Acta Astronautica最新文献_第2页

Explosion risks: Variety of deflagration-to-detonation transition scenarios in smooth tubes 爆炸风险：光滑管道中从爆燃到爆炸的各种过渡情况

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

Acta Astronautica

Pub Date : 2024-10-21 DOI: 10.1016/j.actaastro.2024.10.038

In the framework of comprehensive assessment of explosion risks on board of spacecrafts and on the facilities of launch places, the paper is focused on the detailed analysis of particular scenarios of deflagration-to-detonation transition taking place in smooth tubes filled with acetylene-oxygen mixtures of different compositions. By means of precise numerical simulation it is demonstrated that various scenarios of detonation onset can take place depending on the mixture composition and its initial thermodynamic state. It is demonstrated that independent on the particular scenario always the basic mechanism of detonation onset via the formation of strong enough shock wave takes place. In more reactive mixtures the strong shock originates from the self-sustained process of joint pressure build up and reaction intensification exactly at the flame front. In less reactive mixtures the transient flow behavior leads to the shock waves generation and interaction. As a result, a brand new reaction kernel could arise in the area of shock waves interaction. In number of cases, that leads to the coupling between the shock wave and the newborn reaction front and results in the strong shock formation and further detonation onset.

在对航天器和发射场设施上的爆炸风险进行全面评估的框架内，本文重点详细分析了在充满不同成分的乙炔-氧气混合物的光滑管道中发生爆燃到爆炸转变的特定情况。通过精确的数值模拟证明，根据混合物的成分及其初始热力学状态，可能会发生各种起爆情况。结果表明，与特定情况无关，起爆的基本机制始终是通过形成足够强的冲击波来实现的。在反应性较强的混合物中，强冲击波源自火焰前沿的联合压力积累和反应加剧的自持过程。在反应性较低的混合物中，瞬态流动行为会导致冲击波的产生和相互作用。因此，在冲击波相互作用的区域可能会产生全新的反应核。在许多情况下，这会导致冲击波与新生反应前沿之间的耦合，从而形成强烈的冲击并进一步引发爆燃。

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引用次数: 0

Joint acceleration based adaptive reactionless manipulation of closed-loop multi-arm space robot in post-capture phase 基于联合加速度的闭环多臂空间机器人后捕捉阶段自适应无反作用力操纵

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

Acta Astronautica

Pub Date : 2024-10-20 DOI: 10.1016/j.actaastro.2024.10.022

Space robots will play a crucial role in on-orbit operations like refuelling, servicing, and capture of debris. This paper focuses on capturing a non-cooperative target using a multi-arm space robot and its post-capture control. In the post-capture phase, a target object gets rigidly attached to end-effectors, and arms get into a closed-loop configuration, resulting in added constraints. Further, due to a target object’s unknown inertial parameters, system behaviour becomes unpredictable and poses difficulty in achieving reactionless manipulation to minimize base attitude disturbance. We present acceleration-based adaptive reactionless manipulation in the post-capture phase considering the unknown inertial parameter of a target. The regressor form required for adapting the joint states is derived using the acceleration-based approach. To update unknown parameters recursively immediately after impact, three methods, namely, recursive least square (RLS), weighted recursive least square (WRLS), and Kalman filter (KF), are used and compared. The efficacy of these methods has been demonstrated by using numerical studies of a dual-arm space robot that captures a non-cooperative target. Further, the acceleration-based and the velocity-based approaches are individually compared with RLS, WRLS and KF methods. Investigations have also been carried out to study the effects of change in ratios of base-to-target and base-to-robot masses, as well as angular velocities of a target.

空间机器人将在加油、维修和捕获碎片等在轨操作中发挥至关重要的作用。本文的重点是使用多臂太空机器人捕获非合作目标及其捕获后控制。在捕获后阶段，目标物体被刚性连接到末端执行器上，手臂进入闭环配置，从而增加了限制。此外，由于目标物体的惯性参数未知，系统行为变得不可预测，给实现无反作用力操纵以最小化基本姿态干扰带来了困难。考虑到目标的未知惯性参数，我们提出了在捕获后阶段基于加速度的自适应无反作用力操纵。通过基于加速度的方法，我们得出了适应关节状态所需的回归器形式。为了在撞击后立即递归更新未知参数，使用并比较了三种方法，即递归最小平方法（RLS）、加权递归最小平方法（WRLS）和卡尔曼滤波法（KF）。通过对捕捉非合作目标的双臂空间机器人进行数值研究，证明了这些方法的有效性。此外，还将基于加速度的方法和基于速度的方法分别与 RLS、WRLS 和 KF 方法进行了比较。还对底座与目标、底座与机器人的质量比以及目标角速度变化的影响进行了研究。

