Séminaire Analyse-Proba (Mar GIRALT, mardi 17 mars 2026)

Le prochain séminaire Analyse-Proba aura lieu mardi 17 mars à 10h30 en A711. Mar GIRALT (Observatoire de Paris) nous parlera de :

On the Arnold diffusion mechanism in Medium Earth Orbit

Abstract
Arnold diffusion is a phenomenon in Hamiltonian dynamics in which small perturbations of nearly integrable systems can induce slow but unbounded changes in the action variables. First described by V.I. Arnold (1964), it allows certain trajectories to drift across phase space, despite the perturbations being arbitrarily small.
In this talk, we will introduce the Arnold diffusion mechanism and illustrate an application to orbital mechanics. Focusing on the Medium Earth Orbit (MEO) region, home to navigation satellites such as GPS and Galileo, we show how natural perturbations (in our case, third-body effects) can be exploited to guide satellites toward atmospheric reentry at the end of their operational life.
Using Galileo as a case study, we analyze a hierarchy of Hamiltonian models incorporating the Earth’s oblateness and the Moon’s gravitational attraction. We demonstrate how Arnold diffusion can trigger eccentricity growth along certain trajectories, lowering the satellite into the atmospheric drag domain.
This is a joint work with E.M Alessi, I. Baldomá and M. Guardia.