Early resonances of Tethys and Dione: Implications for Ithaca Chasma

•Phase-space near 2:1 mean motion resonance of Tethys and Dione is investigated.•Capture in 2:1 mean motion resonance by tidal migration is possible early in Tethysâ;; evolution.•In resonance, heat production due to tidal dissipation is sufficient for the formation of Ithaca Chasma.•Orientation of fractures of Ithaca Chasma in high latitude regions corresponds to surface stresses due to orbital expansion.