Abstract: The attitude dynamic equations of a spacecraft with deploying flexible plates are derived by means of the momentum theorem. The dynamic equations by differentiation with respect the mass of the flexible plates are derived with the aid of Newtons second law. When the flexible plates deploying at a uniform velocity the dynamic equations of the system are alternated. By using Runge-Kutta method the numerical results are obtained. The responses of amplitudes of the vibration of the flexible plates to time are given. The responses of attitude angular velocity of the spacecraft to time are given.

Key words: spacecraft, attitudedynamic, flexible deploying plate