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Descripción
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| The research on electrodynamic tethers (EDT) has been a fruitful field since the 70¿s. This technology has been developed thanks to both theoretical studies and demonstration missions. During these decades several technical issues threatened to jeopardize the EDT capabilities, limiting its operation. Among those problems, two of them were especially hazardous. First, the efficient collection of electrons in the rarefies plasma and, second, the instability related to the first librational mode of the EDT in any inclined orbit. These problems have been addressed in previous works. The bare tether concept represents the overcoming of the current scarcity in low density plasma. This method of interaction with the ionosphere is though to increase considerably the intensity along the tether. In turn, the dynamic instability could be avoided thanks to the Self Balanced Electrodynamic Tether (SBET) solution. The purpose of this thesis is to prove the suitability of both concepts working together in several space applications: from mitigation of the space debris to capture in a Jovian orbit. This dissertation deals with the detailed analysis of both proposals. The computation of the electron collection by a bare tether is faced in first place. The semi-analytical method derived in this work allows to calculate accurately and efficiently the intensity which flows along a tether working on the OML (orbit-motion-limited) regime. An energy study is derived, where the EDT is analyzed as an energy converter. This approach provides a link among the different aspects of the problem, both electrical and dynamical outlooks. All the previous considerations will lead to the introduction of control laws based on the SBET concept, enhancing its capabilities. These analysis will be tested in a couple of particular and interesting scenarios. Mitigation of space debris has become an issue of first concern for all the institutions involved in space operations. In this context, EDT have been pointed out as a suitable and economical technology to de-orbit spacecrafts at the end of their operational life. Throughout this dissertation the numerical simulation of different de-orbiting missions by means of EDT will allow to highlight its main characteristics and the different parameters which are involved. The simulations will assess the suitability of the electrodynamic tethers to perform these missions. One of the foremost objectives within Solar System exploration is Jupiter, its moons and their surroundings. Due to the magnetic field and the plasma environment, this scenario turns out to be particularly appropriate for the utilization of EDTs, because they are able to generate power and thrust without propellant consumption. Orbital maneuvers and power generation will be therefore ensured. In this work, the possibility of using self balanced electrodynamic bare tethers to perform a capture in Jovian orbit is analyzed. Within this framework, the dynamics of a tether in the neighborhoods of a Lagrangian point results to be interesting since it can model the motion of a space system near a Jupiter¿s moon. That would allow to study the establishment of a permanent observatory for scientific observation. The analysis of the restricted three body problem is developed without taken into account the electrodynamic perturbation, leaving the inclusion of this feature for further research. | |
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Internacional
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Si |
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ISBN
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Tipo de Tesis
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Doctoral |
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Calificación
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Sobresaliente cum laude |
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Fecha
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28/09/2009 |