The Reference Activity Plan: Collaborative, Agile Planning for NASA's Europa Clipper Mission

Activity planning efforts on planetary exploration missions must effectively translate high-level scientific objectives into command products that execute onboard the spacecraft. In prior flagship-class orbiter missions, this process has been implemented using two approaches: activity plans are either systematically created from scratch for each orbit via a linear planning process, or future orbit plans are developed far in advance and carefully iterated upon to ensure maximum science return. These approaches have been effective, particularly for projects whose science observation strategies vary over the course of the mission, but require a number of operational constraints. Large team sizes, difficulty in relating detailed plans to qualitative science objectives, and the fragile nature of pre-planned activity sets allow limited opportunity for flexibility and optimization of plans during development. The baseline trajectory design for the Europa Clipper mission uses a suite of 45 low-altitude, short-period flybys of Europa at varying geometries to globally map the surface of the moon. In order to effectively integrate the activities of the spacecraft and its ten science instruments into a valid plan on the cadence necessitated by the trajectory design, mission operations engineers have developed a collaborative, agile uplink planning architecture. The foundational product of this planning architecture is the Reference Activity Plan (RAP), a full-mission activity plan that leverages the project's largely repeatable science observation patterns to create a template for planning at both strategic and tactical levels. Activities in the RAP are codified using a common schema and can be placed in the plan using constraint-based scheduling software that is driven by objective and quantifiable science measurement requirements. This approach enables dynamic modification of the whole mission plan in large or small segments, which allows planners to react to new science information or incorporate flight system performance characteristics into future orbit activities. The RAP also allows planners to understand the impact of their activity changes on the rest of the plan; since each subject matter expert has visibility into the entire set of planned activities, and the impact of their proposed changes upon the full plan is simulated, they can more effectively collaborate with the rest of the operations team to develop a conflict-free plan with less iteration. This paper examines unique operations considerations that drove the design of the Reference Activity Plan, the composition and proposed implementation of the RAP, and how the use of a single authoritative activity plan allows collaborative, flexible planning during uplink plan development.