Pub Date : 2024-10-16DOI: 10.1016/j.actaastro.2024.10.037
One of the important tasks of space flight safety is the ability of a wing to maintain stability in an oncoming turbulent flow. In this case, the spacecraft must move the greatest distance. The paper studies the motion of a thin plate near a boundary in an oncoming flow of rarefied gas. At low Reynolds numbers, the effect of the boundary on the plate is studied, and the possibility of self-propulsion is shown.
{"title":"Motion and self-motion of thin bodies in rarefied gas","authors":"","doi":"10.1016/j.actaastro.2024.10.037","DOIUrl":"10.1016/j.actaastro.2024.10.037","url":null,"abstract":"<div><div>One of the important tasks of space flight safety is the ability of a wing to maintain stability in an oncoming turbulent flow. In this case, the spacecraft must move the greatest distance. The paper studies the motion of a thin plate near a boundary in an oncoming flow of rarefied gas. At low Reynolds numbers, the effect of the boundary on the plate is studied, and the possibility of self-propulsion is shown.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.actaastro.2024.10.033
This study explores the modeling and control of the spinning tether system (STS) for maneuvering between arbitrary spinning planes. The spinning tether system garners significant attention for good centrifugal stability and transportation ability. However, conventional STS models face challenges such as singularities and coupling when studying three-dimensional spinning motion. To tackle the aforementioned challenges, a new singularity-adjustable model and a maneuvering control strategy are proposed. Initially, a variable coordinate system is defined, which allows for relocating singularities to unattainable positions during three-dimensional motions. Based on this new coordinate system, the singularity-adjustable Lagrangian model is established. Subsequently, based on the new model, a three-dimensional maneuvering scheme for spatial spinning motions is introduced to define and describe STS maneuvering trajectories in a de-coupled way. Finally, based on the reference maneuvering scheme, a saturated radial basis function network-based controller is designed to attenuate potential disturbances and errors, as electric thrusters used in this work are limited in actuating magnitude. Numerical results demonstrate that, with the new singularity-adjustable Lagrangian model, singularity and coupling phenomena are avoided during the three-dimensional maneuver, and the proposed controller ensures a stable STS three-dimensional maneuvering motion.
{"title":"The three-dimensional maneuver control of spinning tether system under a new Lagrangian model","authors":"","doi":"10.1016/j.actaastro.2024.10.033","DOIUrl":"10.1016/j.actaastro.2024.10.033","url":null,"abstract":"<div><div>This study explores the modeling and control of the spinning tether system (STS) for maneuvering between arbitrary spinning planes. The spinning tether system garners significant attention for good centrifugal stability and transportation ability. However, conventional STS models face challenges such as singularities and coupling when studying three-dimensional spinning motion. To tackle the aforementioned challenges, a new singularity-adjustable model and a maneuvering control strategy are proposed. Initially, a variable coordinate system is defined, which allows for relocating singularities to unattainable positions during three-dimensional motions. Based on this new coordinate system, the singularity-adjustable Lagrangian model is established. Subsequently, based on the new model, a three-dimensional maneuvering scheme for spatial spinning motions is introduced to define and describe STS maneuvering trajectories in a de-coupled way. Finally, based on the reference maneuvering scheme, a saturated radial basis function network-based controller is designed to attenuate potential disturbances and errors, as electric thrusters used in this work are limited in actuating magnitude. Numerical results demonstrate that, with the new singularity-adjustable Lagrangian model, singularity and coupling phenomena are avoided during the three-dimensional maneuver, and the proposed controller ensures a stable STS three-dimensional maneuvering motion.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.actaastro.2024.10.027
Technologies for the removal of space debris fragments of artificial (man-made) origin from near-Earth space is being proposed in order to provide the security of space flights. The fundamental principle of the proposed method is based on the utilization of intense solar radiation to direct and concentrate at space debris fragments with the aim of creating a plasma braking and transferring the fragment from a circular to an elliptical orbit following its subsequent burn up in the dense layers of the atmosphere. At the same time, the generation of substantial solar radiation is facilitated by a synthesized multi-aperture optical system situated in a heliosynchronous space orbit and permanently oriented towards the Sun.
