Metamodel-Based Compaction of Spacecraft Operational Scenario Models for Efficient Review

Owing to the difficulty in performing repairs during flight, spacecraft are operated according to the operational scenarios tested before launch. Operational models, which are a type of SysML activity diagram, can be used to depict these scenarios using model-based systems engineering techniques. Although it aids communication between engineers and stakeholders, the activity diagram can grow rapidly as development progresses. Owing to the extensive operational model, it is challenging to review the activity diagram, which can result in serious issues. Therefore, to make the operational models easier to evaluate, they must be concise. This study presents a metamodel that offers stereotypes that can successfully characterize spacecraft operational scenarios. First, the domain knowledge of spacecraft operations was visualized using a tree structure to organize common knowledge. Second, a stereotype metamodel was created by extracting common behaviors from common knowledge. Utilizing stereotypes can decrease the size of operational models; however, crucial review-related data can be lost. Therefore, tagged values ensure that crucial information is not lost. Several trials were conducted and showed that the number of elements of operational models with stereotypes, as well as their size, was reduced by almost half compared with the original models, allowing for a simplified review process and boosting trust in the accuracy of the operational scenarios.