A model-based approach for the preliminary design of the SAR upstream element for the Italian IRIDE EO constellation based on users’ demand

Traditional approaches to the design of satellite constellations are typically related to technical conditions and financial effort. The use of optimization methods is limited to design specific technical performances of the single spacecraft, miss- ing to resort to a holistic view of the whole mission including user needs. Given the growing significance of large Low Earth Orbit (LEO) constellations of small satellites in Earth Observation, there is a pressing need to develop design tools that can incorporate user needs into the overall preliminary design process of a constellation. This paper aims to formulate and preliminarily test a systematic model-based approach capable of integrating user needs within the entire preliminary design process of a constellation architecture. The purpose of the methodology is to identify cost-effective architectures for more detailed design studies and to propose optimal solutions to fulfill the variety of requests from users. It is composed of five major steps: formulation, enumeration, simulation, evaluation, and down-selection. As a case study, the proposed approach is implemented to define the preliminary architecture of the Synthetic Aperture Radar (SAR) sub-constellation within the IRIDE Italian program. Performance is assessed based on the percentage of satisfied user needs and the volume of downlinked data to ground stations. Five optimal SAR constellations are proposed. Results demonstrate that the approach provides a valuable tool for the optimal preliminary design of a satellite infrastructure, taking into account not only technical performance but also user needs throughout the entire design process.