{"title":"Laser-optical technologies for space debris removal","authors":"","doi":"10.1016/j.actaastro.2024.10.027","DOIUrl":"10.1016/j.actaastro.2024.10.027","url":null,"abstract":"<div><div>Technologies for the removal of space debris fragments of artificial (man-made) origin from near-Earth space is being proposed in order to provide the security of space flights. The fundamental principle of the proposed method is based on the utilization of intense solar radiation to direct and concentrate at space debris fragments with the aim of creating a plasma braking and transferring the fragment from a circular to an elliptical orbit following its subsequent burn up in the dense layers of the atmosphere. At the same time, the generation of substantial solar radiation is facilitated by a synthesized multi-aperture optical system situated in a heliosynchronous space orbit and permanently oriented towards the Sun.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.actaastro.2024.10.028
Several novel active and passive means for the suppression of pilot-induced oscillations are considered in the paper. The potential of the proposed means in eliminating Category I, II, and III pilot-induced oscillations was studied in ground-based simulation for two controlled element dynamics corresponding to an aerospace vehicle and a second-generation supersonic transport. The experiments demonstrated that the highest effectiveness in suppressing pilot-induced oscillations and improving task performance is provided by integrating both proposed active suppressors with one of the passive prefilters.
{"title":"Development of means for suppressing the negative effects of interaction between the pilot and reentry and other high-speed vehicles","authors":"","doi":"10.1016/j.actaastro.2024.10.028","DOIUrl":"10.1016/j.actaastro.2024.10.028","url":null,"abstract":"<div><div>Several novel active and passive means for the suppression of pilot-induced oscillations are considered in the paper. The potential of the proposed means in eliminating Category I, II, and III pilot-induced oscillations was studied in ground-based simulation for two controlled element dynamics corresponding to an aerospace vehicle and a second-generation supersonic transport. The experiments demonstrated that the highest effectiveness in suppressing pilot-induced oscillations and improving task performance is provided by integrating both proposed active suppressors with one of the passive prefilters.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.actaastro.2024.10.023
Illusionism is an eliminativist position about qualia stating that phenomenal consciousness is nothing more than an introspective illusion. The attention schema theory (AST) relates this philosophical stance to a large body of experimental data and states that phenomenal consciousness arises from an internal model of attention control. In this paper, I intend to show that AST and illusionism have significant implications both in the search for extra-terrestrial intelligence and in the explanation of Fermi paradox.
Firstly, on the basis of findings concerning the evolutionary history of phenomenal consciousness on Earth, I argue that extraterrestrial biological life is likely to experience phenomenality. In the second part, I set AST in the context of a post-biological universe, where artificial intelligence (AI) is the dominant form of intelligence. I argue that phenomenal consciousness is probably present in these entities, and that they could even be super-conscious. Finally, I show that because phenomenality grounds value, illusionism has profound revisionary consequences in the field of ethics. This reconsideration of the justifiability of our values paves the way to AI misalignment and may be the source of neocatastrophic scenarios that explain to Fermi paradox.
{"title":"Phenomenal consciousness is alien to us: SETI and the fermi paradox seen through the prism of illusionism and attention schema theory","authors":"","doi":"10.1016/j.actaastro.2024.10.023","DOIUrl":"10.1016/j.actaastro.2024.10.023","url":null,"abstract":"<div><div>Illusionism is an eliminativist position about qualia stating that phenomenal consciousness is nothing more than an introspective illusion. The attention schema theory (AST) relates this philosophical stance to a large body of experimental data and states that phenomenal consciousness arises from an internal model of attention control. In this paper, I intend to show that AST and illusionism have significant implications both in the search for extra-terrestrial intelligence and in the explanation of Fermi paradox.</div><div>Firstly, on the basis of findings concerning the evolutionary history of phenomenal consciousness on Earth, I argue that extraterrestrial biological life is likely to experience phenomenality. In the second part, I set AST in the context of a post-biological universe, where artificial intelligence (AI) is the dominant form of intelligence. I argue that phenomenal consciousness is probably present in these entities, and that they could even be super-conscious. Finally, I show that because phenomenality grounds value, illusionism has profound revisionary consequences in the field of ethics. This reconsideration of the justifiability of our values paves the way to AI misalignment and may be the source of neocatastrophic scenarios that explain to Fermi paradox.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.actaastro.2024.10.036
Technogenic pollution of near-Earth space poses a threat to the functioning of spacecraft. Collisions between space debris (SD) and spacecraft (SC) structures can have catastrophic consequences or cause localized damage, leading to the loss of SC operability or the failure of certain functions. The SC body must effectively protect the internal equipment from various external impacts, be technologically feasible to manufacture, and have as little mass as possible. As a result, the task of designing spacecraft bodies and protective screens for low-orbit SC is particularly relevant due to the large concentration of SD in low Earth orbits.
