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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.

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.

The composition of the Martian atmosphere and its dust content is a key factor for understanding the climate of the Red Planet, which is of vital importance to enable future human exploration. The use of atmospheric LIDARs to characterize densities and sizes of aerosol with a height profile, is commonly used on Earth. However, Earth LIDARs are heavy and very power-demanding, which make them not easily on-boardable for planetary exploration. We propose the development of a compact LIDAR aimed at providing the most precise characterization of the suspended dust and clouds of the atmosphere of Mars to-date, while maintaining very reduced power, mass and volume envelops to facilitate its accommodation in a wide variety of landed assets. Rationale and heritage In the past years, INTA has developed four miniature radiometers for different missions: MetSIS for MetNet Lander [1], DREAMS-SIS for Schiaparelli [2], SIS’20 for Kazachok [3] and RDS for Perseverance [4]. All of them, at different levels depending on their complexity, allow the estimation of the atmospheric optical depth with high time resolution, detection of clouds and estimation of the dust concentration vertical profile. A natural step forward to complement our capabilities, especially for the dust profile and characterization of clouds, is a LIDAR. There is only one LIDAR that has already operated on Mars, on board the Phoenix mission. With a 2-wavelengths configuration at 532 and 1064 nm but without depolarization, it operated in the North Pole of Mars for 90 sols [5]. The laser pulses had a power of 30-40 kW and duration of 10 ns. Total mass was 6 kg and the power consumption 30W. A '2B+1d' LIDAR configuration is proposed here to obtain the Particle Backscatter Coefficient (PBC) at two wavelengths (2B), and the depolarization ratio at one of them (1d). They both are used to obtain three LIDAR parameters relevant for dust and cloud characterization: the particle linear depolarization ratio (PLDR), the lidar ratio (LR), and the colour ratio (CR). The intended range is set around 20 km, depending on the scenario, and depolarization measurement capability shall be incorporated. Key technologies for miniaturization The target mass and power envelop are Pulsed semiconductor laser diodes are proposed for the transmitter, instead of usual (and bulkier) diode-pumped, Q-switched solid-state lasers. This reduces the emitted energy and in turn requires higher repetition rates to improve the Signal-to-Noise ratio. Silicon Photomultipliers, also known as Multi Pixel Photon Counters, will be used as detectors. They allow lower biasing voltages than other high-gain technologies, while they show some trade-offs such as their so-called "cross talk" noise. Its performance under the applicable thermal and radiation environments must be addressed. The use of new synthesis methods to obtain very low thermal expansion coefficient (CTE) materials (crystalline β- eucryptite) to reduce the thermal requirements related to structure and alignment. To reduce the size of the optics and to mitigate the complexity of the collimation of a semiconductor laser (with large spots and emission apertures), 'free form' optics will be considered in the optical design. From the signal processing point of view, the aim is to design a receiver that autonomously adapts the measurement mode (analogue or pulse counting) and parameters (e.g., variable time intervals for pulse-counting) in real time, providing the best signal quality vs. vertical resolution compromise for each altitude. Feasibility To preliminarily assess the feasibility of this LIDAR to reach a scientifically meaningful range, we have performed several simulations of the expected signal and signal-to-noise ratio using extinction and backscattering profiles representative of different dust conditions on Mars, together with technical data extracted from the datasheets of real pre-selected parts and opto-mechanical parameters values that we consider feasible for a compact instrument as the intended one. Emitted pulses have a power of 600W and a duration of 150ns. We have simulated three different background illumination scenarios: night, twilight, and midmorning, as this is critical from the point of view of the “offset” signal it generates (that must be filtered out) and the noise associated with it. We employed worst-case (high) diffuse radiance values on Mars. Extinction and backscattering coefficients have been extracted from Phoenix LIDAR measurements [6], and background illumination values from RDS measurements in Perseverance. The conclusion is that, with adequate signal processing, we should be capable of reaching 4 km during the day, 6-7 at twilight and 15 at night, for the worst-case scenario. 20 km are feasible in better scenarios. On-going activity and next steps A breadboard prototype of the system is being built at INTA for only one channel (one wavelength; no polarization) based on pre-selected pulsed laser diode and silicon photomultiplier, with standard off-the-shelf optical parts and filters. Preliminary laboratory and outdoor measurements will be done to validate the simulations and confirm the feasibility of reaching a meaningful range with the strict miniaturization constraints. Low-temperature characterization of the emitters and detectors, as well as Displacement Damage tests to assess their robustness to the radiation environment will be done by the end of the year. The electronic design has a large heritage from previous Martian sensors as the ones mentioned above, all of them designed to operate down to -130ºC with no heating. Next steps will include thermal cycling testing of the optics and the support materials and feasibility analysis of the optomechanical frame to face such conditions. [1] Ari-Matti Harri et al., Geosci. Instrum. Method. Data Syst., 6, 103–124, 2017. [2] I. Arruego et al., Advances in Space Research 60 (2017) 103–120. [3] I. Arruego, Proc. IPPW 2018. [4] V. Apéstigue et al., Sensors 2022, 22, 2907 [5] J. A. Whiteway et al., Journal Geophys. Res., Vol. 113, E00A08. [6] J. A. Whiteway, et al., Science 325, 68 (2009).

