Abstract: The accurate prediction for aerodynamic drag of spacecraft in very low Earth orbit (VLEO) is a fundamental prerequisite for aerospace missions in VLEO. The present work calculates aerodynamic drag of the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite using the test particle Monte Carlo (TPMC) method. The primary goal is to obtain a comprehensive understanding of surface pressure and skin friction on the spacecraft surface and assess the sensitivity of aerodynamic drag to the gas-surface interaction (GSI) models. Results indicate that surface pressure is mainly distributed on the front of the satellite body and panels while skin friction is primarily distributed on the sides. In addition, as the GSI model changes from diffuse to specular reflection, the total drag coefficient is reduced at operation altitudes above 170 km. Therefore, the satellite surface should be processed so carefully that the GSI remains far from diffuse reflection from the view point of the drag-reduce design.

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