Low Earth Orbits
Mostrando 1-9 de 9 artigos, teses e dissertações.
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1. Picosatellites for Maritime Security Applications - the Lambdasat Case
ABSTRACT: This study explores the potential deployment of small satellites for maritime interdiction and security applications by investigating the available solutions and formulating a generic proposal to optimize the use of those short-lived space assets in support of these operations. The operational background is analyzed with respect to the potential us
J. Aerosp. Technol. Manag.. Publicado em: 2015-12
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2. Trajectory Control During an Aeroassisted Maneuver Between Coplanar Circular Orbits
ABSTRACT: This paper presents the simulation results of an aeroassisted maneuver around the Earth, between coplanar circular orbits, from a geostationary orbit to a low orbit. The simulator developed considers a reference trajectory and a trajectory perturbed by external disturbances combined with non-idealities of sensors and actuators. It is able to operat
J. Aerosp. Technol. Manag.. Publicado em: 2014-06
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3. Thermal Protection System and Trajectory Optimization for Orbital Plane Change Aeroassisted Maneuver
ABSTRACT: The aim of this paper was to identify, for a specific maneuver, the optimal combination between the trajectory and the associated heat shield configuration, namely the locations and thicknesses of the ablative and reusable zones, that maximize the allowable payload mass for a spacecraft. The analysis is conducted by considering the coupling between
J. Aerosp. Technol. Manag.. Publicado em: 2013-03
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4. The algorithmic weak stability boundary in earth-to-moon mission design: dynamical aspects and applicability.
This thesis consists of an extensive study of the Weak Stability Boundary (WSB) concept in low-energy Earth-to-Moon mission design within the mathematical structure provided by the Planar Circular Restricted Three-Body Problem (PCR3BP). By employing the patched three-body approach to approximate the Sun-Earth-Moon-spacecraft system, we examine and characteri
Publicado em: 2011
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5. Development of access-based metrics for site location of ground segment in LEO missions
Abstract: The classical metrics of ground segment site location do not take account of the pattern of ground segment access to the satellite. In this paper, based on the pattern of access between the ground segment and the satellite, two metrics for site location of ground segments in Low Earth Orbits (LEO) missions were developed. The two developed access-b
J. Aerosp. Technol. Manag.. Publicado em: 2010-12
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6. Alternative paths in the Earth-moon system / Trajetórias alternativas no sistema Terra-Lua
The Restricted Three Body Problem predicts the existence of the several families of periodic orbits in the Earth-Moon System. In this work, we studied two of them the Family G of direct periodic orbits around the L1 and the Family H2 of direct periodic orbits around the Moon. Our investigations considered, besides the Restricted Three body Problem, the Four
Publicado em: 2005
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7. Transferências orbitais e dinâmicas na vizinhança dos pontos lagrangianos L1 e L2 / Transfer orbits and dynamics around the lagrangian points L1 e L2
In this work we present a study of the dynamics in the vicinity of the Lagrangian points L1 and L2 in the restricted three-body problem, considering the Sun-Earth and Earth-Moon models. Notwithstanding the hyperbolic character of these points, the reduction to the central manifold allows periodic and quasi-periodic orbits. This procedure is applied through t
Publicado em: 2005
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8. Analysis of attracting and non-attracting chaotic sets in low and high-dimensional dynamical systems: application to the dynamics of plasma waves in the sun-earth connection / Análise de conjuntos caóticos atrativos e não atrativos em sistemas dinâmicos de baixa e alta dimensão: aplicação para a dinâmica de ondas de plasma na conexão sol - terra
In this work we present a numerical study on the interaction between chaotic attractors and nonattracting chaotic sets in mathematical models that describe the nonlinear dynamics of plasma waves in the Sun-Earth connection. The work is divided in two parts. In the first part we analyze a low-dimensional dynamical system describing stationary Alfv´en waves m
Publicado em: 2003
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9. Desenvolvimento de um navegador autônomo, usando GPS, aplicado ao controle autônomo de órbita. / Autonomous orbit navigator development, using GPS, applied to autonomous orbit control.
The appearance of modern global positioning systems motivated the study and development of precise and robust systems for autonomous orbit determination of artificial satellites. These systems maintain, independently from human intervention from the ground, a precise knowledge of the satellite orbital state, through the processing of the information, autonom
Publicado em: 2001