Acta Astronautica最新文献_第3页

Motion and self-motion of thin bodies in rarefied gas 稀薄气体中薄体的运动和自运动

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-16 DOI: 10.1016/j.actaastro.2024.10.037

引用次数: 0

The three-dimensional maneuver control of spinning tether system under a new Lagrangian model 新拉格朗日模型下旋转系绳系统的三维机动控制

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-16 DOI: 10.1016/j.actaastro.2024.10.033

{"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}

引用次数: 0

Laser-optical technologies for space debris removal 用于清除空间碎片的激光光学技术

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-16 DOI: 10.1016/j.actaastro.2024.10.027

引用次数: 0

Development of means for suppressing the negative effects of interaction between the pilot and reentry and other high-speed vehicles 开发抑制飞行员与重返大气层飞行器和其他高速飞行器之间相互作用的负面影响的手段

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-16 DOI: 10.1016/j.actaastro.2024.10.028

引用次数: 0

Phenomenal consciousness is alien to us: SETI and the fermi paradox seen through the prism of illusionism and attention schema theory 现象意识与我们格格不入：从幻觉和注意力模式理论的棱镜看 SETI 和费米悖论

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-16 DOI: 10.1016/j.actaastro.2024.10.023

{"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}

引用次数: 0

Shape of fragments cloud behind heterogeneous screen by a space debris particle impact 空间碎片粒子撞击异质屏幕后碎片云的形状

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-16 DOI: 10.1016/j.actaastro.2024.10.036

{"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}

引用次数: 0

Sensitivity analysis and uncertainty quantification for a three-dimensional rarefied ionized hypersonic flow 三维稀薄离子化高超声速流的灵敏度分析和不确定性量化

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-15 DOI: 10.1016/j.actaastro.2024.09.070

{"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}

引用次数: 0

Numerical and experimental study on effects of net-bullet ejection angles and initial distances on space-debris capture 关于净弹射角和初始距离对空间碎片捕获的影响的数值和实验研究

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-15 DOI: 10.1016/j.actaastro.2024.10.016

{"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}

引用次数: 0

Simulator and hardware emulator of a short electrodynamic tether system 短电动系绳系统的模拟器和硬件仿真器

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-15 DOI: 10.1016/j.actaastro.2024.10.020

{"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}

引用次数: 0

Selective laser melting of partially amorphous regolith analog for ISRU lunar applications 用于 ISRU 月球应用的部分非晶质雷公石模拟物的选择性激光熔化

IF 3.1 2区物理与天体物理

Acta Astronautica Pub Date : 2024-10-15 DOI: 10.1016/j.actaastro.2024.10.024

引用次数: 0