Parametric studies of the whole spacecraft vibration isolation

Whole spacecraft vibration isolation is a direct and effective approach toward improving the dynamic environment that a launch vehicle can provide to its payloads. Any improvement on the dynamic environment can not only raise the reliability but also lighten the structural mass of a spacecraft. In the present paper, with a simplified isolator-spacecraft model, parameters of the isolator and the isolator-spacecraft system that will affect the vibration transmissibility are studied first. These parameters include mass ratio, natural frequency ratio, and damping. Results of analytical and numerical studies show that low isolator stiffness (soft-ride) and damping treatment of high stiffness payload adaptor fitting (hard-ride) can effectively decrease the transmissibility. Experience obtained from this study was used in designing the vibration isolation function of an existing payload adaptor fitting for enabling a satellite to be qualified for launch with a launch vehicle.