorption band around 0.5 µm in addition to the strongest well known pyroxenes absorption band centered at 0.9 µm. We made a scatterplot between the 0.5 µm band depth and the 1.9 µm band depth related to the pyroxenes (Figure 3). In the scatterplot a linear dependance between the two features is evident. This proves that the 0.5 µm absorption band is due to the presence of the pyroxenes. Other features found in the visible range were instead associated to spectral artifacts. This emphasizes the results found by [6]. Figure 3: Correlation between the absorption band at 0.5 µm and the absorption band of the pyroxenes at 1.9 µm. References: [1] Palomba E. et al. (2014) Icarus, 240, 58–72. [2] De Sanctis M. C. et al. (2011) SSR, 163, 329. [3] De Sanctis M. C. et al. (2012) The astrophysical Journal Letters., 758.2, p. L36. [4] McCord T. B. et al. (2012) Nature, 491.7422 , 83-86. [5] de Leuw S., Rubin A. E., Wasson, J. T. (2010) Meteoritics & Planetary Science, 45.4, 513-530. [6] Rousseau B. e al. (2021) Astronomy and Astrophysics, 653.

Introduction The VIR spectrometer on board the NASA’s Dawn spacecraft allowed providing important clues the mineralogical composition of the Ceres regolith (De Sanctis et al., 2015) and of the bright areas widespread across its surface (Palomba et al., 2019; Carrozzo et al., 2018). Some bright spots are thought to be the result of phenomena like cryovolcanism (Ruesch et al., 2016; Russell et al., 2016) and post-impact hydrothermal activities (Bowling et al., 2016). The study of Ceres bright areas is important to understand in more detail the mineralogical composition of the subsurface materials that could host water ice (Prettyman et al., 2017; Schmidt et al., 2017) or have been under aqueous alteration (De Sanctis et al., 2016). In this study different bright areas of Haulani crater (e.g. Southern floor, i.e. ROI3 and North-east crater wall, i.e. ROI4) on Ceres have been studied by creating different analogue mixtures and comparing them with Dawn VIR data. The end-members have been identified based on previous studies (Tosi et al. 2018, 2019) and the analogue mixtures have been produced with grain size 50-100 µm for two bright crater regions. The spectra of two initial analogue mixtures have been acquired in the VIS-NIR spectral range (0.35-4.5 µm) at low temperature, i.e. from 200 K to 300 K similar to Haulani by using the Cold Spectroscopy Facility (CSS; https://cold-spectro.sshade.eu) (IPAG, France). Scientific goals and method The main scientific objectives of this study are: 1) the study of two different bright areas of Haulani crater (hereafter called ROI3 and ROI4, Figure 1) on Ceres in order to study the mineralogy of the sub-surface materials starting from results inferred by Dawn VIR; 2) the identification of the end-members of mineral mixtures of bright areas and production of endmembers and analogue mixtures with grain size 50-100 µm; 3) the acquisition of reflectance spectra of end-members and analogue mixtures in the VIS-NIR spectral range (0.35-4.5 µm); 4) the analysis of appropriate spectral parameters of reflectance spectra and comparison with those obtained by VIR data. In particular, spectral parameters of mixtures will be estimated, focusing on Band Center (BC), Band Depth (BD), Full Width Half at Maximum (FWHM) of bands, reflectance level and spectral slopes (estimated between 1.2 and 1.9 µm). The spectral parameters of analogue mixtures have been compared with the VIR data corresponding to the selected area in order to constrain their mineralogical composition. Data analysis and conclusion Two analogue mixtures (50-100 µm), here called A3-1 and A3-2 have been produced by using the end-members Antigorite (Mg-phyllosilicate); NH4-montmorillonite (ammoniated phyllosilicate); anhydrous Sodium Carbonate (Na-carbonate); Graphite (dark component), Illite (Phyllosilicates) to simulate the two bright crater regions (Figure 1, i.e. southern floor and red spot or ROI3, i.e. north-east inner crater wall or ROI4). Reflectance spectra of the two mixtures have been acquired in the VIS-NIR spectral range (0.35-4.5 µm) at cold temperature, i.e., from 200 K to 300 K (phase angle of 30°) with the SHINE spectro-gonio-radiometer equipped with the CARBONIR simulation chamber (sample in inner cell filled with few mbar of pure N2 gas) at the Cold Spectroscopy Facility (CSS) in IPAG, France (Figure 1, Right). Finally, the analysis of spectral parameters of the reflectance spectra (mainly relative to the absorption bands at 2.7, 3.1, 3.4 µm) and the comparison with VIR data have been performed. The acquired spectra have been finally converted in radiance factor. A first analysis shows that the Mixture A3-1 and A3-2 are not well representative due to the high amount of dark components (up to 86 % for A3-1) and missing Na-carbonate bands (for A3-2). Thus, the A3-2 has been modified (by producing the intermediate mixture) and by reaching 9 % for Na-carbonate, 32 % of dark component (i.e. carbon black) and 25 % of NH4-Montmorillonite in the final mixture named as A3-8. Finally, graphite and NH4-montmorillonite have been added to the A3-8 mixture, obtaining the last mixture A3-9. Thanks to carbon black the reflectance level compared with Haulani spectra is more similar. The analysed mixture were heated in the furnace in air at 120°C for 2 hours before each measurement and then placed in the sample holder under vacuum to remove the adsorbed H2O. The mixtures with a reflectance spectrum similar to the spectra of ROI3 and ROI4 have been analysed in detail. By the spectral analysis, the Mixture A3-8 shows the most representative reflectance spectrum for the Haulani’s areas of interest (even if the difference in the reflectance level is probably due to opaque end-member composition) and exhibits BD values for the 2.7, 3.1 and 3.4 µm bands that are the closest one to the ROI3 and ROI4. The width of the 3.1 µm band (3.1FWHM) of A3-8 has a value similar to the ROI4 (about 0.15). In particular, the 2.7 BD is about 13% lower than ROI3 and ROI4, the 3.1BD is 5-9% higher while the 3.4BD has the same value of ROI4 and 11% lower than ROI3. A more in-depth analysis of the data is in progress. Besides, in order to better reproduce Haulani areas some improvements may be performed, e.g., by adding a low amount of hydrous natrite , e.g. 2-8%, to assess the role of this component found in Haulani bright areas and how it contributes to the 2.7 µm spectral band. References Carrozzo, F.G., et al., 2018. Nature, Sci. Adv. 4 (3); De Sanctis. M. C. et al., 2015. Nature 528, pp. 241-244; De Sanctis, M.C., et al., 2016. Nature 536. Issue 7614, 54–57; Palomba, E., et al., 2019. Icarus 320, 202–212; Prettyman T. H., et al., 2017. Science 355:55–59; Ruesch, O., et al., 2016. Science 353 (6303); Russell, C.T., et al., 2016. Science 353 (6303), 1008–1010; Schmidt B. E. et al., 2017. Nature Geoscience 10:338–343; Tosi, F. et al., 2018. M&P Sci. 53, Nr.9, pp. 1902-1924; Tosi, F. et al., 2019. Icarus 318, pp.170-187.

