Recursos de colección

Archivo Digital UPM (109.118 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Astronomía

Mostrando recursos 1 - 20 de 68

  1. Compact solution of circular orbit relative motion in curvilinear coordinates

    Bombardelli, Claudio; Gonzalo Gomez, Juan Luis; Roa Vicens, Javier
    A compact approximate solution of the highly non-linear relative motion in curvilinear coordinates is provided under the assumption of circular orbit for the chief spacecraft and moderately small inclination and eccentricity for the follower. The rather compact three-dimensional solution, which employs time as independent variable, is obtained by algebraic manipulation of the individual Keplerian motions in curviinear coordinates and Taylor expansion for small eccentricity of the follower orbit. Numerical test cases are conducted to show that the approximate solution can be effectively employed to extend the classical linear Clohessy-Wiltshire solution to include non-linear relative motion without significant loss of accuracy...

  2. A singularity-free DROMO-based regularized method for the propagation of roto-translationally coupled asteroids

    Urrutxua Cereijo, Hodei; Pelaez Alvarez, Jesus
    There are many asteroids for which the attitude coupling imposes harsh demands to the numerical propagation of their dynamics. Special regularization methods are appropriate to overcome such difficulties, where perturbations techniques make their best. The perturbation techniques used to derive the DROMO regularization method for orbital dynamics, have now been extended to the attitude dynamics problem with equally remarkable results both in terms of speed and accuracy. The combination of these DROMO-based techniques is thus appropriate for the propagation of strongly coupled bodies.

  3. Dynamical, electrical and thermal coupling in a new class of electrodynamic tethered satellites

    Lorenzini, Enrico C.; Estes, Robert D.; Cosmo, M. L.; Pelaez Alvarez, Jesus
    A new class of electrodynamic tethers have been recently introduced which provide comparatively high tether currents with relatively short and light tethers. These space systems make use of a bare tether (anode) to collect electrons from the ionosphere rather than the less efficient, conductive, large spherical termination flown in the past. This new technology, which is suitable for propellantless transportation in the ionosphere, will be demonstrated in August 2000 when the Propulsive Small Expendable Deployment System (ProSEDS) attempts the deorbit of a Delta second stage by using electrodynamic forces. This class of space systems exhibits a strong coupling among the...

  4. La Unificación de la Física

    Macho Ortiz, Andrés
    Aunque a lo largo de la historia de la Física hemos avanzado construyendo una serie de teorías parciales que expliquen diferentes fenómenos de nuestra naturaleza aparentemente independientes entre sí, sería muy difícil construir en un solo paso una teoría unificada completa de todo lo que ocurre en el universo. En este trabajo presentamos un breve resumen de la evolución de las diferentes teorías parciales y el intento de unificación por parte de la comunidad científica de todas esas teorías en la denominada Teoría del Todo.

  5. Robotización del observatorio solar Helios: Proyecto CESAR

    Leiva García del Castillo, Elena
    La finalidad del observatorio Helios es monitorizar el Sol diariamente con dos filtrados comenzando al amanecer y finalizando al anochecer. Para llevar a cabo dicha tarea se necesitan un soporte hardware y un software apropiados. En este trabajo de fin de grado se explica la evolución de este proyecto, desde su planificación hasta su puesta en marcha, incluyendo los resultados obtenidos en sus primeros cuatro años de funcionamiento. También se tratarán los diferentes equipos hardware y el software utilizados y cómo se puede acceder a las imágenes resultantes. Respecto a la elección de las infraestructuras se decide el emplazamiento del...

  6. A non-singular DROMO-based regularized method for the propagation of roto-translationally coupled asteroids

    Urrutxua Cereijo, Hodei; Pelaez Alvarez, Jesus
    There are many asteroids for which the attitude coupling imposes harsh demands to the numerical propagation of their dynamics. Special regularization methods are appropriate to overcome such difficulties, where perturbations techniques make their best. The perturbation techniques used to derive the DROMO regularization method for orbital dynamics, have now been extended to the attitude dynamics problem with equally remarkable results both in terms of speed and accuracy. The combination of these DROMO-based techniques is thus appropriate for the propagation of strongly coupled bodies.

  7. Generalized logarithmic spirals for low-thrust trajectory design

    Roa Vicens, Javier; Pelaez Alvarez, Jesus
    Shape-based approaches are practical for finding sub-optimal solutions during the preliminary design of low-thrust trajectories. Logarithmic spirals are the simplest, but of little practical interest due to having a constant flight-path angle. We prove that the same tangential thrust profile that generates a logarithmic spiral yields an entire family of generalized spirals. The system admits two integrals of motion, which are equivalent to the energy and the angular momentum equations. Three different subfamilies of spiral trajectories are obtained depending on the sign of the constant of the generalized energy: elliptic, parabolic, and hyperbolic. Parabolic spirals are equivalent to logarithmic spirals....

