Optimal satellite system architecting considering on-orbit refueling

Abstract

Historically, On-Orbit Servicing (OOS), including refueling, maintenance, or upgrades, has been constrained due to high costs and risks of human involvement and expensive launches. Recently, however, with many commercial entities integrating OOS into their business models and rapidly advancing baseline technologies, the landscape is shifting. A particularly dynamic aspect of this evolution is On-Orbit Refueling (OOR), which potentially introduces a paradigm shift by decoupling design propellant mass from design lifetime. This shift necessitates exploring innovative satellite system architectures, diverging from conventional models. This thesis introduces a novel framework for satellite system architecting, specifically designed to incorporate the distinct elements of OOR. the framework formulates the optimal satellite system architecting problem by treating design lifetime and design propellant mass as independent variables. It employs the mean-variance model, borrowed from Portfolio selection theory, to define objective functions. The evaluation of each proposed architectural solution is facilitated by a new sizing model that treats design propellant mass as an independent variable and a comprehensive satellite lifecycle simulation that includes OOR scenarios. Based on the simulation, a surrogate model-based optimization approach is used as the solution methodology. To validate the framework's practicality and effectiveness, a case study focusing on a geosynchronous equatorial orbit communication satellite is conducted. This study thoroughly analyzes current service parameters and their variations, identifying service cost as a crucial factor influencing the efficiency of satellite system architecture solutions. Additionally, it quantitatively assesses the cost threshold at which alternative system architectures become viable. The case study demonstrates the framework's ability to effectively evaluate the impacts of OOR on satellite system architecture, providing valuable insights for stakeholders in the space sector.