ESA GNC Conference Papers Repository

GALILEO is the civil European Global Navigation Satellite System (GNSS) managed and funded by the European Commission (EC) with European Space Agency (ESA) acting as the design and procurement agent. Once fully deployed, GALILEO will be a constellation of 30 satellites, 24 operational and 6 spare satellites. OHB is the platform prime for (at least) 22 Full Operational Capability (FOC) satellites with Surrey Satellite Technology Ltd (SSTL) producing the navigation payload. OHB as the platform prime is i.a. responsible for the AOCS subsystem, including the design, implementation and verification. With the last launch on 17th of November 2016, the first Work Order (WO1) of 14 satellites is completed and in orbit. In this paper, an overview is given on the AOCS architecture of the OHB GALILEO platform, on the development and verification process of the AOCS SW and on the in orbit experience. One major challenge described in this paper is the AOCS verification and validation, which needed to ensure a thorough testing of the AOCS units ensuring at the same time a handover of these units to MAIT fitting into the short satellite turnaround time due to the series production setup. The paper will further on elaborate on the elliptical L3 orbit injection consequences for the AOCS both in terms of bringing the satellite to an operational state as well as specifics for its in-orbit operation.