This work describes the design of a holder for a quartz crystal microbalance for space application. The main objectives of the conceived system are to hold the quartz crystal providing adequate support in the expected mechanical and thermal environments, and to assure the functionalities of the instrument, i.e. measuring the oscillation frequency and the crystal temperature or heating the crystal during regeneration phases. A kinematic mounting has been designed to be manufactured by stereolithography because this technology allows achieving high spatial resolution and complex shapes that are needed to implement an easy assembling and mounting of the holding system. Moreover, the 3D printing technology would provide a cost-effective solution even for small series production.

The aim of this work is a technical review about Quartz Crystal Microbalance (QCM) sensors used in space missions, i.e. Space Shuttle flights, i.e. NASA Space Transportation System (NASA STS) and satellite missions, that aimed at monitoring the contamination generated by outgassing processes of materials onboard satellites and sensitive payloads. The contamination processes are critical for scientific instrumentation (e.g. optics, telescopes, detectors) because scientific measurements and performances can be jeopardized or worsened by uncontrolled contamination. This issue has been addressed by the space agencies, e.g. NASA, ESA and JAXA that have implemented many different studies to monitor the material outgassing and degradation in space environment. During the past years, the QCM sensors have become the baseline solution for measuring material outgassing and characterizing the on-orbit contamination environment. This work summarizes the main QCM applications in Space and their findings, providing an overview of the sensors’ performances in terms of stability, power, data rate, measurement accuracy and resolution. Different QCM technologies will be compared highlighting the advantages of their use for the next space missions and instrumentations that require an accurate monitoring of contamination environment. In particular, due to more severe contamination requirements for next payloads and instrumentations, QCM sensors would be useful to estimate the cleanliness degree by evaluating the induced contamination and degradation on sensitive instrumentations.

NASA’s Dawn spacecraft acquired images and hyperspectral data of Ceres by means of FC and VIR instruments, and identified some widespread bright areas or bright spots (BS). The most peculiar BS is inside Occator crater and it is characterized by spectral properties very dissimilar from the rest of Ceres’ surface. To perform a mineralogical analysis, absorption bands in reflectance spectra must be properly isolated by removal of continuum, and related descriptors (such as band centers and band depths) can be computed. The method for continuum removal must be applicable to all Ceres spectra, relative to different areas, so that a comparison among spectral parameters can be made and mineralogical interpretation can be achieved. This work focuses on the definition of the most appropriate continuum to isolate absorption bands located at ∼3.1, ∼3.4 and ∼4.0 µm. The ∼3.1 µm feature is related to ammoniated phyllosilicates, while the ∼3.4 and ∼4.0 µm absorption bands are indicative of carbonates. Thermal emission affects the continuum for these bands in the VIR spectral range, which extends up to 5.1 µm, moreover all thermal-removed reliable data stop at 4.2 µm. This implies that the shoulder of bands at longer wavelength cannot be identified. We therefore defined alternative continua, i.e., a linear and two polynomial ones, able to describe spectra of any area (i.e. bright or dark) and regardless of spatial resolution. We found that the linear definition satisfies these requirements best. For the first time, we performed an error evaluation on band depths and band centers introduced by the applied method, which is relevant for comparison of spectral parameters of Ceres regions and to better interpret mineralogy and photometric effects.

