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Tesis:

Self Balanced Bare Electrodynamic Tethers. Space Debris Mitigation and other Applications

  • Autor: SANJURJO RIVO, Manuel

  • Título: Self Balanced Bare Electrodynamic Tethers. Space Debris Mitigation and other Applications

  • Fecha: 2009

  • Materia: Aeronaútica

  • Escuela: E.T.S. DE INGENIEROS AERONAUTICOS

  • Departamentos: FISICA APLICADA A LA INGENIERIA AERONAUTICA

  • Acceso electrónico: http://oa.upm.es/1839

  • Director/a 1º: PELAEZ ALVAREZ, Jesús

  • Resumen: 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 this period, several technical issues were identified and overcome. Among those problems, two of them would entail an important reduction in the operational capabilities of these devices. First, the efficient collection of electrons in rarefied plasma and, second, the dynamic instability of EDTs in inclined orbits. The bare tether concept represents the surmounting of the current scarcity in low density plasma. This method of interaction with the ionosphere promises to considerably increase the intensity along the tether. In turn, the dynamic instability could be avoided by balancing the EDT, as it has been proposed with the Self Balanced Electrodynamic Tether (SBET) concept. 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. 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. Then, 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, from both electrical and dynamical points of view. 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 scenarios of interest. Mitigation of space debris has become an issue of first concern for all the institutions involved in space operations. In this context, EDTs 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 EDTs will allow to highlight its main characteristics and recognize the different parameters which are involved. The simulations will assess the suitability of electrodynamic tethers to perform these kind of mission. On the other hand, one of the foremost objectives within Solar System exploration is Jupiter, its moons and their surroundings. Due to the presence of magnetic field and plasma environment, this scenario turns out to be particularly appropriate for the utilization of EDTs. These devices would be capable 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 bare electrodynamic tethers to perform a capture in Jovian orbit is analyzed. In addition, within this research, the analysis of the dynamics of a tether in the neighborhoods of a Lagrangian point results to be interesting since it models 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 in Jovian orbit. The analysis of the restricted three body problem is developed without taking into account the electrodynamic perturbation, leaving the inclusion of this feature for further research. Finally, within the frame of this dissertation, an additional analysis is presented. The study is related to the possible role of EDT in geodetic missions. The work gathered here describes an initial analysis of the capabilities of a tethered system to recover gravitational signals by means of measuring its tension.