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International audience; There is a large design variety of power buses, with voltage levels typically ranging from 28 to 100V. This state-of-art is well adapted to past and current needs in term of power conditioning and disctribution for science and telecommunication satellites. NEvertheless, a short-term need is rising for higher operating voltages, especially for the new electric propulsion systems and high-power payloads. The currently available solutions are to add DC/DC converters inisde echa user equipement to generate all its necessary internal supply lines for the satellite primary power bus. For high power/high voltage loads, this DC/DC stage leads to power dissipation and lowers the overall efficiency of the power chain. A major step forward would be to increase the voltage directly at the level of the primary bus in order to remove some voltage conversion stages leading to lower mass, cost, volume and power dissipation. The work performed within the European Union H2020 project "HV-EPSA" was aimed to study benefits and impact of the implementation of a bus voltage from 300V to 600V, including solar array, solar array drive mechnism, power conditioning and distribution, Hall effect thruster with direct drive topology, battery and harnesses. The main problematic to solve were arcing at high voltage/low pressure (Paschen law), interaction between plasma (natural and from plasmic propulsion) and solar arrays, and distribution function using GaN mosfet. Several test campaigns were performed and the results are presented in the paper.; Il existe une grande variété de conception de bus d'alimentation, avec des niveaux de tension allant généralement de 28 à 100 V. Cet état de l'art est bien adapté aux besoins passés et actuels en termes de conditionnement et de distribution de puissance pour les satellites scientifiques et de télécommunications. Néanmoins, le besoin à court terme augmente pour des tensions de fonctionnement plus élevées, en particulier pour les nouveaux systèmes de propulsion électrique et les charges utiles à haute puissance. Les solutions actuellement disponibles consistent à ajouter des convertisseurs DC / DC à l'intérieur de chaque équipement utilisateur afin de générer toutes ses lignes d'alimentation interne nécessaires pour le bus d'alimentation primaire du satellite. Pour les charges haute puissance / haute tension, cet étage DC / DC conduit à une dissipation de puissance et diminue l'efficacité globale de la chaîne de puissance. Un grand pas en avant serait d'augmenter la tension directement au niveau du bus primaire afin de supprimer certains étages de conversion de tension conduisant à une diminution de la masse, du coût, du volume et de la dissipation de puissance. Les travaux réalisés dans le cadre du projet H2020 de l'Union européenne "HV-EPSA" visaient à étudier les avantages et l'impact de la mise en œuvre d'une tension de bus de 300V à 600V, y compris les panneaux solaires, les systèmes d'entraînement de panneaux solaires, le conditionnement et la distribution de l'énergie, le propulseur à effet Hall avec topologie à entraînement direct, batterie et cablâge. Les principaux problèmes à résoudre étaient les arcs à haute tension / basse pression (loi de Paschen), l'interaction entre le plasma (naturel et de propulsion plasmique) et les panneaux solaires, et la fonction de distribution à l'aide du mosfet GaN. Plusieurs campagnes de tests ont été réalisées et les résultats sont présentés dans l'article.

International audience; One of the objectives of this work was to contaminate samples by the erosion of different targets in order to study the effect of this contamination on their thermo-optical properties. The second objective was to validate the Spacecraft Plasma Interaction System (SPIS) module dedicated to simulation of erosion and contamination.First, experiments were conducted in IDEFIXe chamber at ONERA to expose OSR and SSM to contamination created by the erosion of targets representing elements of a spacecraft using electric propulsion, subject to ions bombardment. The targets were submitted to Xe+ ions beam. Samples were placed facing the target and were then submitted to the contamination by erosion products. The quantity of contaminants was estimated through a quartz micro-balance. Reflectance of the contaminated samples was then measured to evaluate the effect on their solar absorptance and their surface was characterized by XPS.Different targets and different samples were used allowing us to extract general tendencies and phenomenology.In a second time, simulations of the test were performed with SPIS. These simulations have allowed us reproducing experimental results, validating the code and proposing erosion mechanisms for polymeric materials.

