Acta Astronautica最新文献_第7页

Effect of semifluoroalkyl substituents in the POSS on atomic oxygen exposure POSS 中的半氟烷基取代基对原子氧暴露的影响

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-28 DOI: 10.1016/j.actaastro.2024.09.060

Due to the many recent Earth observation missions, very low Earth orbit (VLEO) have become a pressing topic for satellite research. Since the density of atomic oxygen (AO) in VLEO is higher than in low Earth orbit (LEO), the need for AO-resistant materials based on polyhedral oligomeric silsesquioxane (POSS) is strong. However, the effects of the side-chain groups in the POSS on AO exposure are unclear. In this study, we focused on POSS molecules modified with semifluoroalkyl groups as side chains because fluorocarbon groups, such as fluorinated ethylene propylene (FEP), are known to have high AO resistance. Semifluoroalkyl- and alkyl-substituted POSS films were fabricated and exposed to a laser-detonation AO source. Microbalance measurements showed that the mass losses of the semifluoroalkyl-substituted POSS films were larger than those of alkyl-substituted POSS films. X-ray photoelectron spectroscopy measurements showed that the silica layers formed on the semifluoroalkyl-substituted POSS were thicker than on alkyl-substituted POSS films. Surface observation using a field emission scanning electron microscope revealed microscale cracks on the surface of the semifluoroalkyl-substituted POSS. These findings indicate that POSS molecules with fluorine substituents warrant careful consideration of the AO-barrier performance of the silica layer formed during AO exposure.

由于最近的许多地球观测任务，极低地球轨道（VLEO）已成为卫星研究的一个紧迫课题。由于极低地球轨道中的原子氧（AO）密度高于低地球轨道，因此非常需要基于多面体低聚硅倍半氧烷（POSS）的抗AO材料。然而，POSS 侧链基团对 AO 暴露的影响尚不清楚。在这项研究中，我们重点研究了以半氟烷基作为侧链的改性 POSS 分子，因为氟碳基团（如氟化乙烯丙烯（FEP））具有很高的抗 AO 能力。我们制作了半氟烷基和烷基取代的 POSS 薄膜，并将其暴露在激光爆破 AO 源下。微天平测量结果表明，半氟烷基取代的 POSS 薄膜的质量损失大于烷基取代的 POSS 薄膜。X 射线光电子能谱测量结果表明，半氟烷基取代的 POSS 膜上形成的二氧化硅层比烷基取代的 POSS 膜厚。使用场发射扫描电子显微镜进行的表面观察显示，半氟烷基取代的 POSS 表面出现了微小裂纹。这些发现表明，带有氟取代基的 POSS 分子在暴露于 AO 时形成的二氧化硅层的 AO 阻隔性能值得仔细考虑。

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引用次数: 0

Service spacecraft for space debris removal 清除空间碎片的服务航天器

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-27 DOI: 10.1016/j.actaastro.2024.09.055

The problem of space debris removal from the near-Earth space is being studied in almost every country taking part in space exploration. This is due to the global threat of critical increase in the number of space debris objects predicted for the near future, in particular as a result of significant growth in demand for multi-satellite constellations for various purposes. To date, researchers have proposed a large number of different methods for space debris removal. The work presented is the development of one of the promising contactless methods of space debris removal by an ion beam. The results of modeling and optimization of physical processes in the ion source to be mounted on board a service spacecraft that is necessary for implementing the considered method of space debris removal are presented. Besides, the results of thermal modeling and thermal mapping of the ion source during its operation are presented also, and the calculation results of its output parameters are compared to experimental data, which verified the small divergence angles of the generated ion beam. To assess the prospects of using a system for contactless space debris transportation by an ion beam using the obtained data on the operating parameters of the ion source, the trajectory design and mission analysis were carried out, which revealed the feasibility of removing seven space debris objects out of the protected region in geostationary orbit by a single service spacecraft. Besides, the preliminary service spacecraft design is presented.

