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Autonomy in space systems can drastically reduce the workload of ground crews for satellite missions, especially for clusters of satellites. Additionally, autonomy can increase the efficiency of missions by maximizing the utilization of resources and rapidly handling any issues that arise without having to wait for instructions from the ground. This research presents an agentbased, task-execution approach to onboard spacecraft autonomy. Instead of the traditional approach requiring onboard planning and scheduling, this method uses a combination of constraint and priority parameters associated with every task to ensure robust task execution with behavior as intended. Using this method, tasks will only run under safe conditions (e.g. no conflict with any running tasks), which enables conflicting tasks to be scheduled closer together or even overlapping for lower-priority tasks. This approach manages the execution of tasks on the timescale of seconds, enabling conflicting tasks to run sequentially, thereby increasing productivity if earlier tasks finish ahead of schedule. This framework leverages the NASA-developed, open-source projects cFE and PLEXIL and was tested on development boards comparable to flight hardware.

Autonomy will play a crucial role in achieving complex mission goals and reducing the burden for ground operations for upcoming ambitious aerospace missions. Standalone spacecraft can leverage autonomy concepts to optimize data collection and ensure robust operation. Autonomy can additionally provide a feasible method of ensuring coordination for spacecraft clusters through onboard peer-to-peer scheduling. The core of this framework, the schedule manager (SM), manages tasks by associating constraints with each task including time windows, task priority, conflict categories, and resource requirements, which assures that tasks will only run when capable. This increased control over individual tasks also improves the modularity of the overall mission plan and provides a built-in fail-safe in the event of unexpected task failure through the loading of predefined contingency schedules. Various other capabilities were added to the SM, including the SM data server to simplify commanding, distributed coordination, and integration with NASA Goddard Space Flight Center’s core Flight System (cFS) platform. Software validation was achieved with cFS unit tests, functional tests, and code analysis tools. Demonstrations were tested with a cluster of development boards in the loop as representative flight hardware.

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