Дисертації з теми "Scientific missions"

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
High altitude scientific balloons have been used for many years to provide scientists with access to space at a fraction of the cost of satellite based experiments. In recent years, these balloons have been successfully used for long duration missions of up to several weeks. Longer missions with durations of up to 100 days (Ultra-Long) are on the drawing board. An enabling technology for the growth of the scientific balloon missions is the use of the NASA Tracking and Data Relay Satellite System (TDRSS) for telemetering the health, status, position and payload science data to mission operations personnel. The TDRSS system provides global coverage by relaying the data through geostationary relay satellites to a single ground station in White Sands New Mexico. Data passes from the White Sands station to the user via commercial telecommunications services including the Internet. A forward command link can also be established to the balloon for real-time command and control. Early TDRSS communications equipment used by the National Scientific Balloon Facility was either unreliable or too expensive. The equipment must be able to endure the rigors of space flight including radiation exposure, high temperature extremes and the shock of landing and recovery. Since a payload may occasionally be lost, the cost of the TDRSS communications gear is a limiting factor in the number of missions that can be supported. Under sponsorship of the NSBF, General Dynamics Decision Systems has developed a new TDRSS compatible transceiver that reduces the size, weight and cost to approximately one half that of the prior generation of hardware. This paper describes the long and ultra-long balloon missions and the role that TDRSS communications plays in mission success. The new transceiver design is described, along with its interfaces, performance characteristics, qualification and production status. The transceiver can also be used in other space, avionics or terrestrial applications.

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Bachelors
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Political Science

Le but de cette thèse est d’étudier comment, suite à la conquête de l’Amérique, les Européens se sont approprié des plantes médicinales d’origine mexicaine, caribéenne, andine, ou amazonienne. L’usage fréquent que les praticiens européens du XVIIIe siècle font de substances telles que le quinquina, l'ipécacuanha, le bois de gaïac ou encore le chocolat, révèle l’ampleur du phénomène, mais en masque la complexité. L’emploi d’un remède originaire d’Amérique en Europe implique en effet de nombreux processus. Le prélèvement et la mise en culture des végétaux, la transmission des savoirs indigènes et leur traduction par les allogènes, la commercialisation des drogues à travers l'Atlantique, les expériences réalisées sur les remèdes et les expéditions organisées en Amérique entre le XVIe et le XVIIIe siècle sont ainsi au cœur de cette recherche. Plus qu’un « apport » de l’Amérique à l’Europe, ce phénomène d’appropriation doit être appréhendé comme une modalité du fait colonial. Objet naturel, et en même temps savoir naturaliste et médical, la plante médicinale devient à la suite de la conquête de l’Amérique un enjeu politique. Elle suscite, en 1570, l’une des premières expéditions scientifiques de l’histoire, et inspire à la monarchie espagnole divers projets de monopole au milieu du XVIIIe siècle. De l’autre côté de l’Atlantique, elle est au cœur des conflits opposant l’« Indien » à l’Espagnol, lorsque le second interdit au premier d’utiliser des plantes abortives ou hallucinogènes, et lorsque le premier refuse de transmettre ses savoirs pharmacologiques au second
The aim of this dissertation is to study how, in the aftermath of the Conquest of America, Europeans have appropriated medicinal plants from Mexican, Caribbean, Andean, or Amazonian origin. 18th century European practitioners frequently used substances such as Peruvian bark, ipecacuanha, gaiacum wood, or chocolate – which reveals the extent of the phenomena, yet masks its complexity. Using an American remedy in Europe indeed implied many processes. Crucial to this research are: the sampling and growing of plants; the transmission of indigenous knowledge and its translation by allogenous; the drug trade across the Atlantic; experiences carried out on remedies; and expeditions conducted in America between the 16th and the 18th centuries. More than a “contribution” of America to Europe, this phenomenon of appropriation must be understood as a modality of colonialism. As natural object, and at the same time as naturalistic and medical knowledge, medicinal plants took on a political stake after the Conquest of America. For instance, while in 1570 they had been the target of one of the first scientific expeditions in history, in the middle of the 18th century they also led the Spanish crown to undertake various monopolistic projects. On the other side of the Atlantic, it was at the heart of conflicts between the “Indian” and the Spaniard, when the latter forbade the former from using abortive or hallucinogenic plants, and when the former refused to transmit his pharmacological knowledge to the latter

