A rule-based decision support tool for architecting Earth observing missions

A decision support tool is presented that is especially tailored for architecting Earth observing missions and programs. The tool features both a cost model and a performance model. This paper focuses on the description of the performance model. Indeed, while considerable effort has been put into the development of cost estimating models, comparably much less effort has been put into the development of quantitative methods to assess how well Earth Observing Mission satisfy scientific and societal needs. A literature review revealed that existing methods include a commercial approach, a value-of-information approach, end-to-end simulation, assimilation in Observing System Simulation Experiments, and simple expert judgment. Limitations of these methods include limited applicability, computational complexity, low modeling fidelity (e.g. abstraction of synergies between measurements), and subjectivity. Our method uses a knowledge-based system to store and manage large quantities of expert knowledge in the form of rules-of-thumb that replace expensive computations. Scientific and societal measurement requirements and instrument capabilities are expressed in the form of logical rules and data structures. An efficient pattern matching algorithm performs the comparison of the measurement requirements and the measurement capabilities on the basis of 64 different measurement attributes. The system is demonstrated on the Earth Science Decadal Survey. While the system is still under development, it shows great potential to enhance traceability in the modeling of scientific and societal value of Earth observing missions. Furthermore, the recursive nature of rule-based systems shows potential to model synergies between instruments and measurements, at a sufficient level of fidelity for architectural trade studies, especially for the ones conducted in committees with experts such as Decadal Surveys.