"Stability"@en . "Artificial satellites"@en . "Palaci\u00E1n" . "Perturbation methods"@en . "Frozen orbits"@en . "Jes\u00FAs F. Palaci\u00E1n" . . "Jes\u00FAs F." . "Satellite orbiter"@en . "Periodic orbits"@en . "Restricted problems"@en . "6997e22a1df79e3f550ae8314c317b2b" . "Hill's problem"@en .