Cette thèse se focalise sur l’analyse des missions scientifiques françaises dans la région du Caucase et des collections ramenées en France à la suite de ces expéditions. L’étude couvre la période du milieu du XIXe siècle au début du XXe siècle, avant les grands changements politiques des années 1910-1920. L’attention se porte principalement sur les missions scientifiques mandatées par le ministère de l’Instruction publique, tout en ne négligeant pas les collections issues de voyages non scientifiques ou d’antiquaires. Cette recherche met en lumière l’intérêt de la communauté scientifique française pour le Caucase au XIXe siècle, ainsi que les motivations des chercheurs qui s’y sont rendus et les travaux qu’ils ont menés sur le terrain. Une autre priorité de cette étude était d’examiner les collections archéologiques, ethnographiques et photographiques conservées dans divers musées et archives en France. Pour ce faire, l’inventaire d’une base de données des collections caucasiennes ainsi que la collecte d’informations biographiques sur les chercheurs français ayant contribué à ces missions ont été nécessaires. La contribution de ces collections à la réflexion sur les transferts culturels entre le Caucase et la France est aussi examinée. L’objectif ultime était l’identification et l’étude de ces collections en vue de leur future intégration dans la muséographie, mettant en lumière les noms de chercheurs et de photographes dont les voyages dans le Caucase étaient jusqu’à présent méconnus
This thesis focuses on the analysis of French scientific missions in the Caucasus region and the collections brought back to France following these expeditions. The study covers the period from the mid-19th century to the early 20th century, before the major political changes of the 1910s-1920s. The primary focus is on the scientific missions mandated by the Ministry of Public Instruction, without neglecting collections from non-scientific journeys or antiquarians. This research highlights the interest of the French scientific community in the Caucasus in the 19th century, as well as the motivations of the researchers who went there and the work they conducted in the field. Another priority of this study was to examine the archaeological, ethnographic, and photographic collections held in various museums and archives in France. To do this, an inventory of a database of Caucasian collections and the collection of biographical information on French researchers who contributed to these missions was necessary. The contribution of these collections to the reflection on cultural transfers between the Caucasus and France is also examined. The ultimate goal was the identification and study of these collections for their future integration into museography, highlighting the names of researchers and photographers whose journeys in the Caucasus were previously unknown

This work attempts to focus on the human side of Skylab, America's first space station, from 1973 to 1974. The thesis begins by showing some context for Skylab, especially in light of the Cold War and the “space race” between the United States and the Soviet Union. The development of the station, as well as the astronaut selection process, are traced from the beginnings of NASA. The focus then shifts to changes in NASA from the Apollo missions to Skylab, as well as training, before highlighting the three missions to the station. The work then attempts to show the significance of Skylab by focusing on the myriad of lessons that can be learned from it and applied to future programs.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada
After briefly presenting the TRANSMED mission, the configuration of the Telemetry and Telecommand links is illustrated and the their dimensioning is analyzed. Both links operate at S-band with satellite grade standards. The system composition, the main equipment and the system growth potential are thereafter presented.

SEAM (Small Explorer for Advanced Missions) is a 3U CubeSat developedat KTH Royal Institute of Technology which will provide highqualityDC and AC magnetic field measurements of Earth’s magneticfield. The measurement system requires extended periods of timeup to 1000 seconds without active attitude control. The satellite willuse passive gravity gradient stabilization and dipole cancellation via aseparate set of magnetorquers to satisfy LVLH pointing requirementsduring the coasting phases. In this thesis a detailed model of satellitemagnetic moment is presented which includes dipole moment sourcesfrom on-board current loops. The attitude dynamics of the satelliteis characterized with simulations and a strategy is proposed to estimateand compensate the time-dependent magnetic dipole momentusing the dipole compensation magnetorquers and an offline estimationalgorithm. The algorithm is tested with simulated error sourcesand noise and was found to be able to robustly identify and cancel outthe satellite dipole to satisfy mission requirements.
SEAM (Small Explorer for Advanced Missions) är en 3U CubeSat utveckladpå KTH Kungliga tekniska högskolan för DC och AC magnetiskfältmätningarav Jordens magnetfält. Mätningar kräver längretidperioder upp till 1000 sekunder utan aktiv attitydstyrning. Satellitenkommer använda passiv tyngdkraftsgradientstabilisering samtmagnetisk dipolmomentkompensation med hjälp av ett separat setav magnetiska spolar för att upprätthålla orienteringskrav under perioderutan attitydstyrning. Denna rapport presenterar en detaljeradmodell av satellitens magnetiskt dipolmoment som inkluderar dipolmomentkällorfrån strömslingor ombord satelliten. Satellitens attityddynamikär karaktäriserad med simulationer och en strategi tas framför att estimera och kompensera det tidsberoende magnetiska dipolmomentetgenom att använda dipolkompensations magnetiska spolaroch en offline estimeringsalgoritm. Algoritmen är testad med simuleradefelkällor och brus och har funnits pålitlig för uppskattning avdipolmomentet och dess kompensation för att uppfylla missionskrav.