  8. Efficient trajectory propagation for orbit determination problems

    Roa Vicens, Javier; Peláez Álvarez, Jesús
    Regularized formulations of orbital motion apply a series of techniques to improve the numerical integration of the orbit. Despite their advantages and potential applications little attention has been paid to the propagation of the partial derivatives of the corresponding set of elements or coordinates, required in many orbit-determination scenarios and optimization problems. This paper fills this gap by presenting the general procedure for integrating the state-transition matrix of the system together with the nominal trajectory using regularized formulations and different sets of elements. The main difficulty comes from introducing an independent variable different from time, because the solution needs to...

  9. What does it take to capture an asteroid? A case study on capturing asteroid 2006 RH120

    Urrutxua Cereijo, Hodei; J. Scheeres, Daniel; Bombardelli, Claudio; Gonzalo Gomez, Juan Luis; Pelaez Alvarez, Jesus
    The population of "temporarily captured asteroids" offers attractive candidates for asteroid retrieval missions. Once captured, these asteroids have lifetimes ranging from a few months up to several years in the vicinity of the Earth.1 One could potentially extend the duration of such temporary capture phases by acting upon the asteroid with slow deflection techniques that conveniently modify their trajectories, in order to allow for an affordable access to an asteroid for in-situ study. In this paper we present a case study on asteroid 2006 RH120, which got temporarily captured in 2006-2007 and is the single known member of this category...

  10. Orbit propagation in minkowskian geometry

    Roa Vicens, Javier; Pelaez Alvarez, Jesus
    A more adequate description of perturbed hyperbolic orbits is found in the geometry underlying Minkowski space-time. Hypercomplex numbers appear naturally when describing vectors, rotations, and metrics in this geometry. The solution to the unperturbed hyperbolic motion is well known in terms of hyperbolic functions and the hyperbolic anomaly. From this, a general solution is derived through the Variation of Parameters technique. Hyperbolic geometry leads to a more coherent formulation. The evolution of the eccentricity vector is described by means of its components on the Minkowski plane. The orbital plane is defined in the inertial reference using quaternions, treated as particular...

  11. Regularized formulations in relative motion

    Roa Vicens, Javier; Pelaez Alvarez, Jesus
    Variational methods based on orbital elements depend strongly on the eccentricity of the reference orbit. The resulting Jacobian matrix typically becomes singular when the reference orbit is parabolic or hyperbolic. This singularity can be avoided if the problem is formulated using sets of variables that do not depend on the eccentricity of the reference orbit. The solution to the linear equations of relative motion is derived in this paper from the Sperling-Burdet regularization and the Kustaanheimo-Stiefel transformation. A unified description for circular, elliptic, parabolic, and hyperbolic reference orbits is provided by means of the Stumpff functions. The independent variable is...

  12. Error propagation in relative motion

    Roa Vicens, Javier; Gómez Mora, José Ignacio; Pelaez Alvarez, Jesus
    This paper explores the connection between the concept of synchronism and the accuracy of the solutions to relative motion. If the problem is formulated using an independent variable different from time it is possible to escape from the standard time-synchronism, obtaining an asynchronous solution. The synchronism may be recovered through a first order correction. This correction is based on the dynamics of the problem, and higher-order terms are easily retained. A second order correction introduces nonlinear effects in the solution through simple mechanisms, and improves its accuracy. The proposed correction is a generic concept not restricted to any particular formulation....

  13. Test problems for evaluating the performance of numerical orbit propagators

    Urrutxua, Hodei; Pelaez Alvarez, Jesus
    A collection of test cases is proposed for the validation and testing of numerical orbit propagators. These test problems are designed to characterize the performance of the propagators and intended to highlight their possible deficiencies and expose their limitations. Every problem in the collection is accompanied by an accurate solution, and the performance of several orbit propagators is shown as examples to these problems.

  14. Application surface of CPT, an advanced DInSAR displacement near Itoiz dam, Navarra, Spain

    Fernández, Jose; Arjona, Alicia; Prieto Morin, Juan Francisco; Santoyo, M.A.; Seco, A.; Monells, D.; Pallero, Jose L. G.; Prieto, E.; Luzón, F.; Mallorquí, J.
    Itoiz reservoir is located in Navarra, northern Spain, being a newly constructed gravity dam that stores the water from the Irati and the Urrobi rivers. The dam has a total height of 121 m, a total length of 525 m and a maximum water storage volume of 410 hm3. The aim of this work is to study the surface displacement field during the impoundment of the Itoiz water reservoir. Orbital SAR Differential Interferometry (DInSAR) techniques have been proven to be a useful and powerful tool in tectonic areas for surveying subtle surface deformations over several years related to geodynamic phenomena. An...

