The development and experimental investigation of two low-power electric propulsion concepts using compact heaterless C12A7 electride (C12A7:e-) hollow cathodes is presented. The first concept represents an electrothermal thruster, in which a cathode discharge is used to heat a gas that is subsequently accelerated in a nozzle-shaped anode. The second propulsion system is an attempt to develop a sub-500 W magnetoplasmadynamic thruster (MPDT) that uses a rectangular discharge channel that allows to increase the applied magnetic field and thus lower the necessary discharge current. Extensive parameter studies with both concepts were conducted, and the thrust and discharge properties of different geometric and operational configurations were determined. This work is a follow-up publication of a previous paper (Gondol and Tajmar in CEAS Space J 14:65–77, 2021).

Quick and reliable computational methods for optimized orbital transfers are crucial for projects at preliminary stages. They enable an initial, realistic sizing of the propulsion subsystem, one of the major components of satellite design. This thesis work, conducted at ReOrbit Oy, presents a minimum-time optimal trajectory for the orbit raising of a micro-satellite from GTO to GEO, assuming continuous firing by electric propulsion. The Delta-v requirements resulting from this simulation lead to the selection of an appropriate electric propulsion system, elaborating on the design of its configuration in terms of fuel and thrust requirements. This is done by taking into account, other than the major contribution given by the orbit raising, additions due to in-orbit maneuvers performed twice a day over a 10-year lifetime, like station-keeping corrections and reaction wheels desaturation. The optimization method is a direct-indirect hybrid for low-thrust orbital maneuvers, employing Pontryagin’s Minimum Principle for the transcription into a nonlinear programming problem. The initial guess required to start the optimizer is obtained with Lyapunov control theory. An orbital averaging technique is implemented, enabling fast computation of multiple trajectories during the optimization. Disturbances from the J2 zonal harmonic, solar radiation pressure, third-body effects of the Sun and Moon, and atmospheric drag up to 1500 km of altitude are included in the dynamic model. Eclipse conditions are assessed with a cylindrical shadow model, as the solar electric propulsion experiences a zero thrust period when in Earth’s shadow. The electric propulsion system configuration is determined with trade-off studies and comparisons between different suppliers. The chosen outline includes 4 Xenon thrusters, with complementary power processing units and propellant management systems, resulting in a total transfer time of less than 4 months. The same propulsion system is employed both for the transfer trajectory and the in-orbit maneuvers, by changing the thruster’s configuration once in GEO. / Snabba och pålitliga beräkningsmetoder för optimerade växlingar mellan omloppsbanor är avgörande för projekt i preliminära skeden. De möjliggör en initial, realistisk dimensionering av framdrivningssystemet, ett av huvudkomponenterna i satellitdesign. Detta examensarbete, utfört vid ReOrbit Oy, presenterar en tidsoptimerad bana för en mikrosatellits banhöjning från GTO till GEO, förutsatt kontinuerlig avfyring med elektrisk framdrivning. Simuleringens resulterande Delta-v-krav leder till valet av ett lämpligt elektriskt framdrivningssystem, med utarbetande av dess konfiguration vad gäller bränsle- och drivkraftskrav. Detta uppnås genom att ta hänsyn till (förutom bidraget från växlingen av omloppsbanan) tillägg från manövrar i omloppsbana som utförs två gånger om dagen under en 10-årig livstid, som t.ex. korrigeringar för stationshållning och avmättning av svänghjul. Optimeringsmetoden är en direkt-indirekt hybrid för manövrar i omloppsbanor med låg drivkraft, som använder Pontryagins minimiprincip för omskrivning till ett icke-linjärt programmeringsproblem. Den första gissningen som krävs för att starta optimeraren erhålls med Lyapunovs reglerteori. En teknik for omloppsutjämning implementeras, vilket möjliggör snabb beräkning av flera banor under optimeringen. Störningar från zonövertonen J2, solstrålningstryck, tredjekroppseffekter från solen och månen och luftmotstånd upp till 1500 km höjd ingår i den dynamiska modellen. Förmörkelseförhållanden uppskattas med en cylindrisk skuggmodell, då den elektriska solframdrivningen undergår ett skede utan drivkraft inom jordens skugga. Det elektriska framdrivningssystemets konfiguration bestäms med avvägningsundersökningar och jämförelser mellan olika leverantörer. Förslaget på utformning inkluderar 4 Xenon raketmotorer, med kompletterande kraftbearbetningsenheter och drivmedelshanteringssystem, vilket resulterar i en total överföringstid på mindre än 4 månader. Samma framdrivningssystem används både för överföringsbanan och manövrarna inom omloppsbanorna, genom att ändra motorns konfiguration när satelliten är i GEO.