This thesis work investigates techniques of reducing the thermal effects for the SIMBIO-SYS scientific suite of BepiColombo mission. SIMBIO-SYS is an integrated suite of imaging instruments and it has been selected for the European Space Agency BepiColombo mission to Mercury. It includes a stereo imaging system (STC), an high-resolution imager (HRIC) and a visible–near-infrared imaging spectrometer (VIHI). The payload will have to operate in a very harsh environment, mainly from the thermal point of view. For this reason, dedicated state-of-art heat rejection baffles and thermal control devices have to be analyzed and designed. To overcome this issue, a methodological approach has been followed. Starting from the estimation of thermal environment encountered by the payload during mission lead to a deep knowledge of the thermal environment that the instrument will face during the mission phases and provided a framework to the design of the payload baffling system. A mathematical model has been developed and simulations has been carried out to evaluate the incident fluxes on the front end of the payload for all possible hermian seasons during the orbiting of Mercury Planetary Orbiter (MPO) spacecraft around Mercury. The study allowed to identify the most critical orbits from the thermal point of view. Furthermore the mathematical model assess the Sun aspect angle of the optical axes of the three channels (HRIC, VIHI, STC) and identifies the most critical conditions among the various phases of the mission, providing input data for the design of the baffles and constraints for the verification of their geometry. The mathematical model could be applied also to other planetary observational scientific missions and allows to perform sensitivity or uncertainty analysis of incoming solar, albedo and planetary heat fluxes to orbital or attitude parameters. The geometry of the present configuration of SIMBIO-SYS baffles have been verified against direct Sun illumination and dedicated ray-casting algorithms have been implemented to calculate the angular margin to direct entry of solar rays. Thermal analyses of baffles have been afterwards carried out using lumped parameter thermal network method and implemented in ESARAD/ESATAN software. This allows to predict the main heat transfer mechanisms and temperature distribution and to estimate the performance of baffles in terms of heat rejection capability. A study on the appropriate implementation of the HRIC Stavroudis reflective baffle geometry allows to effectively model this type of baffle; furthermore this study led to the definition of a criterion to evaluate the performance of the Stavroudis and to guide the design of the most appropriate test-bed to be used to evaluate its behaviour. The lay-out of a Mercury thermal environment simulator facility has been designed on the basis of the studies carried out. It will consist of a thermal vacuum chamber with heating and cooling sources to simulate the thermal environment that the payload will face on orbit. The design and analysis methods developed had contributed to the definition of efficient baffling system for the three channels of SIMBIO-SYS scientific suite.
Il progetto di ricerca di questa tesi di dottorato è finalizzato a indagare possibili tecniche di riduzione degli effetti termici per la strumentazione scientifica SIMBIO-SYS della missione ESA BepiColombo a Mercurio. SIMBIO-SYS è una suite integrata di strumenti ottici costituita da tre canali: High Resolution Imaging Channel (HRIC), STereo Imaging Channel (STC), Visual and Infrared Hyperspectral Imager (VIHI). SIMBIO-SYS dovrà operare nell'ambiente termicamente ostile di Mercurio. E' quindi necessaria la progettazione di dedicati ed efficaci sistemi di reiezione del calore e di controllo termico per lo strumento. Il problema è stato affrontato con un approccio il più possibile metodologico al fine di individuare gli aspetti cruciali del problema progettuale. Inizialmente si è valutato l’ambiente termico che lo strumento incontrerà durante le fasi operative in orbita attorno a Mercurio. A tal fine è stato sviluppato un modello matematico in grado di valutare, per le possibili stagioni di Mercurio, i flussi solare, di albedo e planetario incidenti su una superficie orbitante attorno al pianeta secondo l’orbita e l’assetto nominali previsti per il satellite. Lo studio ha reso possibile identificare le orbite maggiormente critiche dal punto di vista termico. Il modello matematico implementato può essere applicato anche a studi riguardanti altre missioni di osservazione planetaria e consente di effettuare agevolmente studi di sensibilità dei flussi orbitali incidenti ai parametri orbitali o di assetto. Il modello matematico implementato permette inoltre di valutare l'angolo di incidenza solare rispetto agli assi ottici dei tre strumenti e ha consentito di identificare le condizioni maggiormnete critiche alla illuminazione solare diretta fornendo vincoli di progetto per le geometrie dei paraluce (baffle) degli strumenti. Le geometrie dei baffle della attuale configurazione prevista dal progetto sono state verificate all'ingresso diretto di raggi solari in orbita grazie alla implementazione di algoritmi di ray-cating ed è stato fornito un corrispettivo margine angolare per ciascun baffle. Successivamente sono stati sviluppati dei modelli termici, con approccio a parametri concentrati, dei baffle dei tre canali di SIMBIO-SYS utilizzando il software ESARAD/ESATAN, stimando così le potenze termiche scambiate, la distribuzione delle temperature e le prestazioni del sottosistema in termini di capacità di reiezione del calore. E' stato approfondito lo studio del baffle riflettente di tipo Stavroudis del canale ad alta risoluzione ed è stata individuata la geometria ottimale per la modellazione con gli attuali software commerciali disponibili di analisi termica. Questo studio ha condotto inoltre alla individuazione di criteri per la valutazione delle prestazionidel baffle Stavroudis utili a guidare il progetto di un apparato sperimentale per la caratterizzazione delle prestazioni del baffle.L'attività di ricerca è poi proseguita con il dimensionamento a livello di sistema di un apparato sperimentale finalizzato a riprodurre a terra l'ambiente termico incontrato dallo strumento in orbita attorno Mercurio. Esso è concepito per riprodurre all'interno di una camera termo vuoto l'andamento dei flussi solare e infrarosso incidenti sullo strumento e le interfacce radiative e conduttive della strumentazione con il satellite, tenendo conto della orientazione dello strumento durante il moto orbitale rispetto alle sorgenti di radiazione. I modelli matematici sviluppati e le analisi termiche eseguite hanno fornito le specifiche di progetto dell'apparato sperimentale ed utili dati numerici per la definizione del simulatore a livello di sistema. I metodi di analisi e di progetto sviluppati hanno contribuito alla definizione di efficienti sistemi di riduzione degli effetti termici per la strumentazione SIMBIO-SYS.

