MODELING OF SLOSHING MODULATED ANGULAR-MOMENTUM FLUCTUATIONS ACTUATEDBY GRAVITY GRADIENT 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 that manage orbital gravity gradient acceleration associated with the slew motion that is acting on the spacecraft fluid systems are derived. The numerical computation of sloshing dynamics is based on the noninertial frame spacecraft-bou nd coordinates and tile solution of time-dependent three-dimensional f ormulations of partial differential equations subject to initial and b oundary conditions. This study discloses the capillary effect of slosh ing dynamics governed liquid-vapor interface fluctuations, angular mom entum and moment fluctuations of fluid system, and also bubble mass ce nter fluctuations driven by the gravity gradient acceleration associat ed with slew motion which affects the stability of the orbital spacecr aft fluid system in a microgravity environment.