Articulated, Flexible Multibody Dynamics Modeling: Geostationary Operational Environmental Satellite-8 Case Study

Abstract

The attitude dynamics of Geostationary Operational Environmental Satellite-8 (GOES-8) is simulated using an articulated,  exible multibody approach, and simulation results are compared with the spacecraft  ight data. The solar array on this spacecraft is lightweight and  exible and is actuated by a stepper motor. The stepping harmonics are shown to excite the vibrational modes of the solar array. Angular displacement sensors for each of the spacecraft attitude degrees of freedom provided data accurate to subarcsecond levels. The simulations provided insights into the on-orbit behavior of the solar array as a function of time of day. The solar array modal data required modiŽ cations to obtain a good agreement with the  ight data. Several causes that could necessitate these modiŽ cations are identiŽ ed. The assumptions behind the structural dynamics modeling and the articulated multibodymodeling of the three-dimensional  exible solar array are highlighted. Although the GOES-8 was not set up to provide a platform for validating multibody dynamics models or approaches, it is concluded that these approaches can indeed be employed for simulating the dynamics of other spacecraft or  exible manipulators even when accuracies at the subarcsecond level are involved.