<p>Prior to the mid-20th century, the idea of electric propulsion had been all but a foreign one that manifested itself in the topic of science fiction. It was around this time when companies and agencies like NASA began to take interest in the topic of space propulsion, as most famously seen in the landing of the Apollo 11 mission on the moon. It was not until the early-1960s where the idea of a pulsed plasma thruster was first realized, with its first test being in 1964 aboard the Russian Zond-2 satellite which contained 6 ablative Polytetrafluoroethylene (PTFE, or “Teflon”) pulsed plasma thrusters.</p> <p>In this paper, a new low-voltage, liquid-fed pulsed plasma thruster was developed, tested, and characterized. This project took influence from the previous low-voltage, liquid-fed pulsed plasma thruster in Purdue’s EPPL and desired to transition it from a current gas-fed system to its intended liquid-fed system. The two main objectives for this project included conducting direct studies of the cathode’s erosion rate using a simple weighing method after simulating a lifetime of discharging the thruster, and completing the initial design of the liquid-fed pulsed plasma thruster using AF-M315E as its propellant while gathering data on its required breakdown voltage, exhaust velocity, and specific impulse.</p> <p>Both objectives were successfully completed, with the following parameters being measured or calculated. The required breakdown voltage was seen to be less than 26kV to keep the ignition spark inside the chamber. For the subsequent results measured however, the breakdown voltage was kept between 10-16kV for all successive tests. The peak current measured for all discharges was an average of 11kA, far exceeding similar geometries such as MPD thrusters. The operational voltage was less than 200V, although an operational voltage closer to 100V is expected after further optimization of the system is completed. The erosion rate of the tungsten cathode at this operational setting was found to be 15.4046 +/- 0.592 microgram/Coulomb which is much less than the cathode spot erosion rate reported for tungsten in literature of about 60 microgram/Coulomb and is beneficial for extending system lifetime. The exhaust velocity was calculated to be 30.6 +/- 4.8km/s which is typical of state-of-the-art PPT electric propulsion devices. The specific impulse was also extrapolated from the ion’s exhaust velocity, calculating to be 3,119 +/- 489 seconds. Future work would require optimization of the propellant injection mechanism to minimize propellant loss.</p>

Electric Propulsion (EP) is widely acknowledged as a crucial technology for future space missions, offering significant propellant savings and enabling exploration of planetary missions with smaller spacecraft (s/c). For precise attitude control of these smaller spacecraft, Field Emission Electric Propulsion (FEEP) has emerged as a favorable option due to its exceptional thrust controllability. However, the successful operation of FEEP, as well as most other EP systems, relies on an electron source, typically a Hollow Cathode (HC), to neutralize the ion beam. This cathode’s behavior must be characterized through ground testing before being integrated with the thruster. Once integrated, the whole thruster undergoes further testing. While the testing phase plays an essential role in achieving mission objectives, there is a scarcity of comprehensive papers describing the design of test setups for cathodes, such as Heaterless Hollow Cathode (HHC), or EP thrusters like FEEP. The lack of detailed information makes it challenging for those not well-versed in this particular testing methodology to effectively replicate the tests. In an effort to address this issue, this thesis utilizes literature studies and thermal analyses to propose a HHC test setup by focusing on the anode configuration and the electrical interface; Subsequently, parts of this HHC test setup are reused in a conceptual vacuum chamber adaptation, facilitating testing of FEEP. Specifically, for the HHC setup, two stainless steel plate-shaped anodes are manufactured, and an accompanying electrical schematic diagram is presented to demonstrate the proper connection of power