Space is one of the most avant-garde sectors for additive manufacturing as the inherent characteristics of this technology allow the creation of complex and lightweight 3D structures. Using this brand-new design tool, it was possible to design the pumping system holder of the MicroMED instrument, a particle analyser developed for ExoMars 2022 mission. The geometry of the holder was optimized using a finite element approach. The effectiveness of the proposed solution was evaluated by comparing the performance of two different designs using the AlSi9Cu3 alloy. One solution was based on micro-milling and the other on Selective Laser Melting. In order to validate the designed SLMed holder, a mockup was produced and successfully tested in the mission's mechanical environment.

With the introduction of visible and infrared Imaging Spectrometers about 20 years ago, we have assisted to a dramatic enhancement of the scientific return achieved by space missions launched for the exploration of the Solar System. This innovative class of instruments are in fact able to conjugate together the imaging capabilities of the cameras with the spectral resolution accomplished by spectrographs. By exploiting such capabilities, planetary scientists can retrieve and map the physical and chemical properties of a target body and correlate them with surface morphological features or with dynamical structures of the atmospheres. It is not by chance that such instruments have become an essential payload on many planetary exploration missions since they have demonstrated their capabilities to allow a better understanding of the composition, processes and evolution of Solar System bodies. In the meanwhile, ongoing photonic research has made available new devices whose technology is mature enough to allow to investigate new optical concepts for color cameras and imaging spectrometers architectures to be implemented in a single integrated instrument (⨏ISPEx), which we present here. The ⨏ISPEx camera design uses a Liquid Crystal Tunable Filter (LCTF) to ensure high flexibility in the selection of the bandpass (between 0.42-0.73 µm) and bandwidth (35 nm at 0.55 µm) of the color filters, which can then be adapted to very different scientific targets. The camera has a broad 3.3°x1.6° FOV and an IFOV of 14 µm allowing to reach a spatial resolution of 0.14 m/px from 10 km distance. Conversely, the ⨏ISPEx VIS (0.4-1.05 µm spectral range, 3.2 nm/band sampling) and IR (0.95-5.0 µm, 8 nm/band) integral field imaging spectrometers use Coded Mask Optical Reformatters (CMOR) based on optical fibers bundles to collect the full hyperspectral cube through a single acquisition resulting in a great reduction of the acquisition time with respect to traditional whiskbroom and pushbroom instruments. The FOV/IFOV are 0.4° (circular)/100 µrad and 0.28°x0.28° (square)/225 µrad for the VIS and IR channel spectrometers, respectively. These values correspond to a 70 m-wide circular hyperspectral image made of 4500 pixels at 1 m/px resolution for the VIS channel and to a 50x50 m image made of 484 pixels at 2.25 m/px for the IR channel for acquisitions made from a distance of 10 Km. These requirements are optimized for remote sensing of asteroids and comets from close distances. Camera’s and spectrometers’ FOV are co-located on the same boresight thanks to the use of a common Three Mirror Afocal Telescope operating with a 2.4X beam reduction factor (entrance pupil diameter 84 mm). By means of a beamsplitter and a dichroic filter the collimated beam generated by the telescope is split to the camera and spectrometers’ pupils. Thanks to the solutions we are developing, the camera and imaging spectrometers will operate at the same time on the same boresight, resulting in a great simplification of their operations. In this respect, the ⨏ISPEx will offer the advantage to allow a better exploitation of the data collected by the three channels resulting in a tremendous advantage for many scientific investigations. With this synergic approach it will be possible to analyze high resolution images to constrain morphology interpretation of a target, while hyperspectral data collected at the same time allow the retrieval of composition and physical properties. The availability of camera images makes possible to apply sharpening algorithms to spectrometer’s ones. Apart this, an integral-field spectrometer will keep the capabilities of more traditional whiskbroom and pushbroom spectrometers but it will overcome them when the target scene is rapidly evolving and changing during the acquisition: traditional instruments are limited by the fact that the cube acquisition process may take a time longer than the temporal scale of the investigated event. This is the case of observations enquiring into the dynamical evolution of planetary atmospheres, lightning events, outbursts, hypervelocity impact or fast-moving targets. By operating with fast readout detectors, an Integral Field spectrometer can adequately resolve the four dimensions of data (2D spatial, spectral and temporal) opening the possibility to perform time-resolved hyperspectral movies. Another substantial advantage of Integral Field spectrometers is their better operability during fast flyby phases, where the distance from the target and illumination geometry are rapidly changing, resulting in limited time periods suitable to observe the target with optimal conditions. By collecting the entire hyperspectral cube in a fraction of the time necessary to complete the scan for a traditional scanning spectrometer, an Integral Field spectrometer can reach a level of imaging flexibility similar to the one achieved by a camera. Within this study we are defining the configuration of the ⨏ISPEx space model operating in the 0.4-5.0 µm spectral range including optical performance analyses, and thermomechanical and electronic architecture. Moreover, we are realizing a development breadboard limited to the 0.4-1.0 µm spectral range to conduct performance tests at system level on LCTF and CMOR devices. We gratefully acknowledge financial contribution from the Agreement ASI-INAF n.2018-16-HH.0.

