The ESPERIA satellite project for detecting seismo-associated effects in the topside ionosphere. First instrumental tests in space

In recent times, ionospheric and magnetospheric perturbations constituted by radiation belt particle precipitations, variations of temperature and density of ionic and electronic components of ionospheric plasma as well as electric and magnetic field fluctuations have been detected on board of the LEO satellites and associated with earthquake preparation and occurrence. Several mechanisms have been suggested as justifying the seismoelectromagnetic phenomena observed in the upper lithosphere and in the topside ionosphere before, during and after an earthquake. Their propagation in these media has also been investigated, but physical knowledge of such processes is below standard. Consequently, coordinated space and ground-based observations based on data gathered simultaneously in space and at the Earth's surface are needed to investigate seismo-associated phenomena. To this end, the ESPERIA space mission project has been designed for the Italian Space Agency (ASI). To date, a few instruments of its payload have been built and tested in space. This paper reports on the justification, science background, and characteristics of the ESPERIA mission project as well as the description and testing of ESPERIA Instruments (ARINA and LAZIO-EGLE) in space

Groundwater helium content related to the Spitak (Armenia) and Karymsky (Russia) earthquakes

The Spitak and Karymsky earthquakes occurred with M46.9 in Armenia and in Kamchatka (Russia), respectively. As regards the Spitak earthquake, we analysed the groundwater helium content data collected by three Georgian and one Armenian measurement sites; as regards the Karymsky earthquake, we analysed the groundwater helium content data collected by two measurement sites in Kamchatka. The first analysis has pointed out that precursory anomalies appeared in the northern area with respect to the Spitak epicentre; on the contrary, only co-post seismic anomalies were revealed in the southern area. As regards the Karymsky earthquake, no pre-co-post seismic variation in the groundwater helium content was revealed at both the measurement sites. The analysis of other hydrogeochemical parameters, collected in these sites, revealed that one site does not show any anomaly; on the contrary, at the other measurement site clear preseimic anomalies appeared in some hydrogeochemical parameters. A possible explanation of the quoted results is presented

Phenomenology of rupture process in homogeneous isotropic media

A statistical method is proposed for the description of the fracture pro::ess in homogeneous isotropic media. In particular, the macroscopic defects formation into a medium due to the application of an external load is studied. The instability connected with the structural transition from these multimacroscopic defects to the final rupture of the body is also discussed. To this purpose, the Volterra logistic growth law is used. The statistical interpretation of the rupture catastrophic phenomenon includes the justification of the characteristic "silent time" (which has been observed to occur in some time intervals prior to the fracture), as an indicator of the above-mentioned structural transition

Tellus Experiment.A multi-instrument Payload for the investigation of the Topside Ionosphere

A new space project, which summarizes previous ones reported in several LNGS Annual Reports, has been proposed by the TELLUS team for the investigation of ionospheric and magnetospheric phenomena within the Earth-near-Earth space couplings. The project includes the study of natural disasters taking place in the Earth surface (as earthquakes) and their possible deterministic prediction on the basis of precursory phenomena to be reconciled with perturbations occurring in the topside ionosphere. After an introductory section on the subject, technical, scientific, and methodological details are given on the project

Tellus Experiment. Method for Signal Conditioning and Data Acquisition System, based on Variable Amplification and Feedback Technique

In many space and ground-based applications of interest for the TELLUS Experiment the amplitude and frequency content of analog signals to be detected is a priori unknown and can lie in a very large range of values [1-5]. This is a particularly challenging problem to be managed, especially when the data acquisition and signal analysis must be carried out in extreme environments where large data processing resources are requested together with a low power consumption and high efficiency of the device. The method is specifically useful when power spectrum of measured signals exhibits a very large variability in the different frequency bands making particularly difficult the runtime signal analysis of the phenomena under study. The method proposed within the TELLUS Experiment is of particular interest in two applications. The first being an analysis of multi-channel analog signals constituted by several frequency components each one of which exhibits very different amplitudes that need to be simultaneously registered by the acquisition system. The second application further enhances the specific characteristics of the method when, in addition to manage multichannel analysis, we should treat multiparameter data (i.e. data relating to signals of different nature associated with parameters or fields different from each other) [6]

METODO A FEEDBACK VARIABILE DI CONDIZIONAMENTO DI SEGNALI E RELATIVO SISTEMA DI ACQUISIZIONE, ANALISI SPETTRALE E GESTIONE DIGITALE DEI DATI

Costituisce oggetto della presente invenzione un metodo a feedback variabile costituito da 3 moduli tra loro interconnessi per il condizionamento l’acquisizione e l’elaborazione di segnali analogici misurati in ambienti diversi (a terra, nello spazio, in laboratorio). Tale schema progettuale permette di determinare con grande accuratezza lo spettro di un qualsiasi segnale analogico. Il metodo consiste nel suddividere in diverse bande di frequenza (canali) un segnale analogico in ingresso e rendere paragonabili tra loro, con un opportuno processo di calibrazione, le diverse ampiezze presenti nei vari canali, assegnando a ciascuno di questi i relativi pesi e gestendone l’acquisizione con un unico convertitore analogico-digitale. In tal modo si ha una utilizzazione ottimale del convertitore analogico-digitale perché se ne massimizza il range dinamico. Il processo di calibrazione, necessario a determinare i pesi, viene effettuato dopo aver eseguito l’analisi spettrale (FFT) sull’uscita del convertitore analogico-digitale. In uscita dal modulo di elaborazione vi sarà lo spettro del segnale analogico analizzato. L’invenzione ha numerosi pregi. Tra essi vanno annoverati la suddetta massimizzazione nell’uso del range dinamico del convertitore analogico-digitale, l’uso di un solo convertitore analogico-digitale per più bande di frequenza ed il metodo di feedback che consente di stimare (con continuità durante l’acquisizione) i pesi da attribuire a ciascun canale e conseguentemente variare l’amplificazione della componente del segnale in ciascun canale. Inoltre contribuiscono all’originalità dell’invenzione e ne costituiscono uno dei pregi fondamentali, la possibilità di gestire contemporaneamente più segnali di diversa natura e una molteplicità di bande di frequenza per ciascun segnale