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Títol: Sloshing characteristics in a satellite propellent tank and consequences for attitude dynamics

Estudiants que han llegit aquest projecte:


Departament: FIS

Títol: Sloshing characteristics in a satellite propellent tank and consequences for attitude dynamics

Data inici oferta: 15-02-2022     Data finalització oferta: 15-10-2022

Estudis d'assignació del projecte:
Tipus: Individual
Lloc de realització: EETAC
Paraules clau:
sloshing, satellite, attitude dynamics and maneuver, liquid filled spacecraft
Descripció del contingut i pla d'activitats:
Modern spacecraft have to carry a considerable amount of liquid fuel to execute the increasing duration and complex space missions. Liquid slosh caused by motion of the spacecraft can degrade the pointing accuracy of the system. In the course of spacecraft attitude maneuvers, the slosh waves caused by the fluid motion inside a tank can produce significant disturbance moments, leading to the control and stabilization problems of a spacecraft. Thus, it is important to study the effect of liquid slosh on the attitude control system of spacecraft. In most modern spacecrafts, momentum exchange techniques are widely used to be integrated into the attitude control system.

The thesis will consist of the modeling and control of a satellite or spacecraft with a large amount of sloshing liquid inside in microgravity conditions. The objective will be to make a useful contribution to the engineering of fuel depots in space which will require precise control.

The required software Matlab, Python, ... is installed in the school virtual cluster (clufa), which will also be used to carry
out the simulations for the project.
Overview (resum en anglès):
Orbital refueling has become a subject of increasing interest as longer, deep space missions and manned missions to the Moon and Mars are being contemplated once again. For fueling depots to become part of the infrastructure in space capable of enhancing deployment and service operations, there remains a slew of technical, operational, and engineering challenges which must be overcome. In this thesis, focus is placed mainly on the issue of fluid slosh and its effects on the spacecraft dynamics and the design of an attitude control system.

In pursuit of overcoming the attitude tracking errors and instability from the fluid slosh, a novel satellite design is presented based on an omnidirectional ball-balanced robot (ball-bot) which aims at minimizing the control effort required to stabilize the satellite while also maximizing the amount of fuel it can carry. The satellite is comprised of two primary elements: a spherical tank, containing the fuel payload and a cuboid bus, containing the attitude control system (ACS) and other subsystems. The satellite bus is mobile and can displace itself over the surface of the sphere and has a sunshield which is deployed in orbit which shields the spherical tank from solar radiation. The cube is mobile and can displace itself on the surface of the sphere to point to the sun ensuring the protection of the fuel payload.

A presentation of the state-of-the-art of orbital fuel depots is first presented, and subsequently, a contextualization of orbital dynamics, along with the mathematical modeling of the satellite, is carried out, complemented by a discussion about the limitations of the work and the assumptions of the model. A simulation of the satellite¿s dynamics with the fluid slosh is conducted using Simulink and the sun-tracking of the cuboid-bus with Mathematica. Finally, a set of conclusions are presented and recommendations for future research and improvements, based on the conclusions, are made.

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