A compact and light-weight set-up to impose medio-lateral vibration while walking has been designed and manufactured. A vibrating plate was actuated by a motor and a linear guide. After the design and finite-element analysis, the set-up has been manufactured and tested in the frequency band 0.5-4 Hz with amplitude below ± 20 mm, that is compatible for human testing. Total harmonic distortion has been measured below −30 dB. Crosstalk values along Z and Y measured at the corners of the moving platform were lower than 0.1 at 4 Hz. Given the previous analyses, the set-up can be used to test in a movement laboratory the effect of vibration during walking, mounting a walking pad on the platform.

The Optical Particle Counter 'MicroMED' will be part of the ExoMars 2022 mission and aims to provide the first ever direct measurement of airborne Martian dust. The instrument has been tested at the INAF - OAC premises, where a Martian chamber is present, simulating the Martian environment in terms of pressure, instrument temperature, atmosphere composition and the presence of dust. However, tests in the presence of wind are also needed for the instrument characterization. To this purpose, a test campaign at the AWTS II simulator at the Aarhus University (Denmark) was performed, testing the instrument in the presence of winds up to 15 m/s. Such tests are important since wind is the main agent of landscape modification on Mars. The present work describes the results of such tests, showing the variation of the instrument detecting ability with the wind speed, as well as the influence of temperature on performances.

High-performance imaging systems play a fundamental role in space and planetary observation. Traditional cameras require actuators coupled with movable elements to scan large scenarios and overcome their limited field of view. Extra equipment increases the mass budget and the instrument complexity, as well as the risk of failure. Panoramic optics constitute a valid solution to enhance the imaging systems robustness while enlarging the camera field of view, all with a single compact device. In this paper, the feasibility of employing an off-the-shelf optical system based on a hyper-hemispheric panoramic lens for planetary observation has been assessed. In particular, the supporting frame of the aforementioned optical system has been designed to withstand a general space environment, i.e. temperature variation between −120°C and + 120°C, and considering loading during launch. A design solution is proposed, resulting from a kinematic-like mounting system to safely endure the thermal environment. In order to validate the obtained design, a mockup has been manufactured, assembled, and tested in a representative mechanical environment, exhibiting good agreement with the dynamic behaviour predicted by the developed numerical models.