A comparative numerical study was conducted to evaluate the effectiveness of various thin shields in protecting against impacts from space debris particles. The study examined homogeneous shields made of A356 aluminum alloy and 316L stainless steel, as well as volumetrically reinforced composite shields produced using additive manufacturing with steel inclusions, and shields with a gradient distribution of steel throughout the thickness of an aluminum matrix, all with the same areal density. In all the heterogeneous plates considered, the volumetric concentration of steel was 36 %. The study covered an interaction velocity range of 2–9 km/s. Numerical modeling results indicated that the structure of the thin heterogeneous plate does not affect the shape of the debris cloud formed behind the protective shield. The findings of this study can serve as a basis for selecting materials for the development of more effective protection for spacecraft against high-velocity impacts.
{"title":"Shape of fragments cloud behind heterogeneous screen by a space debris particle impact","authors":"","doi":"10.1016/j.actaastro.2024.10.036","DOIUrl":"10.1016/j.actaastro.2024.10.036","url":null,"abstract":"<div><div>Technogenic pollution of near-Earth space poses a threat to the functioning of spacecraft. Collisions between space debris (SD) and spacecraft (SC) structures can have catastrophic consequences or cause localized damage, leading to the loss of SC operability or the failure of certain functions. The SC body must effectively protect the internal equipment from various external impacts, be technologically feasible to manufacture, and have as little mass as possible. As a result, the task of designing spacecraft bodies and protective screens for low-orbit SC is particularly relevant due to the large concentration of SD in low Earth orbits.</div><div>A comparative numerical study was conducted to evaluate the effectiveness of various thin shields in protecting against impacts from space debris particles. The study examined homogeneous shields made of A356 aluminum alloy and 316L stainless steel, as well as volumetrically reinforced composite shields produced using additive manufacturing with steel inclusions, and shields with a gradient distribution of steel throughout the thickness of an aluminum matrix, all with the same areal density. In all the heterogeneous plates considered, the volumetric concentration of steel was 36 %. The study covered an interaction velocity range of 2–9 km/s. Numerical modeling results indicated that the structure of the thin heterogeneous plate does not affect the shape of the debris cloud formed behind the protective shield. The findings of this study can serve as a basis for selecting materials for the development of more effective protection for spacecraft against high-velocity impacts.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.actaastro.2024.09.070
The “communications blackout” phenomenon has bothered the aerospace industry for several decades. However, the unsatisfying numerical methods and the rapidly changing inflow conditions make the estimation of electrons’ density inaccurate. To lay the first step for model calibration and the anti-blackout design, the Artificial Neural Networks and the direct simulation Monte Carlo (DSMC) method with the quantum-kinetic (Q-K) model are brought together to perform the global sensitivity analysis and uncertainty quantification. The three-dimensional RAM-C II (the second flight of the Radio Attenuation Measurement experiments) head flows are simulated considering aleatory uncertainties (inflow uncertainties) and epistemic uncertainties (reaction parameters uncertainties). Under the inflow condition of an 81 km atmosphere and a velocity of 7.8 km/s, aleatory uncertainties are found to be the dominant type of uncertainty for the number density of electrons, especially the freestream velocity, which means the accurate measurement of the vehicle’s velocity is much more critical than the calibration of the model. The importance ranking is listed, and the “Three rules” for finding the essential reactions are proposed. The probability that the real value is smaller than the nominal value considering both uncertainties is 27%–68%.