几乎每个参与空间探索的国家都在研究从近地空间清除空间碎片的问题。这是因为预计在不久的将来，特别是由于出于各种目的对多卫星星座的需求大幅增长，空间碎片物体的数量将急剧增加，从而对全球构成威胁。迄今为止，研究人员已经提出了大量不同的空间碎片清除方法。本文介绍的工作是开发一种利用离子束清除空间碎片的前景看好的非接触式方法。本文介绍了对安装在服务航天器上的离子源的物理过程进行建模和优化的结果，这是实施所考虑的空间碎片清除方法所必需的。此外，还介绍了离子源运行期间的热建模和热绘图结果，并将其输出参数的计算结果与实验数据进行了比较，实验数据验证了所产生离子束的发散角较小。为了利用所获得的离子源工作参数数据评估使用离子束非接触式空间碎片运输系统的前景，进行了轨迹设计和飞行任务分析，结果表明用一个服务航天器将七个空间碎片物体移出地球静止轨道保护区是可行的。此外，还介绍了服务航天器的初步设计。

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引用次数: 0

Study to integrate Delay-Tolerant Network protocols in IoT LEO constellations for flood prevention 研究在物联网低地轨道星座中整合容时网络协议，用于防洪

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-27 DOI: 10.1016/j.actaastro.2024.09.004

In the era of the Internet of Things (IoT) the development of Direct-to-Satellite IoT (DtS-IoT) applications are becoming increasingly relevant. These applications are based on enabling IoT devices to communicate directly with satellites. In this scenario, LEO satellites can provide global IoT service coverage, becoming essential to connect devices in remote areas. As an example, the deployment of NarrowBand-IoT (NB-IoT) service is being actively investigated with the apparition of Non-Terrestrial Network (NTN) and DtS-IoT concepts. Although some initiatives propose seamless and ubiquitous service, these features may not be required for IoT applications. This relaxes the requirements in the satellite constellation architecture, enabling it to be more sparse. The connection between sensors, satellites and ground segment becomes intermittent and discontinuous in these non-dense architectures. Delay/Disruptive-tolerant protocols are essential to coexist with this network characteristics. Unfortunately, traditional IoT protocols have not been designed with this delay-tolerant feature. This work tackles this challenge by integrating Delay-Tolerant Network protocols with NB-IoT architecture. Specifically, the integration is based on interconnecting the Bundle Protocol and IP traffic through a novel interface. This development has been divided in three phases: (1) The definition of an architecture and protocol stack to tackle NTN IoT scenarios with discontinuities, (2) the analysis from simulated data of the resulting protocol stack in a realistic scenario based on flooding prevention, and (3) the implementation and validation of it in a laboratory testbed. The proposed case study uses a Direct-to-Satellite IoT architecture to create an early warning flooding detection system. The simulation results provide insights of the achieved performance with these architectures when servicing hundreds of sensing nodes.

在物联网（IoT）时代，开发直接对卫星物联网（DtS-IoT）应用变得越来越重要。这些应用的基础是使物联网设备能够直接与卫星通信。在这种情况下，低地轨道卫星可提供全球物联网服务覆盖，对连接偏远地区的设备至关重要。例如，随着非地面网络（NTN）和 DtS-IoT 概念的出现，人们正在积极研究部署窄带物联网（NB-IoT）服务。虽然一些倡议提出了无缝和无处不在的服务，但物联网应用可能并不需要这些功能。这就放宽了对卫星星座架构的要求，使其更加稀疏。在这些非密集架构中，传感器、卫星和地面段之间的连接变得断断续续、不连贯。要与这种网络特性共存，延迟/中断容忍协议是必不可少的。遗憾的是，传统的物联网协议在设计上并不具备这种延迟容忍特性。这项工作通过将延迟容忍网络协议与 NB-IoT 架构集成来应对这一挑战。具体来说，这种集成是通过一个新颖的接口将捆绑协议和 IP 流量互连起来。开发工作分为三个阶段：（1）定义架构和协议栈，以解决具有不连续性的 NTN 物联网场景；（2）根据模拟数据分析基于洪水预防的现实场景中产生的协议栈；（3）在实验室测试平台上实施和验证。建议的案例研究使用直接对卫星物联网架构来创建洪水预警检测系统。仿真结果提供了这些架构在为数百个传感节点提供服务时所实现的性能。

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引用次数: 0

Robust Model Predictive Control for an Ion Beam Shepherd in a large-debris removal mission 大型碎片清除任务中离子束牧马人的鲁棒模型预测控制

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-26 DOI: 10.1016/j.actaastro.2024.09.054

The increasing accumulation of space debris poses significant risks to spacecraft, making the development of effective debris mitigation technologies necessary. This paper explores the Ion Beam Shepherd (IBS) method as a potential contactless solution for deorbiting large debris objects. The IBS system concept involves a spacecraft equipped with an ion thruster to direct a controlled ion beam at the debris, generating a small force that gradually lowers its orbit. A proposed configuration of the chaser’s actuator system integrates radial and out-of-plane cold-gas thrusters along with in-track ion thrusters to enhance control and safety while maintaining low mission costs. A robust Model Predictive Control (MPC) strategy is implemented, using the theory of MPC for Tracking to ensure accurate positioning and effective deorbiting. This theoretical approach addresses uncertainties and perturbations to robustly guarantee safe distances between the chaser and the debris. Additionally, a new ray-marching-based algorithm is introduced to estimate the force and torque exerted by the ion beam on the target, considered as a 6 degrees of freedom object, improving simulation accuracy and control performance assessment. A comprehensive simulation of the deorbit of a large debris object is performed, demonstrating the potential of the IBS technology for future large-debris removal missions. This research advances the conceptual framework and control techniques for the IBS technology, advancing towards its future implementation in space debris mitigation.

