CASTOR - STRUCTURAL DYNAMICS IN THE MIR STATION

Prediction and reduction of space structure vibrations have become cri tical issues over the last ten years. Motivating factors include optic al systems with high stability requirements, large antennas, sensitive micro gravity payloads, compatibility of flexible appendages with att itude control, and large orbital infrastructure surviving. The experim ent ''CASTOR'' (French acronym for ChAracterisation of STructures in O Rbit) is dedicated to the identification of the structural dynamic mod es of the MIR station and to the investigation of the dynamic behaviou r-in zero g conditions-of a truss mock-up equipped with various passiv e and active damping technologies. The measured modal parameters of MI R are to be compared with the results of a finite element model analys is. The differences between in-flight and on-ground dynamics of the tr uss will be thoroughly analysed. This project has been conceived and i s managed by CNES. The flight hardware will be delivered by the end of 1995, and the experimental work will be performed by a French cosmona ut within the framework of the CASSIOPEE mission in June 1996. In the first place, a comprehensive overview of CNES activities in the predic tion of in-flight structural dynamics, and of similar experimental eff orts found in literature will be discussed. Afterwards, the motivation s behind the CASTOR experiment will be shown, followed by a full descr iption of its equipment. The results of the ground tests and analyses, and the in-orbit test plan will then be presented extensively. Partic ular emphasis will be laid on the performances of the active damping s ystems which will be validated in flight. In conclusion, the potential re-utilisation of the experiment material within the framework of lat er flights will be highlighted. (C) 1997 Elsevier Science Ltd.