ESA GNC Conference Papers Repository
AOCS design for solar orbiter, a mission to 0.28 a.u. from the sun
Solar Orbiter is the first mission of ESA's Cosmic Vision 2015-2025 program and will explore how the Sun creates and controls the heliosphere with its ten instruments providing both in situ and remote sensing observations. During the 10 years mission lifetime, the spacecraft developed by AIRBUS Defence and Space will experience a very wide range of Sun distances; from an aphelion of 1.467 AU during the Cruise phase down to the smallest perihelion distance of 0.28 AU during the Operational phase where the inclination to the solar equator will increases over time, reaching up to 25deg at the end of the nominal mission and up to 34deg in the extended mission phase. The Solar Orbiter AOCS is required to maintain the heatshield accurately pointing at the Sun under any circumstances in order to keep the spacecraft within its thermal limit. In addition, the Solar Orbiter AOCS must accommodate distinct and challenging scientific pointing requirements from the high number of instruments. After consolidating the Solar Orbiter AOCS design, including a change of reaction wheels and a design update to the survival mode, the AOCS has now reached its validation phase with performance simulation campaign on the Functional Verification Bench. This paper presents an overview of the Solar Orbiter AOCS design and its key design drivers. It then describes impact of recent design evolutions and how they were accommodated. Finally it presents results from the AOCS Simulation Campaign.