{"title":"Sensitivity analysis and uncertainty quantification for a three-dimensional rarefied ionized hypersonic flow","authors":"","doi":"10.1016/j.actaastro.2024.09.070","DOIUrl":"10.1016/j.actaastro.2024.09.070","url":null,"abstract":"<div><div>The “communications blackout” phenomenon has bothered the aerospace industry for several decades. However, the unsatisfying numerical methods and the rapidly changing inflow conditions make the estimation of electrons’ density inaccurate. To lay the first step for model calibration and the anti-blackout design, the Artificial Neural Networks and the direct simulation Monte Carlo (DSMC) method with the quantum-kinetic (Q-K) model are brought together to perform the global sensitivity analysis and uncertainty quantification. The three-dimensional RAM-C II (the second flight of the Radio Attenuation Measurement experiments) head flows are simulated considering aleatory uncertainties (inflow uncertainties) and epistemic uncertainties (reaction parameters uncertainties). Under the inflow condition of an 81 km atmosphere and a velocity of 7.8 km/s, aleatory uncertainties are found to be the dominant type of uncertainty for the number density of electrons, especially the freestream velocity, which means the accurate measurement of the vehicle’s velocity is much more critical than the calibration of the model. The importance ranking is listed, and the “Three rules” for finding the essential reactions are proposed. The probability that the real value is smaller than the nominal value considering both uncertainties is 27%–68%.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.actaastro.2024.10.016
The increasing volume of space debris in the outer space poses a significant threat to operational spacecraft. Hence, net capture systems have emerged as a promising technique for removing space debris. These systems operate by deploying a net to envelop and capture the debris. The effectiveness of debris capture using nets depends on ejection parameters such as speed, ejection angle, and the crucial initial distance between the net and debris. Simulations are performed to examine various scenarios of active debris removal. In addition, the experiments involved meticulously calibrated net and debris ejector systems, where bullets are utilized for net deployment by varying the angle of bullet ejection (). The net trajectory is determined using simplified equations of motion, while considering both the ejection dynamics and its interaction with the debris. The findings of this study reveal the correlations between the initial parameters and net performance pertaining to space debris capture. Larger ejection angles and greater distances between the net and the debris-hindered debris capture. Despite slight simultaneous net and debris ejection delays, the results of the real-world experiments validated the simulation results.
{"title":"Numerical and experimental study on effects of net-bullet ejection angles and initial distances on space-debris capture","authors":"","doi":"10.1016/j.actaastro.2024.10.016","DOIUrl":"10.1016/j.actaastro.2024.10.016","url":null,"abstract":"<div><div>The increasing volume of space debris in the outer space poses a significant threat to operational spacecraft. Hence, net capture systems have emerged as a promising technique for removing space debris. These systems operate by deploying a net to envelop and capture the debris. The effectiveness of debris capture using nets depends on ejection parameters such as speed, ejection angle, and the crucial initial distance between the net and debris. Simulations are performed to examine various scenarios of active debris removal. In addition, the experiments involved meticulously calibrated net and debris ejector systems, where bullets are utilized for net deployment by varying the angle of bullet ejection (<span><math><mi>θ</mi></math></span>). The net trajectory is determined using simplified equations of motion, while considering both the ejection dynamics and its interaction with the debris. The findings of this study reveal the correlations between the initial parameters and net performance pertaining to space debris capture. Larger ejection angles and greater distances between the net and the debris-hindered debris capture. Despite slight simultaneous net and debris ejection delays, the results of the real-world experiments validated the simulation results.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.actaastro.2024.10.020
A simulator and a hardware-in-the-loop (HIL) setup for the study of the electric system made by a short electrodynamic tether (EDT), an Electric Power Module (EPM) and a heaterless Hollow Cathode (HC) are presented. In the simulator, the EDT is modeled by the current–voltage (IV) characteristic of a bare EDT, the EPM involves a power supply and a variable resistor, and the IV curves of the emitter and the keeper of the HC are given by the linear fittings of the experimental curves obtained in the laboratory. The simulator was used to study an important problem for short EDT: the minimum power required by the power supply to reach an electric current at the cathode above the critical threshold to keep the plasma discharge as a function of ambient variables (the motional electric field and plasma density). Regarding the HIL, it emulates the EDT with a programmable power supply and a resistor, the EPM with a power supply and a set of resistors, and the HC by a set of Zener diodes. Additionally, the emulator has a computer and a microcontroller that allow to measure key electrical variables and command in real time and in closed-loop the programmable power supply to ensure that the EDT emulator satisfy the bare EDT IV curve. The three elements of the HIL were tested and compared with the theoretical model to validate its correct implementation and operation. Finally, the HIL was used to test and verify the electronic boards of the device of the E.T.PACK-F project.
