ESA GNC Conference Papers Repository

Eurostar E3000: ADCS evolutions for full electric satellites
M.F. Fondeville, M.G. Guyot, I.L. Laine, J.F. Fischer, D.M. Mignon, S.K. Kowaltschek
Presented at:
Salzburg 2017
Full paper:

Airbus Defence and Space has qualified a full electric version of the E3000 telecom satellite product line. This major platform evolution leads to decisive benefits for the mission: the payload / platform mass ratio is improved, allowing both a significant extension of the Eurostar E3000 payload capacity and a decrease of launch costs. One of the main enabler is the upgrade of the Attitude Determination and Control System (ADCS) to answer the new needs and constraints associated with electric propulsion all along the spacecraft life, starting from the electric orbit raising (EOR), then during the operational lifetime with full electric station keeping, up to the end of life to reach the graveyard orbit. The robotic arm, named Deployed Thruster Module Assembly (DTMA), is the key innovation on which the ADCS design relies. This 3-axis mechanism accommodating the Hall Effect Thrusters allows switching of thruster orientation, depending on the mission phase. The electric manoeuvre delta-V efficiency is therefore optimised while providing ADCS control capability. New on-board functions and algorithms are developed to command and control the DTMA, fulfilling orbit control, attitude control and momentum management performance requirements. In addition, a main ADCS design improvement is the satellite autonomy. The mission is maintained as far as possible thanks to an enhanced on-board Failure Detection Isolation and Recovery (FDIR) strategy to fulfil system needs in EOR phase where ground visibility is only intermittent. Unnecessary EOR manoeuvre interruptions are avoided, thanks to autonomous unit reconfiguration without manoeuvre stop. In case of severe anomaly requiring thrust interruption, the backup ADCS mode is designed to keep the spacecraft safe, with an enhanced management of ADCS actuators. These FDIR improvements apply also in operational phase once on-station, providing robustness and avoiding mission interruption in most anomaly cases. The system operational concept takes benefits from these ADCS improvements, leading to an easy-to-use platform: during the EOR phase, operations to load the manoeuvre plan are minimised thus compatible with short weekly commanding periods; in on-station phase, the full electric station keeping strategy allows fine orbit control, while providing at the same time 3-axis momentum off-loading capacity without requiring additional operations. The station keeping manoeuvre plan is computed thanks to user-oriented ground software. All these ADCS evolutions are now qualified and soon in-orbit.