International audience; In the framework of JUICE Photovoltaic Assembly, development and testing activities have been carried out in order to verify the effectiveness of grounding networks solution against ESDs occurrence in charging environment. During prequalification phase, dedicated coupons have been manufactured and submitted to environmental test campaigns, including ESD characterization. As the PVA design has progressed, a new ESD coupon with more representative technologies has been then manufactured and tested for electrons charging, so to compare results and assess new design and materials. This paper firstly describes the coupons manufactured for ESD testing, then an overview on ESD characterizations performed is provided. Lastly, relevant conclusions and comparisons between the results are discussed.

Primary discharge occurs on solar arrays due to their interaction with the space plasma. A solar cell may suffer degradation of electrical performance if the primary discharge occurs at the cell edge. To estimate the power generated at the end of life, it is necessary to study the details of solar cell degradation. However, throughout the world, primary discharge has not been recognized as a cause of solar cell degradation. There is now an international collaboration among institutions in Japan, France, and the United States toward a common international standardization of solar array electrostatic discharge test methods. Round-robin tests were carried out as part of this collaborative research. Laboratory experiments were performed at the same time in three institutions using the same test method and identical solar cells. Solar cell degradation was confirmed at all three institutions. It was found that a multijunction solar cell is more susceptible to damage from primary discharge than a crystalline silicon solar cell. Throughout the round-robin tests, discharge has been shown to be a significant cause of solar cell degradation.

第6回宇宙環境シンポジウム (2009年2月29日-30日. 北九州国際会議場), 6th Spacecraft Enivironment Symposium (February 29-30, 2009. Kitakyushu International Conference Center), 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0064542007, レポート番号: JAXA-SP-09-006

International Symposium on "SM/MPAC & SEED Experiment" (International Congress Center EPOCHAL TSUKUBA, 10-11 March 2008), Physical characteristics: Original contains color illustrations, 資料番号: AA0064307020, レポート番号: JAXA-SP-08-015E

La propulsion plasmique expose certaines parties de satellites au bombardement ionique par des ions Xe⁺ de quelques centaines d’eV. Il apparaît alors un risque de diminuer la durée de vie ou les performances des satellites à cause des phénomènes d’érosion ionique ou de contamination par les produits d’érosion sur certaines surfaces du satellite. Des études expérimentales et numériques ont été entreprises afin de comprendre ces phénomènes et acquérir la capacité de produire des données expérimentales fiables. L'installation expérimentale lDEFlXe nous a ainsi permis de mettre au point une technique particulièrement efficace de mesure de taux d’érosion par microbalances à quartz (QCM). Nous avons alors validé la mesure du taux d’érosion à incidence normale, ainsi que pour des incidences obliques avec des métaux (argent et cuivre). La contamination quant à elle a été étudiée par deux techniques complémentaires : la spectrométrie de masse qui étudie l’émission et la contamination sur QCM. Parallèlement aux études expérimentales, nous avons développé le code CSiPl de type Monte Carlo permettant de produire des données quantitatives sur l'érosion, et l'émission (direction et énergie). Ce code reprend les fondements de TRIM en améliorant la description des collisions à la surface. On retrouve ainsi par la simulation les résultats expérimentaux. En utilisant des mesures expérimentales et CSiPI, nous avons pu interpréter des résultats faisant intervenir des cibles plus complexes. Nous avons en particulier étudié l'influence de la rugosité de la cible sur la pulvérisation ionique ainsi que celle des ions implantés dans la cible. Plasma propulsion can induce ion bombardment by energetic Xe+ (hundreds of eV) on some external parts of satellites. This induces a risk of efficiency and lifespan reduction due to sputtering (typically on solar arrays) or contamination by sputtered materials on the satellite. For a better comprehension of these phenomena we performed experimental and simulation experiments. The final aim is to produce confident data for satellite design. IDEFIXe is a setup which allowed us to develop efficient sputtering yield measurement by Quartz Crystal Microbalances (QCM). We validated it by measuring sputtering yields for various Xe+ ions energies and incidences on Silver and copper. In an other hand contamination was studied by directive mass spectrometry and contamination on QCM. Furthermore we developed CSiPI, a Monte Carlo simulation tool for quantitative Ion Sputtering and emission calculation. This code is based on the TRIM approach of collision cascades, with an improved description of surface collisions. CSiPI reproduces experimental results in the case of metals bombardment. Using the experimental and simulation tools that we developed, we studied the case of some complicated target. Especially, we studied and highlighted the strong influence of surface roughness and ofimplanted ions on sputtering and emission.