Galileo disposal strategy: Stability, chaos and predictability

Aaron J. Rosengren, Jérôme Daquin, Kleomenis Tsiganis, Elisa Maria Alessi, Florent Deleflie, Alessandro Rossi, Giovanni B. Valsecchi

Research output: Contribution to journalArticlepeer-review


Recent studies have shown that the medium-Earth orbit (MEO) region of the global navigation satellite systems is permeated by a devious network of lunisolar secular resonances, which can interact to produce chaotic and diffusive motions. The precarious state of the four navigation constellations, perched on the threshold of instability, makes it understandable why all past efforts to define stable graveyard orbits, especially in the case of Galileo, were bound to fail; the region is far too complex to allow for an adoption of the simple geosynchronous disposal strategy. We retrace one such recent attempt, funded by ESA's General Studies Programme in the frame of the GreenOPS initiative, that uses a systematic parametric approach and the straightforward maximum-eccentricity method to identify long-term-stable regions, suitable for graveyards, as well as large-scale excursions in eccentricity, which can be used for postmission deorbiting of constellation satellites.We then apply our new results on the stunningly rich dynamical structure of the MEO region towards the analysis of these disposal strategies for Galileo, and discuss the practical implications of resonances and chaos in this regime. We outline how the identification of the hyperbolic and elliptic fixed points of the resonances near Galileo can lead to explicit criteria for defining optimal disposal strategies.

Original languageEnglish
Pages (from-to)4063-4076
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - 1 Feb 2017
Externally publishedYes


  • Celestial mechanics
  • Chaos
  • Methods: analytical
  • Methods: numerical
  • Planets and satellites: dynamical evolution and stability
  • Planets and satellites: general


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