The dynamic characteristics of a two-step deployable bidirectional solar array system with flexible panels and clearance joints are studied in this paper. Driving mechanisms, closed cable loop configurations, and latch mechanisms are considered in this system where normal contact force is established using a nonlinear spring damping model and the friction effect is determined by a modified Coulomb friction model. With the simulation strategy of activating different constraint states and applying latch torques, the multiple deployment and locking processes of the system are implemented. The results indicate that the second locking causes obvious vibration on the dynamic responses of the yoke and main panels and leads to a complex bidirectional vibration of the main panel connected to the side clearance joints. The equivalent suspension damping property produced by the coupling of the flexibility and clearances can reduce the vibration of the deployable components. Moreover, the attitude and orbital motion results reveal the effect of different deployment methods of the system on the spacecraft attitude. Finally, the trajectories of journal centers and contact forces are analyzed to indicate the foundation of the dynamic behavior of the system.

The multi-body dynamic model of the SAR satellite and the Ruze formula are used to investigate the antenna gain loss’s sensitivity to the control moment gyroscope. First, by using the finite element method, the satellite’s dynamic model is created and the modal characteristic is then determined. Then the distribution of input disturbance and CMG diagram is established. And the effect of each CMG disturbance on the antenna gain is studied. The sensitivity parameters of gain loss to disturbance are computed by using the One-at-a-Time (OAT) method. The results show that for CMGs, although they are placed asymmetrically and have the same loading characteristics, their effects on the antenna gain are different and need to be considered separately. The method and ideas proposed in this paper can be used to quantify the influence of various disturbances’ sensitivity and control system design.