Arcing on Solar Generators by Collection of Ionospheric Plasma Currents

International audienceThere are several well-known possibilities to trigger a secondary arc on solar arrays by creation of conductive plasma produced in the gap between two solar cell strings. It could be by electrostatic discharges due to an inverse potential gradient condition, micrometeoroid impacts or laser impacts. The development of electrical propulsion for satellites requires higher voltages on solar arrays. These voltages strongly modify the plasma-satellite interactions, especially by increasing the collection of plasma currents. By studying this plasma collection current on solar cell samples, we have detected secondary arcs between two strings without any triggering event as previously described. Focusing on this event, we found that a series of physical phenomena may lead to secondary arcing situation: heating by plasma current collection, outgassing, Paschen discharge conditions and then secondary arcing. We have reproduced on solar cell like samples what occurs when an arc starts and the conditions for its occurrence. Thereby, we have defined when this phenomenon is able to happen on real solar arrays

Dégradation de l’absorptance solaire de matériaux thermo-optiques contaminés par la propulsion électrique

International audienceOne 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 Round-Robin Tests on Solar Cell Degradation Due to Electrostatic Discharge

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

Étude de la pulvérisation ionique (application aux effets de jet de la propulsion plasmique)

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 ables. 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'in uence de la rugosité de la cible sur la pulvérisation ionique ainsi que celle des ions implantés dans la cible.TOULOUSE-ISAE (315552318) / SudocSudocFranceF

Open PEA measurements on irradiated polymers and space charge distribution modelisation

International audienc

International Round-Robin Tests on Solar Cell Degradation Due to Electrostatic Discharge

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