ESA GNC Conference Papers Repository
The Gaia Attitude & Orbit Control System
The Gaia spacecraft is an ESA astronomy mission to investigate the structure and evolution of the galaxy by measuring the positions of one billion stars to unprecedented accuracy . Gaia is being developed by Astrium SAS (prime), with Astrium Ltd developing the electrical service module, including the AOCS. The challenges for the AOCS design are to provide attitude control within a restricted pointing domain, due to thermal constraints, and to provide a fine pointing mode with relative pointing error (RPE) of a few milli-arcseconds (mas). The fine pointing mode needs to use the scientific payload as an AOCS sensor in order to measure angular rate to the accuracy required. New proportional cold gas thrusters are used to provide actuation with micro-N noise. This paper presents an overview of the AOCS design.