Fog Computing in Optically Networked Space Constellations

This article provides an overview of computing models to describe the frontier in space-based computing, and describes the definitions and ecosystem historically termed “cloud” and “edge.” It is proposed that optically internetworked, proliferated low-Earth orbit space-based computing should be considered fog computing, not cloud nor edge. Space-based computing should orient toward software paradigms observed in fog computing such as internetworked, secure, reactive services. Definitions are provided, with comparisons between cloud, fog, edge, and near-term space-based computing. Implications and the ecosystem around space-based computing are discussed. Specifically, improper application of edge or cloud computing models to space systems causes misrepresentations and can have real consequences to investments and technology development. To call such systems “edge” is to underrepresent their capabilities, and suggests a misleading limitation of resources and unreliability of networks. To call such systems “cloud” is to overrepresent their capabilities, and incorrectly suggest an ease of deployment and operation of commercially available distributed computing technologies in space. Acceptance of fog computing as the model for on-orbit processing will advance usage of reactive service-based software instead of less scalable architectures. Unresolved trends and technical risks to fruition of fog computing in space are also presented.