An integrated approach for the probabilistic risk assessment of the mars relay network

The Mars relay network consists of Mars orbiters, relay radios, and ground systems from several different countries. It provides communications, timing, and navigation services to in-situ probes at and near Mars. The Mars relay network currently consists of the NASA Mars global surveyor and Mars Odyssey orbiters, and the ESA Mars express orbiter. The NASA Mars reconnaissance orbiter will join these orbiters in 2006. Estimations of risk, robustness and capability are important to the Mars Program Office for long-term decisions about the relay network. One element of this is the expected reliability of the relay capability of each of the orbiters. This paper addresses the generation of a unified framework for the reliability analysis of the Mars relay network. The proposed analysis is based on the development of probabilistic models for the reliability assessment of each of the current and planned Mars orbiters and the integration of these reliability measures into a framework for a system level analysis of the network. The results emphasize the sensitivity of the input data and the need for further research and investigation into the failure characteristics of the system elements being modeled. Furthermore, a multi-state risk analysis, in addition to the reliability analysis, may be conducted to determine the probability of various states for each of the orbiters