MESSENGER SciBox, An Automated Closed-loop Science Planning and Commanding System

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MESSENGER SciBox is an automated closed-loop planning and commanding system used to optimize orbital science operations for the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. The system plans all science observations for the seven science instruments on the spacecraft and also automatically generates the command sequences that drive the instruments, the guidance and control system, the solid-state recorder, the solar panels, and the radio-frequency communication system. MESSENGER SciBox interacts with the instrument scientists, mission operations team, downlink processing system, and mission design engineers to form a closed-loop system. In orbital operation, the systems employ a feedback loop, with a one-week time step, to improve the system performance. Feedback inputs are used to predict observational performance, to track all science observations, to avoid planning redundant tasks, and to recover from operational anomalies. The software tool is automated because the entire process, from ingesting the feedback inputs to creating the spacecraft and instruments commands, can function without manual interaction. I. Introduction Science operation centers for most space missions generally consist of two components: the uplink system and the downlink system. The uplink system deals with planning and scheduling of science observations, whereas the downlink system deals with the processing of observations returned from the spacecraft. Traditionally, the planning and scheduling of science observations, and the creation of associated spacecraft and instrument commands for science operation, are so time-consuming and labor-intensive that little time is left for the planning team to have close interactions with the data processing team. Any such interactions tend to be ad hoc and informal. On some missions, the two subsystems are so decoupled that they are even housed in different institutions and on separate networks. The lack of tightly coupled interaction frequently results in inefficient use of resources and a less-thanoptimum operational schedule. In this paper we describe an automated planning and commanding system that uses a closed-loop iterative process to continuously refine the science operation schedule and to generate spacecraft and instrument commands for uploading to a spacecraft. The planning system iteratively interacts with the instrument scientists, mission operations center personnel, mission design team, and downlink processing system to produce a scienceobservation-packed operational schedule and to improve the precision of planned operations. The process of ingesting feedback information from the downlink system to the generation of spacecraft and instrument commands for uplink is completely automated. This closed-loop architecture has been implemented as part of science operations for the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft now in orbit about Mercury, and it has allowed the MESSENGER team to maximize scientific return for the community with a relatively small operational staff. The closed-loop architecture and its application to MESSENGER orbital operations are the focus of this paper.