Abstract:This paper introduces the development of dynamics of space mechanisms for aerospace,and discusses the important senses to study nonlinear clearance models for both designing the structures of new spacecrafts and analyzing the performances of spacecrafts on orbit.Some key problems to be solved are proposed,which include the dynamic modeling and analyzing of space mechanisms with clearances,the movement stability analysis of the mechanisms,the simulation software for realizing the global simulations of performances of the mechanisms.