Impact of identified causal factors to "system of systems" integration complexity from a defense industry perspective

Multi-mission projects such as Missile Defense Agency's (MDA) Ballistic Missile Defense (BMD) program involve systems with unique capabilities developed by different companies to communicate together. While system integration for an independent system is a challenge in itself, integration for system of systems is a huge complex effort in part due to interoperability challenges. The focus of this paper is research, analyze, and prioritize some of the causal factors of system integration complexity, such as interoperability, for complex systems such as BMD. Complex system integration is used interchangeably with system of systems integration in this paper because currently in the defense industry, system of systems integration is the new complex system integration. From the defense industry perspective, an attempt is made to contribute in developing a cause and effect relationship model between system requirements, system architecture (specifically open system architecture), and system of systems integration process complexity.