Abstract: Modern complex spacecrafts usually have large flexible appendages, the elastic deformations of which are usually described by finite element method. However, the number of finite element nodal coordinates is large, which leads to a large computational burden on dynamics and control. Therefore, model order reductions of flexible solar arrays are investigated in this paper. The rigidflexible coupling dynamic equations of a spacecraft with solar arrays are derived based on oneway recursive assembly formulation. Modal truncation method, modal value analysis method and Krylov method are used to reduce the degreesoffreedom of solar arrays. The results using those order reduction methods are compared with the results using the finite element method. The numerical simulations show that with the Krylov method smaller orders are needed, which is in good agreement with that of the finite element method. It means that Krylov method is an efficient method in reducing the degreesoffreedom of flexible spacecraft, which will improve the efficiency of dynamic simulation and the implement of control.

Key words: solar array, rigidflexible coupling, dynamic simulation, model reduction, Krylov method