Improvement of Launching Capability with Enhanced GEO Satellite Design

搭載能力提升方案在地球同步軌道衛星設計中的應用

Student thesis: Doctoral Thesis

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Award date27 May 2021

Abstract

GEO (Geosynchronous Earth Orbit) Telecommunication satellites are satellites that provide signal relay service while orbiting at an altitude of 35786km synchronously around the Earth. In a typical practice, the launch vehicle injects the satellite into an intermediate orbit, GTO (Geosynchronous Transfer Orbit). Once the satellite reaches GTO, it will be separated from the launch vehicle and raised by its propulsion system to GEO. The transition of the satellite from GTO to GEO is known as the Orbit Raising (OR). The OR requires to consume a huge amount of propellant. Maximizing the efficiency of the OR launching process is a common goal for all stakeholders in satellite industry including operators, manufacturers, and end-customers.

China has adopted a combination of the Long March 3BE launch vehicle and DFH-4 satellite for improving the efficiency of the launching process. In this thesis, we develop and explore two OR strategies based on previous studies and efforts on the Chinese launching system. The proposed solutions aim to reduce OR propellant consumption and hence improve efficiency and capability of the launching process. The proposed solutions intended to supplement the existing solution pool as they featured low cost, low technical risk, low scheduling. To evaluate and validate the effectiveness of the proposed strategies, we have developed a set of mathematical models for deriving quantitative evaluation on each solution. We also conduct a set of sensitivity analyses on various parameters in the process design. An assessment Tool Kit is also developed in EXCEL to incorporate all relevant elements and for quick assessment. This Tool Kit enhances system designer in engineering practice during satellite design. Finally, case studies are conducted and presented to validate and demonstrate the effectiveness of the proposed solutions in real world applications.