Autonomous Formation and Operation of Fractionated Spacecraft

这项研究是对新空间时代对可扩展的分布式结构的迫切需要的回应，这种结构可以合并多个被称为分离航天器的小型航天器，每个航天器具有有限但互补的能力，以便共同执行复杂的任务，如地球观测、在轨服务和深空探索。这种空间基础设施的一个关键推动因素是航天器团队的编队和运作的自主权。根本问题是：如何在组织上和功能上组建一支小型化的异质航天器团队，使他们能够在信息不完整、感觉噪声、环境扰动以及硬件和通信故障等现实世界条件下，自主协同地执行集体任务。这项研究承诺使由分散的航天器组成的空间飞行任务完全自主成为现实，使小组能够a)根据现有资源动态调整飞行计划；b)根据更新后的计划重新配置飞行编队；以及c)在非结构化和不可预测的环境中，在集体(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)三个层面上提高飞行任务期间的业绩。它将采用由PI为移动机器人团队开发的基于自由控制概念的主机-代理-化身组织结构，并将包括任务规划、任务分配和编队飞行在内的各种软件代理定义为独立于安装在航天器平台不同模块(化身)上的机载处理器(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联网以及可扩展的特别团队形成，而且还为使用稳健的并发马尔可夫决策过程开发故障恢复和统一的组学习机制奠定了适当的基础。将根据并行工程方法，通过对微型航天器最先进的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，来设计功能架构。作为功能结构的关键组成部分，这项研究还将开发一种基于分散虚拟结构的分布式控制方案，用于处理和通信有限且驱动能力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，将设计一个分离的航天器基础设施，用于在不同轨道上部署各种有效载荷，用于地球观测。这项研究将培养两名硕士研究生。2名博士生和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.