ATV on-board flight control monitoring design and trajectories safety assessment

The Automated Transfer Vehicle (ATV) is an unmanned supply vehicle for the International Space Station (ISS) developed by EADS Space Transportation under European Space Agency (ESA) contract. One of the main issues of an automated rendezvous mission towards a manned facility is to ensure the safety of the trajectories even in case of contingencies. The Flight Control Monitoring (FCM) is one dedicated monitoring function implemented on-board the ATV, independent from the nominal GNC function, that shall detect the situation where the ATV is not on a safe trajectory with respect to the ISS and trigger the adequate recovery manoeuvre. This paper presents the design of the monitoring performed by the FCM in terms of relevant parameters to monitor and the associated values of the detection thresholds for the far Rendez-Vous phases. The compliance wrt safety criteria of the resulting FCM design will at last be evaluated using an innovative method based on the assumption that the ATV evolution can be represented as a linear continuous state system.