bluuebunny/crossref_metadata_2025_split huggingface dataset:
Most influential factors in the detection of potential conflicts between en-route aircraft by ATCO
Authors: Jurado Raquel Delgado-Aguilera , Comendador Víctor Fernando Gómez , Suárez María Zamarreño , Moreno Francisco Pérez , Gallego Christian Eduardo Verdonk , Valdés Rosa María Arnaldo 
Published: June 2023

Abstract
The objective of this methodology is to create a model capable of analysing and predicting the identification of potential conflicts between aircraft during en-route flights by air traffic control operators (ATCOs). This aspect is crucial to prevent Separation Minima Infractions (SMIs) and ensure safety. Initially, a Bayesian Network Model (BNM) is developed to define the safety event and its key dimensions. Using descriptive analysis and statistical knowledge, appropriate models are selected to represent the frequency of safety events. In addition, a data-driven approach is used to enhance model development. The BNM is calibrated, adjusted and subjected to sensitivity analysis using real data. The explanatory power and mixed effects of models and independent variables are assessed. By considering mixed effects in the sensitivity analysis, safety performance is characterised not only in terms of individual dimensions, but also in terms of their combinations. This allows the identification of threshold values that would minimise the occurrence of safety incidents.
Is it possible to evaluate the event-based taskload of an air traffic controller using an air traffic control simulator?
Authors: Suárez María Zamarreño , Valdés Rosa María Arnaldo , Moreno Francisco Pérez , Jurado Raquel Delgado-Aguilera , Frutos Patricia María López de , Comendador Víctor Fernando Gómez 
Published: June 2023

Abstract
Air Traffic Controllers (ATCOs) perform safety-critical tasks and face a wide variety of demands to manage aircraft safely and efficiently. In order for these demands to not result in a degradation of their performance, they need to be within certain upper and lower limits. In the field of human factors in aviation, one option to establish these limits is to study neurophysiological variables related to human performance. The problem is that the study of these variables can only be done on the basis of an adequate taskload baseline, which allows to accurately define the situation of the scenario during the course of the experiment. Taskload is a measure that quantifies the difficulty a person encounters in completing a task. CRITERIA project (atC event-dRiven capacITy modEls foR aIr nAvigation) aims to establish capacity models and study neurophysiological variables against taskload distribution profiles based on ATC events that appear in real-time simulations. This study presents the methodology defined in CRITERIA to evaluate the taskload of ATCOs based on ATC events, as well as the analysis of the first results obtained from a set of real-time simulations of four exercises with six participants using SkySim simulator.
Probabilistic and Statistical Analysis of Aviation Accidents
Authors: Amaral Yanne , Santos Luís F. F. M. , Valério Duarte , Melicio Rui , Barqueira Ana 
Published: June 2023

Abstract
The aim of this paper is to study the role that probabilistic and statistical analysis tools, such as ARIMA models, can have in the improvement of aviation safety levels. This is to be achieved by using available accident data, organizing it probabilistically, based on the different variables involved giving a better understanding of them as well as trough time series analyses forecast future values and trends. The results achieved provide valuable information usable by different aviation entities to be used on the accident prevention field through a proactive approach with regards to identified key areas.
Machine learning in aviation: Is it possible to predict when an ATC Sector or Air Traffic Flow will be regulated?
Authors: Moreno Francisco Pérez , Comendador Víctor Fernando Gómez , Jurado Raquel Delgado-Aguilera , Suárez María Zamarreño , Janisch Dominik , Valdés Rosa María Arnaldo 
Published: June 2023

Abstract
Due to the increasing complexity of airspace, the ATC system does not have sufficient capacity to cope with aircraft demand. For this reason, the ATFCM system needs to implement more and more measures to balance capacity and demand. These measures are the ATFCM regulations. In this paper, a methodology to predict ATFCM capacity regulations based on a machine learning model is proposed. This model will try to predict whether an ATC sector will be regulated or not at a specific time based on the time of prediction and certain operating variables in the sector. A test has been carried out in the LECMPAU sector of Spanish airspace. With results of 91% accuracy in predicting whether the sector will be regulated or not and a logical explainability, it can be concluded that with the sufficient historical operation and certain operational variables, it is possible to predict when an ATFCM regulation capacity will appear in the airspace. It can also be concluded that without a detailed knowledge of the operation in a sector, it is possible to make this prediction because patterns can be found in historical behaviour.
Ammonia fuelled space electric propulsion systems using C12A7:e- electride as electron emitter
Authors: Plaza J. F. , Toledo J. , Post A. 
Published: June 2023