supplies and other necessary equipment. For the FEEP setup, a chevron beam target, an aluminum shield to protect the pump, and a heat-dissipating stand are introduced. These two test setups, along with the underlying motivation, can ideally simplify future cathode and thruster testing processes, especially for those having limited familiarity with this subject matter. / Elektrisk framdrivning är allmänt erkänt som en avgörande teknologi för framtida rymduppdrag eftersom elektrisk framdrivning erbjuder betydande bränslebesparingar och möjliggör utforskning av planetära uppdrag med mindre rymdfarkoster. För exakt styrning av dessa mindre rymdfarkoster har fältjonisationsframdrivning framträtt som ett fördelaktigt alternativ på grund av sin exceptionellt styrbara drivkraft. Dock är den framgångsrika driften av fältjonisationsframdrivning, liksom de flesta andra elektriska framdrivningssystem, beroende av en elektronkälla, vanligtvis en hålkatod, för att neutralisera jonstrålen. Denna katods beteende måste karakteriseras genom marktester innan den integreras med drivsystemet. Efter integrationen genomgår hela drivsystemet ytterligare tester. Trots att testfasen spelar en avgörande roll för att uppnå uppdragsmålen finns det en brist på omfattande rapporter som beskriver utformningen av testupplägg för katoder, såsom värmelösa hålkatoder, eller elektriska framdrivningssystem så som fältjonisationsframdrivning. Den bristfälliga informationen gör det svårt för dem som inte är insatta i denna specifika testmetodik att effektivt replikera testerna. I ett försök att lösa detta problem använder denna avhandling litteraturstudier och termiska analyser för att föreslå en testuppsättning för en värmelös hålkatod genom att fokusera på anodkonfigurationen och det elektriska gränssnittet; Därefter återanvänds delar av denna värmelösa hålkatods-testuppsättning i en konceptuell vakuumkammar-anpassning för att underlätta testning av fältjonisationsframdrivning. Specifikt för den värmelösa hålkatods-uppsättningen tillverkas två platta anoder av rostfritt stål, och ett tillhörande schematiskt diagram över det elektriska gränssnittet presenteras för att demonstrera korrekt anslutning av strömförsörjning och annan nödvändig utrustning. För fältjonisationsframdrivnings-uppsättningen introduceras ett chevron-mönstrat jonstråle-mål, ett aluminiumskydd för pumpen och ett värmeavledande stativ. Dessa två testuppsättningar, tillsammans med den underliggande motiveringen, kan i bästa fall förenkla framtida testprocesser för katoder och drivsystem, särskilt för dem som har begränsad kännedom om ämnet.

<p>This doctoral thesis presents new ideas and research results on control of marine electric power system.</p><p>The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions.</p><p>Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines.</p><p>As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power.</p><p>The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions.</p><p>The main contributions of this PhD thesis are:</p><p>− A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds).</p><p>− New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel.</p><p>− Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft</p><p>accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm.</p><p>− A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers.</p><p>− Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers.</p><p>The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.</p>

This doctoral thesis presents new ideas and research results on control of marine electric power system. The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions. Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines. As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power. The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions. The main contributions of this PhD thesis are: − A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds). − New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel. − Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm. − A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers. − Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers. The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.

