Survivability and Resiliency of Spacecraft and Space-Based Networks: A Framework for Characterization and Analysis

Considerations of survivability and resiliency have always been of importance in the design and analysis of military systems. Over the p ast two decades, the importance of survivability and resiliency has expanded beyond mi litary systems to include public networks and infrastructure systems. The analysis a nd assessment of networked systems with respect to survivability has become particular ly acute in recent years, as attested to by a growing technical literature on the subject. In this paper, we bring these considerations of su rvivability and resiliency to bear on spacecraft and space-based networks. We develop a framework for comparing the survivability and resiliency of different space arc hitectures, namely that of a monolithic design and a distributed (or networked) space syste m architecture. There are multiple metrics along which different space architectures c an be benchmarked and compared. We argue that if survivability and resiliency are not accounted for, then the evaluation process is likely to be biased in favor of monolithic spacecra ft. We show that if in a given context survivability and resiliency are an important requi rement for a particular customer, then a distributed architecture is more likely to satisfy this requirement than a monolithic spacecraft design. We discuss in the context of our framework differe nt classes of threats, as well as the high-frequency and low-frequency system response to (or coping strategies with) these shocks or damaging events. We illustrate the import ance of this characterization for a formal definition of survivability and resiliency a nd a proper quantitative analysis of the subject. Finally, we propose in future work to inte grate our framework with a design tool that allows the exploration of the design trade-spa ce of distributed space architecture and show how survivability can be “optimized” or traded against other system attributes.