System modeling process with SysML assuming the use of models

In Model-Based System Engineering with SysML, describing a valuable system model for a system engineer is important. The system model which is a descriptive model is intended to support the system engineers in decision making. Therefore, the system model is required to present information and utilization that supports system engineers in the decision making that consider the characteristics of the system. However, SysML does not provide information when and which diagrams should be selected and how to describe relationships between model elements. Therefore, if too many relationships are described, the system model loses its value to the system engineers because inability to extract information needed for decision making. Space crafts are operated in harsh environments, so it is essential to analyze physical constraints (e.g., limited communication, power, attitude etc.) at the system level of high architectural hierarchy. Therefore, system engineers need to not only model the behavior that satisfies the needs of stakeholders, but also model to ensure that the architecture of the system satisfies the physical constraints. Due to the high complexity and multiple architectural layers of spacecraft, the SysML model also describes a lot of relationships exponentially. The result is a model that is not informative for the system engineer’s decision making. To solve that problem, we proposed a modeling process that extends No Magic’s grid approach based on a Zachman-style matrix. It is useful to describe constraints between structural elements and pre/post conditions of functions in SysML for system engineers to confirm trade-off analysis and impact of changes. This paper proposes a method to describe the relationship of model elements from the purpose of model utilization (e.g., architectural change), and how to modeling a usable system model that is valuable to system engineers.