Application of the Hori Method in the Theory of Nonlinear Oscillations

Some remarks on the application of the Hori method in the theory of nonlinear oscillations are presented. Two simplified algorithms for determining the generating function and the new system of differential equations are derived from a general algorithm proposed by Sessin. The vector functions which define the generating function and the new system of differential equations are not uniquely determined, since the algorithms involve arbitrary functions of the constants of integration of the general solution of the new undisturbed system. Different choices of these arbitrary functions can be made in order to simplify the new system of differential equations and define appropriate near-identity transformations. These simplified algorithms are applied in determining second-order asymptotic solutions of two well-known equations in the theory of nonlinear oscillations: van der Pol equation and Duffing equation

An Adaptive Remeshing Procedure for Proximity Maneuvering Spacecraft Formations

We consider a methodology to optimally obtain reconfigurations of spacecraft formations. It is based on the discretization of the time interval in subintervals called the mesh and the obtainment of local solutions on them as a result of a variational method. Applied to a libration point orbit scenario, in this work we focus on how to find optimal meshes using an adaptive remeshing procedure and on the determination of the parameter that governs it

An Adaptive Remeshing Procedure for Proximity Maneuvering Spacecraft Formations

We consider a methodology to optimally obtain reconfigurations of spacecraft formations. It is based on the discretization of the time interval in subintervals called the mesh and the obtainment of local solutions on them as a result of a variational method. Applied to a libration point orbit scenario, in this work we focus on how to find optimal meshes using an adaptive remeshing procedure and on the determination of the parameter that governs it

Mapping Natural Orbits around Io

As the most volcanically active celestial body in the Solar System, Io is a natural satellite of Jupiter due to its proximity to the planet and the fact that it is in mean motion resonance, known as the Laplace resonance, with the natural satellites Europa and Ganymede. This natural satellite is a good candidate to be visited by future missions. In this sense, the present work has the goal of studying and mapping the best initial orbital conditions for orbits around Io, considering the symmetrical or asymmetical perturbative effects of a third body (Jupiter) and the J2 term from the mass configuration of Io. The initial orbital parameters of the probe were investigated through a set of numerical simulations. The results showed that although most orbits around Io have lifetimes of less than 6 months, some regions were found where the initial conditions of the orbits provided satisfactory times for the accomplishment of future missions around Io

Celestial mechanics: from the errant stars to guidance of spacecrafts

Celestial mechanics is one of the most ancient science. It is dedicated to the study of the motion of planets, moons, asteroids, comets and other celestial bodies. It probably started when humans discovered that some special stars differentiate from the others in the sense that they move on the celestial sphere. Currently, it is responsible for successfully guiding spaceships to distant objects in our solar system aiming to explore them. As an introduction to this Focus Issue in Celestial Mechanics, we make here a historical overview of developments in this area and present the articles that comprise this special issue.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Safety fences and barriers

SIGLEGBUnited Kingdo

Spectroscopic studies of alkali vapours in intense laser fields

SIGLEAvailable from British Library Document Supply Centre- DSC:DX71621/87 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Somatic hybridization studies in the genus Lycopersicon

SIGLEAvailable from British Library Document Supply Centre- DSC:D44780/83 / BLDSC - British Library Document Supply CentreGBUnited Kingdo