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Aerodynamic configuration of the capsule for manned re-entry at the second cosmic speed requires a relatively higher lift-to-drag ratio compared to the configuration for manned re-entry at the first cosmic speed. The present capsule configurations with high lift-to-drag ratio, for instance, the Apollo and the Orion, have secondary statically stable trim points, which is highly undesirable since it would cause disastrous result once the vehicle flies at the secondary trim point during re-entry. In the present study, effective design methodology for improving the monostability characteristics of re-entry capsules without compromising the lift-to-drag ratio is revealed based on flow field characteristics analysis. As a result, aerodynamic configuration design of a capsule with high lift-to-drag ratio and monostable characteristics is proposed. And the aerodynamic characteristics of the capsule ranging from subsonic to hypersonic speed are predicted by numerical simulations. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of ablation on the re-entry capsule, numerical simulation is used to analyze the trim characteristic of Soyuz re-entry capsule. The aerodynamic characteristic and the trim characteristic are researched as the aerodynamic configuration is changed due to the recession of thermal protection thickness. The result indicates that absolute value of the trim angle of attack and trim lift-drag ratio of Soyuz re-entry capsule are decreased with mach number increasing in hypersonic flow (Ma>8),and the effect of recession is to increase absolute value of the trim angle of attack and trim lift-drag ratio. The results compare well with the conclusion of CEV in overseas reference. The Soyuz and CEV have same changes in the law about trim characteristic, and recessed configuration of them also have similar changes in trends. The research offers reference for the aerodynamic configuration design and improve of the Soyuz re-entry capsule. [ABSTRACT FROM AUTHOR]