GEO TELECOM SATELLITE STRUCTURE PRIMARY CURRENT RETURNS MAPPING ANALYSIS

In order to satisfy the goal of harness mass and volume saving, the last generation of Thales Alenia Space GEO Telecom satellite family was designed with an electrical power architecture based on primary current returns flowing through the satellite structure between the PCU (Power Conditioning Unit) of the service module and mainly the equipment of the telecom payload. Compared to an usual current return via twisted pairs wiring for which impedances along the current paths and conducted/radiated EMC aspects including magnetic momentum are well managed by electrical designers, the validation of a concept where return currents paths are scattered across the service and payload modules structures requires to identify the mapping of the different currents and their associated electrical and magnetic fields in order to verify there is no electrical or electromagnetic interference that could disrupt the proper functioning of the satellite. For this purpose a 3D electrical modeling of the overall structure including all conductive elements that may be traversed by return currents between the PCU ground reference point and the ones of the other equipment was built to be used for electrical and EMC simulations using CST studio tool. This paper presents: •the method followed for the establishment of the 3D model with CATIA import interface, the selected level of granularity of the structural elements, the electrical models and stimuli used for the simulations. •the different types of simulation performed allowing the verification that the satellite electrical, EMC and functional performances are still compliant with requirements and if it is not the case to study modifications of the structure elements grounding and bonding in order to recover the compliance. •The main lessons learnt on using Software for this type of analysis and conclusion.