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引用次数: 0

Numerical search for the effective thermal conductivity of cracked media 裂纹介质有效热导率的数值搜索

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

Acta Astronautica

Pub Date : 2024-10-19 DOI: 10.1016/j.actaastro.2024.10.042

Spacecraft parts accumulate damage during operation and defects that are invariably present even in new designs may grow. This leads to changes in the behavior of individual parts of the space vehicle and, consequently, to the risk of fracture. A more accurate assessment of spacecraft safety requires internal defects to be included in the material models under consideration. One of the main hazardous effects on space objects is multiple temperature heating and cooling due to periodic action of solar rays. This paper presents a study of thermal conduction of media containing cracks. It is carried out with the help of a technique developed by the authors to determine the effective thermal conductivity of materials and based on approximate numerical solution of the steady-state thermal conduction problem for a three-dimensional medium with cracks by the boundary element method. This technique allows to obtain the distribution of the temperature field and heat flux density at any point of the body under consideration, as well as to calculate the effective parameters of materials with high accuracy at relatively low calculation time using ordinary personal computers of average power. The basis of the numerical method presented in this paper is the decomposition of the desired solution into a series of some pre-calculated analytical solutions of the heat conduction equations. The dependence of the effective thermal conductivity on the density of thermally insulated cracks was considered. The formula of this dependence is proposed. Verification of the proposed methodology was carried out by comparing the numerical results of a number of problems with the results of other authors.

航天器部件在运行过程中会累积损坏，即使在新设计中也必然存在的缺陷可能会增加。这导致航天器单个部件的行为发生变化，进而产生断裂风险。要更准确地评估航天器的安全性，就必须将内部缺陷纳入所考虑的材料模型中。对空间物体的主要危险影响之一是太阳光周期性作用下的多重温度加热和冷却。本文对含有裂缝的介质的热传导进行了研究。该研究借助了作者开发的一种确定材料有效热传导率的技术，并基于边界元法对含有裂缝的三维介质的稳态热传导问题进行近似数值求解。利用这种技术，可以获得被研究体任意点的温度场分布和热流密度，并利用平均功率的普通个人电脑，在相对较短的计算时间内，高精度地计算出材料的有效参数。本文所介绍的数值方法的基础是将所需的解分解为一系列预先计算过的热传导方程分析解。考虑了有效热导率与隔热裂缝密度的关系。提出了这种依赖关系的计算公式。通过将一些问题的数值结果与其他作者的结果进行比较，对所提出的方法进行了验证。

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引用次数: 0

A novel tether-net configuration with double-linked bullets for suppressing reshrinking motion after full deployment 新型系绳网配置与双链子弹，用于抑制完全展开后的回缩运动

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

Acta Astronautica

Pub Date : 2024-10-19 DOI: 10.1016/j.actaastro.2024.10.035

Tether-nets have attracted considerable attention as tools for capturing space debris. However, owing to the lack of aerodynamic drag to resist collapse in space, tether-nets tend to shrink back after deployment because of tension in the tether. Various strategies have been proposed to suppress this reshrinking motion before debris capture, such as equipping bullets with thruster modules to control their trajectory after ejection and incorporating a bullet ejection-angle adjustment mechanism. However, these approaches complicate the tether-net design and/or ejection systems. In this study, a novel tether-net configuration comprising double-linked bullets, wherein the inner and outer bullets are connected via a tether, was proposed to prevent the tether-net from reshrinking after full deployment. Upon full deployment, as the bullets start to rebound due to impulsive tension, the outer bullets fly outward, pulling the inner bullets and exchanging momentum to suppress their rebounding motion. The effectiveness of the double-linked bullets in suppressing the reshrinking motion of the tether-net was demonstrated by comparing the results with those obtained using typical single-linked bullets. Furthermore, the influence of the inner and outer bullet mass ratio on the tether-net deployment and reshrinking motion was numerically analyzed to identify the optimal mass ratio for effectively suppressing the reshrinking motion. The results indicate that a mass ratio of 1.0, or slightly less, between the outer and inner bullets is most effective in suppressing tether-net reshrinking.

