ESA GNC Conference Papers Repository
PROBA-2: AOCS Software Validation Process and Critical Results
This paper presents ESA Planck mission Failure Detection, Isolation and Recovery (FDIR) strategy, Planck Survival Mode, and the worst case failure of a thruster left open, leading to an excursion of the Sun Aspect Angle (SAA) outside the Spacecraft contingency domain. This excursion would provoke illumination of the cryogenic payload, which is highly harmful, and therefore it has been a design driver for the FDIR, the Survival Mode, and important parts of the ACMS. This paper will introduce the problem, will present the analyses done and the mitigation means taken, will outline the Requests for Deviation issued against the contingency zone, and will provide the impact at System level of the risk of excursion.