Federated satellite systems (FSS) are a new class of space-based systems which emphasize a distributed architecture. New information exchanging functions among FSS members enable data transportation, storage, and processing as on-orbit services. As a system-of-systems, however there are significant technical and social barriers to designing a FSS. To mitigate these challenges, this paper develops a multi-stakeholder interactive simulation for use in future design activities. An FSS simulation interface is defined using the High Level Architecture to include orbital and surface assets and associated transmitters, receivers, and signals for communication. Sample simulators (federates) using World Wind and Orekit open source libraries are applied in a prototype simulation (federation). The application case studies a conceptual FSS using the International Space Station (ISS) as a service platform to serve Earth-observing customers in sun-synchronous orbits (SSO). Results identify emergent effects between FSS members including favorable ISS power conditions and potential service bottlenecks to serving SSO customers.