作为捕获空间碎片的工具，系绳网引起了相当大的关注。然而，由于缺乏空气动力阻力来抵抗空间坍塌，系留网在部署后往往会因系留的张力而回缩。为了在捕获碎片之前抑制这种回缩运动，人们提出了各种策略，例如在子弹上安装推进器模块，以控制子弹弹射后的轨迹，以及安装子弹弹射角度调整机制。然而，这些方法都使系留网设计和/或弹射系统复杂化。在这项研究中，提出了一种新型系留网配置，该配置由双连式子弹组成，其中内子弹和外子弹通过系留连接，以防止系留网在完全展开后重新收缩。完全展开后，当子弹因脉冲拉力开始反弹时，外层子弹向外飞出，拉动内层子弹并交换动量以抑制其反弹运动。通过与使用典型单链子弹的结果进行比较，证明了双链子弹在抑制系绳网回缩运动方面的有效性。此外，还对内外弹质量比对系绳网展开和回缩运动的影响进行了数值分析，以确定有效抑制回缩运动的最佳质量比。结果表明，内外弹质量比为 1.0 或略低于 1.0 时，能最有效地抑制系绳网的再收缩。

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引用次数: 0

Descriptive models for lunar High-Ti deposits 月球高钛矿床的描述性模型

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

Acta Astronautica

Pub Date : 2024-10-18 DOI: 10.1016/j.actaastro.2024.10.031

High-Ti deposits on the Moon may emerge as a key resource for oxygen extraction. Descriptive models are the first qualitative step toward quantitative assessments of natural resources. Such models provide a structured framework for understanding the formation processes and spatial distribution of discrete types of resource deposits. In this study, we provide the first lunar descriptive models, characterizing high-Ti lunar deposits, drawing parallels with established models used in assessing mineral deposits on Earth.

Our methodology involves utilizing remote sensing datasets and geological maps to identify and describe high-Ti deposits. This is supplemented by data extrapolated from Apollo missions. However, there remain critical knowledge gaps, particularly regarding petrography, subsurface information, surface characteristics, and physical properties of high-Ti deposits, which necessitate further exploration and analysis.

月球上的高钛矿床可能成为提取氧气的关键资源。描述性模型是对自然资源进行定量评估的第一步。这些模型为了解离散类型资源矿床的形成过程和空间分布提供了一个结构化框架。在这项研究中，我们提供了首个月球描述性模型，描述了高钛月球矿床的特征，并将其与用于评估地球矿床的成熟模型进行了比较。我们的方法包括利用遥感数据集和地质图来识别和描述高钛矿床。我们的方法包括利用遥感数据集和地质图来识别和描述高钛矿床，并辅以从阿波罗任务中推断出的数据。然而，我们的知识仍存在重大差距，尤其是在高钛矿床的岩相学、地下信息、地表特征和物理特性方面，这就需要我们进一步探索和分析。

引用次数: 0

No laughing matter: How autonomous agents can improve well-being and teamwork 没有笑料：自主代理如何改善福利和团队合作

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

Acta Astronautica

Pub Date : 2024-10-18 DOI: 10.1016/j.actaastro.2024.10.039

Autonomous agents are a critical factor for maintaining the well-being and health of astronaut teams in long duration spaceflight. As autonomous agents become more independent, and interdependent the need to understand how they can interact effectively with humans not only becomes more necessary, but will become the paradigm for future team research. In our paper, we describe a conceptual model that explains how autonomous agents and human team members can learn to implicitly coordinate through humorous social interaction and effective task interdependence. We argue that to build a shared mental model between autonomous agents and human team members, HATs need to develop trust with one another, albeit through different mechanisms, to work together effectively.

在长时间太空飞行中，自主代理是维持宇航员团队福祉和健康的关键因素。随着自主代理变得更加独立和相互依赖，了解它们如何与人类有效互动不仅变得更加必要，而且将成为未来团队研究的范例。在我们的论文中，我们描述了一个概念模型，解释了自主代理和人类团队成员如何通过幽默的社交互动和有效的任务相互依存学会隐性协调。我们认为，要在自主代理和人类团队成员之间建立一个共享的心智模型，HATs 需要通过不同的机制建立彼此间的信任，从而有效地协同工作。

引用次数: 0

Analysis of fly-around mission with spinning tether system for space station observation 利用旋转系绳系统进行空间站观测的绕飞飞行任务分析

