An ensemble MCDM strategy for orbit design in Genesis-like missions

The main goal of this paper is to introduce a new ensemble-based Multi-Criteria Decision-Making (MCDM) strategy to rank multiple orbit configurations and identify those that maximize the objectives of a satellite mission. The strategy combines five diverse MCDM methods with five objective weighting techniques to determine orbit regions that maximize the performance across a set of selected criteria. As an example, we apply this strategy to the recently ESA-approved Genesis mission. Genesis, approved by ESA in 2022, is designed to co-locate the four space geodetic techniques (DORIS, GNSS, SLR and VLBI) on board a single satellite. Its main goal is to improve the accuracy of the International Terrestrial Reference Frame (ITRF) by overcoming systematic biases in the four techniques and replacing ground-based ties with continuous space ties. The effectiveness of this mission depends, among other factors, on the selection of a proper orbit configuration, as it directly influences the visibility, tracking geometry, thermal conditions and calibration capabilities. This study aims to thoroughly assess and identify orbit configuration regions by applying the new ensemble MCDM strategy, with the objective of maximizing the mission’s geodetic contribution and strengthening the realization of the ITRF. This was accomplished by evaluating 6700 circular orbit configurations, with keplerian parameters ranging from 1000 to 10000km for altitude and 0 ∘ to 180 ∘ in inclination, based on eleven criteria. These criteria are related to orbital constraints, GPS visibility, ground network tracking distribution and multi-technique visibility. In order to ensure a robust ensemble MCDM application, multicollinearity and distribution analyses of the criteria were performed. In addition, extensive comparisons among the MCDM and weighting methods were conducted to evaluate their consistency, sensitivity, and influence on the final orbit rankings. This paper presents a comprehensive orbit design framework for Genesis-like satellites, where the ensemble MCDM strategy is applied to identify orbit configuration regions that are optimal under the applied criteria and the assumptions made in each criterion of this study. In support of this strategy, single-criterion analyses were first carried out to assess the consistency and structure of the applied criteria, while also revealing best- and poor-performing regions for each criterion individually. To our knowledge, this is the first application of an ensemble MCDM approach to orbit design in space geodesy.