Characterization of dust activity on Mars from MY27 to MY32 by PFS-MEX observations

We present spatial and temporal distributions of dust on Mars from Ls = 331 in MY26 until Ls = 80 in MY33 retrieved from the measurements taken by the Planetary Fourier Spectrometer (PFS) aboard Mars Express. In agreement with previous observations, large dust opacity is observed mostly in the southern hemisphere spring/summer and particularly over regions of higher terrain and large topographic variation. We present a comparison with dust opacities obtained from Thermal Emission Spectrometer (TES) - Mars Global Surveyor (MGS) measurements. We found good consistency between observations of two instruments during overlapping interval (Ls = 331 in MY26 until Ls = 77 in MY27). We found a different behavior of the dust opacity with latitude in the various Martian years (inter-annual variations). A global dust storm occurred in MY28. We observe a different spatial distribution, a later occurrence and dissipation of the dust maximum activity in MY28 than in other Martian years. A possible precursor signal to the global dust storm in MY 28 is observed at Ls = 200 - 235 especially over west Hellas. Heavy dust loads alter atmospheric temperatures. Due to the absorption of solar radiation and emission of infrared radiation to space by dust vertically non-uniformly distributed, a strong heating of high atmospheric levels (40 - 50 km) and cooling below around 30 km are observed.Comment: in press in Icarus. 47 pages, 15 figure

Daedalus-CAM Project Plan

Through its Open Space Innovation Platform, in August 2019 ESA opened a campaign for novel ideas to address detecting, mapping and exploring lunar caves and lava tubes. Amongst these ideas, ESA selected the project “Daedalus” to participate in its Concurrent Design Facility (CDF) to study the feasibility and planning the mission. The Mission is planned to last one full lunar day (12+2 contingency), with the possibility to extend the mission time within the cave and to rely on communication with Earth in the following lunar day. The CDF Internal Final Report on Daedalus is now available on request. The Daedalus robot hosts two payloads, one lidar (responsibility University of Würzburg) and one stereoscopic panoramic camera (Daedalus-CAM, responsibility INAF). The present document has been issued to describe the Project Plan of the Daedalus–CAM imaging payload

12 years of atmospheric monitoring by the Planetary Fourier Spectrometer onboard Mars Express

We use thermal-infrared spectra returned by the Mars Express Planetary Fourier Spectrometer (PFS-MEx) to retrieve atmospheric and surface temperature, and dust and water ice aerosol optical depth. More than 2,500,000 spectra have been used to build this new dataset, covering the full range of season, latitude, longitude, and local time. The data presented here span more than six Martian years (from MY26, Ls = 331°, 10 January 2004 to MY 33, Ls = 78°, 6 December 2015). We successfully retrieved atmospheric temperatures and aerosols opacity in the polar regions, including the polar nights. By exploiting PFS/MEx capability to perform observations at different local times (LT), this dataset allows investigation of the daily cycles of suspended dust and ice. We present an overview of the seasonal and latitudinal dependence of atmospheric quantities during the relevant period, as well as an assessment of the interannual variability in the current Martian climate, including spatial, daily (LT), seasonal, and interannual variations of the aphelion equatorial cloud belt. With unprecedented spatial and temporal coverage and details revealed, this dataset offers new challenges to the GCMs and, at the same time, a new reference for the MYs complementary to those observed by MGS-TES

Design and CFD Analysis of the Fluid Dynamic Sampling System of the “MicroMED” Optical Particle Counter

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’s fluid dynamic design should allow dust grains to cross the laser-illuminated sensing volume. The instrument’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’s Flight Model

Martian environmental chamber: Dust system injection

NessunaThe aim of this work is to describe the development and implementation of an experimental setup able to reproduce some characteristics of the Martian atmosphere. The development of such setup fits into the context of MicroMED project, that foresees the development of an optical particle counter to be accommodated on the ExoMars 2020 Surface Platform, as part of the suite of sensors named Dust Complex. MicroMED will perform the first direct measurement of the size distribution of the powder close to Martian surface. The experimental setup is able to reproduce the characteristics of the Martian atmosphere: pressure, atmospheric composition, the actual temperature in which MicroMED will operate (from 20 C to 40 C) and the most important thing: the presence of suspended dust. The main result obtained in this work was the right configuration of an experimental setup in which to test sensors or instruments that work in Martian conditions. In particular, a dust injection system has been developed in order to obtain a dust distribution that was localized and without the formation of particles aggregates, for a correct calibration of the instrument