In this work, the optimization of the optical bench for the MicroMED dust analyzer is presented. A nonconventional design technique has been exploited to obtain a mass saving, valuable achievement in aerospace and space instruments design. Topology optimization has been coupled to the finite element approach to improve the optical bench design, whose performance has been assessed and compared with the actual one. The optimization results proved the robustness of the adopted workflow and provided interesting results for a possible design enhancement of the MicroMED dust analyzer. A saving of about 55% of the available design domain mass budget has been achieved, and the dynamic behavior of the structural component has been improved, providing about 50% increase of the first eigenfrequency value.

The future of spaceborne observations is strongly oriented toward miniaturization of payloads without reducing their performances. In this framework telescopes equipped with deployable structures would guarantee either an improvement of the performances or a considerable volume reduction which, due to the limitations on the launcher, translates into a lower cost of in-orbit commissioning. This paper aims at comparing possible mechanism layouts for a deployable space telescope designed for Earth observation in the infrared spectrum. The design considers a classical Cassegrain telescope and aims at packaging the secondary mirror as close as possible to the primary; the trade-off analyses among different technological solutions and configurations are presented. This is a preliminary study performed in the framework of DORA (Deployable Optics for Remote sensing Applications), a project aiming at developing a deployable telescope for minisatellites, and concludes with the assessment of the most feasible layouts which are going to be considered in the next phases of the project.

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.

This paper describes a system for the measurement of the internal and external temperature profiles of PET preforms used in the Injection Stretch Blow Moulding (ISBM) process. Many works in literature highlighted the importance of these quantities to improve the production quality of PET bottles, but none addressed the development of a measuring system suitable for this scope. A measuring system based on two thermopiles for the identification of the internal temperature profile and a thermal camera for the measurement of the external one has been designed. The adopted sensors were individually calibrated and the uncertainty budget, accounting for both instrumental uncertainties and the effect of multiple reflections, was derived. A prototype of the measuring system was tested on an industrial ISBM machine. The dependence of the preforms temperature profile on the settings of the ISBM machine was investigated. Results evidenced that the minimum variations of the machine settings induced temperature differences significantly larger than the measurement uncertainty, thus proving the effectiveness of the proposed system.

This work describes the results of a test campaign aimed to measure the propagation of longitudinal, torsional, and flexural stress waves on a drill bit during percussive rock drilling. Although the stress wave propagation during percussive drilling has been extensively modeled and studied in the literature, its experimental characterization is poorly documented and generally limited to the detection of the longitudinal stress waves. The activity was performed under continuous drilling while varying three parameters, the type of concrete, the operator feeding force, and the drilling hammer rotational speed. It was found that axial stress wave frequencies and spectral amplitudes depend on the investigated parameters. Moreover, a relevant coupling between axial and torsional vibrations was evidenced, while negligible contribution was found from the bending modes. A finite element model of the drill bit and percussive element was developed to simulate the impact and the coupling between axial and torsional vibrations. A strong correlation was found between computed and measured axial stress spectra, but additional studies are required to achieve a satisfactory agreement between the measured and the simulated torque vibrations.

A bifocal panoramic stereoscopic camera (BIPS) has been designed a realized as a terrestrial prototype. The core of the camera is a novel Bifocal Panoramic Lens (BPL) we designed and realized, which is able to carry out a panoramic field of 360° in azimuth, 100° in elevation (+60°/-40° with respect to the horizon) and, simultaneously, an enlargement of a part of the panoramic field. All of that using an unique image sensor and avoiding any moving part. BIPS consists of a twin couple of BPLs settled in an appropriate stereoscopic baseline. It allows the monitoring of the surrounding environment in stereoscopic (3D) mode and, simultaneously, to capture a higher resolution stereoscopic images to analyze scientific cases. If mounted on a planetary rover, BIPS merge engineering stereoscopic capabilities for autonomous driving with an optical stereoscopic channel for scientific purpose, making it a new paradigm in the planetary rovers' framework. The operational aims include the identification of boulders, crevasses and other surfaces that can be obstacles for rover trafficability, in addition to the 3D reconstruction of exploration sites for improving situation awareness during both roving and human operations. On the other hand, the correct and detailed 3D reconstruction of exploring sites allows detailed measurements of many geological features such as: sedimentary structures (strata attitudes, geometry and thickness); fracturing networks (attitudes and persistence); folds and faults systems (orientation, vergence and displacement); veining systems (frequency, orientation and thickness); mounds, vents and ridges (slope and aspect); boulders (size frequency distribution). All these measurements are pivotal for the understanding of tectonic, sedimentologic, volcanic, erosive, fluid-rock interaction and impact processes on planetary surfaces. In this paper we describe the optical characteristics of a BPL, the realized terrestrial BIPS, the stereoscopic calibration and some possible scientific cases within the lunar exploration framework.