空间碎片的日益积累给航天器带来了巨大风险，因此开发有效的碎片缓减技术十分必要。本文探讨了离子束牧羊人（IBS）方法，将其作为一种潜在的非接触式解决方案，用于使大型碎片物体脱离轨道。IBS 系统的概念包括一个配备离子推进器的航天器，将受控离子束射向碎片，产生一个小的力，逐渐降低碎片的轨道。建议的追逐者推进器系统配置集成了径向和平面外冷气体推进器以及轨道内离子推进器，以加强控制和安全性，同时保持较低的任务成本。利用跟踪模型预测控制（MPC）理论，实施了稳健的模型预测控制（MPC）策略，以确保精确定位和有效脱轨。这种理论方法可解决不确定性和扰动问题，从而稳健地保证追逐者与碎片之间的安全距离。此外，还引入了一种新的基于射线行进的算法，用于估算离子束对目标施加的力和扭矩，将目标视为一个 6 自由度物体，从而提高了仿真精度和控制性能评估。对一个大型碎片物体的脱轨过程进行了全面模拟，展示了离子束控制技术在未来大型碎片清除任务中的潜力。这项研究推进了 IBS 技术的概念框架和控制技术，为今后在空间碎片缓减领域实施该技术奠定了基础。

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引用次数: 0

Gamification as a tool to identify and address ongoing challenges in space activities: the case of space debris mitigation 游戏化作为确定和应对空间活动中持续存在的挑战的工具：空间碎片减缓案例

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-26 DOI: 10.1016/j.actaastro.2024.09.057

This article outlines a project aimed at developing a serious game to address the challenge of space debris mitigation within the broader context of space security. The first section examines the current state of space activity issues and their gamification. The second section introduces the concept of the game utilizing the ARDI model, emphasizing the significance of each element in addressing these challenges. The third section focuses on the practical refinement of the proposed game concept. The article suggests that the game could serve as a tool for identifying and resolving ongoing challenges in space activity.

本文概述了一个旨在开发严肃游戏的项目，以便在更广泛的空间安全背景下应对减少空间碎片的挑战。第一部分探讨了空间活动问题及其游戏化的现状。第二部分介绍了利用 ARDI 模型的游戏概念，强调了每个元素在应对这些挑战中的重要性。第三部分侧重于对所提出的游戏概念进行实际改进。文章认为，该游戏可作为确定和解决空间活动中持续存在的挑战的工具。

引用次数: 0

An insight on technical regulations for new activities in space 洞察太空新活动的技术规范

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-26 DOI: 10.1016/j.actaastro.2024.09.056

Space Traffic Management (STM) is becoming increasingly important as new space activities emerge, such as mega-constellations, on-orbit servicing etc. These developments, although promising great advances, nevertheless present complicated issues that demand stringent technical constraints. Effective STM necessitates extensive rules to ensure the safety, sustainability, and orderly execution of space operations. This research emphasizes the critical need for updated technical regulations that address the operational complexities involved with these new activities. It seeks to build a secure and collaborative space environment by establishing detailed legislative frameworks and emphasizing international cooperation, so ensuring the long-term profitability and success of space exploration and usage. Through meticulous analysis, the paper identifies regulatory gaps and proposes a robust framework capable of accommodating the evolving landscape of regulations. Drawing upon humanity's collective experience across different domains, the proposed framework aims to foster responsible growth in outer space while safeguarding its integrity for future generations. This paper examines the existing regulatory framework applicable to four distinct categories of New Technologies and Activities in space; identifies gaps where they exist; and suggests a capable and robust regulatory framework. This framework leverages humankind's experience in other domains to nurture and assist responsible growth in the outer space domain while ensuring proper stewardship of that domain, now and in the future. This paper is based on the report prepared by members of working group 4.2 of the Space Traffic Management Committee (TC 26).

