The development of space systems involves complex interdisciplinary systems engineering. To manage such complexity, simulation and calculation models are becoming an integral part of it, where different domain-specific models (power, thermal, structure, propulsion, communication, etc.) are developed using different tools. Every domain model contains valuable knowledge of a respective discipline. However, creating such models takes an ample amount of time and efforts. Therefore, a common management for these models is needed to preserve the knowledge and to reuse them in future space missions. The project Simulation Model Library (SimMoLib) at the German Aerospace Center (DLR) develops guidelines and best practices regarding model development, model documentation, validation and verification, as well as model reviews to establish a collection of reusable models. To efficiently catalog the models, an innovative software system is created to support collaborative development, submission, archiving, review, search, and utilization of models. In SimMoLib, a model linking concept has been developed and implemented to enhance the model search and their probable reuse. Along with regular keyword-based search, a direct and an indirect linking between the models in the library has been implemented. Therefore, the model linking increases the visibility and consequently promotes the reuse of single and interdependent models within the library. The paper further describes different types of model relationships, categories, hierarchical levels of model development, implementation and presentation of model linking in detail.