Orbit Insertion Dynamics of a Pico-Satellite with Respect to Coupled Solid-Liquid Dynamics

Abstract

Liquid dynamics in microgravity is one of the most challenging factors in spacecraft design. Performance and safety especially for a manned spacecraft contribute to a big extend to the exact knowledge of the mass properties (centre of gravity and inertia) at any time during the mission. Therefore, a Pico-satellite is being designed at Augsburg University of Applied Sciences in order to analyze liquid dynamics in microgravity. This satellite features a liquid reservoir that is used as experimental test bed. The physical characteristics of the liquid inside the reservoir become an important driver for the dynamics of the satellite. For the launch sequence of the satellite, safety requirements have to be fulfilled. The liquidstructure interaction must not influence the satellite’s trajectory during the insertion into orbit sequence. The target of this paper is to highlight an innovative scheme that allows the assessment of mass property disturbances during insertion into orbit of a Pico-satellite with respect to liquid dynamics due to unexpected failures. Among the possible failures considered here are the breaking of a release spring and an early injection of the test liquid from the sealed reservoir into the sphere test tank. The analysis is done by numerical simulation using a three-dimensional time accurate particle-cluster method that has been successfully validated against experimental findings from test cases defined for the analysis of liquid sloshing. Here, the liquid dynamics simulation tool has been coupled with a Newtonian trajectory simulation of the orbit insertion sequence. A disturbance envelope for the liquid-solid interaction will be provided for two failure modes considered here, release spring break and liquid-solid interaction during the release. An outlook is provided showing the potential of this method for the Pico-satellite orbit dynamics simulation using spinning wheels.