CFD analysis and optimization of the sensor “MicroMED” for the ExoMars 2020 mission

Characterization of dust is a key aspect in recent space missions to Mars. Dust has a huge influence on the planet's global climate and it is always present in its atmosphere. MicroMED is an optical particle counter that will be part of the "Dust Complex" suite led by IKI in the ExoMars 2020 mission and it will determine size distribution and concentration of mineral grains suspended in martian atmosphere. A Computational Fluid Dynamic (CFD) analysis was performed aimed at the optimization of the instrument's sampling efficiency in the 0.4-20 μm diameter range of the dust particles. The analysis allowed to understand which conditions are optimum for operations on Mars and to consequently optimize the instrument's fluid dynamic design

Uncertainty-based combination of signal processing techniques for the identification of rotor imbalance

This paper describes a method for the uncertainty-based combination of signal processing techniques for the identification of rotor imbalance. The main idea of the proposed method is to compute the imbalance with different algorithms and to average the different algorithmsâ\u80\u99 results. The method is based on the data fusion at feature level and uses the measurement uncertainty of the imbalance as a figure of merit for the weight computation. A static, a dynamic, and a hybrid implementation are presented. In the static one, the weights are computed in a dedicated training phase, in which four algorithms (Fourier transform and quasi-harmonic fitting of signal denoised with Hilbert-Huang Transform, Hilbert Vibration decomposition, and Wavelet Packet decomposition) have been used to estimate the known imbalance of car wheels. In the dynamic one, the weights are computed at runtime by estimating the difference between each predictor and the actual signal. The hybrid approach is the combination of the two algorithms. Results of simulations and experiments evidenced the validity of the data fusion, with uncertainty reductions between 10 and 40%, with larger benefits in presence of non-stationary disturbances

About the dynamic characterization of micro-bolometric infrared cameras

This work describes two methods for the dynamic characterization of a microbolometer infrared camera. The time constant, parameter commonly used for microbolometers dynamic performance identification, has been addressed in literature with studies mainly focused on theoretical computation and only seldom supported by testing activity. In this paper, alternative methods for the dynamic characterization of infrared sensors are presented and related uncertainty budgets are assessed. The infrared camera NEC TH7102WX has been tested with the proposed methods and results have been compared. The microbolometer behavior has proved to strongly deviate from the common first order model so that the time constant is no more a characterizing parameter. Depending on the definition of "equivalent time constants", the measured parameters changed by more than 50%, with values ranging between 30 and 50 ms

Metodi di misura senza contatto della temperatura di fili sottili in movimento

L’articolo descrive la progettazione di due sistemi di misura, senza contatto, della temperatura di fili sottili che sfruttano il principio base dei pirometri a radiazione totale e bicolore. Gli schemi ottici degli strumenti sono stati analizzati con simulazioni numeriche allo scopo di evidenziare la sensibilità delle configurazioni proposte all’oscillazione trasversale del filo. L’incertezza di misura attesa è stata utilizzata per effettuare il confronto tra le prestazioni di diverse scelte progettuali con alcuni sensori infrarossi in presenza di tipici effetti di disturbo, come la variazione della temperatura di background e dell’emissività della sorgente

Characterization of embedded temperature sensors on QCM in cryogenic environment

This work deals with the temperature characterization of embedded resistors deposited on a quartz crystal microbalance developed for thermogravimetric analyses in Space, i.e. the Contamination Assessment Microbalance project. The instrument allows in-situ thermogravimetric analyses thanks to the deposited resistors on the quartz crystals. Developed technology would improve the thermal control of the microbalance, but linearity of the deposited materials within the expected temperature range is of primary importance to provide accurate temperature measurement and get reliable results from the instrument thermogravimetric analyses. Thus, linearity of the Cr-Au material has been assessed down to cryogenic temperatures, lowest limit of the intended application