The technological developments that led to the miniaturization of satellites, bringing to the market mini ( Small platforms allow reducing costs of development and management of single missions but also ease the possibility of using distributed systems in space making use of more satellites flying in formation or as a constellation. Furthermore, mini, micro and nano satellites are optimal candidate as platforms for the test and validation in space of innovative technologies with a lower level of maturity and thus not directly usable onboard “standard” sized satellites. The new generation of mini, micro and nano satellites can be proficiently used for the exploration and commercial utilization of small bodies of the Solar System (NEA, NEO, MBC, Asteroids); the characterisation of those bodies, in terms of composition, dimensions and interior structure, is of fundamental importance for the study of the evolution of our Solar System but also for the exploitation of extraterrestrial natural resources. There is a considerable advantage in using deployable systems onboard small satellites as these have considerable limitations in some of the resources, mainly mass and volume. The identification of payloads capable of minimising resources usage at launch, still guaranteeing in flight performances analogues to those of more “expensive”, in terms of resources, instruments is an extremely valuable benefit. The capability of using deployable telescopes allows to access scientific objectives and applications otherwise difficult to reach. In fact, remote sensing payload in the VIS/IR is strongly handicapped by the limited resources available onboard a mini-satellite which limits the size of the primary mirror and/or the length of the telescope assembly, thus resulting in reduced performances in terms of spatial resolution and signal to noise ratio. Precision-deployable, stable, optical telescopes that fit inside smaller, lower cost launch vehicles and small platform are a prime example of a technology that will yield breakthrough benefits for future scientific as well as more commercially-oriented applications. The DORA (Deployable Optics for Remote sensing Applications) project has been funded by the Italian Ministry of Research in the framework of the Italian National Research Plan 2015-2020 with a 30 months contract in a partnership between private companies (led by SITAEL the largest Italian privately-owned Company operating in the Space Sector), INAF (IAPS-Rome and Astronomical Observatory of Padua) the Parthenope University in Naples and Politecnico of Milan. Objective of the project is the design, realisation and test of a prototype of deployable optical system for Remote Sensing applications in the VIS and IR spectral ranges; a deployable telescope and straylight shield will be interfaced to a focal plane instrument (e.g. camera, imaging spectrometer, Fourier spectrometer). The telescope shall be stored in a closed configuration during launch to minimize volume and will be fully deployed in operative configuration once in flight by means of actuators. Similar deployable systems can be used to extend antennas used in microwave instrumentations (e.g., radiometers). The range of applications of such optomechanical technologies, in a space environment and onboard small satellites, are potentially very wide extending from Earth Observation satellites, used for environmental monitoring and for risk management, to Solar System exploration missions. In the framework of the DORA study the deployable optical system will be interfaced to an infrared Fourier spectrometer. We are taking advantage of the availability of the prototype of a miniaturised Fourier Spectrometer named MIMA (Mars Infrared MApper) [1] originally designed and built for the ExoMars 2020 mission but finally not among the selected payload; MIMA will be interfaced as a focal plane instrument to the Deployable telescope. MIMA is a double pendulum interferometer providing spectra in the 2 – 25 μm wavelength domain with a resolving power of 1000 at 2 μm and 80 at 25 μm. The radiometric performances are SNR >40 in the near infrared and a NEDe = 0.002 in the thermal region. The instrument design is very compact, with a total mass of 1 kg and an average power consumption of 5 W. The prototype has been tested and reached a Technology Readiness Level (TRL) of 5 level of development. The original FOV of the MIMA instrument was 3.2° which, although adequate for the in-situ analysis of the Martian soil, it is not sufficient to guarantee challenging results for typical Remote Sensing applications; thus MIMA will be matched to a 30 cm diameter, f/#=16, Cassegrain deployable telescope to reduce the FOV to ≤0.3°. The large sized primary mirror will guarantee the increase in collecting area needed to compensate for the considerable reduction of the FOV of the instrument. Such a combined instrument can be used proficiently for the study of small bodies of the Solar System. These bodies are remnants of original planetesimals from which the planets were formed. Differently from planets, which have experienced alterations during their evolution, the majority of small-sized asteroids underwent much less internal heating, resulting in a better preservation of their pristine composition. Since small bodies were the impactors of the primordial Earth, they may have been the principal carriers of water and organic material, the building blocks necessary to create life. A MWIR spectrometer like MIMA onboard a small mission will improve our understanding of the primordial cosmochemistry from small bodies remote sensing observations, providing unique data related to surface properties, mineralogy and thermal inertia. The scientific objectives can be summarised as: Analyse the thermophysical properties of the surface by measuring the temperature changes occurring during the diurnal cycle; Provide information on surface mineralogical composition and physical properties (grain size distribution, roughness); Search for thermal anomalies associated to the presence of surface rocks; Measure the thermal inertia of the surface The presentation will describe the development status of the DORA project providing detailed information on its expected performances. Acknowledgments. This study is funded by Ministry of Research PNR 2015-2020, specialisation area “aerospace” project n.ARS01_00653 References: [1] G. Bellucci et al., (2007). Proc. SPIE 6744, Sensors, Systems, and Next-Generation Satellites XI, 67441R, doi: 10.1117/12.737912