Magnetic nozzles, like Laval nozzles, are observed in several natural systems and have application in areas such as electric propulsion and plasma processing. Plasma flowing through these nozzles is inherently tied to the field lines and must separate for momentum redirection or particle transport to occur. Plasma detachment and associated mechanisms from a magnetic nozzle are investigated. Experimental results are presented from the plume of the VASIMR® VX-200 device flowing along an axisymmetric magnetic nozzle and operated at two ion energies to explore momentum dependent detachment. The argon plume expanded into a 150m3 vacuum chamber where the background pressure was low enough that charge-exchange mean-free-paths were longer than experiment scale lengths. This magnetic nozzle system is demonstrated to hydrodynamically scale up to astrophysical plasmas, particularly the solar chromosphere, implying general relevance to all systems. Plasma parameters were mapped over a large spatial range using measurements from multiple plasma diagnostics. The data show that the plume does not follow the magnetic field lines. A mapped integration of the ion flux shows the plume may be divided into three regions where 1) the plume briefly follows the magnetic flux, 2) diverges quadratically before 3) expanding with linear trajectories. Transitioning from region 1→2, the ion flux departs from the magnetic flux suggesting ion detachment. An instability forms in region 2 driving an oscillating electric field that causes ions to expand before enhancing electron cross-field transport through anomalous resistivity. Transitioning from region 2→3 the electric field dissipates, the trajectories linearize, and the plume effectively detaches. A delineation of sub-to-super Alfvénic flow aligns well with the inflection points of the linearization without a change in magnetic topology. The detachment process is best described as a two part process: First, ions detach by a breakdown of the magnetic moment when the quantity |v/fcLB| becomes of order unity. Second, the turbulent electric field enhances electron transport up to a factor of 4±1 above collisional diffusion; electron cross-field velocities approximate that of the ions and depart on more centralized field lines. Electrons are believed to detach by breakdown of magnetic moment further downstream in the weaker magnetic field.

Abstract<p><p>1.\ / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

[ES] En el presente trabajo se explora posibles soluciones a dos hechos correlacionados que podrían comprometer hasta cierto punto nuestro futuro. Por un lado, el crecimiento de la flota de aeronaves pequeñas en los próximos años, ya sean tripuladas o no, es una realidad. El acceso a estas aeronaves por parte de un público cada vez más mayoritario crece año a año y, al mismo tiempo, los fabricantes adaptan sus aeronaves a misiones que hace unos años no éramos capaces de contemplar. Por otro lado, y por desgracia, el cambio climático también es una realidad que no solo compromete nuestro futuro, sino también nuestro presente. Hoy en día la alerta climática es y debe ser elevada, y si no encontramos soluciones que ayuden a paliar este problema, la vida en el planeta podría cambiar irremediablemente para peor. Ambos hechos se encuentran implícitamente relacionados. La fabricación y operación de vehículos contribuye notablemente a aumentar la huella de carbono. Por lo tanto, el aumento de flota en los próximos años puede tener un impacto notablemente negativo en las emisiones contaminantes y gases de efecto invernadero globales. Es por ello por lo que organismos oficiales y sectores de desarrollo científico y tecnológico impulsan la investigación de posibles soluciones. Este trabajo intenta poner su grano de arena para minimizar este problema común. Se propone la utilización de múltiples tecnologías con el objetivo de disminuir el combustible requerido por aeronaves de 25kg al despegue, y de esta forma, disminuir las emisiones asociadas a su operación. Las tecnologías aplicadas son la hibridación eléctrica en serie, la propulsión eléctrica distribuida y la ingestión de capa límite. Por separado, estas tecnologías han demostrado múltiples ventajas, especialmente en términos de mejora propulsiva y aerodinámica de las aeronaves, lo que repercute directamente en el consumo de combustible. Sin embargo, este trabajo propone la utilización simultánea de todas ellas con el objetivo de disminuir aún más el consumo de combustible y, por tanto, las emisiones contaminantes y gases de efecto invernadero. Para ello, tras estas páginas se eligen los parámetros principales de esta aeronave y se acompaña de un exhaustivo análisis del comportamiento fluidodinámico. Con la comprensión de su comportamiento, es posible optimizar la selección de sus componentes, de forma que se obtienen mejoras importantes