ESA GNC Conference Papers Repository

Spacebus Neo is the new Thales Alenia Space telecom satellite product line, developed to meet the market needs and launcher landscape. It complements the Spacebus 4000 product line catalogue and enables to embark all types of telecom mission payload with the usage of xenon plasma propulsion for orbit raising and geostationary orbit control. The Guidance Navigation Control (GNC) safe mode (SHM) on the Spacebus Neo product line is based on Multi-Head Star Tracker (MHSTR). The classical Coarse Sun Sensor (CSS) solution of the Spacebus 4000 platform is not retained. The orbit raising strategy on Spacebus Neo is purely based on xenon plasma propulsion. It includes the management of the first perigee crossings in Guided Waiting Phase (GWP) during which spacecraft attitude follows a guidance law provided by the ground, based on Star Tracker measurement, but no thrust is performed. The electric propulsion (XPS) is used in Guided Raising Phase (GRP) to perform the electrical orbit raising while controlling (closed loop control) the angular momentum stored on the reaction wheels using the command on a pair of diagonal thruster orientation mechanisms (Two-Axes Thruster Mechanisms, TATM). The GNC software on the product line is based on three applications for attitude and orbit control (AOCS), solar arrays management (SADM) and electrical thruster orientation management (TATM). All the applications are developed in a Matlab Simulink development environment and the GNC software is designed following the automatic code generation process described in [1]. The paper will present the developed concepts and the strategy used for the validation of the safe mode and orbit raising strategy on SpaceBus Neo, and will illustrate them by giving some results of simulations done during the development phases.