Ph.D. Thesis Proposal

Euihyeon Choi

(Faculty advisor: Professor Koki Ho)

"Optimization of Sustainable Space Logistics Systems"

Wednesday, September 16

10:00 a.m. -12:00 p.m.

MK 317

Abstract: 

As human space exploration transitions from Apollo-era single-spacecraft missions to interconnected, multi-asset space systems, maximizing system performance requires collaboration among orbital assets. Long-term sustainability in these complex operations demands rigorous mathematical modeling and systematic optimization. However, extending terrestrial routing studies to space logistics is inherently challenging. Because orbital mechanics are nonlinear and nonconvex, no universal solvers exist, so problem-specific optimization frameworks are needed.

This thesis presents optimization frameworks to enable sustainable space logistics systems, focusing on Earth-orbiting satellite servicing, orbital infrastructure, and resource operations. First, a mathematical formulation and solution methodology are presented to determine in-space depot placement in continuous orbital space for multi-satellite servicing, overcoming the combinatorial complexity and potential suboptimality of conventional orbit discretization. Second, multi-satellite servicing architectures with en route refueling are formulated as arc-based and path-based formulations to determine coupled decisions on visiting sequences, refueling amounts, and transfer trajectories, accompanied by a comparative analysis of the two formulations. Finally, for a space circular economy, this thesis unifies active debris removal and on-orbit servicing into an integrated orbital resource harvesting and redistribution framework, reducing reliance on supply launches from Earth.

Collectively, this thesis establishes integrated optimization frameworks for continuous depot placement, satellite servicing with trajectory design and en route refueling, and in-space resource recycling, providing insights for sustainable space logistics systems.

Committee:
Dr. Koki Ho (advisor), School of Aerospace Engineering
Dr. Koki Ho, School of Aerospace Engineering
Dr. Brian C Gunter, School of Aerospace Engineering
Dr. Glenn Lightsey, School of Aerospace Engineering