Autonomous Formation and Operation of Fractionated Spacecraft

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This research is a response to the urgent need of the new space era for scalable, distributed architectures that can consolidate multiple small space vehicles, dubbed as fractionated spacecraft, each with limited but complementary capabilities, in order to perform complex missions collectively, such as Earth observation, on-orbit servicing and deep space exploration. A critical enabler for such space infrastructures is autonomy in the formation and operation of teams of spacecraft. The fundamental question is: "how to form, organizationally and functionally, a team of miniaturized heterogeneous spacecraft enabling them to synergistically carry out a collective task autonomously, under real-world conditions such as incomplete information, sensory noise, environment perturbations, and hardware and communication malfunctions." The research promises to make full autonomy a reality for space missions composed of fractionated spacecraft, through enabling the team to a) dynamically adapt the mission plan to the available resources; b) reconfigure its flight formation given the updated plan; and c) enhance its performance during the mission at the three levels of collective (individual functionality), cooperative (task reallocation and formation reconfiguration), and collaborative (resource and knowledge sharing), in unstructured and unpredictable environments. It will adopt the Host-Agent-Avatar organizational architecture, based on the notion of Control ad Libitum, developed by the PI for mobile robot teams, and define various software agents for the fractionated operation, including mission planning, task allocation, and formation flying, as distributed Markov decision processes independently from the onboard processors (hosts) mounted on different modules (avatars) of spacecraft platforms. Such a framework would not only allow for distributed processing and networking as well as scalable ad hoc team formation, but also pave a proper ground for the development of failure recovery and unified group learning mechanisms using robust concurrent Markov decision processes. The functional architecture will be designed based on a concurrent engineering methodology, through a systematic functional assessment of state-of-the-art modules for miniaturized spacecraft, considering their reliability by means of Monte Carlo analyses. As a key constituent of the functional architecture, the research will also develop a distributed control scheme, based on a decentralized virtual structure, for autonomous formation reconfiguration (both orbit and attitude) of an ad hoc team of small spacecraft with limited processing and communication and underactuated capabilities. To validate the research outcomes, a fractionated spacecraft infrastructure will be designed for deploying various payloads in different orbits for Earth observations. The research will train 2 M.A.Sc. and 2 Ph.D. students as well as 1 postdoctoral fellow, to be recruited from a diverse pool of candidates.