随着超大型星群、在轨服务等新空间活动的出现，空间交通管理（STM）变得越来越重要。这些发展虽然有望取得巨大进步，但也带来了复杂的问题，需要严格的技术限制。有效的 STM 需要广泛的规则，以确保空间操作的安全性、可持续性和有序执行。这项研究强调，亟需更新技术规范，以解决这些新活动所涉及的复杂操作问题。它旨在通过建立详细的立法框架和强调国际合作，建立一个安全和协作的空间环境，从而确保空间探索和利用的长期盈利能力和成功。通过缜密的分析，本文找出了监管漏洞，并提出了一个能够适应不断变化的监管环境的稳健框架。借鉴人类在不同领域的集体经验，拟议框架旨在促进外层空间负责任的发展，同时为子孙后代保护外层空间的完整性。本文研究了适用于四类不同空间新技术和新活动的现有监管框架；找出了存在的差距；并提出了一个有能力的、强有力的监管框架。该框架利用人类在其他领域的经验，促进和协助外层空间领域负责任的发展，同时确保现在和将来对该领域的适当管理。本文以空间交通管理委员会（TC 26）4.2 工作组成员编写的报告为基础。

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引用次数: 0

Secular dynamics and the lifetimes of lunar artificial satellites under natural force-driven orbital evolution 自然力驱动轨道演变下的月球人造卫星的周期动态和寿命

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-26 DOI: 10.1016/j.actaastro.2024.09.051

In this paper, we study the long-term (time scale of several years) orbital evolution of lunar satellites under the sole action of natural forces. In particular, we focus on secular resonances, caused either by the influence of the multipole moments of the lunar potential and/or by the Earth’s and Sun’s third-body effect on the satellite’s long-term orbital evolution. Our study is based on a simplified secular model obtained in ‘closed form’, i.e., without expansions in the satellite’s orbital eccentricity. Contrary to the case of artificial Earth satellites, in which many secular resonances compete in dynamical impact, we give numerical evidence that for lunar satellites only the

2 g -

resonance (

\dot{ω} = 0

) affects significantly the orbits at secular timescales. We interpret this as a consequence of the strong effect of lunar mascons. We show that the lifetime of lunar satellites is, in particular, nearly exclusively dictated by the

2 g

resonance. By deriving a simple analytic model, we propose a theoretical framework which allows for both qualitative and quantitative interpretation of the structures seen in numerically obtained lifetime maps. This involves explaining the main mechanisms driving eccentricity growth in the orbits of lunar satellites. In fact, we argue that the re-entry process for lunar satellites is not necessarily a chaotic process (as is the case for Earth satellites), but rather due to a sequence of bifurcations leading to a dramatic variation in the structure of the separatrices in the

2 g

resonance’s phase portrait, as we move from the lowest to the highest limit in inclination (at each altitude) where the

2 g

resonance is manifested.

在本文中，我们研究了月球卫星在自然力单独作用下的长期（数年时间尺度）轨道演变。我们尤其关注月球势能多极矩的影响和/或地球和太阳对卫星长期轨道演变的第三体效应所引起的世俗共振。我们的研究基于以 "封闭形式 "获得的简化世俗模型，即不对卫星轨道偏心率进行扩展。在人造地球卫星中，许多世俗共振在动态影响方面相互竞争，与此相反，我们给出的数值证据表明，对月球卫星而言，只有 2g 共振（ω=0）在世俗时间尺度上对轨道产生重大影响。我们将此解释为月球马斯康子强烈影响的结果。我们的研究表明，月球卫星的寿命几乎完全由 2g 共振决定。通过推导出一个简单的分析模型，我们提出了一个理论框架，该框架允许对数值获得的寿命图中的结构进行定性和定量解释。这包括解释月球卫星轨道偏心率增长的主要驱动机制。事实上，我们认为月球卫星的重返过程并不一定是一个混乱的过程（就像地球卫星的情况一样），而是由于一系列分岔导致 2g 共振相位图中的分离矩阵结构发生了巨大变化，因为我们从倾角的最低极限到最高极限（在每个高度上）都会出现 2g 共振。

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引用次数: 0

Cathode-less RF plasma thruster design and optimisation for an atmosphere-breathing electric propulsion (ABEP) system 用于大气呼吸电力推进（ABEP）系统的无阴极射频等离子推进器的设计与优化

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-25 DOI: 10.1016/j.actaastro.2024.09.041

Atmosphere-breathing electric propulsion (ABEP) is a concept that ingests residual atmospheric gases as a source of propellant for an electric thruster, removing the need for onboard propellant storage. This would enable continuous low-thrust drag compensation, extending the lifetime of spacecraft in Very-Low Earth Orbit (VLEO);