This work describes technical innovations to improve the data quality and volume for the Fast Plasma Investigation (FPI) on board the Magnetospheric Multiscale mission (MMS). A parametric study of wavelet compression has shown that plasma count data can be compressed to high compression ratios with a minimal effect on the integrated plasma moments. Different regions of the magnetosphere are analyzed for both electron and ion count data. The FPI trigger data, intended as a data ranking metric, has been adapted and corrected to a point where scientifically accurate pseudo moments can be generated and released to the research community, drastically increasing the availability of high time resolution data. This is possible due to a scaling system that tunes the dynamic range of the system per region, and the method of using a neural network to correct for exterior contamination effects, such as spacecraft potential. Finally, a map of detection angle bias has been generated that can be used to correct raw count for errors in look direction of incoming particles. This map was generated by statistically sampling particle flight paths through a charged spacecraft environment, validating against flight data. All three of these efforts lead toward the overarching goal of improving data quality and volume for the FPI suite, and future missions to come.

In this thesis it is argued that a full and complete understanding of the eugenics movement may only be gained by examining those who were implicated in its criticisms. Using the example of three Christian missionary organisations that worked amongst largely poor and immigrant communities in London and New York, it is demonstrated that eugenics was a pervasive ideology outside its 'official' societies. Moving away from an understanding grounded in ideas of conflict and concession, it will be demonstrated that those whose work was challenged by eugenic claims were able to interpret the ideology according to their existing reformist agendas. Hereditarian ideas did not sound the death knell for reformers, and these organisations demonstrated both the willingness and capacity to shape eugenic ideas within and outside their organisations. From these examples it is argued there is a need to move beyond definitions of eugenics that limit the movement to a small subset of its methods. Far from being a peripheral aspect to the history of eugenics, it will be seen that these missionary agencies occupied a position at the centre of eugenicists' concerns. As prominent providers of charity, a work charged by eugenicists with unnaturally hindering the natural laws of selection, religious communities were, in part, one of the reasons that eugenics was deemed necessary in the first place. This picture is confirmed by an examination of two eugenics societies, one on each side of the Atlantic, where the impact of religious sentiment and ideas exerted a dramatic effect upon policies and propaganda work. There was no one-way flow of ideology from eugenicists towards reformers, but rather a two-way dialogue which created a marked impression on both groups.

Java is a very commonly used computer programming language, although its use amongst the scientific and High Performance Computing (HPC) communities remains relatively low. In this thesis, the option of using Java for developing scientific applications intended for execution in HPC environments is investigated. The data reduction pipeline for the Gaia space astronomy mission is an example of a large software project that has been written in Java, and will run in HPC environments. The efficient execution of the Gaia data reduction pipeline was one of the main motivations behind this thesis, although this thesis largely remains a general investigation into the use of Java in HPC. HPC is a fast changing field, in terms of hardware, software, and the scale of the problems that are being tackled. Amongst the most significant trends in HPC in recent years have been the increase in the number of cores per computing node, and the increase in the size of datasets that must be processed. A significant challenge in HPC is ensuring that data is made available in a particular node, when a core is ready to process it, thereby avoiding deadtime and providing high throughput. One danger to throughput is a decrease in the performance of shared storage devices, as the number of concurrent processes that are accessing those devices increases. Given the trends mentioned above, efficient data communication is very important for many applications running in HPC environments. In this thesis, we present an investigation into the current options for providing efficient data communication to Java applications in HPC environments. We investigate a number of implementations of Message Passing in Java (MPJ) and compare their performance. We present a new communication middleware application, called MPJ-Cache. This middleware makes use of an underlying implementation of Message-Passing in Java (MPJ), and adds prefetching, caching, and file-splitting functionality. It presents application developers with a high-level API, thus providing high-performance, as well as enabling high productivity amongst application developers. We compare the aggregate data rate that can be achieved though the use of this middleware, against that which can be achieved though direct access of a high performance shared storage device (GPFS), while distributing data amongst the nodes of a computer cluster. The use of MPJ-Cache has shown to provide an aggregate data rate of up to 103Gbps. Java applications are executed within a Java Virtual Machine (JVM), which is a managed runtime environment. The execution of applications within such a runtime environment is very different from the execution of native code, that was compiled ahead-of-time. The Java runtime environment consists of several sophisticated components, including the core runtime system, a garbage collector and a Just-In-Time (JIT) compiler. Modern JVMs strive to provide out-of-the-box high-performance, however in some situations, users may want to tune the JVM to better suit the behaviour and needs of a particular application. In order to do this, a profile of the target application should be obtained.

