Derivation and combination of impedance matrices for flexible satellites

The concept of the impedance matrix of a dynamical system is presented as a tool for the study of the small vibrations about equilibrium of a satellite with flexible appendages (attitude dynamics). A method which avoids the derivation of the equations of motion of the global system and does not require discretization of the flexible appendage a priori is developed. The impedance of the global system enables the study of the attitude dynamics and it can be constructed, in a systematic way, from the subsystem impedances. Impedances for typical subsystems of spinning satellites are derived. The method of combination of the subsystem impedances is used to derive global system impedances for GEOS, ISPM, ISEE-B, ESRO-4 and IMP-J satellites.