To extend the limited scope of autonomy used in prior missions for operation in distant and complex environments, there is a need to further develop and mature autonomy that jointly reasons over multiple subsystems, which we term system-level autonomy. System-level autonomy establishes situational awareness that resolves conflicting information across subsystems, which may necessitate the refinement and interconnection of the underlying spacecraft and environment onboard models. However, with a limited understanding of the assumptions and tradeoffs of modeling to arbitrary extents, designing onboard models to support system-level capabilities presents a significant challenge. In this paper, we provide a detailed analysis of the increasing levels of model fidelity for several key spacecraft subsystems, with the goal of informing future spacecraft functional- and system-level autonomy algorithms and the physics-based simulators on which they are validated. We do not argue for the adoption of a particular fidelity class of models but, instead, highlight the potential tradeoffs and opportunities associated with the use of models for onboard autonomy and in physics-based simulators at various fidelity levels. We ground our analysis in the context of deep space exploration of small bodies, an emerging frontier for autonomous spacecraft operation in space, where the choice of models employed onboard the spacecraft may determine mission success. We conduct our experiments in the Multi-Spacecraft Concept and Autonomy Tool (MuSCAT), a software suite for developing spacecraft autonomy algorithms.

翻译：为扩展先前任务中用于远距离复杂环境操作的有限自主能力，需进一步开发并完善能够跨多子系统协同推理的自主技术，我们将此称为系统级自主。系统级自主建立态势感知能力，可消除各子系统之间的冲突信息，这可能需要优化和互联航天器及其环境在轨模型之间的基础关联。然而，由于对建模任意程度的假设与权衡缺乏充分理解，设计支持系统级能力的在轨模型面临重大挑战。本文针对多个关键航天器子系统，详细分析了模型保真度的提升层级，旨在为未来航天器功能级与系统级自主算法及其验证所用的物理模拟器提供参考依据。我们并非主张采用特定保真度类别的模型，而是强调在不同保真度层级下，使用模型进行在轨自主控制及物理模拟时所涉及潜在权衡与机遇。我们以小天体深空探测为分析背景——这是航天器自主运行的新兴前沿领域，航天器所采用的模型选择可能直接决定任务成败。实验基于多航天器概念与自主工具（MuSCAT）软件套件开展，该套件专用于开发航天器自主算法。