SLOSHING DYNAMICS MODULATED ANGULAR-MOMENTUM FLUCTUATIONS ACTUATED BYGRAVITY GRADIENT ACCELERATION ASSOCIATED WITH SPACECRAFT SLEW MOTION

The mathematical formulation of orbital spacecraft sloshing dynamics f or a partially filled cryogenic superfluid liquid helium II in a dewar container actuated by the gravity gradient acceleration associated wi th slew motion is studied. The Advanced X-Ray Astrophysics Facility-Sp ectroscopy (AXAF-S) spacecraft is chosen as a practical example in thi s study. Explicit mathematical expressions which manage orbital gravit y gradient acceleration associated with slew motion which is acting on the spacecraft fluid systems are derived. The numerical computation o f sloshing dynamics is based on the non-inertia frame spacecraft bound coordinates and the solution of time-dependent, three-dimensional for mulations of partial differential equations subject to initial and bou ndary conditions. This study discloses the capillary effect of sloshin g dynamics governed liquid-vapor interface fluctuations, angular momen tum and moment fluctuations of fluid system, and also buble mass cente r fluctuations driven by the gravity gradient acceleration associated with slew motion which affects the stability of the orbital spacecraft fluid system in a microgravity environment.