Maneuver Development Orchestration for the Europa Clipper Mission

The Europa Clipper mission employs over 250 maneuversto transport the spacecraft to Jupiter’s orbit and navigateflybys of the Jovian satellites. The science conducted during the4.3-year tour phase is enabled by strategic use of deterministicand stochastic maneuvers, sometimes placed only days apart.This operations paradigm demands an agile, accurate, robustand flexible ground maneuver development capability that isable to respond efficiently to a high volume of design demands.MAST, the Maneuver Automation Systems Tool, is designed tooperate within a carefully constructed maneuver implementationparadigm to support this capability for the Clipper mission.The maneuver implementation process dictates the generation,verification, and validation of the maneuver uplink products. Inthe most restrictive timeline, the orchestration of these products,including validation, is constrained to a tight 8-hour windowthat could occur during non-standard work shifts. Thus, theprimary considerations for maneuver implementation include:(i) staged-planning efforts to incorporate long-term, mid-term,and short-term knowledge as they become available, and (ii)efficient interactions within the uplink planning suite to deliveraccurate products in a time-sensitive operations regime that alsoallows for a smaller, more efficient operations team.The staged-planning efforts begin by initially specifying maneuverkeep-out zones prior to launch in the Clipper ReferenceActivity Plan (RAP), a blueprint for all the planned events ina given timeframe. The latest navigation knowledge in conjunctionwith ongoing resource trending and reconstruction effortsinform the modification of planned activities within a maneuverblock. These activities are translated to spacecraft commandsthat then enable the flight system to prepare for and executea maneuver, as well as reconfigure the spacecraft to a postmaneuverstate. An adaptation of NASA’s Advanced Multi-Mission Operations System (AMMOS) is leveraged to trackfinite resources consumed during maneuver execution and othermission requirements. Hardware-in-the-loop testbed verificationis also leveraged during the design cycles.MAST manages the time criticality associated with maneuverdevelopment by coordinating efficient data relay betweenvarious operations tools. MAST is an interactive and semiautomatedground orchestration tool that consists of a multiuserfront-end GUI that interfaces with a singular backendAPI. The multi-user functionality allows parallel yet restrictedpermutations of maneuver initial conditions to support timesensitiveoperations. The backend facilitates the actions of eachuser to maintain consistency. Simultaneously, it also executesthe sub-tasks of each run, including gathering initial conditions,managing dependencies between different subsystem tools, runningsimulations and generating reports. A discrete task completionapproach enables MAST’s self-cognizance of its locationin a run, allowing new users to pick up where others left off. Theclose coordination between MAST and subsystem analysis toolsdeveloped by navigation, propulsion, and Guidance, Navigation&Control (GN&C), as well as the AMMOS-adapted uplink toolsuite,enables an efficient maneuver development paradigm onClipper.

欧罗巴快船（Europa Clipper）任务需执行超250次轨道机动（maneuver），将航天器送入木星轨道，并完成对木星卫星的飞越观测。该任务为期4.3年的探测阶段所开展的科学观测，可通过策略性使用确定性与随机性轨道机动实现，部分机动的执行间隔仅为数日。此种作业范式亟需一套敏捷、精准、可靠且灵活的地面轨道机动开发能力，以高效应对海量的设计需求。
机动自动化系统工具（Maneuver Automation Systems Tool，以下简称MAST）的设计初衷是在一套精心构建的轨道机动实施范式中运行，为欧罗巴快船任务提供所需的地面开发能力。轨道机动实施流程需完成轨道机动上行链路产品（uplink products）的生成、校验与验证。在最严苛的时间约束下，包括验证环节在内的所有上行链路产品的编排工作，被限制在仅8小时的紧凑窗口内，且该窗口可能落在非标准工作时段。因此，轨道机动实施的核心考量要点包括：(i) 采用分阶段规划（staged-planning）方案，在相关信息逐步获取后，依次纳入长期、中期与短期的任务知识；(ii) 在上行链路规划套件（uplink planning suite）中实现高效交互，以在时间敏感型作业体制下交付精准的产品，同时适配规模更小、效率更高的作业团队。
分阶段规划工作始于发射前，在欧罗巴快船参考活动计划（Clipper Reference Activity Plan，简称RAP）中预先划定轨道机动禁入区（maneuver keep-out zones）——该计划是特定时段内所有规划任务的蓝图。结合最新导航知识、持续开展的资源趋势分析与重建工作，可对单个机动批次（maneuver block）内的规划活动进行调整。这些规划活动将被转化为航天器指令，使飞行系统（flight system）能够完成轨道机动的准备与执行，并将航天器重新配置至机动后状态（postmaneuver state）。项目采用经适配改造的美国国家航空航天局（National Aeronautics and Space Administration，简称NASA）先进多任务作业系统（Advanced Multi-Mission Operations System，简称AMMOS），以追踪轨道机动执行过程中消耗的有限资源及其他任务需求。在设计周期内，还会采用硬件在环测试台（hardware-in-the-loop testbed）进行校验验证。
MAST通过协调各类作业工具间的高效数据传输，解决轨道机动开发过程中的时间紧迫性问题。MAST是一款交互式、半自动化的地面作业编排工具，由支持多用户的前端图形用户界面（Graphical User Interface，简称GUI）与单一后端应用程序编程接口（Application Programming Interface，简称API）组成。多用户功能支持对轨道机动初始条件进行并行且受约束的排列组合，以适配时间敏感型作业。后端可协调各用户的操作以确保一致性；同时，它还会执行单次运行的各项子任务，包括收集初始条件、管理不同子系统工具间的依赖关系、运行仿真并生成报告。离散任务完成机制使MAST能够感知自身在单次运行中的进度，支持新用户接续其他用户未完成的工作。MAST与导航、推进及制导、导航与控制（Guidance, Navigation & Control，简称GN&C）团队开发的子系统分析工具，以及经适配改造的AMMOS上行链路工具套件间的紧密协作，为欧罗巴快船任务构建了高效的轨道机动开发范式。