Missing Links explores relationships between objects. It is an empirical exercise in equivalence and divergence, an experiment in the visual nomenclature of enumeration and classification and a dissertation on the materiality of the construction of systems of thought. It is concerned with the manufacture and production of particular histories through the formal analysis of fifty specimens. The specimens, or objects, under investigation are constructed from recycled corrugated cardboard, water-activated brown tape and hot glue. These materials are transformed and renewed through a series of repetitive processes and activities including cutting, slicing, rolling, joining, gluing…The material is receptive and provisional in nature. The specimens exist as a series of models, one made after the other, each made in response to the one before, and as thus present an unfolding of thoughts and material experiences. They represent a genealogy of the imagination ; creating relationships and dialogues within and between external physical manifestations. The study of natural history informs this collection with particular reference to the nineteenth century work of Charles Darwin. In his attempts to understand the temporal arrangement of the natural world in The Origin of the Species, Darwin posited the notion of infinite change. This project is inspired by Darwin's emphasis of the sheer multiplicity of living objects, their complexity and the possibility of a transformational and material history. The objects in Missing Links were produced in response to the prolific nature of the natural world, its endless variations and ability to produce exquisite material adaptations. As a collection, they contain, support and enact a layered history, an archive of process and a document of action. Missing Links also references the procedures of the laboratory - the facilitation of controlled conditions under which experiments, documentary exercises and data collection and collation can take place. It is the merging of these two realms and activities that lies at the heart of the project. The synergy of the artistic world and the scientific activities the project employs highlight similarities and discontinuities between seemingly disparate practices. This is a productive coupling; facilitating interesting juxtapositions between objects and ideas and signalling the potential for the collection to coalesce in a multiplicity of orders in response to the systems of thought that contain and constrain it.

Cette thèse s’inscrit dans le cadre de la préparation de la mission spatiale franco­-chinoise SVOM (Space Variable Object Monitor) opérationnelle à l’horizon 2021 et qui aura pour but de détecter et caractériser les sursauts gamma. La première partie de la thèse consiste au développement d’un logiciel de simulation de COLIBRI (Catching OpticaL and Infrared BRight transIents), un télescope de suivi au sol de SVOM. Il comporte un simulateur de sursauts gamma, un exposure time calculator, un simulateur d'image, un algorithme estimant le redshift photométrique. Il a permis d'une part d’estimer les performances scientifiques du télescope afin de s'assurer qu'elles satisfont le cahier des charges, et d'autre part d'estimer une précision sur l'estimation de la distance du sursaut de l'ordre de 10% et 15% sur le redshift pour les sursauts à 3.5 < z < 8 et z > 8. La deuxième partie de la thèse porte sur l’étude de la propriété des poussières au sein des galaxies dans lesquelles se produisent ces sursauts gamma, mais aussi à l’étude de leur activité de formation stellaire. J'ai comparé les courbes d'extinction mesurées sur la ligne de visée de 7 GRBs à la courbe d'atténuation de leurs galaxies à l'aide d'un code de SED fitting, CIGALE. En comparant à un code de transfert radiatif on obtient des informations sur la distribution étoiles / poussière au sein de ces galaxies. Sur un échantillon élargi, on montre que les courbes d'atténuation pentues (plates) corrèlent avec des galaxies avec une faible (grande) atténuation due à la poussière, les moins (plus) activent en formation stellaire et les moins (plus) massives
This thesis lies within the framework of the sino-french SVOM (Space Variable Object Monitor) mission to be launched in 2021 whose objective is the detection and characterisation of Gamma-Ray Bursts (GRBs). The first part consists in the development of an end-to-end software for COLIBRI (Catching OpticaL and Infrared BRight transIents), a SVOM ground follow-up telescope. It consists in a GRB simulator, an Exposure Time Calculator, an image simulator and a photometric redshift algorithm. It allowed to estimate the telescope scientific performances to ensure that the optical design was fulfilling the scientific requirements. The relative accuracy on the photometric redshift delivered by COLIBRI is estimated to be about 10% and 15% for GRBs at 3.5 < z < 8 et z > 8. The second part of the thesis deals mainly with the study of dust properties in GRB host galaxies, but also with the star formation activity in these galaxies. We compare extinction curves measured along the GRB line of sight for 7 GRBs to the attenuation curve of their host galaxies measured with CIGALE, a SED fitting code. By comparing these curves to the results of a radiative transfer code, we obtain information about the geometrical distribution of dust and stars in these galaxies. On a larger sample of 23 galaxies, we show that the steepest (flattest) attenuation curves are associated to galaxies with a large (small) amount of dust attenuation, less (more) active in star formation and less (more) massive galaxies