This work describes the metrological characterization of an automatic measurement system for the identification of the diameter of rectified cylinders with multiple LVDT sensors. This system varies its temperature because of the fluctuation of the ambient temperature (from 15 to 35°C) while the workpiece exhibits temperature gradients along its axis because of the grinding process used to obtain the final diameter; the effect of these temperature variations can reach up to 25 micrometers, that is very large considering a manufacturing tolerance of 12 micrometers. The first part of the work focused on the evaluation of the repeatability and reproducibility of measurements. The second part aimed to develop a compensation algorithm, for the interfering effects of temperature, based on multiple thermocouple measurements. The algorithm uses two Coefficients of Linear Thermal Expansion estimated by fit-to-purpose experiments, for the workbench and for the measurands respectively. This method allows to reduce measurement uncertainty to 1.1 micrometers.

This paper describes a measurement method for the quality control of cylinders for printing machines based on roll-to-roll presses. If the surface finishing of the cylinders is not adequate, the printing is unacceptable, and the defective cylinders must be reworked. The performed quality check of the cylinder surface roughness by means of contact methods was unable to identify the cylinder defects, and acceptance of the manufactured cylinders before integration was demanded to the visual inspection performed by trained operators. In this work a contactless measurement method based on the eddy current displacement sensor was proposed and validated as a tool for quality check as an alternative to optical roughness measurements. A test bench for the characterization of printer cylinders was designed and manufactured, allowing for the validation of the proposed method on different batches of cylinders and the identification of a threshold to guide the acceptance of tested cylinders prior to mounting on the roll-to-roll press.

The interest of manufacturing complex devices is steadily growing for high technological application fields, such as the aerospace and biomedical ones, due to the possibility of coupling structural and functional properties. Additive manufacturing (AM) allows to produce 3D complex geometries such as lattice structures, offering lightness together with good mechanical properties. Herein, static and dynamic mechanical properties of Ti6Al4V lattice structures, produced by selective laser melting, are investigated and compared with fully dense material, as reference. In detail, the effects of heat treatment on mechanical properties and damping performance are investigated through tensile testing and dynamic compression measurements at different excitation frequency and deformation amplitude. The lattice structure can express a damping capacity of an order of magnitude higher than the fully dense material, correlated to good mechanical behavior. In the prospective of newly designed parts for vibration suppression in aerospace applications, the opportunity of enhancing damping behavior by means of light structural components is allowed by the use of lattice structures.

In the Additive Manufacturing (AM) field, Selective Laser Melting (SLM) process is one of the most promising manufacturing technologies for the production of 3D complex parts. High-tech sectors, like aerospace, show growing interest for the use of AM, because it can offer unique opportunities in terms of freedom in the design and integration of some specific functionalities in lightweight structures. Together with lightness of materials, another important requirement is the capacity of vibrations damping, relevant e.g. for the vibro-acoustic environment during launch in the aerospace field. This work focuses on the correlation between the damping behavior of AlSi10Mg specimens and residual stresses induced during SLM, i.e. in as-built condition, or after different post-additive heat treatments, specifically studied for this Al alloy. Indeed, residual stresses have a well-known influence on the static and fatigue mechanical behavior, but a few literature works are present relating residual stresses with damping capacity. Results of the performed experimental tests showed that the damping capacity decreases with the increase of the heat treatment temperatures, i.e. damping can be modulated by customized thermal treatments.

