ESA GNC Conference Papers Repository

Space systems have high reliability and availability requirements associated with them. Engineering and project management activities conducted towards the assurance of these requirements are collectively known as system health management (SHM). While SHM has only relatively recently convalesced into an integrated, distinct stream of its own, the activities involved - analysis (like FMECA, fault trees, probabilistic analysis etc.) and FDIR design were conducted before - but as part of separate disciplines. For instance disciplines like safety and reliability engineering, quality assurance, operations were all dealing with parts of what is now included in SHM as were the domain specific disciplines (AOCS, propulsion, power etc.). SHM integrates these activities as a systems engineering activity at the level of projects. The case of satellites and spacecraft poses unique challenges to SHM – for instance while very simple rule based monitors are conventionally utilized for fault detection locally, complexity emerges when these monitors and associated parameters are composed across subsystems designed by different teams. In particular the transparency between parameter settings and the underlying physical behavior and interactions is challenging to consistently maintain. We consider in this paper the development and application of certain SHM activities such as FMECA, FDIR system development and verification and their interface to operations. These activities have been conducted for a low earth orbit bus aimed at earth observation and scientific missions.