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada
This paper addresses the research conducted at U.C. Berkeley Space Sciences Laboratory, Center for Extreme Ultra Violet Astrophysics between 1994 and 1995 on the NASA EUVE ion-orbit satellite. It includes the results from conducting a scientific analysis called a prognostic analysis completed on all satellite subsystem equipment. A prognostic analysis uses equipment analog telemetry to measure equipment remaining usable life. The analysis relates equipment transient behavior, often referred to as "cannot duplicates" in a variety of industries caused from accelerated aging to the equipment end-of-life with certainty. The analysis was confirmed by using proprietary, pattern recognition software by Lockheed Martin personnel Lockheed Martin personnel completed an exploration into the application of statistical pattern recognition methods to identify the behavior caused from accelerated aging that experts in probability reliability analysis claims cannot exist. Both visual and statistical methods were successful in detecting suspect accelerated aging and this behavior was related to equipment end of life with certainty. The long-term objective of this research was to confirm that satellite subsystem equipment failures could be predicted so that satellite subsystem and payload engineering personnel could be allocated for only the time that equipment failures were predicted to occur, lowering the cost of mission operations. This research concluded that satellite subsystem equipment remaining usable life could be measured and equipment failures could be predicted with certainty so that engineering support for mission operations could be greatly reduced.

ECLAIRs, l'imageur à rayons X dur de la mission sino-française SVOM, est dédié à la détection et à la localisation en quasi temps réel de sources transitoires cosmiques dans la plage d'énergie allant de 4 à 150 keV. Cet instrument est une caméra grand champ, munie d'un plan de détection pavé de 6400 détecteurs Schottky CdTe, qui permet de créer des images du ciel en rayons X durs grâce à un système de localisation appelé " masque codé ". Les travaux exposés dans ce manuscrit détaillent la conception, la réalisation et la mesure des performances de modules hybrides de 32 détecteurs lus par un ASIC (appelés modules XRDPIX), qui constituent les briques de base du plan de détection, et qui permettent d'atteindre des performances inégalées pour ce type d'instrument avec un seuil en énergie égal à 4 keV. Après avoir posé la problématique de détection des sources cosmiques transitoires en rayons X, en s'appuyant sur le contexte astrophysique de la mission SVOM, puis détaillé son instrument principal, j'expose, dans ce mémoire de thèse, mon travail sur la réalisation de grands plans de détection pixélisés pour l'astronomie gamma, avec en particulier ma contribution à l'étude et à la réalisation du module XRDPIX. Le développement des modules XRDPIX, fait appel à la fois à une conception faible bruit et à l'utilisation de technologies innovantes. Les détecteurs CdTe sont polarisés jusqu'à -450V et régulés à basse température (nominalement 20°C) afin de minimiser le courant de fuite et de limiter les effets de polarisation. Le seuil bas en énergie requis pour la mission spatiale est atteint grâce à une caractérisation approfondie des éléments constituant les 200 XRDPIX de vol, qui forment la caméra ECLAIRs. Je présente de façon détaillée les caractéristiques physiques et technologiques de ces modules, les différentes étapes de leur développement, en justifiant les solutions et les compromis techniques qui ont jalonné leur fabrication. Ensuite, en me basant sur un échantillon statistique abondant, obtenu lors des nombreux tests et qualifications réalisés sur plusieurs centaines de modules et sous-modules, j'expose les résultats de mesures qui démontrent les excellentes performances du module XRDPIX, en termes de résolution spectrale, de seuil bas en énergie, de gain et de comptage. Des études annexes sont également montrées, afin de compléter la validation des XRDPIX par l'analyse de l'influence de divers paramètres physiques sur les performances, comme par exemple la température. En conclusion, grâce à ces analyses de données abondantes, et à des modélisations du bruit total équivalent, je propose des réglages optimaux pour deux paramètres de configuration clés : la valeur de polarisation pour la haute tension et le peaking time, qui permettent d'obtenir le seuil en énergie de 4 keV exigé par la mission SVOM, avec une bonne uniformité sur l'ensemble du plan de détection. Finalement, je présente ce retour d'expérience, couplé à l'étude des paramètres clés qui déterminent la sensibilité d'un imageur grand champ dans le domaine des X durs (surface de détection, gamme d'énergie, champ de vue, ...), ce qui m'amène à proposer des pistes pour la réalisation d'instruments ambitieux avec des gains en sensibilité significatifs dans le futur
ECLAIRs, the hard X-ray imager of the Chinese-French SVOM mission, is dedicated to the detection and localization in near real-time of cosmic transient sources in the energy range from 4 to 150 keV. This instrument is a wide field camera, equipped with a detection plane paved with 6400 CdTe Schottky detectors, which allows to create hard X-ray images of the sky thanks to a localization system called "coded mask". The work presented in this manuscript details the design, the realization and the measurement of the performances of hybrid modules of 32 detectors read by an ASIC (called XRDPIX modules), which constitute the basic bricks of the detection plan, and which make it possible to reach unequalled performances for this type of instrument with a threshold in energy equal to 4 keV. After having posed the problem of detection of transient cosmic sources in X-rays, based on the astrophysical context of the SVOM mission, and then detailed its main instrument, I present, in this thesis, my work on the realization of large pixelated detection plans for gamma-ray astronomy, with in particular my contribution to the study and the realization of the XRDPIX module. The development of the XRDPIX modules, calls for both a low noise design and the use of innovative technologies. The CdTe detectors are biased down to -450V and regulated at low temperature (nominally 20°C) in order to minimize the leakage current and to limit the polarization effects. The low energy threshold required for the space mission is reached thanks to a thorough characterization of the elements constituting the 200 flight XRDPIX, which form the ECLAIRs camera. I present in detail the physical and technological characteristics of these modules, the various stages of their development, justifying the solutions and technical compromises that have marked their manufacture. Then, based on an abundant statistical sample, obtained during the numerous tests and qualifications carried out on several hundreds of modules and sub-modules, I present the results of measurements which demonstrate the excellent performances of the XRDPIX module, in terms of spectral resolution, low energy threshold, gain and counting. Additional studies are also shown, in order to complete the validation of the XRDPIX by analyzing the influence of various physical parameters on the performances, such as temperature. In conclusion, thanks to these abundant data analyses, and to models of the total equivalent noise, I propose optimal settings for two key configuration parameters: the bias value for the high voltage and the peaking time, which allow to obtain the 4 keV energy threshold required by the SVOM mission, with a good uniformity on the whole detection plane. Finally, I present this feedback, coupled with the study of the key parameters that determine the sensitivity of a wide field imager in the hard X-ray domain (detection area, energy range, field of view, ...), which leads me to propose avenues for the realization of ambitious instruments with significant gains in sensitivity in the future

