Abstract: In a certain deep space exploration and sampling mission, the returner needs to enter the  earth ’s  atmosphere by spin separation, and needs to maintain its own attitude stability. Based on the self developed spin separation mechanism, the multi body dynamic simulation model of the spin separation of the returner is established.The comprehensive sensitivity analysis of multi parameters, the coupling analysis of sensitive parameters and the analysis of multi parameter coverage are carried out. The result shows that the spring lateral installation deviation and the returner ’s transverse center of mass deviation have the most obvious influence on the separation attitude；it is helpful to improve the initial separation attitude of the returner by adjusting the horizontal position of the spring and the position of the mass horizontal center of the returner；the spin separation index is further verified by multi parameter coverage simulation analysis. The research content of this paper can provide theoretical guidance for the engineering technology for deep space exploration sampling.

Key words: Reentry return, Spin separation, Dynamics, Separation attitude