Acta Astronautica最新文献

{"title":"Shape of fragments cloud behind heterogeneous screen by a space debris particle impact","authors":"A.E. Buzyurkin,&nbsp;V.M. Fomin,&nbsp;A.E. Kraus,&nbsp;E.I. Kraus,&nbsp;I.I. Shabalin","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":"226 ","pages":"Pages 169-177"},"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}

{"title":"Phenomenal consciousness is alien to us: SETI and the fermi paradox seen through the prism of illusionism and attention schema theory","authors":"Guillaume Friconnet","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":"226 ","pages":"Pages 42-49"},"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}

{"title":"Multi-aperture telescopes at the quantum limit of superresolution imaging : Detecting subRayleigh object near a star","authors":"Amit Kumar Jha ,&nbsp;Stephen Fleming ,&nbsp;Nicolas Deshler ,&nbsp;Aqil Sajjad ,&nbsp;Mark Neifeld ,&nbsp;Amit Ashok ,&nbsp;Saikat Guha","doi":"10.1016/j.actaastro.2024.09.064","DOIUrl":"10.1016/j.actaastro.2024.09.064","url":null,"abstract":"<div><div>Angular resolution is a critical aspect of astronomical observation, as it determines the minimum resolvable angle between two objects. This is governed by the Rayleigh criterion, which states that the minimum resolvable angle is proportional to the wavelength (<span><math><mi>λ</mi></math></span>) over the diameter (<span><math><mi>D</mi></math></span>) of the aperture of a monolithic telescope. While larger aperture telescopes have advantages such as smaller angular resolution and higher sensitivity to dim and small exoplanets, they also have disadvantages such as higher launch cost, design intricacies, and high mission cost. Using multi-aperture telescopes can be a cost-effective alternative as they work on the principles of baseline interferometry, making the minimum resolvable angle proportional to <span><math><mrow><mi>λ</mi><mo>/</mo><mi>B</mi></mrow></math></span>, where <span><math><mi>B</mi></math></span> is the baseline. In this work, we compare the performance of a single monolithic telescope to a multi-aperture alternative with the same effective glass area in the context of hypothesis testing between two scenarios - <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> (a star) and <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> (a star with an exoplanet). We formulate the theory based on likelihood ratio tests and find that the multi-aperture telescope performs better than the monolithic telescope when direct detection is used on the focal plane. While this is expected, the performance can be further improved by using quantum-inspired detecting strategies. We utilize Quantum Binary Spatial Mode Demultiplexing (BSPADE) to process the point spread function (PSF) of the telescopes and find better performance compared to the respective direct detection measurement. Therefore, our efforts can be viewed as one of the initial steps toward employing quantum-inspired detection techniques in sparse aperture configurations for high-contrast imaging applications. In conclusion, our work shows that multi-aperture telescopes are an effective alternative to monolithic telescopes for object discrimination and potentially for super-resolution imaging and their performance can be further improved by using quantum-inspired detection strategies. With their cost-effectiveness (see Appendix C) and potential for high performance, multi-aperture telescopes can significantly advance our ability to observe and study exoplanets and other celestial objects. Future research can explore ways to optimize the performance of multi-aperture telescopes and further improve their capabilities for astronomical observation, potentially facilitating the detection and imaging of Earth-like exoplanets.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"226 ","pages":"Pages 531-541"},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593298","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}

{"title":"Sensitivity analysis and uncertainty quantification for a three-dimensional rarefied ionized hypersonic flow","authors":"Dongming Ding ,&nbsp;Xiaobo Liu ,&nbsp;Linying Li ,&nbsp;Bin Zhang ,&nbsp;Hong Liu","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":"226 ","pages":"Pages 157-168"},"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}

{"title":"Numerical and experimental study on effects of net-bullet ejection angles and initial distances on space-debris capture","authors":"Andry Renaldy Pandie,&nbsp;Hirohisa Kojima","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":"226 ","pages":"Pages 361-374"},"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}

{"title":"Simulator and hardware emulator of a short electrodynamic tether system","authors":"Angel del-Pino-Jimenez ,&nbsp;Amadeo Velasco ,&nbsp;Gonzalo Sanchez-Arriaga","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":"226 ","pages":"Pages 298-308"},"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}

{"title":"Selective laser melting of partially amorphous regolith analog for ISRU lunar applications","authors":"Julien Granier ,&nbsp;Thierry Cutard ,&nbsp;Patrick Pinet ,&nbsp;Yannick Le Maoult ,&nbsp;Serge Chevrel ,&nbsp;Thierry Sentenac ,&nbsp;Jean-Jacques Favier","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":"226 ","pages":"Pages 66-77"},"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}