Recovery and transport of returned samples is a crucial importance issue, because it has the fundamental duty to avoid forward contamination (i.e., contamination of the sample from the terrestrial environment) and, in the case of samples returned from a planetary body possibly hosting any life form, backward contamination (i.e., contamination of non-terrestrial organisms to humans). This chapter reviews how sample return missions dealt with this issue, through description of: i) landing sites and their influence on recovery and transport operations; ii) analysis of techniques and technologies used so far to transport extra-terrestrial samples from landing sites to curation facilities as well as among laboratory environments; iii) regulatory issues for packaging and transport of restricted samples, i.e., potentially hosting biological molecules.

Sample return missions are among the most exciting space missions, providing both scientifically unique information and an unparalleled mechanism for the inspiring the public. Returned samples allow us to make critical ground truth measurements that can calibrate remote sensing measurements from spacecraft. Some scientific studies can only be done in laboratories rather than remotely or with landed spacecraft. Currently Europe does not have a facility suitable for the curation of returned extra-terrestrial samples. This not only hinders European Space Agency (ESA) missions, but also renders European institutions and Principal Investigators unable to fully participate as equal participants in missions implemented by other countries. The EURO CARES project was the first European attempt to review and evaluate the current state-of-the-art in curatorial practice for sample return missions, and determine the different and necessary steps in order to create a fully functional European Extra-terrestrial Sample Curation Facility to match the ESA requirements.

1. Introduction (4) Vesta is the second most massive body in the main asteroid belt and exhibits absorption features indicative of basaltic minerals [1]. The discovery of new basaltic objects taxonomically classified as V-type asteroids [2] is probably linked to the fragments produced during a catastrophic event where Vesta is believed to have lost about one percent of its mass less than a billion years ago. VIR spectra of Vesta’s and V-type asteroids surface show absorption bands centred at approximately 0.9 and 1.9µm, confirming the pyroxenes presence [1] and they have a reflectance spectrum which is very similar to HED. We aim to infer the modal mineralogical compositions and regolith grain size of some V-type asteroids using the Hapke radiative transfer model, basing on the results of scatterplot analysis of spectral parameters such as Band Center I (hereafter BCI) and Band Center II (hereafter BCII), Band depth (hereafter BDI) and Band depth II (hereafter BDII) and Half-width-half-maximum (hereafter HWHM). It is also foreseen to test the genetic linkages between V-type asteroids and HED meteorites and Vesta. 2. Data and method We analysed 76 V-type asteroids normalized spectra in the infrared from 0.7-0.8 µm to 2.5 µm, divided in two datasets. The first group was from [3] and the second was from [4, 5, 6]. All the spectra were downloaded from the Planetary Data System (PDS). To study the spectral properties and to understand the mineral composition and possibly the physical characteristics of the regolith (i.e., effective grain size), we introduced spectral parameters such as the band BC, BD and HWHM as defined in [7] and compared the results obtained from V-type asteroid with HED meteorites used in [7]. We also applied Hapke’s bidirectional reflectance model to retrieve compositional and grain size information for the V-type asteroids and HED analysed in this work. The whole procedure can be schematized as follows: Retrieve the mineralogy of each V-type asteroid dataset, by comparing them with HED in BCI versus BCII scatterplot (Figure 1) Retrieve the grain size regolith range of each V-type asteroid dataset, by comparing them with HED in BDI versus BDII and HWHM I dx versus BDII scatterplot (Figure 2, Figure 3) Application of the Hapke’s bidirectional reflectance model to the spectral deconvolution of the selected asteroids and meteorites. The used end-members in the Hapke retrieval are clinopyroxene, orthopyroxene and plagioclase [8]. We assume that the scattering is isotropic and no backscattering is considered. In order to simulate HED mineralogy, abundance limits on fractional mass of pyroxene (40% to 100%) and of plagioclase (0% to 60 %) were set in the Hapke retrieval. In addition, the grain size for each mixture was varied (in step of 5 µm) from 5 µm up to a limit of 80 µm, in agreement with scatterplot analysis (Figure 2, Figure 3). Figure 1: Band I Center versus Band II Center scatterplot of HED and V-type group 1 and group 2. For the entire legend see [9] . Figure 2: BDI versus BDII scatterplot on Eucrite, Howardite and V-type group 1 and group 2. Figure 3: HWHM I DX vs BDII scatterplot on Eucrite, Howardite and V-type group 1 and group 2. 3. Results and conclusions Through the scatterplot analysis (Figure 1) we observed that the asteroids have the same mineralogy of HED (same trend line) and an upper limit of grain size of 80 µm. Basing on these results, we applied Hapke retrieval on asteroid sample using the main endmembers of HED (plagioclase, clinopyroxene and orthopyroxene) and a fixed grain size range (Figure 2, Figure 3) to simulate spectra. In order to find the best fit, a R2 statistical test was performed. Hapke procedure tested on HED spectra with known composition from [8] gave a global R2 with a mean value of 0.92. The 86 % of grain size, resulting from Hapke model on HED (with known and unknown composition [8]), lied in the declared range . The Hapke procedure on asteroids sample had a R2 mean value of 0.97, in addition a mean grain size of ≈20 µm is given. This is in agreement with previous analyses. So, our Hapke implementation, basing on the results of scatterplot analysis, is able to reproduce the spectral shapes and absorption features for all the V-type asteroids examined here, providing a globally satisfactory fit, confirming a link between V-type asteroids, HED meteorites and Vesta. References [1] M. C. De Sanctis, Meteoritics & Planetary Science 48, n. Nr 11, p. 2166–2184, 2013. [2] F. E. DeMeo, Icarus 202, p. 160–180, 2009. [3] N. A. Moskovitz, Icarus 208, p. 773–788, 2010. [4] P. S. Hardersen, «,» The Astronomical Journal, 156:11, p. 16, 2018. [5] P. S. Hardersen, The Astrophysical Journal Supplement Series, 221:19, p. 12, 2015. [6] P. S. Hardersen, Icarus 242, p. 269–282, 2014. [7] E. Palomba, Icarus 240, p. 58–72, 2014. [8] D. W. Mittlefehldt, Chemie der Erde 75, pp. 155-183, 2015. [9] M. Angrisani, «Master degree thesis,» Università Federico II, 2021.