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

Acta Astronautica

Pub Date : 2024-10-18 DOI: 10.1016/j.actaastro.2024.10.032

This paper presents the mission scenarios of using spinning tether system to conduct space stations fly-around mission and validates its feasibility. The main challenge of fly-around mission lies in the difficulty of balancing low fuel consumption and long-term fly-around observation. To deal with this problem, a novel spinning tether system is proposed. Firstly, the fly-around process with spinning tether system is introduced, and the tether system is modeled based on Newton-Euler method with a novel description of spinning motion. Secondly, Given the unique structural limitations of space stations, two fly-around schemes and referenced fly-around trajectories are detailed. Thirdly, a backstepping controller is proposed for tracking the reference motion of fly-around satellites, and the fuel consumption among different fly-around schemes is compared and analyzed. In the end, numerical results validate that under the proposed control strategy, the spinning tether system can maintain a stable fly-around configuration in both the planar and vertical plane, the symmetrical formation configuration prevents the central space station from being affected by the motion of fly-around satellites. Moreover, energy consumption analysis indicates that tethered system can save 62.8 % of impulse compared to traditional schemes when flying in the planar plane, making it the most energy-efficient option.

本文介绍了利用旋转系绳系统执行空间站绕飞任务的飞行方案，并验证了其可行性。绕飞任务的主要挑战在于难以兼顾低燃料消耗和长期绕飞观测。为解决这一问题，提出了一种新型旋转系绳系统。首先，介绍了旋转系链系统的绕飞过程，并基于牛顿-欧拉法建立了系链系统模型，对旋转运动进行了新颖的描述。其次，考虑到空间站独特的结构限制，详细介绍了两种绕飞方案和参考绕飞轨迹。第三，提出了一种用于跟踪绕飞卫星参考运动的反步进控制器，并对不同绕飞方案的燃料消耗进行了比较和分析。最后，数值结果验证了在所提出的控制策略下，旋转系绳系统可以在平面和垂直面上保持稳定的绕飞配置，对称的编队配置可以防止中心空间站受到绕飞卫星运动的影响。此外，能耗分析表明，与传统方案相比，系留系统在平面飞行时可节省 62.8%的冲量，是最节能的方案。

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引用次数: 0

Influence of constant and alternating electric fields on the deformation and destruction of a liquid droplet 恒定和交变电场对液滴变形和破坏的影响

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

Acta Astronautica

Pub Date : 2024-10-17 DOI: 10.1016/j.actaastro.2024.10.012

Examining the impact of electromagnetic field, which provides thrust in contemporary rocket engines, is turning into a significant issue. Its resolution is required to guarantee the safety of space flight by enhancing engine performance and lowering fuel consumption. Spacecraft propulsion is achieved by low-thrust rocket engines. The principle of operation for ion colloid engines is the electrostatic acceleration of charged droplets. A static electric field accelerates charged liquid droplets created by electrospraying them in a low-thrust colloid engine. A promising technology in many industries is the active control of droplet motion and deformation with electric field. An electromagnetic field impact on droplet deformation and destruction in a viscous liquid is examined. The effect of electromagnetic field on individual droplets and emulsions is examined in terms of their physical mechanisms. Constant and alternating electric field effects on liquid droplet are represented numerically. The effects of droplet electric capillary number and viscosity ratio on droplet unsteady deformations is explored. The parameters that correspond to the droplet destruction are found. The results obtained have potential applications in enhancing the efficiency of current industrial electric dehydrators and in advancing the development of new electromagnetic field-based demulsification technologies.

电磁场为当代火箭发动机提供推力，研究电磁场的影响正成为一个重要问题。要通过提高发动机性能和降低燃料消耗来保证太空飞行的安全，就必须解决这个问题。航天器的推进由低推力火箭发动机实现。离子胶体发动机的工作原理是带电液滴的静电加速。在低推力胶体发动机中，通过电喷雾产生的静态电场可加速带电液滴。利用电场主动控制液滴的运动和变形是许多行业中一项前景广阔的技术。本文研究了电磁场对粘性液体中液滴变形和破坏的影响。从物理机制的角度研究了电磁场对单个液滴和乳液的影响。用数值表示了恒定和交变电场对液滴的影响。探讨了液滴电毛细管数和粘度比对液滴非稳态变形的影响。找到了与液滴破坏相对应的参数。所得结果可用于提高当前工业电脱水机的效率，并推动基于电磁场的新型破乳化技术的发展。

