Spacecraft maneuvers and slosh control

Slosh is a problem in spacecrafts, which often carry considerable amounts of fuel for trajectory maneuvers and momentum dumping. As fuel is consumed, the tank becomes increasingly empty, and the remaining fuel is excited by the motion of the spacecraft. Since the reaction forces and moments caused by fuel slosh can degrade the pointing accuracy of the system, it is important to predict the effect of slosh on the spacecraft attitude control system. This paper presents the development of Sloshsat (Facility for Liquid Experimentation and Validation in Orbit) FLEVO used to study the dynamics of slosh and its impact on spacecraft attitude control. The primary objective of the Sloshat FLEVO mission is to perform a variety of maneuvers while collecting detailed measurements on the resulting slosh. For validation, the computational fluid dynamics (CFD) simulations must result in highly similar behavior. CFD predictions can then serve as a truth model for assessing the performance of simpler models for developing control algorithms.