We characterized the 67P/Churyumov–Gerasimenko’s dust activity, by analysing individual dust particle velocity and momentum measurements of Grain Impact Analyser and Dust Accumulator (GIADA), the dust detector onboard the ESA/Rosetta spacecraft, collecting dust from tens to hundreds of kilometres from the nucleus. Specifically, we developed a procedure to trace back the motion of dust particles down to the nucleus, identifying the surface’s region ejecting each dust particle. This procedure has been developed and validated for the first part of the mission by Longobardo et al. and was extended to the entire GIADA data set in this work. The results based on this technique allowed us to investigate the link between the dust porosity (fluffy/compact) and the morphology of the ejecting surface (rough/smooth). We found that fluffy and compact particles, despite the lack of correlation in their coma spatial distribution (at large nucleocentric distances) induced by their different velocities, have common ejection regions. In particular, the correlation between the distributions of fluffy and compact particles is maintained up to an altitude of about 10 km. Fluffy particles are more abundant in rough terrains. This could be the result of past cometary activity that resurfaced the smooth terrains and/or of the comet formation process that stored the fluffy particles inside the voids between the pebbles. The variation of fluffy particle concentration between rough and smooth terrains agrees with predictions of comet formation models. Finally, no correlation between dust distribution on the nucleus and surface thermal properties was found.

