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Safe-event pruning in spacecraft conjunction management

Astrodynamics 2023年第4期7卷 401-413页

作者： Sébastien Henry Roberto Armellin Thibault Gateau Guggenheim School of Aerospace Engineering Georgia Institute of TechnologyAtlantaGA 30332USA te punaha atea-space institute The University of AucklandAuckland 1010New Zealand Department of Aerospace Vehicles Design and Control Institut Superieur de I'Aeronautique et de I'EspaceToulouse 31055France

spacecraft conjunction management plays a crucial role in the mitigation of space *** a conjunction event occurs,resources and time are spent analyzing,planning,and potentially maneuvering the *** work contributes to a subpart of the problem:Confidently identifying events that will not lead to a high collision probability,and therefore do not require further *** method reduces the dimensionality of the data via principal component analysis(PCA)on a subset of ***-risk regions are then determined by clustering the projected data,and events that do not belong to a high-risk cluster are pruned.A genetic algorithm(GA)is developed to optimize the number of clusters and feature selection of the ***,an ensemble learning framework is proposed to combine the suboptimal models for better *** results show that the first set of parameters pruned approximately 50%of the events in the testing set with no false negatives,whereas the second set of parameters pruned 70%of the events and maintained a near-perfect *** results could benefit the optimization of operational resources and allow operators to focus better on the events of interest.

关键词： space situational awareness collision avoidance genetic algorithm(GA) ensemble learning

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Design and guidance of a multi-active debris removal mission

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Astrodynamics 2023年第4期7卷 383-399页

作者： Minduli C.Wijayatunga(B) Roberto Armellin Harry Holt Laura Pirovano Aleksander A.Lidtke te Pūnaha atea–space institute The University of AucklandAuckland 1010New Zealand Astroscale Japan Inc. 1-16-4-16 KinshiSumida-kuTokyoJapan

space debris have become exceedingly dangerous over the years as the number of objects in orbit continues to *** debris removal(ADR)missions have gained significant interest as effective means of mitigating the risk of collision between objects in *** study focuses on developing a multi-ADR mission that utilizes controlled reentry and *** mission comprises two spacecraft:a Servicer that brings debris to a low altitude and a Shepherd that rendezvous with the debris to later perform a controlled reentry.A preliminary mission design tool(PMDT)was developed to obtain time and fuel optimal trajectories for the proposed mission while considering the effect of J2,drag,eclipses,and duty *** PMDT can perform such trajectory optimizations for multi-debris missions with computational time under a *** guidance schemes are also studied,taking the PMDT solution as a reference to validate the design methodology and provide guidance solutions to this complex mission profile.

关键词： active debris removal(ADR) trajectory design optimization autonomous guidance low-thrust electric propulsion △u-law guidance Q-law guidance

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Message from the Guest Editors of the Special Issue on space Traffic Management

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Astrodynamics 2023年第4期7卷 381-381页

作者： Yu Jiang Roberto Armellin Zhihui Li State Key Laboratory of Astronautic Dynamics Xi’an Satellite Control CenterXi’an 710043China te punaha atea–space institute the University of AucklandAuckland 1010New Zealand China Aerodynamics Research and Development Center Beijing BranchBeijing 100191China

Dear authors and readers,Since 1957,over 6400 rocket launches have deployed more than 15,900 satellites into the Earth’s *** then,there have been more than 600 fragmentation events caused by collisions,explosions,aerodynamic break-ups,and other *** that the space environment is a finite and shared resource,there is a growing need for space traffic management(STM).

关键词： fragmentation finite break

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A Novel Method for Resolving and Completing Authors' Country Affiliation Data in Bibliographic Records

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Journal of Data and Information Science 2020年第3期5卷 97-115页

作者： Ba Xuan Nguyen Jesse David Dinneen Markus Luczak-Roesch School of Information Management Victoria University of WellingtonWellingtonNew Zealand Posts and telecommunications institute of technology Ho Chi Minh CityVietnam Berlin School of Library and Information Science Humboldt-Universitat zu BerlinBerlinGermany te punaha Matatini-The New Zealand Centre of Research Excellence for Complex Systems and Networks New Zealand

Purpose: Our work seeks to overcome data quality issues related to incomplete author affiliation data in bibliographic records in order to support accurate and reliable measurement of international research collaboration(IRC).Design/methodology/approch: We propose, implement, and evaluate a method that leverages the Web-based knowledge graph Wikidata to resolve publication affiliation data to particular countries. The method is tested with general and domain-specific data ***: Our evaluation covers the magnitude of improvement, accuracy, and consistency. Results suggest the method is beneficial, reliable, and consistent, and thus a viable and improved approach to measuring *** limitations: Though our evaluation suggests the method works with both general and domain-specific bibliographic data sets, it may perform differently with data sets not tested here. Further limitations stem from the use of the R programming language and R libraries for country identification as well as imbalanced data coverage and quality in Wikidata that may also change over *** implications: The new method helps to increase the accuracy in IRC studies and provides a basis for further development into a general tool that enriches bibliographic data using the Wikidata knowledge ***: This is the first attempt to enrich bibliographic data using a peer-produced, Webbased knowledge graph like Wikidata.

关键词： International research collaboration measurement Bibliographic data Country identification Knowledge graphs Wikidata Open data

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