<

250 km. VLEO is an appealing region for spacecraft operations, enabling new remote sensing missions with improved radiometric performance and spatial resolution, whilst reducing size, mass and power requirements, as well as mission cost. A preliminary design review and optimisation is therefore conducted for an ABEP system that uses the cathode-less radio frequency (RF) plasma thruster from Technology for Innovation & Propulsion (T4i) S.p.A. This removes the issue of thruster erosion by means of magnetic confinement and offers reduced susceptibility to varying atmospheric composition. A semi-empirical oxygen-nitrogen global source model (GSM) has been developed which considers the volume-averaged flux, momentum, and energy balance of the RF discharge. This includes a detailed chemistry model for the complex electron-molecular reactions and energy-loss channels of air plasma in the ionisation chamber. The GSM is coupled to an analytical model of flux balance for an air intake, verified by Direct Simulation Monte-Carlo (DSMC) simulation, to consider its design for maximum collection efficiency. This is then utilised in a robust multi-objective optimisation of the ABEP system, accounting also for spacecraft aerodynamics and power requirements.

大气呼吸电力推进器（ABEP）是一种利用残余大气气体作为电力推进器推进剂来源的概念，无需机载推进剂存储。这将实现持续的低推力阻力补偿，延长极低地球轨道（VLEO）上航天器的寿命。甚低地球轨道对航天器的运行来说是一个很有吸引力的区域，它可以执行新的遥感任务，提高辐射性能和空间分辨率，同时减小体积、质量和功率要求，降低任务成本。因此，对 ABEP 系统进行了初步设计审查和优化，该系统使用了 Technology for Innovation & Propulsion (T4i) S.p.A. 公司的无阴极射频（RF）等离子推进器。我们开发了一个半经验氧氮全球源模型（GSM），该模型考虑了射频放电的体积平均通量、动量和能量平衡。其中包括电离室中复杂的电子-分子反应和空气等离子体能量损失通道的详细化学模型。GSM 与进气口的通量平衡分析模型相结合，并通过直接模拟蒙特卡洛（DSMC）仿真进行验证，以考虑最大收集效率的设计。然后利用该模型对 ABEP 系统进行稳健的多目标优化，同时考虑航天器空气动力学和功率要求。

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引用次数: 0

Outgassing properties of bamboo-derived cellulose nanofiber for space applications 用于太空应用的竹制纤维素纳米纤维的除气特性

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-24 DOI: 10.1016/j.actaastro.2024.09.048

In this study, the outgassing properties of bamboo-derived cellulose nanofibers (CNFs) for space applications were investigated. Outgassing rate tests based on ASTM E1559 were conducted on bamboo, bamboo-derived CNF, and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized CNF (T-CNF). The results showed that CNF emitted only water, while bamboo and T-CNF emitted outgas that is not water and had the peaks at

-

40 °C and 55 °C, respectively, in quartz crystal microbalance thermogravimetric gas analysis. These findings reveal that CNFs are promising materials for low-outgassing applications. Moreover, the results indicate that the TEMPO treatment produces outgassing sources into the CNF.

本研究调查了用于太空应用的竹制纤维素纳米纤维 (CNF) 的放气特性。根据 ASTM E1559 对竹子、竹子衍生的 CNF 和 2,2,6,6- 四甲基哌啶-1-氧（TEMPO）氧化 CNF（T-CNF）进行了放气率测试。结果表明，在石英晶体微天平热重气体分析中，CNF 只释放出水，而竹子和 T-CNF 释放出的气体不含水，峰值分别为 -40 °C 和 55 °C。这些研究结果表明，CNFs 是很有前景的低放气应用材料。此外，研究结果表明，TEMPO 处理会在 CNF 中产生放气源。

引用次数: 0

Advantages of laser etching of metals and semiconductors when working in space 在太空工作时对金属和半导体进行激光蚀刻的优势

IF 3.1 2区物理与天体物理 Q1 ENGINEERING, AEROSPACE

Acta Astronautica

Pub Date : 2024-09-24 DOI: 10.1016/j.actaastro.2024.09.052

To work in space, it is necessary to create high-tech production facilities in orbit. It seems that they should include a universal, compact, powerful laser device to perform various tasks. The paper considers only one, relatively new, direction of laser use, designed to improve the fire safety of a spacecraft. An environmentally safe method of "dry" laser etching for the rapid detection of the structure of metals and semiconductors is proposed.

要在太空工作，就必须在轨道上建立高科技生产设施。这些设施似乎应包括一个通用、紧凑、功能强大的激光装置，以执行各种任务。本文只考虑了一个相对较新的激光使用方向，旨在提高航天器的防火安全。本文提出了一种环境安全的 "干式 "激光蚀刻方法，用于快速检测金属和半导体的结构。

引用次数: 0