ESA GNC Conference Papers Repository

Meteosat Third Generation (MTG) is the next-generation European geostationary meteorological satellite system - a collaborative EUMETSAT/ESA program, equipped with high resolution payloads. The MTG mission, which will be operated in orbit between 2018 and 2038, is constituted by a common platform serving the following 3-axis highly accurate and stable pointing satellites: a) 4 MTG-I (MTG-Imaging mission satellite); b) 2 MTG-S (MTG-Sounding mission satellite). OHB is responsible for the design, implementation and verification of the AOCS, together with the procurement of the AOCS units, development of the needed simulators and test benches. The concept and implementation of the AOCS fine pointing control mode is in close cooperation with the main system contractor, TAS-F. The AOCS in particular for this mission shall: a) Perform the transfer to GEO orbit, maintenance of the orbit, relocation and disposal; b) Support the operations of the payloads (main driver for the performance in terms of stability and knowledge) and the data transmission to ground, granted by the Fine Pointing Mode; c) Guarantee the operability and safety of the mission and in particular of the payload, providing an independent and autonomous safe mode; d) Be common between MTG-I and MTG-S. This AOCS architecture is composed by the AOCS SW and beside the typical equipments for a geostationary satellite, particular attention is given for the following equipments, to respect the strong pointing requirements: a) 1 Star Tracker assembly, with 3 sensors and a merging software to combine the measurements; b) 1 Very High Performance Gyro Unit, 4-axes; c) 1 Reaction Wheel Assembly composed of 5 wheels mounted on isolators to damp the induced microvibrations.