DIX Planetary Science Seminar

Satellites, debris, and natural material in the Earth-Moon environment occupy a dynamical regime that departs sharply from the classical terrestrial domain. Beyond the Laplace radius, lunisolar torques overtake Earth's oblateness, and long-term motion is shaped by a secular-resonant skeleton that includes octupolar modifications to von Zeipel--Lidov--Kozai (vZLK) dynamics, together with interactions involving the Moon's orbital and precession frequencies. In parallel, lunar mean-motion resonances (MMRs) — notably the 3:1 and 2:1 interior commensurabilities — organize cislunar phase space into stable islands bounded by separatrices, surrounded by chaotic layers that mediate transport and resonance switching. In this talk, I will connect perturbed-Hamiltonian intuition (local resonance half-widths) to a global geometric portrait in the (planar) restricted three-body problem, where resonance zones are defined rigorously by unstable resonant periodic orbits and their stable/unstable manifolds.
A central theme is connectivity: Earth-Moon L1/L2 gateways regulate motion between inner and outer domains, and (in the CR3BP setting) overlapping L1–L2 Lyapunov tubes can furnish heteroclinic links between exterior resonant families (e.g., 1:3) and interior resonances (e.g., 2:1), providing natural ballistic corridors across lunar-distance thresholds. In translunar space, exterior lunar commensurabilities (e.g., 1:3, 1:4, 1:5 and adjacent ratios) form broad, overlapping instability zones that scaffold long-range transport. I will introduce a physically interpretable spatiography that partitions circumterrestrial space by dynamical boundaries, resonances, and tides, and I will highlight a newly identified outer transition: a lunisolar tidal parity boundary just beyond the Earth-Moon Hill sphere, with plausible analogs in other planet–satellite systems. Finally, I will connect these structures to lunar ejecta transport: because the Earth–Moon system lies unusually close to a critical escape threshold, modest variations in ejection speed and launch geometry can separate bound outcomes from conditional and guaranteed escape into heliocentric space — linking circumlunar dynamics to interplanetary material exchange.