Dynamics of Liquid-Filled Flexible Spacecraft under Pulse Excitation

This paper investigates the rigid–liquid–flexible coupled dynamic characteristics of geostationary orbit (GEO) satellites under impulsive thrust perturbations induced by station-keeping maneuvers. For the symmetrically mounted plate-type solar panels (flexible appendages), the Kirchhoff–Love (KL) plate theory is adopted for modeling, and the coupled vibration equations are derived via D’Alembert’s principle; the governing equations are further transformed into nonlinear state-space formulations through spatial discretization and order truncation for efficient numerical calculation. For liquid sloshing in the axisymmetric propellant tank, the carrier velocity potential is solved based on the motion of a characteristic point in the tank, and the relative velocity potential is expanded as a Gaussian hypergeometric series. Hamilton’s variational principle is employed to establish the integrated coupled governing equations that incorporate liquid propellant sloshing, satellite rigid-body dynamics, and flexible plate vibrations. The proposed coupled dynamic model is comprehensively validated against satellite on-orbit telemetry measurements and ground experimental data of liquid-filled propellant tanks. Moreover, the on-orbit dynamic responses of the satellite are systematically analyzed under north–south and east–west station-keeping processes driven by 10-N thrusters. Comparative numerical simulations are conducted to reveal the critical coupling behaviors among liquid sloshing, flexible structural vibration, and satellite attitude motion, as well as quantify the influences of liquid fill ratios and thruster firing modes on satellite attitude pointing accuracy and stability. The results provide a theoretical basis for the design and control of high-precision GEO spacecraft with liquid-filled tanks and flexible appendages.