Simulation of spacecraft functioning processes with regard to accumulated failures of opboard system elements

We consider an approach that allows simulating processes of spacecraft (SC) functioning with regard to the possibility of accumulated failures of onboard system (SC) elements. For describing and analyzing mathematical models we suggest using the formal apparatus of macro-E-nets (updated Petri nets) theory. It is characterized by the possibility of hierarchical description of systems with regard to the dynamics of changing technical state of the spacecraft, the simplicity of presenting events and great descriptive power. The possibility of taking into account accumulated element failures separated in time is shown.