  15. On the applicability of an advanced DInSAR techniques near Itoiz and Yesa reservoirs, Navarra, Spain

    Arjona, Alicia; Santoyo, M.A.; Fernández, Jose; Monells, D.; Prieto Morin, Juan Francisco; Pallero, Jose L. G.; Prieto, E.; Seco, A.; Luzón, F.; Mallorquí, J.
    In this paper we show the applicability of orbital Synthetic Aperture Radar (SAR) Differential Interferometry (DInSAR) with multiple images for terrain deformation episodes monitoring. This paper is focused on the Coherent Pixels Technique (CPT). This technique has been tested with ERS SAR and ENVISAT ASAR data for the period 1992-2008 from The Itoiz and Yesa reservoirs. These ones, located in Navarra, northern Spain, are constructed gravity dams that stores the water from the Irati and the Urrobi rivers, and the Aragón river respectively. The results has been compared with theoretical results obtained using an analytical model.

  16. Estudio y análisis numérico de sistemas hamiltonianos

    Fernández Canosa, Alejandro
    Un sistema hamiltoniano puede ser definido como un sistema dinámico gobernado por las ecuaciones de Hamilton. En este trabajo se estudian las propiedades más destacables de estos sistemas de manera numérica a partir de cuatro ejemplos concretos. En primer lugar, se estudia un sistema hamiltoniano sencillo de un grado de libertad, se presentan varios esquemas numéricos típicos y se comparan sus propiedades con el integrador simpléctico de orden 4, el cual conserva la energía con un alto grado de precisión. En segundo lugar se analiza numéricamente uno de los sistemas hamiltonianos más estudiados a lo largo de la historia: el...

  17. Optimal impulsive collision avoidance in low earth orbit

    Bombardelli, Claudio; Hernando, Javier
    This paper presents a high-accuracy fully analytical formulation to compute the miss distance and collision probability of two approaching objects following an impulsive collision avoidance maneuver. The formulation hinges on a linear relation between the applied impulse and the objects? relative motion in the b-plane, which allows one to formulate the maneuver optimization problem as an eigenvalue problem coupled to a simple nonlinear algebraic equation. The optimization criterion consists of minimizing the maneuver cost in terms of delta-V magnitude to either maximize collision miss distance or to minimize Gaussian collision probability. The algorithm, whose accuracy is verified in representative mission...

  18. Osiris— The optical, spectroscopic and infrared remote imaging system for the Rosetta orbiter

    Thomas, N.; Keller, H. U.; Arijs, E.; Barbieri, C.; Grande, M.; Lamy, P.; Rickman, H.; Rodrigo, R.; Wenzel, K. P.; A'Hearn, M.F.; Angrilli, F.; Bailey, M. E.; Barucci, M.A.; Bertaux, J. L.; Brieb, K.; Burns, J. A.; Cremonese, G.; Curdt, W.; Deceunick, H.; Emery, R.; Festou, M.; Fulle, M.; Ip, Wing; Jorda, L.; Korth, A.; Koschny, Detlef; Kramm, J.R.; Kürth, Ekkehard; Lara, L.M.; Llebaria, A.; López Moreno, José Luis; Marzari, Francesco; Moreau, L.; Muller, Claas; Murray, C.; Naletto, G.; Nevejans, D.; Ragazzoni, R.; Sabau, L.; Sanz Andres, Angel Pedro; Sivan, J. P.; Tondello, G.
    The scientific objectives, design, and implementation of the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) for the International Rosetta Mission are described. The instrument comprises two camera systems with a common electronics box. A narrow angle camera will provide high resolution images of the structure and morphology of the nucleus of a comet. A wide angle camera with high straylight rejection and dynamic range will be used to investigate the innermost coma and the emission process at the surface of the comet. An infrared imaging system, which dramatically enhances the scientific return has been included in the narrow angle...

  19. The experiment CPLM (comportamiento de puentes líquidos en microgravedad) on board Minisat 01

    Sanz Andres, Angel Pedro; Rodriguez de Francisco, Pablo; Santiago Prowald, Julián B.
    The Universidad Politécnica de Madrid participates in the MINISAT 01 program as the experiment CPLM responsible. This experiment aims at the study of the fluid behaviour in reduced gravity conditions. The interest of this study is and has been widely recognised by the scientific community and has potential applications in the pharmaceutical and microelectronic technologies (crystal growth), among others. The scientific team which has developed the CPLM experiment has a wide experience in this field and had participate in the performance of a large number of experiments on the fluid behaviour in reduced gravity conditions in flight (Spacelab missions, TEXUS...

  20. Sonic anemometry of planetary atmospheres

    Cuerva Tejero, Alvaro; Sanz Andres, Angel Pedro
    The application of a recently developed model of sonic anemometers measuring process has revealed that these sensors cannot be considered as absolute ones when measuring spectral characteristics of turbulent wind speed since it is demonstrated that the ratios of measured to real spectral density functions depend on the composition and temperature of the considered planetary atmosphere. The new model of the measuring process of sonic anemometers is applied to describe the measuring characteristics of these sensors as fluid/flow dependent (against the traditional hypothesis of fluid/flow independence) and hence dependent on the considered planetary atmosphere. The influence of fluid and flow...

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