Introduction Dust is a ubiquitous component of our galaxy and Solar System. The Earth accumulates roughly 100 tons of space dust per day, with dimensions ranging from nanometers up to millimeter [1]. Measurements of dust proper]ties and their distribution provide important information to space science in modelling the birth and growth of the Solar System [2]. The information gained from studying these small particles has been valuable for improving our understanding of the ongoing physical processes of asteroids, comets, Kuiper Belt objects, and planetary rings [3]. The dust particles majority originate within the Solar System, typically are produced by cometary activity or by impacts on planetary or asteroid surfaces. A portion of dust dates back to the birth of the Solar System and a small fraction is of interstellar origin. These particles travel with hypersonic speeds typically in the range 10–70 km/s. The interest to these particles is caused by the fact that they are (1) samples of a distant astonomical bodies, (2) major conrtibutors in the planetary surface growth, and (3) they provide information about the origin and dynamics of the early Solar System GIADA instrument onboard Rosetta/ESA space probe, an example of dust impact sensor. The Grain Impact Analyzer and Dust Accumulator (GIADA) on board the ESA Rosetta probe performed the dynamical study of the dust ejected by the comet 67P/Churyumov-Gerasimenko. [5]. GIADA measured speed, optical cross section and momentum of dust particles larger than 60 μm and the cumulative dust flux for particles smaller than 5 μm. One of the three sub-systems constituting GIADA, the Impact Sensor (IS – Figure 1) [5], measured the momentum of individual dust particle [6]. The GIADA-IS consisted in a squared aluminium plate with a sensitive area of 100 mm x 100 mm, five ceramic piezoelectric sensors (PZTs), with a resonant frequency of 200 kHz, connected to the Al plate (in the plate center and at the 4 corners). A dust particle impact generates the Lamb waves propagating over Al plate.. The PZTs detect these waves and convert them into an electric potential proportional to the particle’s momentum. We propose to include an instrument of similar concept as GIADA-IS in the scientific payload of Comet Interceptor (and cubesats) for measuring dynamical properties of dust. Figure 1 GIADA impact Sensor DISC onboard Comet Interceptor spacecrafts. DISC (Figure 2) is a dust impact sensor, part of Dust Field and Plasma instrument., This instrument will be mounted on two of the three Comet Interceptor (CI) spacecrafts, It will provide an in situ characterization of dust particles in the coma of a Dynamically New Comet or an interstellar object. In particular, it will measure the momentum of individual dust particles during the high-speed CI flyby to its target. From the momentum, knowing the speed of the S/C, individual particle speed is retrieved. DISC overall aims are to determine: dust particle mass distribution; dust particle count; dust particle impact duration; dust particle density/structure; dust coma structures. The sensor capabilities will allow to measure during CI close encounter: dust mass distribution from particles with mass 10-15–10-8 kg ejected from the nucleus (this measurement will be performed by DISC onboard 2 different CI spacecrafts to disentangle the dust flux coming directly from the nucleus and the dust flux of particles reflected by the solar radiation pressure. DISC will be able to count particles with mass >10-15 kg. Despite the difference in physical processes in the hyper speed impacts (the fly by speed of CI will be from 7 to 70 km/s) and low speed impacts (measured by GIADA-IS during Rosetta mission), DISC mechanical configuration will allow provide particles momentum measurements. In fact, the shockwaves generated by the high-speed impacts become Lamb wave (measured by GIADA-IS) in the close proximity of the particle impact point. Figure 2 DISC exploded view. Impact Particle Monitor-a proposed dust sensor for cubesat We propose to equip one of the external panels of a cubesat with PZT transducers. This external panel will act as a dust sensitive surface and will be able to detect and monitor particles impacting the cubesat (Figure 3). This configuration can be applied in different mission scenario: • Low Earth Orbit to monitor μm- to mm-sized debris (high speed impacts) Small exploration cubesat: detection of stable or transient dust structures around small bodies, planets or satellites. In situ detection of dusty or icy plumes with cubesats . Figure 3 ILP mounted on an external face of a 6U Cubesat: left) sensing surface; right) PZT transducers. Acknowledgements This research was supported by the Italian Space Agency (ASI) within the ASI-INAF agreement I/032/05/0. References [1] F.J.M. Rietmeijer, et al. 2016, Laboratory analyses of meteoric debris in the upper stratosphere from settling bolide dust clouds, Icarus, 266, 217-234. [2] M. Fulle, et al. 2016, Comet 67P/Churyumov-Gerasimenko preserved the pebbles that formed planetesimals, Monthly Notices of the Royal Astronomical Society, 462, issue Suppl 1, pp. S132-S137. [3] M. Fulle, et al. 2017, The dust-to-ices ratio in comets and Kuiper belt objects, Monthly Notices of the Royal Astronomical Society, Mon. Not. R. Astron. Soc., 469 (Suppl_2): S45-S49 [4] Della Corte et al. 2014 GIADA: its status after the Rosetta cruise phase and on ground activity in support of the encounter with comet 67P/Churyumov-Gerasimenko, Journal of Astronomical Instrumentation [5] Esposito et al. 2002, Physical aspects of an Impact Sensor for the detection of cometary dust momentum onboard the Rosetta Space mission. Adv. Space Research. [6] Della Corte, V. et al., 2016, 67P/C-G Inner Coma dust properties from 2.2 AU inbound to 2 AU outbound to the Sun, Monthly Notices of the Royal Astronomical Society, 462, pp. S210-S219.

This work deals with temperature characterization of Cr-Au and Ti-Au deposited resistors on quartz crystal microbalances designed for Space. The advantage of the proposed configuration is that direct heating of the electrode’s area can be obtained as well as a measurement of the quartz crystal temperature. In this view, characterization of the deposited materials is of primary importance to provide accurate temperature measurement and retrieve reliable results for thermogravimetric analyses. The behavior of the deposited material has been verified down to cryogenic temperatures. The characterization in cryogenic condition evidenced that the linearity error is limited to 4 °C at the liquid nitrogen temperature but the regression standard deviation can be reduced to one order of magnitude if a third-order polynomial is used to fit the experimental data.