本文介绍了用于研究由短电动系绳（EDT）、电力模块（EPM）和无加热器空心阴极（HC）组成的电力系统的模拟器和硬件在环（HIL）设置。在模拟器中，EDT 是通过裸 EDT 的电流-电压（IV）特性建模的，EPM 包括一个电源和一个可变电阻器，而 HC 发射器和保持器的 IV 曲线则是通过在实验室中获得的实验曲线的线性拟合给出的。模拟器被用来研究短 EDT 的一个重要问题：根据环境变量（运动电场和等离子体密度）的函数，要使阴极的电流达到临界阈值以上以保持等离子体放电，电源所需的最小功率。关于 HIL，它通过一个可编程电源和一个电阻器模拟 EDT，通过一个电源和一组电阻器模拟 EPM，通过一组齐纳二极管模拟 HC。此外，仿真器还配有计算机和微控制器，可以测量关键的电气变量，并对可编程电源进行实时闭环控制，以确保 EDT 仿真器满足 EDT IV 曲线的要求。对 HIL 的三个要素进行了测试，并与理论模型进行了比较，以验证其实施和运行的正确性。最后，HIL 被用于测试和验证 E.T.PACK-F 项目设备的电子板。
{"title":"Simulator and hardware emulator of a short electrodynamic tether system","authors":"","doi":"10.1016/j.actaastro.2024.10.020","DOIUrl":"10.1016/j.actaastro.2024.10.020","url":null,"abstract":"<div><div>A simulator and a hardware-in-the-loop (HIL) setup for the study of the electric system made by a short electrodynamic tether (EDT), an Electric Power Module (EPM) and a heaterless Hollow Cathode (HC) are presented. In the simulator, the EDT is modeled by the current–voltage (IV) characteristic of a bare EDT, the EPM involves a power supply and a variable resistor, and the IV curves of the emitter and the keeper of the HC are given by the linear fittings of the experimental curves obtained in the laboratory. The simulator was used to study an important problem for short EDT: the minimum power required by the power supply to reach an electric current at the cathode above the critical threshold to keep the plasma discharge as a function of ambient variables (the motional electric field and plasma density). Regarding the HIL, it emulates the EDT with a programmable power supply and a resistor, the EPM with a power supply and a set of resistors, and the HC by a set of Zener diodes. Additionally, the emulator has a computer and a microcontroller that allow to measure key electrical variables and command in real time and in closed-loop the programmable power supply to ensure that the EDT emulator satisfy the bare EDT IV curve. The three elements of the HIL were tested and compared with the theoretical model to validate its correct implementation and operation. Finally, the HIL was used to test and verify the electronic boards of the device of the E.T.PACK-F project.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.actaastro.2024.10.024
As the idea of crewed outposts on the Moon gains momentum, In-Situ Resource Utilization (ISRU) technologies tend to become imperative to fulfill astronauts' needs. This article explores a way to use the lunar regolith as a source material for the additive manufacturing of complex objects, based on the selective laser melting (SLM) technique. A lunar regolith analog, Basalt of Pic d’Ysson (BPY), is used as a starting point for this study, to investigate the now demonstrated impact of amorphous analog content in the powder bed, substrate type, and post-SLM annealing treatments on the mechanical properties of 3D-printed objects. Improvements to the manufacturing and sample extraction stages are proposed to systematically reproduce the high compressive strength values obtained, thus contributing to the robustness and reliability of the process.
随着在月球上建立载人前哨站的想法日益强烈，原地资源利用（ISRU）技术成为满足宇航员需求的当务之急。本文以选择性激光熔融（SLM）技术为基础，探讨了一种将月球碎屑岩用作复杂物体增材制造源材料的方法。本研究以月球残积岩类似物--Basalt of Pic d'Ysson (BPY)--为起点，研究现已证明的粉末床中非晶类似物含量、基质类型和选择性激光熔融（SLM）后退火处理对 3D 打印物体机械性能的影响。本研究建议改进制造和样品提取阶段，以系统地再现所获得的高抗压强度值，从而提高工艺的稳健性和可靠性。
{"title":"Selective laser melting of partially amorphous regolith analog for ISRU lunar applications","authors":"","doi":"10.1016/j.actaastro.2024.10.024","DOIUrl":"10.1016/j.actaastro.2024.10.024","url":null,"abstract":"<div><div>As the idea of crewed outposts on the Moon gains momentum, In-Situ Resource Utilization (ISRU) technologies tend to become imperative to fulfill astronauts' needs. This article explores a way to use the lunar regolith as a source material for the additive manufacturing of complex objects, based on the selective laser melting (SLM) technique. A lunar regolith analog, Basalt of Pic d’Ysson (BPY), is used as a starting point for this study, to investigate the now demonstrated impact of amorphous analog content in the powder bed, substrate type, and post-SLM annealing treatments on the mechanical properties of 3D-printed objects. Improvements to the manufacturing and sample extraction stages are proposed to systematically reproduce the high compressive strength values obtained, thus contributing to the robustness and reliability of the process.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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