Abstract
Given the significant changes taking place in the geopolitical global situation, and the derived supply chain issues for some traditional electric propulsion propellants like xenon, alternative propellants issue is perceived as a strategic topic to tackle, and ammonia (NH3) is becoming one serious candidate. Ammonia is increasingly being investigated to extend green hydrogen use by overcoming the storage and transportation issues of hydrogen. Ammonia characteristics like its superior energy density and low temperature and/or pressure needs for storage (10 bar at 20°C for liquid ammonia), make it very valuable for simplified unexpensive energy storage and transportation, and these characteristics makes it also especially suitable for on-board spacecrafts electric propulsion purposes. Based on our research activities on ammonia generation and dissociation processes with C12A7:e- electride as catalyst, this work will describe the most relevant characteristics and properties associated to the advantages of using the cheap and abundant ammonia, and will also present and discuss the results of the first successful tests performed with ammonia as fuel for a C12A7:e- electride based neutralizer, including relevant endurance tests in operation conditions. Additionally, the dual application as propellant and on-board energy generation system of ammonia will also be discussed.
International planetary sunshade concept with a function-integrated and scalable support structure based on coreless filament winding
Authors: Maheswaran Tharshan , Mindermann Pascal , Acker Denis , Gresser Götz T. , Fasoulas Stefanos 
Published: June 2023

Abstract
Despite all current efforts, climate change is the greatest challenge of the 21st century. Since existing measures will fail to prevent critical tipping points from being reached, in addition to terrestrial geoengineering methods, efforts are underway to explore new ways to implement space-based geoengineering methods into the short-term construction of a buffer solution - the International Planetary Sunshade (IPSS). The IPSS system reduces solar irradiation mitigating the global mean temperature rise while offering a sustainable energy supply. The developement of the system poses multifaceted challenges only to be mastered by a collaboration of space agencies and private companies, while supported by society. Therefore, tackling the IPSS within international roadmaps is essential to exploit synergies, shorten development time, and promote international cooperation. An evolutionary concept achieves stepwise Earth independence by utilizing lunar resources. The feasibility of the IPSS also depends on the foil’s supporting structure. Therefore, a lightweight manufacturing technology that meets several criteria, such as scalability, adaptivity, material compatibility, full automation, on-orbit manufacturing, in-situ resource utilization, and digital design including function integration, must be adopted. Hence, coreless filament winding (CFW) may be a suitable technology for realizing the demanded mass savings. The prerequisite for the superiority of CFW structures is an application- and material-compliant component and fiber net design. Previous experience with CFW cannot be directly transferred to the IPSS system due to the changed requirements for space application. This paper will present a systematic design concept for the IPSS, initially exploring a CFW support structure by discussing segmentation and modularity, proposing a new connection system, and implementing function integration.
An Analysis of the Requirements for a Sustainable Lunar Transportation System to Enable Initial DIANA Infrastructure
Authors: Acker Denis , Gutierrez Elizabeth , Calatayud Javier Palacios , Modi Prishit , Kugic Alma , Khan Sajeel 
Published: June 2023

Abstract
The Dedicated Infrastructure and Architecture for Near-Earth Astronautics (DIANA) is a design concept for a self-sustainable lunar village near the de Gerlache crater, on the lunar South Pole, comprising tourists and astronauts alike. The village will be permanently inhabited and will exploit future technologies to achieve independence from a majority of Earth resupply missions. Execution of the initial construction phase of the DIANA infrastructure depends primarily on the persistent supply of in-situ construction material, regolith. Lunar raw materials also primarily contribute to the life support systems (LSS) and the radiation protection for the inhabited modules. To enable ISRU, resources need to be transported using diverse locomotion systems on the unexplored lunar terrain. A self-sustainable lunar base requires to be built on an ecosystem that facilitates continuous transportation of materials, humans (astronauts and tourists) and robotic systems. This paper focuses on a detailed comprehension of the design, feasibility, and economic requirements of a transportation ecosystem concept explicitly dedicated to the establishment and development of the DIANA lunar village. The mission objectives and top level requirements pertaining to the individual transportation systems will be derived from the detected necessities that are defined for alternative transportation technologies that efficiently provide large amounts of lunar raw material for the construction of lunar infrastructure as well as water ice from the de Gerlache Crater, which shall primarily contribute to the LSS and the production of rocket fuel. While transporting humans, factors such as time, comfort, and risk mitigation play a major role, and are therefore, discussed thoroughly within the framework of this study. Using this study as the principal foundation, a phase 0/A design study illustrating a novel transportation infrastructure concept based on magnetic levitation technology would be developed for efficient transportation of resources and people across the lunar surface. This transportation concept shall be sustainably manufactured using the abundant lunar resources to minimize costs and resupply missions in the long term to pave the way for an independent lunar village.
Structural efficiency evaluation of innovative reusable launch vehicles
Authors: Trifa Panagiotis , Rellakis Dimitrios , Psoni Georgia 
Published: June 2023