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Olivine is one of the main abundant mineral in the Solar System, and the determination of its abundance on a surface may give fundamental information about its evolution. The study of surface distribution of olivine on asteroid (25143) Itokawa through near-Infrared reflectance spectroscopy is a difficult goal because olivine and pyroxene bands centred at 1 μm and 2 μm are not entirely included in Hayabusa/NIRS’ spectral range. In this work, the retrieval of olivine abundance has been performed by applying two different methods: the first one uses some spectral indices to retrieve olivine abundance, whilst the second one consists of the application of the Hapke’s theory in order to create synthetic spectra aimed at fitting a selection of NIRS’ spectra. The analysis performed with the first method brought to an approximately homogeneous distribution of olivine content (60 ± 15% on average) on Itokawa’s surface, with the exception of Sagamihara region, which has a slightly (up to 10%) lower olivine content. The second method brought to an average 60 ± 7.5% olivine content within 5 selected spectra, with the same reduction found in the spectrum from the Sagamihara region. All these values are in agreement with literature values on this topic, especially with the ones retrieved from particles sampled in Muses Sea by the Hayabusa probe.

We characterized 67P/Churyumov-Gerasimenko's cometary activity during its inbound arc before perihelion (2014 August-2015 January). We focused on the geomorphological regions of the Northern hemisphere observed by the ESA/Rosetta space probe during this time period. The GIADA dust detector characterized the physical properties of the fluffy and compact particles ejected from the nucleus; the VIRTIS imaging spectrometer detected exposed water ice.

The Near-Earth Asteroid 162173 Ryugu (1999 JU3) was investigated by the JAXA Hayabusa2 mission from June 2018 to November 2019. The data acquired by NIRS3 spectrometer revealed a dark surface with a positive near-infrared spectral slope. In this work we investigated the spectral slope variations across the Ryugu surface, providing information about physical/chemical properties of the surface. We analysed the calibrated, thermally and photometrically corrected NIRS3 data, and we evaluated the spectral slope between 1.9 μm and 2.5 μm, whose values extend from 0.11 to 0.28 and the mean value corresponds to 0.163±0.022. Starting from the mean value of slope and moving in step of 1 standard deviation (0.022), we defined 9 “slope families”, the Low-Red-Slope families (LR1, LR2 and LR3) and the High-Red-Sloped families (HR1, HR2, HR3, HR4, HR5, HR6). The mean values of some spectral parameters were estimated for each family, such as the reflectance factor at 1.9 μm, the spectral slope, the depth of bands at 2.7 μm and at 2.8 μm. A progressive spectral reddening, darkening and weakening/narrowing of OH bands is observed moving from the LR families to the HR families. We concluded that the spectral variability observed among families is the result of the thermal metamorphism experienced by Ryugu after the catastrophic disruption of its parent body and space weathering processes that occurred on airless bodies as Ryugu, such as impact cratering and solar wind irradiation. As a consequence, the HR1, LR1, LR2 and LR3 families, corresponding to equatorial ridge and crater rims, are the less altered regions on Ryugu surface, which experienced the minor alteration and OH devolatilization; the HR2, HR3, HR4, HR5 families, coincident with floors and walls of impact craters, are the most altered areas, result of the three processes occurring on Ryugu. The strong reddening of the HR6 family (coincident with Ejima Saxum) is likely due to the fine-sized material covering the large boulder.

We present here a novel experimental setup able to measure the enthalpy of sublimation of a given compound by means of Piezoelectric Crystal Microbalances (PCM). This experiment was performed in the TG-Lab facility in IAPS-INAF, dedicated to the development of TGA sensors for space measurements, such as detection of organic and non-organic volatile species and refractory materials in planetary environments. In order to study physical-chemical processes concerning the Volatile Organic Compounds (VOC) present in atmospheric environments, the setup has been tested on Dicarboxylic acids. Acids with low molecular weight are among the components of organic fraction of particulate matter in the atmosphere, coming from different sources (biogenic and anthropogenic). Considering their relative abundance, it is useful to consider Dicarboxylic acid as "markers" to define the biogenic or anthropogenic origin of the aerosol, thus obtaining some information of the emission sources. In this work, a temperature controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC re-condensed onto the PCM quartz crystal allowing the determination of the deposition rate. From the measurements of deposition rates, it was possible to infer the enthalpy of sublimation of Adipic acid, i.e. Δ Hsub: 141.6 ± 0.8 kJ mol−1, Succinic acid, i.e. 113.3 ± 1.3 kJ mol−1, Oxalic acid, i.e. 62.5 ± 3.1 kJ mol−1 and Azelaic acid, i.e. 124.2 ± 1.2 kJ mol−1 (weight average values). The results obtained are in very good agreement with literature within 10 % for the Adipic, Succinic and Oxalic acid.

