Abstract-Polymers are widely used on spacecraft for different specific functions : thermal and electrical insulation, mechanical support, adhesion... These polymers are highly sensitive to radiation met in space. Their electric properties is especially significantly altered leading to very specific behaviour in term of charge transport and discharge processes. Different dedicated facilities have been developed at ONERA, with CNES support, for the characterisation of space used materials in representative conditions. Thanks to the use of these different facilities, it has indeed been demonstrated that radiation induced conductivity of space polymers strongly affects the charging surface potential and depends on several parameters (radiation dose rate, total radiation dose, temperature and on the induced electric field) through complex physical mechanisms that are described in this paper. The sensitivity of polymers on these different parameters strongly depends upon polymer trap distribution and molecular configuration. Experimental as well as numerical results shall be presented in this paper, coupled with the different experimental techniques developed and applied in this work.

Polymer materials have been tested in the dedicated experimental facility SIRENE (ONERA, Toulouse, France) designed to reproduce the electron energy spectrum met in space in the (0-400 keV) energy range and to perform electric analysis on the materials through dedicated protocols with potential, current, and contactless pulsed-electro acoustic (CNES patent) measurements. A Novel experimental approach shall as well be presented, which allowed bringing into evidence the complex response of polymers under irradiation: polarization and charge differential mobility as well as physical structural changes have been analyzed with these new techniques allowing a better understanding and prediction of charging behavior and radiation-induced conductivity evolution of these polymers under space conditions.

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An electric power system is a network of electrical components used to supply, transmit, and use electric power. An example of an electric power system is the network that supplies a region's homes and industry with power. Due to the complexity and nonlinearity of the power system, hand calculations may be very complicated in some cases, especially when the number of buses or inputs is very large. Here comes the role of software for convergence, time saving, and accuracy. The "Electric Power System Simulator" focuses on three main concepts in power system analysis, the "Power Flow Calculation,""Faults Calculation," and "Economic Dispatch Calculation."

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This work is focused on the improvement of the condition number of the transfer function matrix in a pulsed electro-acoustic (PEA) cell. A numerical electro-acoustic model is developed with the software COMSOL. This model is one-dimensional and the system of equations with partial differential functions is solved using a finite element method in non-stationary situations. Using this model, we can establish the output voltage of the piezoelectric sensor and acoustic pressure at each point of the calculation domain. Our approach consists in recovering the charge distribution within the sample using a deconvolution method between the simulated output voltage and the transfer function of the PEA cell. Results show why some changes of the PEA cell such as the nature of materials or sensor geometry involve an ill-posed problem or ill-conditioned problem, and why other arrangements lead to a well-conditioned problem, more amenable to giving the appropriate solution.

This paper deals with a new method of PEA signal processing used for space materials. The aim of this new approach of deconvolution technique is first to obtain a charge density with an optimized spatial resolution and second to have an estimated charge density without handle any parameters. This new method is compared with the current PEA signal processing widely developed in the literature. After a brief description of the both methods, an experimental comparison is realized with irradiated materials. Results show an enhancement of the spreading of charges at vicinity of electrodes.