Artificial satellite dynamics

Abstract

Artificial satellites are nowadays part of daily life as well instruments for advanced research in fields such as geodynamics, astrophysics of the solar system (atmosphere composition, magnetic field of planets), astrobiology ( water content and other materials essential to life as we know it), cosmology (Hubble and its new generation missions), communication satellites, weather and territory monitoring (deforesting of regions like the Amazon), the omnipresent military activity, possible mining of asteroids or their destruction in case of danger of collision with the Earth (on a not too much science fiction studies), etc.. Every other citizen has GPS devices to guide their trips in cities and roads. All these application require an adequate determination and control of the orbits and attitudes depending on the objective of the mission. Furthermore, these objectives have to be attained within constraint of cost and and/or time: tripulated missions have to have to be in the shortest time while equipment carrying can take very low cost orbits which take a considerable longer time span. The latter is the case of satellites travelling through unstable directions towards the Lagrangian collinear unstable regions such as SOHO (already accomplished mission) James Webb Space Telescope substituting the Hubble Telescope. Missions to planetary satellites have been planned and executed with very specific design of orbits: polar, critically inclined, frozen, synchronized with the rotation of the natural satellite; multisatellites: tethered satellites, formation flight (Terrestrial Planet Finder mission - TPF, now cancelled due to international crises) requiring nano precision; low cost orbits at the Langrangian collinear equilibria, etc. The high precision requirements leads to developing more sophisticated modeling of the forces: non-gravitational forces and resonances have to be considered simultaneously. Moreover missions to Solar System bodies require a good knowledge of the dynamical evolution of these bodies. Engineers, technicians and researchers involved in the aerospace field - (flight dynamics, mission analysis, control, aerodynamics, propulsion, structure, materials, projects, systems, etc - need a solid common basic formation on so that they can performed their tasks in a integrated form, as pointed in the PNAE 2007-2013.The project is distributed in four interconnected parts classified as: A) Orbital Perturbations -coordinated by Helio Koiti Kuga B) Stability - coordinated by Teresinha de Jesus Stuchi C) Trajectory Optimization - coordinated by Sandro da Silva Fernandes D) Attitude Dynamics- coordinated by Maria Cecília Zanardi. The above listed researchers will coordinate the respective part of the project. However, each one of the four parts will be developed by at least three of the six main researchers, together with other collaborators (researchers and students). All parts will be developed simultaneously, existing direct connections among them. The goal of this project is to gather researchers, with solid scientific experience in Orbital and Attitude Dynamics, to explore the translational and rotational motion of natural and artificial celestial bodies subject to polygenic and non-polygenic forces and also resonances. Influence spheres, orbital evolution of particles (natural and artificial), potential evaluation of non-uniform mass distributions (planets, natural satellites, asteroids, etc.), frozen and sun-synchronous orbits, tethered satellites, matter transport using topological features of the gravitational field shall be considered. Mathematical methods from dynamical system theory such as Birkhoff-Hori-Lie normal forms are to be applied to aerospace engineering and technology. (AU)