This paper presents the VISTA (Volatile In Situ Thermogravimetry Analyser) instrument, conceived to perform planetary in-situ measurements. VISTA can detect and quantify the presence of volatile compounds of astrobiological interest, such as water and organics, in planetary samples. These measurements can be particularly relevant when performed on primitive asteroids or comets, or on targets of potential astrobiological interest such as Mars or Jupiter's satellite Europa. VISTA is based on a micro-thermogravimetry technique, widely used in different environments to study absorption and sublimation processes. The instrument core is a piezoelectric crystal microbalance, whose frequency variations are affected by variations of the mass of the deposited sample, due to chemical processes such as sublimation, condensation or absorption/desorption. The low mass (i.e. 40 g), the low volume (less than 10 cm3) and the low power (less than 1 W) required makes this kind of instrument very suitable for space missions. This paper discusses the planetary applications of VISTA, and shows the calibration operations performed on the breadboard, as well as the performance tests which demonstrate the capability of the breadboard to characterize volatile compounds of planetary interests. © 2015, Springer Science+Business Media Dordrecht.

This research activity investigates the temperature-frequency relationship of quartz crystal microbalance for thermogravimetric analyses in space. The microbalance configuration is innovative because of built-in heater and temperature sensor made by metallic films deposited on the crystal. This configuration allows direct temperature measurement over the sensing area, an essential feature for a thermogravimetric sensor that must operate in a wide temperature range, in transient conditions and/or with unknown external heat flux. In fact, beside the deposited mass, the oscillating frequency of the crystal strongly depends on the temperature of the electrode area. In this work, the effect of the temperature on the microbalance frequency has been addressed for the case of uniform distribution, in the temperature range from −20°C to 100°C but the methodology hereafter presented, can be applied to vider temperature ranges where a specific microbilance might be required to operate.

VISTA (Volatile In Situ Thermogravimetry Analyser) is a µ-Thermogravimeter sensor developed by Consortium of Italian Institutes. ThermoGravimetric Analysis (TGA) is a widely used technique to monitor thermal processes involving volatile compounds, e.g. deposition/sublimation and absorption/ desorption. The instrument core is composed by a Piezoelectric Crystal Microbalance (PCM), equipped with built-in heater and built-in temperature sensor, and provided of its own Proximity Electronics (PE). The PCM oscillation frequency linearly depends on the mass deposited on its sensible area (according to Sauerbrey equation) while the PCM temperature can be increased by means of integrated heaters. Thus, mass and volatile composition can be inferred by the frequency change and by desorption temperature, respectively. The instrument is divided in two sensor heads: VISTA1, able to monitor outgassing processes in space, and VISTA2, able to reach higher temperatures, studying the dehydration and organics decomposition in minerals in different environmental conditions. An Engineering Model of VISTA1 and a laboratory breadboard of VISTA2 have been developed. Pure organic compounds and contaminant have been characterized by using deposition processes and TGA cycles obtaining some physical-chemical parameters, i.e. enthalpy of sublimation/evaporation, $\Delta \pmb{H}_{sub, evap}$ , deposition rates, $\pmb{k}$ and vapor pressures, $P_{vap}$ . The instrument concept, the scientific objectives and the laboratory measurements are explained in this work.

Quartz crystal microbalances have been used as measuring and monitoring devices for particle deposition on sensitive surfaces such as optical mirrors, thermal radiators, solar arrays, and other equipment used in space exploration. Moreover, microbalances have been applied in space to perform thermo-gravimetric analyses in order to infer about the type of volatile and condensable material. When the object of contamination monitoring is an intrinsically cold surface, e.g. a radiator, an effective cooling is required to achieve the same (or slightly lower) condensing temperature. The cooling problem of the microbalance sensing area has found promising solution from the use of thermoelectric coolers, the only compact and lightweight devices that can be housed in a typical microbalance envelope. Nevertheless, performance of the thermoelectric element at low temperature is a known issue so that restricts most applications above −40°C therefore there is a lack of data about performances below that temperature and characterization in expected environment is generally required. Thus, in this work cooling performance of commercial thermoelectric elements has been assessed at low temperature along with its survival to thermal cycling in off condition, in order to assess its applicability for the space borne microbalance under development.

Thermogravimetry (TG) or Thermogravimetric Analysis (TGA) is a widely used technique to obtain information about thermal stability and composition and to monitor different thermal processes of materials. The TGA analysis is frequently used to monitor the deposition/sublimation and absorption/desorption processes of volatiles compounds in different environments: outgassing rates from degassing in space [1], dehydration and organics decomposition in minerals [2] and the fate of various materials in atmospheric environments [3]. In particular, it is possible to obtain a characterization of organic compounds by using Quartz Crystal Microbalance (QCM)-based sensors, equipped with an integrated heater in order to study the deposition and desorption processes. In this work, an organic compound (used as contaminant source) was characterized by using the breadboard of a QCM-based sensor, i.e. CAM (Contamination Assessment Microbalance), which shows several improvements compared to the previous Quartz Crystal Microbalance sensors used by European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) [1,4]. CAM instrument aims to monitor contaminants and outgassing materials which are released by spacecrafts during in-orbit space missions characterizing the contaminant source by means of Thermogravimetric technique. The organic compound desorption rates and the enthalpy of sublimation (ΔHsub) were retrieved by using the Langmuir relation while the sensor regeneration was obtained by means of thermal cycles by using the integrated heaters on crystal surface. The CAM breadboard validation, the experimental procedure and results are presented, and compared previous works.