The dissertation underlines an approach towards mission, where the epistemology, hermeneutical key and methodology centre around relationship. This, by tracing trends in the pastoral context, verified through research and an analysis of congregational surveys. The results were then analysed in terms of biblical revelation (the creation narratives, God's covenental relationship with Israel, Christ as the New Israel, Christ's missiological methodology and an understanding of the Holy Trinity). The resulis were then also brought into conversation with recent developments in science, recognising the interdependence of all things, and also exploring recent definitions of mission. The study then grapples with a new way of engaging in theology. This new model simultaneously promotes the symbiotic nature of theologies, while placing them within the framework of relational objectives; using dialogue as medium, Holland and Henriot's Social Analysis and quantifiable relationship goals to engender a theological process accessible to people from all contexts and backgrounds.
Christian Spirituality, Church History and Missiology
M. Th. (Missiology)

GIADA (Grain Impact Analyser and Dust Accumulator) è lo strumento italiano integrato a bordo della sonda Rosetta ed è dedicato allo studio dei flussi di polveri emesse dal nucleo della cometa 67P/Churyumov-Gerasimenko durante la sua fase di avvicinamento al Sole e alla misura delle caratteristiche fisiche e morfologiche dei singoli grani di polvere (quantità di moto, velocità, massa e dimensioni). L’obiettivo principale della Tesi di Dottorato è stato quello di studiare il comportamento dello strumento GIADA in volo durante la fase di crociera di Rosetta e in varie condizioni operative. L’attività di ricerca, dunque, è stata finalizzata allo sviluppo e alla preparazione delle operazioni preliminari ai test periodici in volo, all’elaborazione e all’analisi critica dei dati relativi ai medesimi test e alla catalogazione ed archiviazione dei dati già analizzati seguendo i format e le codifiche standard dell’ESA. Le metodologie sviluppate sono state di tipo sperimentale e numerico.