MicroMED (Micro Martian Environmental Dust Systematic Analyzer (MEDUSA)) instrument was selected for the ExoMars 2020 mission to study the airborne dust on the red planet through in situ measurements of the size distribution and concentration. This characterization has never been done before and would have a strong impact on the understanding of Martian climate and Aeolian processes on Mars. The MicroMED is an optical particle counter that exploits the measured intensity of light scattered by dust particles when crossing a collimated laser beam. The measurement technique is well established for laboratory and ground applications but in order to be mounted on the Dust Suite payload within the framework of ExoMars 2020 mission, the instrument must be compatible with harsh mechanical and thermal environments and the tight mass budget of the mission payload. This work summarizes the thermo-mechanical design of the instrument, the manufacturing of the flight model and its successful qualification in expected thermal and mechanical environments.

Suspended dust has a prominent role in Martian climatology. Several significant dust related phenomena can be observed at various scales, starting from global dust storms to local dust devils, which have important effects such as the increase of troposphere temperature, the modification of the wind regime and the localized motion of sand at the surface. These phenomena depend on dust grain characteristics such as the size distribution or the chemical and bulk composition. Currently, we do not have direct measurement of the dust properties; the only available information in this regard are derived from spectrometric measurements, optical depth, and albedo coming from instruments aboard satellites and in-situ. Herein, we describe the tests performed on the optical particle counter named MicroMED, designed and built to perform the first ever direct in-situ measurement of suspended dust grains in the Martian atmosphere close to the surface. MicroMED is a dust particle size analyzer which was selected to join the Dust Complex payload aboard the ESA/Roscosmos ExoMars 2022 mission. It has the capability to suck in dust that is suspended in atmosphere and to measure the sizes of single grain. The sensor sucks in the dust grains using a sampling system, guides the grains through ducts and concentrates them in an area illuminated by laser. Detecting the intensity of the light scattered by the grains during the crossing through the illuminated area, it is possible to determinate the size of grain. Here we present the innovative techniques in order to verify the performances in terms of dust suction efficiency of the MicroMED Flight Model, using a prototype called MM1.

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.

MicroMED is an optical particle counter that will be part of the ExoMars 2020 mission. Its goal is to provide the first ever in situ measurements of both size distribution and concentration of airborne Martian dust. The instrument samples Martian air, and it is based on an optical system that illuminates the sucked fluid by means of a collimated laser beam and detects embedded dust particles through their scattered light. By analyzing the scattered light profile, it is possible to obtain information about the dust grain size and speed. To do that, MicroMED&rsquo, s fluid dynamic design should allow dust grains to cross the laser-illuminated sensing volume. The instrument&rsquo, s Elegant Breadboard was previously developed and tested, and Computational Fluid Dynamic (CFD) analysis enabled determining its criticalities. The present work describes how the design criticalities were solved by means of a CFD simulation campaign. At the same time, it was possible to experimentally validate the results of the analysis. The updated design was then implemented to MicroMED&rsquo, s Flight Model.

This work describes the qualification of MEMS differential pressure sensors to be used in a particle analyzer for Mars 2020. Two different types of sensors have been initially considered MEMS-33A-001D and NPH-8-002.5-GH, in order to select the most suitable in terms of S/N ratio and sensitivity. Sensors have been calibrated at ambient pressure using as reference a water column differential manometers, selected for the unmatchable stability, key property for tests expected to span across many days. The pressure signal has been generated using the water column manometer itself, allowing to reach the full scale of the instruments and by means of a vane pump in low pressure environment where a capacitive manometer has been used as reference. No variation in the sensor sensitivity has been evidenced after exposure to the expected temperature range for the instruments mounted on the platform of the ExoMars Lander. The final selection of the sensor to be flight-qualified has been made on the SNR because both candidates proved to be compatible with the mechanical loads expected during launch and Martian landing and the expected space environment through all mission phases.