This paper introduces the concept of Resilience Engineering in the context of space systems design and a model
of Global System Reliability and Robustness that accounts for epistemic uncertainty and imprecision. In particular,
Dempster-Shafer Theory of evidence is used to model uncertainty in both system and environmental
parameters. A resilience model is developed to account for the transition from functional to degraded states, and
back, during the operational life and the dependency of these transitions on system level design choices and
uncertainties. The resilience model is embedded in a network representation of a complex space system. This
network representation, called Evidence Network Model (ENM), allows for a fast quantification of the global
robustness and reliability of system. A computational optimisation algorithm is then proposed to derive design
solutions that provide an optimal compromise between resilience and performance. The result is a set of design
solutions that maximise the probability of a system to recover functionalities in the case of a complete or partial
failure and at the same time maximises the belief in the desired target value of the performance index.
