{"682306":{"#nid":"682306","#data":{"type":"event","title":"PhD Defense by Yuri Shimane","body":[{"value":"\u003Cp\u003EYuri Shimane\u003Cbr\u003E(Advisor: Prof. Koki Ho)\u003Cbr\u003Ewill defend a doctoral thesis entitled,\u003Cbr\u003EModeling, Optimization, and Validation of In-Space Facility Location Problem\u003Cbr\u003Eon\u003Cbr\u003EWednesday, May 21 at 9:00 a.m.\u003Cbr\u003ECODA C1015 Vinings\u003Cbr\u003E756 West Peachtree Street, Atlanta, GA 30332\u003Cbr\u003EAbstract\u003Cbr\u003EThis thesis is centered on in-space facility location problems (FLPs). The FLP provides a general\u0026nbsp;\u003Cbr\u003Eframework to consider the placement and allocation of in-space assets, for applications ranging\u0026nbsp;\u003Cbr\u003Efrom in-space servicing to cislunar space situational awareness. Compared to terrestrial problems,\u0026nbsp;\u003Cbr\u003Ein-space applications require considerations of the underlying \u0026nbsp;orbital \u0026nbsp;mechanics \u0026nbsp;and \u0026nbsp;the \u0026nbsp;\u003Cbr\u003Eassociated \u0026nbsp;nonlinear, \u0026nbsp;potentially \u0026nbsp;time-varying performance metrics. This thesis presents general\u0026nbsp;\u003Cbr\u003Econsiderations to determine whether a static or a time-expanded in-space FLP formulation is\u0026nbsp;\u003Cbr\u003Eappropriate for the application at hand; then, example space-based problems for both static and\u0026nbsp;\u003Cbr\u003Etime-expanded cases are provided. With the time-expanded FLP, where the problem dimension becomes\u0026nbsp;\u003Cbr\u003Eparticularly large due to the time dependency of performance metrics and, consequently, of the\u0026nbsp;\u003Cbr\u003Eallocation decisions, a customized Lagrangian relaxation algorithm together with a set of\u0026nbsp;\u003Cbr\u003Especialized heuristics is proposed.\u003Cbr\u003EIn the context of cislunar infrastructures, libration point orbits (LPOs) provide relatively stable\u0026nbsp;\u003Cbr\u003Eand geometrically diverse orbits for assets to be located. Motivated by the signi\ufb01cantly lower\u0026nbsp;\u003Cbr\u003Enumber of existing missions in cislunar libration point orbits (LPOs), this thesis also provides\u0026nbsp;\u003Cbr\u003Eorbital validation of LPOs in a high-\ufb01delity ephemeris model (HFEM). The validation consists of two\u0026nbsp;\u003Cbr\u003Esteps: \ufb01rst, the nominal ballistic and quasi-ballistic design problem is considered through an\u0026nbsp;\u003Cbr\u003Eoptimal control approach. Then, station-keeping along the designed baseline in the presence of\u0026nbsp;\u003Cbr\u003Euncertainties and operational constraints is studied. A targeting model predictive control scheme,\u0026nbsp;\u003Cbr\u003Esuitable for both ballistic and quasi-ballistic baselines, is devised and demonstrated to provide\u0026nbsp;\u003Cbr\u003Esatisfactory station-keeping performance, both in terms of cumulative cost and tracking deviation,\u0026nbsp;\u003Cbr\u003Eover extended durations.\u003Cbr\u003ECommittee\u003Cbr\u003E\u2022 \u0026nbsp;Prof. Koki Ho \u2013 School of Aerospace Engineering (advisor)\u003Cbr\u003E\u2022 \u0026nbsp;Prof. Glenn Lightsey \u2013 School of Aerospace Engineering\u003Cbr\u003E\u2022 \u0026nbsp;Prof. John Christian \u2013 School of Aerospace Engineering\u003Cbr\u003E\u2022 \u0026nbsp;Dr. Dario Izzo \u2013 European Space Agency\u003Cbr\u003E\u2022 \u0026nbsp;Dr. Gregory Badura \u2013 Georgia Tech Research Institute\u003Cbr\u003E\u0026nbsp;\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EModeling, Optimization, and Validation of In-Space Facility Location\u003Cbr\u003EProblem\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Modeling, Optimization, and Validation of In-Space Facility Location Problem"}],"uid":"27707","created_gmt":"2025-05-09 15:28:47","changed_gmt":"2025-05-09 15:29:16","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-05-21T09:00:00-04:00","event_time_end":"2025-05-21T11:00:00-04:00","event_time_end_last":"2025-05-21T11:00:00-04:00","gmt_time_start":"2025-05-21 13:00:00","gmt_time_end":"2025-05-21 15:00:00","gmt_time_end_last":"2025-05-21 15:00:00","rrule":null,"timezone":"America\/New_York"},"location":"CODA C1015 Vinings","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}