Autonomous Formation and Operation of Fractionated Spacecraft

这项研究是对新太空时代对可扩展的分布式架构的迫切需求的回应，这些架构可以整合多个小型航天器，称为细分航天器，每个航天器的能力有限但互补，以便共同执行复杂的任务，例如地球观测，在轨服务和深空探索。这类空间基础设施的一个关键推动因素是航天器组的组成和运行的自主权。根本问题是：“如何在组织上和功能上形成一个小型化异构航天器团队，使它们能够在现实世界的条件下，如不完整的信息，感知噪音，环境扰动以及硬件和通信故障，协同自主地执行集体任务。这项研究有望使由分散的航天器组成的空间任务实现完全自主，方法是使团队能够a）根据可用资源动态调整使命计划; B）根据更新的计划重新配置其飞行编队;和c）在三级集体的使命期间提高其绩效（个人功能）、合作（任务重新分配和编队重新配置）和协作（资源和知识共享），在非结构化和不可预测的环境中。它将采用主机-代理-化身的组织架构，基于PI为移动的机器人团队开发的自由控制概念，并定义各种软件代理的细分操作，包括使命规划，任务分配和编队飞行，作为独立于航天器平台上不同模块（化身）上安装的机载处理器（主机）的分布式马尔可夫决策过程。这样的框架不仅允许分布式处理和网络以及可扩展的特设团队的形成，但也铺平了一个适当的地面故障恢复和统一的组学习机制，使用强大的并发马尔可夫决策过程的发展。将根据并行工程方法设计功能结构，对小型化航天器的最新模块进行系统的功能评估，并通过蒙特卡罗分析考虑其可靠性。作为功能结构的一个关键组成部分，该研究还将开发一种分布式控制方案，该方案以分散式虚拟结构为基础，用于处理和通信能力有限且驱动不足的小型航天器特设小组的自主编队重新配置（轨道和姿态）。为了验证研究成果，将设计一个分块航天器基础设施，用于在不同轨道部署各种有效载荷进行地球观测。该研究将培养2名硕士和2名博士。学生以及1名博士后研究员，将从不同的候选人库中招聘。

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.