The problem of predicting the dynamic behavior of an expanding multi rigid-body system with intermittent motion is considered. The symbolic manipulation system is employed to obtain the system equations of motion in the Kane formulation. Velocities and angular velocities of a main body and a hinge angle are selected as system variables to represent the system equations in a form of first-order linear differential equations. When an impulse input is applied or when a hinge is locked, the intermittent behavior occurs with discontinuities in velocity vector. To define the jump discontinuities in terms of velocity, the relations between the velocity and the impulse force are presented at a point in time at which an intermittent event occurs. The dynamic behavior of spacecraft expanding panels is solved numerically by integrating the system equations in time.