Abstract
This work is focused on evaluating the structural design of the innovative reusable micro launcher MESO, originated from the RRTB, a funded project by EU. The structural efficiency of MESO is evaluated in association with its mass budget, which is based on project’s early adopted requirements. In this particular design loop, the reusability concept is intergraded by implementing the fail-safe design approach, considering the exclusive use of high TRL aluminum alloys. The main objective of this work is achieved by developing a global Finite Element Model (FEM), comprising a set of sub-models, which represent the primary structure, the secondary structures, the equipment and their interfaces as well.
The paper proceeds with the description of the modelling approach regarding mesh development and the connections created between the sub-models for assembling the integrated Global FEM of the launcher. The first iteration of the load analysis loop resulted in the extraction of the Design Limit Loads (DLL). The DLL investigated in both ground and flight cases, which comprise the most severe combination of quasi-static loads. The FEM is verified and subjected to various types of preliminary structural analysis, taking into consideration the required ECSS design and safety factors for static strength and stability assessment.
The analyses results indicated the order of magnitude and the location of all weak areas of the launcher. Subsequently a preliminary sizing procedure is performed in order to prevent all failure modes according to the structural design requirements. The conclusions derived from the structural analysis of the first design loop influence the design modifications to be considered for the next design loop, where the same steps are going to be followed until the structural design requirements are satisfied once again.
Iterative design development of a reusable micro-launcher within the RRTB project
Authors: Bergström Rasmus , Pilori Daniele , Pinheiro Miguel , Zamprotta Alessandro , Medici Giovanni , Trovarelli Federico , Oton Raquel Marey 
Published: June 2023

Abstract
The Recovery and Return-To-Base European Reusable Micro-Launcher project, part of the European Commission’s H2020 programme, intends to develop a novel reusable micro launcher system to bring independent and cost-effective access-to-space for the European small satellite market. The multi-disciplinary project focuses on the optimization of aerospike tail-first atmospheric re-entry of the MESO vehicle, together with the design and manufacturing of reusable cryogenic tanks, and the effort is divided into two design loops, where each design loop starts from establishing early design decisions and assumptions so that dedicated subsystem work may progress immediately. The multiple design loop approach allows for unsuitable design decisions, or risky and speculative assumptions to be revised or excluded at the project half-way point, thereby acting as a form of risk management. Throughout the work performed in the first design loop several conclusions were reached. The design presented both novel design features, but also critical issues which became better understood as the fidelity of the subsystem designs and mission analysis increased. These issues ultimately lead to the overall system design and CONOPS to be updated for the second loop, with several of the early design choices being modified, especially through the removal of the EDF landing system, based on the results of the first loop. For the second design loop, the design is updated to alleviate the most critical problem drivers, and to improve the system’s ability to fulfil the top-level requirements and objectives. The updated design uses a Mid-Air Catch approach, and leverages on the heritage of the previous design loop, implementing tailored changes based on the outcome of the trade-offs performed at mission and system levels.
Breadboard of Microchip and Avalanche Photodiode in Linear and Geiger Mode for LiDAR Applications
Authors: Sousa Ana , Pinto Rafael , Couto Bruno , Nadal Beltran , Onderwater Hugo , Gordo Paulo , Abreu Manuel , Melicio Rui , Michel Patrick 
Published: June 2023

Abstract
This paper reports the implementation of two critical technologies used in LiDARs: 1) A microchip Q-switched laser breadboard and 2) breadboard of an Indium gallium arsenide avalanche photodiode working at 300 K with high reverse polarization voltages. Microchip Q-switched lasers are small solid state back pumped lasers, that can generate high energy short pulses. The implemented breadboard used an Erbium and Ytterbium co doped phosphate glass, a COMALO crystal with 98% (initial transparency) and an output coupler of 98% reflectivity. For the sensor test, a system for the simultaneous operation in vacuum and wide range of temperatures was developed. Avalanche photodiodes are reverse polarized photodiodes with high internal gain, due to their multiple layer composition, capable of building up high values of photocurrent from small optical signals by exploiting the avalanche breakdown effects. The test avalanche photodetector was assembled to be operated in two modes: Linear and Geiger mode, to achieve this behavior, a transimpedance amplifier circuit was implemented. These two technologies are critical for mobile LiDAR applications, due to its low mass and high efficiency. The paper describes the breadboard implementation method and sensor characterization at low temperature and high voltage (beyond breakdown voltage).
Satellite Star Tracker Breadboard with Space Debris Detection Capability for LEO
Authors: Filho Joel , Gordo Paulo , Peixinho Nuno , Gafeira Ricardo , Melicio Rui , Silva André 
Published: June 2023