en el consumo de combustible. Este ahorro de combustible se muestra en comparación con aeronaves similares en tamaño y peso, pero que no incluyen estas tecnologías, logrando para un mismo alcance un ahorro del 16% del peso del combustible. La realización de este trabajo se centra en el empleo de herramientas computacionales apoyándose sobre todo en la dinámica de fluidos computacional (CFD). Esta herramienta principal se verá complementada con el uso de descomposición modal para realizar los análisis y de la creación de una base de datos que ayude a crear modelos rápidos útiles en futuros diseños preliminares y conceptuales de aeronaves de este tipo. / [CA] En aquest treball s'exploren possibles solucions a dos fets correlacionats que podrien comprometre d'alguna manera el nostre futur. Per un costat, el creixement de la flota d'aeronaus de xicoteta dimensió en el futur, tant tripulades com no tripulades, és una realitat. L'accés a aquestes aeronaus per part d'un públic cada cop més majoritari creix any rere any i, al mateix temps, els fabricants adapten les aeronaus a feines que anys enrere no eren capaços d'assolir. Per l'altre costat, malauradament, el canvi climàtic és un fet que compromet tant el nostre futur com el nostre present. Hui en dia l'alerta climàtica és elevada i, si no trobem solucions per a pal·liar aquest problema la vida al nostre planeta, podria canviar irremeiablement a pitjor. Ambdós fets es troben implícitament relacionats. La fabricació i l'operació de vehicles contribueix notablement a augmentar l'empremta de carboni. Per tant, l'increment de flota en els pròxims anys pot tindre un efecte negatiu molt notable en les emissions contaminants i gasos d'efecte hivernacle globals. És per això que organismes oficials i sectors de desenvolupament científic i tecnològic impulsen la investigació de possibles solucions. Aquest treball intenta aportar el seu granet de sorra per minimitzar aquest problema comú. Es proposa la utilització de múltiples tecnologies amb l'objectiu de reduir el combustible emprat per aeronaus de fins a 25kg i, per tant, disminuir les emissions associades a la seua operació. Les tecnologies aplicades són la hibridació elèctrica en sèrie, la propulsió elèctrica distribuïda i la ingestió de capa límit. Separadament, aquestes tecnologies han demostrat múltiples avantatges, especialment en termes de millora propulsiva i aerodinàmica de les aeronaus, repercutint directament en el consum de combustible. No obstant, aquest treball proposa la utilització simultània de totes elles amb l'objectiu de reduir encara més el consum de combustible i, per tant, les emissions contaminants i gasos d'efecte hivernacle. Per fer-ho, en les darreres pàgines es trien els paràmetres principals de l'aeronau i s'acompanyen d'una exhaustiva anàlisi del comportament de la dinàmica de fluids. Comprenent el seu comportament, és possible optimitzar la selecció dels seus components, de manera que s'obtenen millores importants en el consum de combustible. L'estalvi de combustible es mostra en comparació amb aeronaus similars en mida i pes, però que no inclouen aquestes tecnologies, aconseguint per a un mínim abast un estalvi del 16% del pes del combustible. La realització d'aquest treball es centra en l'ús d'eines computacionals recolzant-se sobretot en la dinàmica de fluids computacional (CFD). Aquesta eina principal es veurà complementada amb l'ús de descomposició modal per a elaborar les anàlisis i de la creació d'una base de dades que ajude a crear models ràpids i útils en futurs dissenys conceptuals i preliminars d'aeronaus d'aquest tipus. / [EN] The present work explores possible solutions to two correlated events that could compromise our future to some extent. On the one hand, the growth of the fleet of small aircraft in the coming years, whether manned or not, is a reality. Access to these aircraft by an increasing majority of the public grows year after year and at the same time, manufacturers adapt their aircraft to missions that we could not contemplate a few years ago. On the other hand, and unfortunately, climate change is also a reality that compromises not only our future but also our present. Today the climate alert is and must be elevated. If we do not find solutions that help alleviate this problem, life on the planet could irremediably change for the worse. Both facts are implicitly related. The manufacture and operation of vehicles contribute significantly to increasing the carbon footprint, so the increase in the fleet in the coming years may have an extremely negative impact on global polluting and greenhouse gas emissions. That is why official organizations and scientific and technological development sectors promote research for possible solutions. This work tries to do its bit to minimize this common problem. Multiple technologies are proposed to reduce the fuel required by 25kg