Mission Reliability Analysis of Phased-Mission Systems-of-Systems with Data Sharing Capability

System-of-systems (SoS) are increasingly the preferred solution to meeting capability requirements. An SoS solution may be quicker and more affordable, especially by utilizing existing systems, and offers more flexibility to changing requirements and technology upgrades. The challenge is in achieving interoperability among the physically independent systems and evaluating the key performance metric for SoS mission effectiveness; mission reliability. In this paper, we present an approach for estimating lower bound mission reliability for an SoS in which SoS is operating a phased mission and its constituent systems are capable of exchanging data. This approach is based on defining and describing the mission of an SoS in terms of phases, i.e. durations, mission essential functions and success criteria. Since data sharing among the systems is the key enabler of effective SoS operation, we modeled the function of data generation and sharing as a redundant common SoS mission essential function. This approach has wide applicability in planning an SoS capability using existing systems as well as development of future SoSs. Data generation and sharing concepts, such as moving the data generation from certain systems to other means, can readily be evaluated in terms of SoS mission reliability. The problem of mission reliability modeling and analysis for an SoS with data sharing capability is illustrated through a realistic case of a search and rescue mission.