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引用次数: 0

Femtosatellite mission architectures and mission assurance strategies 超小型卫星飞行任务架构和飞行任务保证战略

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

Acta Astronautica

Pub Date : 2024-10-17 DOI: 10.1016/j.actaastro.2024.10.019

Since its inception, the femtosatellite has developed into a complex and capable spacecraft. However, despite such advances the implementation of predicted applications remains elusive. In response, this paper explores three femtosatellite mission architectures, the drone, swarm, and hive, to characterize what possible femtosatellite mission could be envisioned for true space applications. Starting from a single femtosatellite, each architecture represents an increase in network complexity, so the use of graph theory is proposed as a means for characterizing, understanding, and modelling femtosatellite systems. A simple reliability model is also proposed for each of the mission architectures, and a simulation is carried out to generate a profile of the system’s lifecycle. The results are discussed for each of the architectures in relation to potential applications. Each of the architectures was shown to be feasible for short duration missions due to the inherent unreliability of femtosatellites. Additionally, mid- and long-duration missions were shown to be possible for swarms and hives with sufficiently large populations. Finally, applications are re-examined considering the lifecycle profile exhibited by each system.

自问世以来，超小型卫星已发展成为一个复杂而有能力的航天器。然而，尽管取得了这些进步，预期应用的实现仍然遥遥无期。为此，本文探讨了三种飞星任务架构，即无人机、蜂群和蜂巢，以描述真正太空应用中可能的飞星任务。从单个飞卫星开始，每种架构都代表着网络复杂性的增加，因此本文提出使用图论来描述、理解和模拟飞卫星系统。还为每种任务架构提出了一个简单的可靠性模型，并进行了模拟，以生成系统生命周期的概况。针对每种结构的潜在应用对结果进行了讨论。由于微小卫星固有的不稳定性，每种结构对于短时间飞行任务来说都是可行的。此外，中长期飞行任务对于具有足够大种群的蜂群和蜂巢来说也是可行的。最后，考虑到每个系统的生命周期情况，对其应用进行了重新审查。

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引用次数: 0

Along-track deployment control of space tether system for SAR-GMTI mission 用于 SAR-GMTI 飞行任务的空间系留系统的沿轨部署控制

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

Acta Astronautica

Pub Date : 2024-10-17 DOI: 10.1016/j.actaastro.2024.10.041

Global, 24/7, and all-weather Synthetic Aperture Radars (SARs) are optimal platforms for Ground Moving Target Indication (GMTI) missions, and the tether constraint provides a stable mechanic connection for such configurations. To fulfill the requirements of such missions, the Space Tether System (STS) must be deployed to horizontal positions to form the necessary along-track interference baseline, which is unstable relative to traditional vertical positions and has not received adequate focus. To deal with this problem, this study focuses on the deployment control of the STS to the unstable horizontal positions. Firstly, the properties of the STS at the horizontal position are analyzed, and a synthetic criterion of measurement error is defined based on the observation principle of the GMTI mission. Secondly, two deployment control strategies are proposed, and corresponding desired trajectories are generated by considering two occasions respectively. In the end, considering the instability of horizontal positions, an adaptive closed-loop controller is designed utilizing the backstepping method to address gravitational moment and other disturbances. Simulations demonstrate that the system can successfully attain the desired horizontal positions under both deployment strategies, and the designed controller can quickly track trajectories under initial state errors and external disturbances.

全球、全天候和全天时合成孔径雷达（SAR）是地面移动目标指示（GMTI）任务的最佳平台，系留约束为此类配置提供了稳定的机械连接。为满足此类任务的要求，空间系留系统（STS）必须部署到水平位置，以形成必要的沿轨干扰基线，而这相对于传统的垂直位置是不稳定的，也没有得到足够的重视。为解决这一问题，本研究将重点放在将空间系留系统部署到不稳定水平位置的控制上。首先，分析了 STS 在水平位置的特性，并根据 GMTI 任务的观测原理定义了测量误差的合成标准。其次，提出两种部署控制策略，并分别考虑两种情况生成相应的期望轨迹。最后，考虑到水平位置的不稳定性，设计了一个自适应闭环控制器，利用反步进方法来解决重力力矩和其他干扰。仿真结果表明，在两种部署策略下，系统都能成功达到所需的水平位置，并且所设计的控制器能在初始状态误差和外部干扰下快速跟踪轨迹。

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引用次数: 0