Estimation of Responses of Spacecraft to High Frequency Shock Loads and Comparison with Test Results

Abstract

To arrive at shock levels for the equipment of spacecraft, one needs to have a suitable analytical prediction model. One of the prediction techniques is explicit time integration of the governing equation of motion. This methodology is in use for determining the responses due to an impact where the force of impact is known. But they have not been applied to spacecraft where the force is not known, but the accelerations are known. Also, the frequency range of interest covers higher order modes. In this work theoretical estimation of response of spacecraft to high frequency shock excitation is attempted using an explicit time integration scheme. The parameters required for the response estimation are first established. The influence of dynamic relaxation parameter on the estimated responses is discussed. The acceleration responses of two typical spacecraft are measured during their separation from the vehicle adaptor. The responses are theoretically estimated using the parameters established in this work. In both the spacecraft the estimated results are in very good agreement with the measured results with some differences seen at locations far away from the source.