This paper uses a direct simulation Monte Carlo (DSMC) approach to simulate rarefied aerodynamic characteristics during the aerobraking process of the NASA Mars Global Surveyor (MGS) spacecraft. The research focuses on the flowfield and aerodynamic characteristics distribution under various free stream densities. The variation regularity of aerodynamic coefficients is analyzed. The paper also develops an aerodynamics-aeroheating-trajectory integrative simulation model to preliminarily calculate the aerobraking orbit transfer by combining the DSMC technique and the classical kinematics theory. The results show that the effect of the planetary atmospheric density, the spacecraft yaw, and the pitch attitudes on the spacecraft aerodynamics is significant. The numerical results are in good agreement with the existing results reported in the literature. The aerodynamics-aeroheating-trajectory integrative simulation model can simulate the orbit transfer in the complete aerobraking mission. The current results of the spacecraft trajectory show that the aerobraking maneuvers have good performance of attitude control.