{"title":"Characterization of the outgassing event during BepiColombo second Venus flyby using Italian Spring Accelerometer data","authors":"Umberto De Filippis ,&nbsp;Carlo Lefevre ,&nbsp;Marco Lucente ,&nbsp;Carmelo Magnafico ,&nbsp;Francesco Santoli","doi":"10.1016/j.actaastro.2024.09.062","DOIUrl":"10.1016/j.actaastro.2024.09.062","url":null,"abstract":"<div><div>The BepiColombo ESA-JAXA mission, launched on October 20, 2018, is scheduled to reach Mercury in November 2026. The Mercury Composite Spacecraft comprises three modules: the Mercury Planetary Orbiter, the Mercury Magnetospheric Orbiter, and the Mercury Transfer Module. Currently, BepiColombo is in its seven-year cruise phase, having completed one Earth flyby, two Venus flybys, and three Mercury flybys. The spacecraft is equipped with the high-accuracy Italian Spring Accelerometer, capable of measuring non-gravitational acceleration variations at frequencies between <span><math><mrow><mrow><mo>[</mo><mn>3</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup><mo>,</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>]</mo></mrow><mspace></mspace><mi>Hz</mi></mrow></math></span>. Interpreting accelerometer data can be challenging due to overlapping dynamic effects. During the second Venus flyby, the accelerometer data revealed significant signatures of the gravity gradient signal induced by the planet on the proof masses. Notably, a large, unexpected acceleration spike was detected near the closest approach, lasting a few minutes. Further analysis determined that this spike was most likely caused by outgassing from the Mercury Planetary Orbiter radiator. This paper analyzes the Italian Spring Accelerometer data from the second Venus flyby, focusing on the unexpected acceleration spike. By combining the torque data from the reaction wheel with accelerometer data, the team was able to estimate the outgassing location, confirming it as the spacecraft radiator. Additionally, data from the Mass Spectrum Analyzer sensor, part of the Mercury Plasma Particle Experiment, suggest that <span><math><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi></mrow></math></span> outgassing occurred. The estimated mass of sublimated water is approximately 2 grams.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"226 ","pages":"Pages 11-19"},"PeriodicalIF":3.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444905","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}

{"title":"NASA's impact on medical innovation: Breakthrough technologies from space research","authors":"Jay Michael Jaber ,&nbsp;Joshua Ong ,&nbsp;Ethan Waisberg ,&nbsp;Prithul Sarker ,&nbsp;Nasif Zaman ,&nbsp;Alireza Tavakkoli ,&nbsp;Andrew G. Lee","doi":"10.1016/j.actaastro.2024.10.026","DOIUrl":"10.1016/j.actaastro.2024.10.026","url":null,"abstract":"<div><div>Outer space is an austere environment filled with unique and potentially dangerous stressors that can impact the physiologic function of astronauts during and after their stay above the atmosphere. Within 24 h of flight, astronauts may experience nausea and malaise, coined space motion sickness, due to vestibular and ocular sensory mismatch and changes in cranial and other fluid pressures. Although temporary, long-lasting conditions also arise. Spaceflight Associated Neuro-Ocular Syndrome is associated optic disc edema, globe flattening, and hyperopic refractive error shifts, and may lead to permanent structural changes. In addition, astronauts during space flight can lose up to 30 % of their muscle mass and 8–12 % of bone density. Some of these changes require months of rehabilitation and adaptation to make a full recovery. Radiation and secondary cellular alterations can lead to carcinogenesis, microbiome shifts, and immunological dysfunction. To combat these changes, NASA has continually researched ways to improve the spaceflight experience. New spin off technology from NASA to address these astronaut health concerns often find their way into the terrestrial consumer and healthcare markets. This paper aims to identify NASA associated breakthroughs in medical innovation including cutting-edge technology created for laser tracking of ballistic missiles, durable polymers for high-speed air travel, refractive eye surgery, and cardiac resynchronization devices.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"226 ","pages":"Pages 34-41"},"PeriodicalIF":3.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444907","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}

{"title":"Landmark-aware autonomous odometry correction and map pruning for planetary rovers","authors":"Chenxi Lu ,&nbsp;Meng Yu ,&nbsp;Hua Li ,&nbsp;Hutao Cui","doi":"10.1016/j.actaastro.2024.10.025","DOIUrl":"10.1016/j.actaastro.2024.10.025","url":null,"abstract":"<div><div>Planetary rover autonomous localization is paramount for a planetary surface exploration mission. However, existing methods demonstrate limited localization accuracy, mostly due to the unstructured texture characterization of planetary surface. In response, this study presents a novel Neural Radiance Field (NeRF) driven visual odometry correction method that allows for high-precision 6-DoF rover pose estimation and local map pruning. First, an innovative image saliency evaluation approach, combining binarization and feature detection, is introduced to meticulously select landmarks that are conducive to rover re-localization. Subsequently, we conduct 3D reconstruction and rendering of the chosen landmarks based on <em>a-priori</em> knowledge of planetary surface images and their Neural Radiance Field (NeRF) models. High-precision odometry correction is achieved through the optimization of photometric loss between NeRF rending images and real images. Simultaneously, the odometry correction mechanism is employed in an autonomous manner to refine the NeRF model of the corresponding landmark, leading to an improved local map and gradually enhanced rover localization accuracy. Numerical simulation and experiment trials are carried out to evaluate the performance of the proposed method, results of which demonstrate state-of-the-art rover re-localization accuracy and local map pruning.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"226 ","pages":"Pages 86-96"},"PeriodicalIF":3.1,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534984","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}