Introduction to the Special Issue on Federated and Fractionated Satellite Systems

Abstract

T HEFederated and Fractionated Satellite SystemsWorkshop (F&FSS)was founded in 2012 in recognition of the emerging role of distributed satellite system concepts in present and future space missions. At the beginning of the space era, satellites were built as single, monolithic systems. As the number and complexity of functions embedded in space systems grew over time, distributed satellite concepts gained increasing prominence and attention by the scientific and engineering communities. It is not uncommon for large monolithic spacecraft to cost tens or hundreds of millions of dollars, over lifetimes between 5 and 10 years. Distributed satellite concepts, on the other hand, offer the opportunity to trade nonrecurring and recurring costs, increase affordability, and reduce risk.More modern concepts also distribute ownership and operations of the assets across different organizations and offer opportunities to view satellites as services; this is the idea behind the collaborative sharing of resources envisioned in federated satellite systems. The successful deployment of fractionated and federated spacecraft opens several technical challenges as well as challenges of business and policy nature. Technical advances are needed both at subsystem and system level. At subsystem level, these include advances in attitude determination and control, high-precision thrusting, in-space and space-to-ground communications, and onboard data processing. At system level, these include advances in interfacing, modularity, formation flying, autonomous decision making, intersatellite networks, and cybersecurity. Business challenges include the establishment of commercial markets of in-orbit space resources. The business case of these new concepts remains to be validated and depends upon to-be-definedmarket structures and pricing policies, similar perhaps to those used in electrical smart grids on Earth. Policy issues encompass complex spectrum allocation schemes and liability questions associatedwith the interoperability of heterogeneous, multiparty-owned assets in opportunistic resource exchange networks. This special issue offers a peer-reviewed selection of three research papers presented and discussed at the third F&FSS workshop held 27– 28 August 2015 at Cornell University, Ithaca, New York. These include a systems architecture analysis of information security services in federated satellite systems; an algorithm performance analysis of coordination of Earth observation by a CubeSat constellation; and amanuscript on resource-considerate data routing through satellite networks. Together, these three papers address three important technical challenges in F&FSS: cybersecurity, coordination, and networking. The issue is complemented with a state-of-the-art survey, which resulted from the roundtable discussions on the conclusive day of the workshop, including a discussion on a research agenda for advancements in this emerging field. Are fractionated and federated satellite services within the domain of today’s technical possibilities? The answer is most likely yes; the major foreseen challenges are of policy and business nature, and not technical. Will cloud-based services in space enabled by distributed satellites be commercially successful? We believe that the answer is most probably yes. Will they completely replace traditional systems? Here, we believe the answer is probably no. Just like on Earth, where many organizations are moving part of their processes and data on the cloud, the satellite industry will see a hybrid landscape where fractionated and federated missions will be very competitive and others where traditional design concepts will prevail. Finding the sweet spot for distributed satellite applications is one of the main goals of the research ahead in this field.