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1.
Strategies for plane change of Earth orbits using lunar gravity and derived trajectories of family G
C. F. de Melo E. E. N. Macau O. C. Winter 《Celestial Mechanics and Dynamical Astronomy》2009,103(4):281-299
The dynamics of the circular restricted three-body Earth-Moon-particle problem predicts the existence of the retrograde periodic
orbits around the Lagrangian equilibrium point L1. Such orbits belong to the so-called family G (Broucke, Periodic orbits
in the restricted three-body problem with Earth-Moon masses, JPL Technical Report 32–1168, 1968) and starting from them it
is possible to define a set of trajectories that form round trip links between the Earth and the Moon. These links occur even
with more complex dynamical systems as the complete Sun-Earth-Moon-particle problem. One of the most remarkable properties
of these trajectories, observed for the four-body problem, is a meaningful inclination gain when they penetrate into the lunar
sphere of influence and accomplish a swing-by with the Moon. This way, when one of these trajectories returns to the proximities
of the Earth, it will be in a different orbital plane from its initial Earth orbit. In this work, we present studies that
show the possibility of using this property mainly to accomplish transfer maneuvers between two Earth orbits with different
altitudes and inclinations, with low cost, taking into account the dynamics of the four-body problem and of the swing-by as
well. The results show that it is possible to design a set of nominal transfer trajectories that require ΔV
Total less than conventional methods like Hohmann, bi-elliptic and bi-parabolic transfer with plane change. 相似文献
2.
A. Gabàs A. Macau B. Benjumea F. Bellmunt S. Figueras M. Vilà 《Surveys in Geophysics》2014,35(4):983-1002
3.
In this paper we present a site effects analysis carried out in Málaga city’s historical centre (Southern Spain). Two different methodologies have been used: an experimental technique using ambient noise measurements and a 1D numerical method. Soil fundamental frequencies have been obtained from the first technique, and soil transfer functions have been calculated from the numerical methodology. In order to use these results in vulnerability studies, intensity increments for each type of soil have also been estimated. From this information, a seismic microzonation has been proposed for the city centre, classified in six types of soils. Soil fundamental frequencies vary between above 5.0Hz at the hills of the city (where rock arises on the surface), and 1.0Hz near Guadalmedina river. The results show regions with high intensity increments (ΔI = +1.5) corresponding to areas which suffered heavy damage in the 1680 earthquake (Imax = VIII–IX). Moreover, most of the monuments and historical buildings in the city are located in these high risk areas. Results underline the importance of this kind of studies for seismic risk mitigation, historical preservation and emergency planning in the main cities’ historical centres. 相似文献
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Elbert E. N. Macau 《Celestial Mechanics and Dynamical Astronomy》2003,87(3):291-305
The purpose of this work is to show that chaos control techniques (OGY, in special) can be used to efficiently keep a spacecraft around another body performing elaborate orbits. We consider a satellite and a spacecraft moving initially in coplanar and circular orbits, with slightly different radii, around a heavy central planet. The spacecraft, which is the inner body, has a slightly larger angular velocity than the satellite so that, after some time, they eventually go to a situation in which the distance between them becomes sufficiently small, so that they start to interact with one another. This situation is called as an encounter. In previous work we have shown that this scenario is a typical situation of a chaotic scattering for some well-defined range of parameters. Considering this scenario, we first show how it is possible to find the unstable periodic orbits that are located in the chaotic invariant set. From the set of unstable periodic orbits, we select the ones that can be combined to provide the desired elaborate orbit. Then, chaos control technique based on the OGY method is used to keep the spacecraft in the desired orbit. Finally, we analyze the results and make considerations regarding a realistic scenario of space exploration. 相似文献
7.
A novel automatic seamless stitching method is presented.Compared to the traditional method,it can speed the processing and minimize the utilization of human resources to produce global lunar map.Meanwhile,a new global image map of the Moon with spatial resolution of ~120 m has been completed by the proposed method from Chang’E-1 CCD image data. 相似文献
8.
F. J. T. Salazar C. F. de Melo E. E. N. Macau O. C. Winter 《Celestial Mechanics and Dynamical Astronomy》2012,114(1-2):201-213
An alternative transfer strategy to send spacecraft to stable orbits around the Lagrangian equilibrium points L4 and L5 based in trajectories derived from the periodic orbits around L1 is presented in this work. The trajectories derived, called Trajectories G, are described and studied in terms of the initial generation requirements and their energy variations relative to the Earth through the passage by the lunar sphere of influence. Missions for insertion of spacecraft in elliptic orbits around L4 and L5 are analysed considering the restricted three-body problem Earth–Moon-particle and the results are discussed starting from the thrust, time of flight and energy variation relative to the Earth. 相似文献
9.
Asten Michael W. Yong Alan Foti Sebastiano Hayashi Koichi Martin Antony J. Stephenson William J. Cassidy John F. Coleman Jacie Nigbor Robert Castellaro Silvia Chimoto Kosuke Cornou Cécile Cho Ikuo Hayashida Takumi Hobiger Manuel Kuo Chun-Hsiang Macau Albert Mercerat E. Diego Molnar Sheri Pananont Passakorn Pilz Marco Poovarodom Nakhorn Sáez Esteban Wathelet Marc Yamanaka Hiroaki Yokoi Toshiaki Zhao Don 《Journal of Seismology》2022,26(4):757-780
Journal of Seismology - Site response is a critical consideration when assessing earthquake hazards. Site characterization is key to understanding site effects as influenced by seismic site... 相似文献
10.
Héloïse Cadet Albert Macau Beatriz Benjumea Fabian Bellmunt Sara Figueras 《Soil Dynamics and Earthquake Engineering》2011
As local site effects have a drastic influence on seismic hazard, it is a major issue to characterize them in vulnerable areas such as highly urbanized zones, like Barcelona city. The aim of this work is to improve the knowledge of geophysical characteristics of Barcelona in the perspective of a seismic microzonation that takes into account site effect. The first step was to gather the existing data from geological, geotechnical, geophysical, and seismological investigations, bringing us to keep the four zones proposed by previous work as a base of zonation. The second step was to characterize each zone by time-averaged shear-wave velocity and fundamental resonance frequency, with ambient noise techniques over 17 sites, providing new knowledge about the soil of Barcelona. The third step was to propose an amplification function between an average soil for each zone and a standard reference rock site, using empirically based propositions and to compare them to previous numerical approaches. 相似文献