Il lavoro esamina le trasformazioni nei meccanismi di produzione e di trasmissione del sapere scientifico nella nuova cornice della società della conoscenza. Quello che è stato definito il passaggio da un'era "accademica" a un'era "post-accademica" della scienza (Ziman 1987) introduce un profondo mutamento sia epistemologico che pratico del mondo di fare scienza che implica il superamento dei confini disciplinari da un lato e l'apertura verso nuovi centri di produzione della conoscenza dall'altro. Analoghe trasformazioni si riscontrano anche sul versante della trasmissione della conoscenza scientifica sia in termini di insegnamento che di trasferimento della conoscenza agli ambienti produttivi. Da ultimo, la natura di "bene pubblico" che la conoscenza assume nella società contemporanea impone che venga posta l'attenzione anche sulla comunicazione esterna della scienza e sulle possibilità che il pubblico dei "non esperti" ha di accedere ed utilizzare le conoscenze scientifiche nell'esercizio dei propri diritti di cittadinanza. Il quadro teorico così delineato viene specificato all'interno del contesto universitario, assunto come campo di osservazione empirica dell'indagine. Da sempre istituzione egemonica nella produzione della conoscenza scientifica, l'università contemporanea è, infatti, sottoposta a diverse pressioni, dovendo raccogliere le sfide dell'era post-accademica pur continuando a offrire una base solida di ricerca e didattica. Le trasformazioni riguardanti la produzione, la trasmissione e la comunicazione della scienza, infatti, si ripercuotono sull'accademia ridefinendo le sue tradizionali "missions" – insegnamento e ricerca - a cui se ne aggiunge una terza – la "terza missione", appunto - che racchiude le diverse e complesse modalità di relazione con il mondo esterno. Tra i diversi attori coinvolti in questo sistema in trasformazione la figura dello scienziato accademico riveste un ruolo particolare in quanto, operando sia sul piano della produzione del sapere che su quello della sua trasmissione, dentro e fuori l'accademia, è chiamato a raccogliere le nuove sfide che la società impone all'università. La parte empirica di questo lavoro, prende le mosse da una serie di interviste in profondità a un gruppo di docenti della Sapienza, membri del Cerms (Centro di Ricerca in Metodologia delle Scienze) e afferenti a diversi settori scientifico-disciplinari, assunti come testimoni privilegiati di questi cambiamenti. Attraverso una traccia articolata in tre sezioni dedicate rispettivamente alla dimensione della ricerca, della didattica e della comunicazione della scienza si sono delineati i principali tratti del mutamento e il ruolo che l'università sta assumendo in questo nuovo scenario. Dal punto di vista metodologico, l'analisi delle interviste è stata svolta ricorrendo ad un approccio mixed che integra l'analisi lessicometrica e l'analisi ermeneutica dei testi, svolte con l'ausilio dei software TalTac2, SPAD e Atlas.ti. In particolare, l'analisi statistica dei frammenti ha consentito, in primo luogo, di far emergere delle prime dimensioni semantiche attraverso la prossimità delle parole presenti nei frammenti di testo analizzato, che hanno guidato la successiva fase ermeneutica di codifica dei contenuti. Questa, a sua volta, ha permesso di addentrarsi all'interno dei concetti espressi dagli intervistati, realizzando una convergenza tra i risultati dei due metodi. Infine, a partire dalle evidenze emerse, si è giunti alla formulazione di un modello interpretativo, rappresentato in una mappa concettuale, attraverso cui leggere le trasformazioni in atto all'interno dell'università sia in chiave epistemologia che in chiave empirica, alla luce del contesto socio-culturale della società della conoscenza in cui essa è inserita.

I profondi cambiamenti socio-economici avvenuti nell’ultimo secolo hanno portato a un’attenzione crescente da parte dei governi nei confronti dell’Università e delle politiche inerenti la ricerca scientifica. Uno dei temi principali su cui si è spostato l’interesse è quello dell’apporto che l’Università dovrebbe fornire non solamente in termini di progresso della conoscenza e di insegnamento superiore, ma anche di crescita e sviluppo di tutta quella parte della società “esterna” al mondo universitario. Si delinea per l’Università una finalità aggiuntiva, una “terza missione”, concetto abbastanza nebuloso che indica il complesso delle interazioni tra università e società nel contesto della “società della conoscenza”. Nella realtà spesso viene erroneamente utilizzato come sinonimo di “trasferimento tecnologico”, ritenendolo per tale motivo non pertinente alla ricerca umanistica. Laddove però con terza missione si intenda la partecipazione dell’Università alla costruzione della cittadinanza scientifica, ecco che le scienze umane possono (e devono) giocare un ruolo attivo. Il progetto di ricerca mira ad approfondire quale sia (e possa essere) questo ruolo e la percezione degli umanisti italiani in tal senso: se all’estero il concetto di terza missione è oramai ben radicato, nel nostro paese è stato introdotto solo recentemente nella normativa universitaria e principalmente in funzione della sua valutazione. La mancanza di una riflessione organica in tal senso rischia perciò di essere controproducente sotto molti punti di vista, specialmente in un paese che a partire dagli anni Settanta ha perseguito un modello di “sviluppo senza ricerca”.