Manobras ótimas de atitude de satélites artificiais utilizando algoritmos genéticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Orientação exterior de imagens orbitais usando modelos rigorosos com feições retas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pertubação orbital devida a um terceiro corpo com distribuição não uniforme de massa e em órbita elíptica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estabilidade de órbitas congeladas em torno de satélites planetários utilizando o sistema hamiltoniano na forma normal

Pós-graduação em Física - FEG

Dinâmica do sistema binário Plutão-Caronte

Pós-graduação em Física - FEG

Reanálise das defasagens de Prometeu e Pandora

In the present work it is proposed to do a revision on some studies on the dynamics of the Prometheus-Pandora system. In special, those studies that deal with anomalous behaviours observed on its components, identi ed as angular lags in these satellite`s orbits. Initially, it is presented a general description, contextualising the main characteristics of this system. The main publications related to this subject are analised and commented, in chronological order, showing the advances made in the knowledge of such dynamics. An analysis of the initial conditions, used by Goldreich e Rappaport (2003a ,b) e Cruz (2004), obtained through observations made by the Voyager 1 and 2 spacecrafts and by the Hubble space telescope, it is made in order to try to reproduce their results. However, no clear conclusion of the values used were found. The tests addopted in the analysis are from Cruz (2004), which reproduced the results and o ered a new explanation on the origin of the observed angular lags. The addopetd methodology involves the numerical integration of the equations of motion of the system, including the zonal harmonics J2, J4 and J6 of Saturn's gravitational potential. A fundamental consideration in this study is the use of geometric elements instead of osculating elements. It was found the set of initial data that best reproduces the results from Goldreich e Rappaport (2003a, b) and Cruz (2004)

Sobre a dinâmica de rotação de um planeta através de um sistema médio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Analisando a possibilidade de um anel ao redor de um satélite

On November 26 th, 2005, Rhea, one of Saturn's moons, is found by Cassini spacecraft approximately at 5.105 km from Saturn. Observations in situ reveal that electrons are depleted in the moon's vicinity. However, Rhea is considered massive enough to retain a thin atmosphere. Assumption was that the atmosphere of Rhea was not composed exclusively of gas, its likely contains solid material that can absorb magnetospheric particles. According to Jones et al. (2008), these particles were in a speci c position so that at the moment of observation the electrons could not be detected. In opposition to this idea there is a group, Tiscareno et al. 2010, Cornell University Library, that underwent intensive search for any material that might be orbiting Rhea using Cassini images, however the could not identify any. Second recommendation made by American researchers and other countries, and accepted by the National Board of Research the Cassini Equinox Mission will continue in orbit around Saturn until 2016.The probe will perform several maneuvers with high inclination to delve into the main ring system, and then enter in Saturn's atmosphere and collide with planet. This research is of great importance because until today no rings were found orbiting satellites. The goal of this work is to analyze the orbital evolution of a set of particles around Rhea disturbance of Saturn, J2 e J4 and check results by the numerical simulations and the possibility of a stable ring orbiting Rhea.

Estudos de estabilidade no sistema Ʋ andromedae A

Pós-graduação em Física - FEG

Estudos sobre as defasagens de Prometeu e Pandora

Pós-graduação em Física - FEG

O invariante E(G, W, M): algumas propriedades e aplicações na teoria de decomposição de grupos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cálculo diferencial e integral no movimento dos planetas

Pós-graduação em Matemática em Rede Nacional - IBILCE

Estudo de manobras evasivas com perturbações orbitais

Pós-graduação em Física - FEG

Regiões de estabilidade no ambiente de um sistema de asteroide triplo

This work was developed from the study by Araujo, R.A.N. et al. Stability regions around the components of the triple system 2001 SN263. (Monthly Notices Of The Royal Astronomical Society, 2012, v. 423(4), 3058-3073 p.) where it was studied the stable and unstable regions system (2001 SN263), which is a triple asteroid system, and these are celestial orbiting our sun. Being close to the Earth is characterized as NEA (Near-Earth Asteroids), asteroids and which periodically approach the Earth's orbit, given that there is great interest in the study and exploitation of these objects, it is the key can carry features that contribute to better understand the process of formation of our solar system. Study the dynamics of bodies that govern those systems proves to be greatly attractive because of the mutual gravitational perturbation of bodies and also by external disturbances. Recently, NEA 2001 SN263 was chosen as a target of Aster mission where a probe is sent for this triple system, appearing therefore the need for obtaining information for characterizing stable regions internal and external to the system, with respect to the effects of radiation pressure. First, this study demonstrated that the integrator used showed satisfactory results of the orbital evolution of bodies in accordance with previous studies and also the characterization of stable and unstable regions brought similar results to the study by Araujo et al. (2012). From these results it was possible to carry out the implementation of the radiation pressure in the system in 2001 SN263, in a region close to the central body, where the simulations were carried out, which brought as a result that the regions before being characterized as stable in unstable true for small particles size from 1 to 5 micrometers. So the next orbital region to the central body and the ... ( Complete abstract click electronic access below)

Potencial gravitacional lunar

We know that the orbit of a lunar satellite, and consequently its orbital lifetime is mainly inuenced by the gravitational field of the Moon, Earth and Sun. In this text we study the Lunar gravitational potential and its influence on the gravitational field. We adapted a program in order to map the Moon gravitational field. To that end it was necessary to develop a program that allows the simulation and mapping the lunar full potential. Our program was based on the program developed by Hélio Kuga, and adapted to our case (Moon). We used the model proposed by Konopliv et al. 2001, we proposed various degree and order expansions of spherical harmonics that served us to compare and validate our program