This work deals with temperature characterization of embedded resistors deposited on CAM (Contamination Assessment Microbalance), quartz crystal microbalances developed for thermogravimetric analyses in Space. Designed instrument is innovative thanks to the deposited resistors that allow quartz crystal thermal control by direct heating of the sensing area. Characterization of the deposited materials is of primary importance to provide accurate temperature measurement and retrieve reliable results from the instrument thermogravimetric analyses. Linearity of the Cr-Au material has been verified between −20 and 100 °C and confirmed at cryogenic temperatures. Characterization has been complemented with thermal mapping of an instrument mockup in air. Agreement between reading of the deposited sensor and IR thermography of the crystal has been achieved and the measured thermal map allowed validation of the instrument design.

Piezoelectric Crystal Microbalances (PCM’s) are widely used to study the chemical processes involving volatile compounds in any environment, such as condensation process. Since PCM’s are miniaturized sensor, they are very suitable for planetary in situ missions, where can be used to detect and to measure the mass amount of astrobiologically significant compounds, such as water and organics. This work focuses on the realization and testing of a new experimental setup, able to characterize volatiles which can be found in a planetary environment. In particular the enthalpy of sublimation of some dicarboxylic acids has been measured. The importance of dicarboxylic acids in planetology and astrobiology is due to the fact that they have been detected in carbonaceous chondritic material (e.g. Murchinson), among the most pristine material present in our Solar System. In this work, a sample of acid was heated in an effusion cell up to its sublimation. For a set of temperatures (from 30 °C to 75 °C), the deposition rate on the PCM surface has been measured. From these measurements, it has been possible to infer the enthalpy of sublimation of Adipic acid, i.e. ΔH = 141.6 ± 0.8 kJ/mol and Succinic acid, i.e. ΔH = 113.3 ± 1.3 kJ/mol. This technique has so demonstrated to be a good choice to recognise a single compound or a mixture (with an analysis upstream) even if some improvements concerning the thermal stabilization of the system will be implemented in order to enhance the results’ accuracy. The experiment has been performed in support of the VISTA (Volatile In Situ Thermogravimetry Analyzer) project, which is included in the scientific payload of the ESA MarcoPolo-R mission study.

International audience; The dwarf planet Ceres is an airless body composed of Mg-phyllosilicates, NH4-phyllosilicates, Mg/Ca-carbonates and a dark component. The subsurface of Ceres, investigated by the material composing the peak of complex craters (ccp, crater central peak material; Galiano et al., 2019), reveals a composition similar to the surface, with an increasing abundance of phyllosilicates in the interior. A moderate trend between age of craters’ formation and spectral slope of ccps suggests that younger ccps show a negative/blue slope and older ccps are characterized by positive/red slope. To investigate the causes of different spectral slope in ccps, different grain-sized Ceres analogue mixtures were produced and spectrally analysed. First, the end-members of the Ceres surface (using the antigorite as Mg-phyllosilicate, the NH4-montmorillonite as NH4-phyllosilicate, the dolomite as carbonate and the graphite as dark component), were mixed, obtaining mixtures with different relative abundance, and identifying the mixture with the reflectance spectrum most similar to the average Ceres spectrum. The selected mixture was reproduced with grain size of 0–25 μm, 25–50 μm and 50–100 μm. The three mixtures were heated and spectrally analysed, both with an acquisition temperature of 300 K (room temperature) and 200 K (typical for surface Ceres temperature during VIR observations). The best analogue Ceres spectrum is coincident with a mixture composed of 18 M% (mass percentage) of Dolomite, 18 M% of Graphite, 36 M% of Antigorite and 28 M% of NH4-montmorillonite, after experiencing a heating process. The heating process produces: 1) a darkening and reddening of spectrum, as consequence of the devolatilization of OH group in phyllosilicates and a more dominant effect of opaque phase; 2) a deepening in the intensity of the 3.4 and 4.0 μm band, as well as the 2.7 and the 3.1 μm band, likely due to the loss of absorbed atmospheric water; 3) narrowing of 3.1 μm band and the shift of band center toward longer wavelength (i.e. at 3.06 μm) coincident with mean Ceres spectrum, related to the loss of absorbed atmospheric water. The analysis of the best Ceres analogue mixture, reproduced at different grain size and after heating process, reveals a weakening of 2.7, 3.1, 3.4 and 4.0 absorption bands in coarser samples, likely related to large size of dark grains which reduce the spectral contrast. Furthermore, spectra of coarser mixtures are more red-sloped, suggesting that this trend is more affected by the dark component. The best analogue Ceres mixture produced in this work is almost coincident with the mean spectrum of Haulani ccp, the youngest ccps on Ceres and therefore representative of less altered material on Ceres. The redder spectral slope observed in the older ccps is probably the consequence of the space weathering effects on the original material composing the peak.