aircraft at takeoff and, thus, reduce the emissions associated with their operation. The applied technologies are electric series hybridization, distributed electric propulsion, and boundary layer ingestion. Separately, these technologies have shown multiple advantages, especially in terms of improving aircraft propulsion and aerodynamics, which directly affects fuel consumption. Nevertheless, this work proposes the simultaneous use of all of them to reduce fuel consumption further and, therefore, polluting and greenhouse gas emissions. To do this, after these pages, the main parameters of this aircraft are chosen and accompanied by an exhaustive analysis of the fluid dynamic behavior. With an understanding of its behavior, it is possible to optimize its components' selection so that significant fuel consumption improvements are obtained. This fuel saving is shown in comparison with similar aircraft in size and weight, but that does not include these technologies, achieving a saving of 16% of fuel weight for the same range. This work's conduction focuses on employing computational tools mainly based on computational fluid dynamics (CFD). This primary tool will be complemented by the use of modal decomposition to carry out the analyses, and the creation of a database that will help create quick models useful in future conceptual and preliminary designs of this type of aircraft. / The respondent would like to acknowledge the financial support received through contract FPI-UPV PREDOCFD/19 of Subprograma 2 of Universitat Politècnica de València / Varela Martínez, P. (2023). On the Analysis and Design of Series Hybrid Distributed Electric Propulsion with Boundary Layer Ingestion of Remotely Piloted Aircraft [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/192805

Plume-spacecraft interactions play an important role in the performance and integrity of spacecraft during their missions in space. The study encompasses a thruster’s plume simulation and its impact on spacecraft geometries to understand and predict the effects and consequences of the impingement on spacecraft surfaces, such as erosion, contamination, forces, and torques. The initial focus of the thesis is to simulate an electric thruster current density for both space and vacuum chamber measurements. This estimates the artificial broadening of the plume produced by low-pressure background air particles inside a vacuum chamber. Subsequently, the study adopts a conservative approach by considering a current density obtained from vacuum chamber measurements, which allowed for an evaluation of the potential effects on spacecraft surfaces, thus delivering insights into erosion, contamination, as well as the distribution of forces and torques. The results highlight the importance of considering spacecraft charging in plume interactions, as the surface potential significantly affects the impact of the thruster’s plume on spacecraft surfaces. The outcome obtained throughout this project suggests that the effects of particle impingement on erosion, contamination, forces, and torques in plume-spacecraft interactions are influenced by the thruster location and the spacecraft’s surface potential. It is important to note that additional factors, including thermal effects, radiation, and magnetic fields, which were not addressed in this thesis, may also pose potential threats to spacecraft performance and should be considered in future investigations. / Interaktioner mellan plym och rymdfarkoster spelar en viktig roll i rymdfarkosternas prestanda och integritet under deras uppdrag i rymden. Studien omfattar simulering av en raketmotors plym och dess inverkan på rymdfarkostens geometrier för att förstå och förutsäga effekterna och konsekvenserna av kollisionen på rymdfarkostens ytor, såsom erosion, förorening, krafter och vridmoment. Avhandlingens initiala fokus är att simulera strömtäthet i plymen från en elektrisk raketmotor för både rymd- och vakuumkammarmätningar. Detta uppskattar den artificiella expansionen av plymen som produceras av de molekyler som närvarar i det låga trycket inuti en vakuumkammare. Därefter antar studien ett konservativt tillvägagångssätt genom att överväga en strömtäthet erhållen från vakuumkammarmätningar, vilket möjliggjorde en utvärdering av de potentiella effekterna på ytorna på en rymdfarkost, och därmed leverera insikter om erosion, förorening, såväl som fördelningen av krafter och vridmoment. Resultaten understryker vikten av att överväga laddning av rymdfarkoster i plyminteraktioner, eftersom ytpotentialen signifikant påverkar raketmotorplymens påverkan på rymdfarkostens ytor. Resultatet som erhållits genom hela detta projekt tyder på att effekterna av partikelkollision på erosion, förorening, krafter och vridmoment i växelverkan mellan plym och rymdfarkoster påverkas av raketmotorns placering och rymdfarkostens ytpotential.