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Descripción
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| Asteroids and space debris pose relevant menaces to civilization, both on ground and in space. Simultaneously, they present a number of common engineering and scientific challenges that must be tackled in the realm of Space Situational Awareness (SSA). As to improve current and future SSA technologies, robust and efficient orbit propagation methods are required. The main goal of the present thesis is to demonstrate that regularized for- mulations of dynamics entail significant advantages in the most demanding orbit propagation problems for asteroids and space debris. Regularized formulations are obtained by eliminating the 1/r^2 singularity in Newtonian equations of motion through an analytical procedure. The resulting regularized equations exhibit an excellent numerical performance. In this thesis, we consider the Kustaanheimo-Stiefel formulation and several methods of the Dromo family, which represent the trajectory through a set of non-classical orbital elements. In the first part, we focus on the orbit propagation of planetary close encounters, taking into account several test cases. As scenarios of relevant practical importance, we propagate resonant returns of several fictitious asteroids and measure the error in the b-plane coordinates. To generalize the results, we carry out large-scale simulations in the Circular, Restricted Three-Body Problem by means of a bi-dimensional parametrization. We analyse the case of the asteroid (99942) Apophis, devoting particular attention to the amplification of the numerical error consequent to its deep close encounter in 2029. The second part is dedicated to the long-term prediction of Earth satellite orbits. We compare regularized formulations to a semi-analytical method based on equinoctial elements for several orbital regimes and perturbations. The parameters affecting the semi-analytical propagation efficiency are fine-tuned by analysing the different contributions to the integration error, which also gives insight on the limits of applicability of semi-analytical methods. Regularized formulations compare very favourably for highly elliptical and super-synchronous orbits, which encourages their application to lifetime analyses and numerical explorations of the cislunar space. Applications to asteroid impact avoidance are presented in the third part. We show the results of a geographical deflection of the fictitious asteroid 2015PDC obtained with an Ion Beam Shepherd spacecraft. Finally, we perform a systematic study of the potential resonant returns of the fictitious asteroid 2017PDC after its deflection by a nuclear device. | |
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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 |
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Fecha
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10/07/2017 |