Tradespace exploration of in-space communications network architectures

Making architectural decisions in long lifecycle systems is challenging because the time between system definition and end of operations can span multiple decades, resulting in shifts in stakeholder needs and major advances in technologies. Space-based communications using relay satellite constellations is one such example, requiring substantial up-front planning to define capabilities and size capacity due to the large investment of time and resources. Additionally, there are numerous viable system architectures. In this paper, we build on existing methods to develop a graph-based decision method to assess and explore architectural flexibility in the future evolution of long lifecycle systems. The tradespace graph defines edges between similar architectures, quantifies the switching cost between architectures, using graphs to analyse the potential system evolution pathways. In a test case on NASA communication satellites, we find that hosting government communications payloads, in particular optical payloads, on commercial satellites could reduce cost and increase flexibility of the NASA network.