Published on: March 25, 2026

AAE Special Seminar: Dr. Aaron Rosengren - 4.28

Event Date:

April 28, 2026

Time:

1:30PM - 2:20PM

Location:

RHPH 172

Priority:

College Calendar:

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Toward a Spatiography of Circumterrestrial Space

DR. AARON ROSENGREN

Assistant Professor

Jacobs School of Engineering and the Center for

Astrophysics & Space Studies

University of California San Diego

Abstract:

Satellites, debris, and natural material in the Earth- Moon environment occupy a dynamical regime that departs sharply from the classical

terrestrial picture. Beyond the Laplace radius, lunisolar torques over- take Earth’s oblateness, and long-term evolution is organized by an

intertwined secular-resonant skeleton: von Zeipel-Lidov-Kozai-like coupling (with higher-order modications) and commensurabilities involving

lunar precession frequencies shape the orientation and eccentricity evolution of high-altitude orbits. Super-posed on this secular architecture,

lunar mean-motion resonances- most notably the 3:1 and 2:1 interior commensurabilities -partition cislunar phase space into stable

islands bounded by separatrices, surrounded by chaotic layers that mediate transport and resonance switching. In this talk, I connect two

complementary viewpoints. The first is local, perturbed-Hamiltonian intuition: analytical averaging and resonance half-width estimates

that explain where long-lived structures can exist and why neighboring regimes become chaotic. The second is global and geometric: in the

restricted three-body problem, resonance zones and transport corridors are defined by unstable resonant periodic orbits and their stable/

unstable manifolds, with Earth-Moon L1 and L2 gateways regulating connectivity between the cislunar and translunar realms. A key outcome

is a physically interpretable spatiography of circumterrestrial space built from boundaries that are both operational and dynamical: an

inner, topology-based cislunar demarcation tied to the L1/L2 gateways; a translunar transition defined by lunisolar tidal parity, marking when

geocentric motion becomes increasingly organized by Sun-Earth phase-space structure; and an outer boundary at the Sun-Earth Hill sphere,

beyond which trajectories are no longer meaningfully Earth-bound and are instead governed by heliocentric dynamics. I will close by illustrating

how this combined geometric-and-tidal partition clarifies long-term predictability, stable graveyard behavior, chaotic transport corridors,

and disposal pathways that preferentially target bounded evolution versus conditional escape.

Biography:

Aaron J. Rosengren is an Assistant Professor in the Jacobs School of Engineering and the Center for Astrophysics & Space Studies at the

University of California San Diego. He previously served from 2017- 2020 as an Assistant Professor in the College of Engineering and of

the Interdisciplinary Graduate Program in Applied Mathematics at the University of Arizona. He completed his postdocs at the Aristotle

University of Thessaloniki in Greece in the Department of Physics (2016 - 2017), as a member of the EU H2020 Project, REDSHIFT, and at the

Institute of Applied Physics Nello Carrara of the Italian National Research Council (2014 - 2016), as a Marie Curie Fellow in the FP7 Stardust

Network. He has held visiting researcher positions at UNSW Canberra in Australia, the Asher Space Research Institute at Technion

in Israel, the University of Rome Tor Vergata in Italy, and the Belgrade Astronomical Observatory in Serbia. Dr. Rosengren is Fellow of the

Outer Space Institute (OSI) for the sustainable development of space at the University of British Columbia and currently serves on the

External Advisory Board of the Ann and H.J. Smead Department of Aerospace Engineering Sciences at the University of Colorado Boulder

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