Abstract
This paper evaluates the possibility of having a star tracker device running space debris algorithms. A simple star tracker breadboard was developed to evaluate the possibility of having a device running both stellar identification and space debris algorithms. The breadboard was built with commercial off-the-shelf components, representing the current star tracker resolution and field of view. A star tracker device and space debris algorithms were implemented and tested, respectively: Tetra and ASTRiDE. The device concept was tested by taking pictures of the night sky with satellite streaks. Seeking to overcome such limitations, a dual-purpose star tracker with stars detection and optical debris detection capability is proposed. Star trackers are usually used in satellites for attitude determination and therefore have a vast potential to be a major tool for space debris detection. The rapid increase of space debris poses a risk to space activities, so it is vital to detect it. Ground-based radar and optical telescope techniques used for debris detection are limited by a size threshold, detecting only a tiny amount of the total, reason why evaluating the possibility of detecting them in space is of major importance.
The design of a flexible RF generator for driving Acousto-Optical devices in space applications
Authors: Vanhamel J , Stutman D 
Published: June 2023

Abstract
Acousto-Optical (AO) devices are not only used for filtering purposes in spectral imaging, but also in optical communications and spatial tracking systems. Some AO devices with space applications are AO Tunable Filters (AOTFs), Modulators (AOMs), Deflectors (AODs) and Frequency Shifters (AOFSs). Though these device’s applications differ, they are all controlled with Radio-Frequency (RF) signals. These signals are converted by a transducer into an acoustic wave, which propagates inside the AO device. The interaction between the incoming light and the acoustic waves inside the birefringent AO material creates multiple output beams. This interaction can result in filtering, modulation, deflection or frequency shifting, depending on the AO device in question. This research focuses on the design of a flexible, uniform RF generator, applicable to all AO devices in the space applications domain. The RF output maximizes the performance of the AO device, while the use of components available in space qualified grades eases integration with future space missions. Its design is a key step towards a miniaturized, space qualified, general-purpose RF generator. This research presents schematics, design and preliminary component test results.
Outcomes of the PERIOD project on In-Space Manufacturing, Assembly and Refuelling Technologies
Authors: Estable Stéphane , Ahrns Ingo , Regele Ralf , Jankovic Marko , Brinkmann Wiebke , Gancet Jeremi , Barrio A. M. , Leiter Pierre , Colmenero Francisco J. , Ampe Annelies , Ordoubadian Björn , Chamos Apostolos , Caujolle Romain , Silveira Daniel , Soto Isabel , Shilton Mark , Vogel Torsten , Bartsch Sebastian , Manz Marc 
Published: June 2023

Abstract
Traditionally, satellites and other space-specific assemblies (e.g., antennas, spacecraft, etc.) are built on Earth and then sent into orbit. New approaches are pursuing direct on-orbit manufacturing and assembly using robotics, autonomy, and modularity. The advantages are many, ranging from virtually unlimited overall volume and design of large satellite antennas to numerous options for building larger space infrastructures such as large reflectors and modular space stations. In addition, in-space manufacturing and assembly (ISMA) technologies can enable the upgrade and repair of existing spacecraft and satellites already in orbit, promoting the sustainable use of space through plug-and-play modularity. The PERIOD project is pursuing a concept in which an orbital demonstrator is being developed for satellite manufacturing and assembly, as well as docking and refuelling experiments. This paper describes the background of the development, the PERASPERA building block technologies ESROCOS (European Space Robotics Control and Operating System), ERGO (European Robotic Goal-Oriented Autonomous Controller) and InFuse (Data Fusion) used, the test setup of the demonstrator and first results. The successful implementation and validation of ISMA technologies will lead to the generation of independent European capacities allowing Europe to build future orbital infrastructure and to be competitive on the ISMA markets
Continuing education in green chemical processes for aerospace manufacturing: The case of drag-out
Authors: Aptoglou M. , Papachristodoulou S. , Gounaris N. , Peta D. , Vourdas N. 
Published: June 2023

Abstract
In the new era of job market in the EU zone and abroad, novel Occupational Profiles dictate the development and the update of Learning Outcome-based Curricula. This stands for all disciplines and specialties and for various Qualification Levels (QL), from after-school education up to the highest QL. The pertaining Curricula should allude to specific knowledge, skills, and behaviours, that are being mandated from the respective Occupational Profiles. For intermediate QL, namely in between secondary school and University, there is an utmost need for new, updated, attractive Curricula covering current and new market needs. Such Curricula should be supported from Course Units that are technologically updated, thus providing the trainees the skills and knowledge to cover the current and novel Learning Outcomes and Performance Criteria for the specified QL. We herein present a newly developed Course Unit, part of the Green Special Processes course that can be offered in the context of a continuing Vocational Education Training (cVET) Program targeting a QL equivalent to the European QL 5. This Course Unit covers the case of drag-out, which has significant environmental and economic impacts on the engineering of wet chemical processes entailing multiple process baths and requiring rinsing. Such processes are widely used also in Aircraft manufacturing and the related environmental impacts have become very important. Part of the basic theory, as well as part of the practical training are presented herein.