Browse Topic: Spacecraft

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Fine-tuned Large Language Model Enhanced Nonlinear Model Predictive Control for Spacecraft Attitude Stabilization2026-99-296610/19/2026
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Guo, Zili, Gao, Sihong, Liu, Yuhan, Wang, Pengyu, Guo, Yanning
Simulation Study on the Influence of Acceleration on Mass Flow Distribution of Supercritical Carbon Dioxide inside Complex Capillary Pipeline Structures2026-99-296110/19/2026
Supercritical carbon dioxide (sCO2) power cycles present promising application prospects in spacecraft and mobile energy systems owing to their outstanding advantages including high thermal efficiency and compact system structure. As a key component of sCO2 heat exchange systems, the complex capillary pipeline structure significantly influences heat transfer performance and system stability through its internal flow distribution uniformity. In this study, a multi-physics numerical simulation approach is employed to establish a complex capillary pipeline model with four compartments labeled A, B, C and D, aiming to explore the effects of different acceleration (overload) conditions on internal flow distribution. Various acceleration cases are considered, such as zero gravity, horizontal placement (0, 1g, 0), vertical placement (-1g, 0, 0), (0.15g, -0.7g, 0), (5g, -3g, 0) and (8g, -3g, 0). Meanwhile, the regulation effect of orifice plates on flow distribution is analyzed. The results demonstrate that both the magnitude and direction of acceleration exert remarkable impacts on the flow distribution ratio within the pipeline. Under vertical acceleration, flow distribution among the different branches becomes more uneven. Under high acceleration conditions, compartment A is prone to obvious flow deviation, which deteriorates overall flow uniformity. Orifice structures adjust flow distribution under acceleration pretty well—they work by changing the flow resistance characteristics. The present research provides reliable theoretical foundation and data support for the optimal design of complex capillary pipeline structures under variable acceleration environments.
Chen, Weihua, Wei, Xiaorui, Yang, Tianyu, Wang, Cong, Qin, Jiang
An Integrated Fault Diagnosis and Prediction Method for Planetary Gears Based on Ensemble Learning2026-99-294410/19/2026
Planetary gears are key transmission components in spacecraft drive systems and are prone to failures under long-term operation in harsh environments. To address the problem that fault diagnosis and life prediction are treated separately in existing research, this paper proposes an integrated diagnosis-prediction method. First, order tracking and time synchronous averaging are used to preprocess vibration signals, eliminating speed fluctuations and noise interference. Then, fault features are extracted via VMD/EEMD decomposition, and the gear health condition is identified through a deep convolutional neural network. Finally, ensemble learning prediction models are established separately for different fault states to realize life prediction. Experimental results show that the VMD+CNN method achieves higher diagnostic accuracy than traditional methods for gears in healthy, cracked, spalled, and pitted conditions. The ensemble prediction models matched with different states can further reduce the life prediction error. This method provides effective technical support for condition-based maintenance of spacecraft planetary gears.
Liu, Yanyan, Gao, Tongxin, Zhu, Yangsong
A Deep Learning Approach for Space Target Pose Estimation Based on Multi-Task Joint Training2026-99-298110/19/2026
The growing number of space objects raises collision risks and demand for on-orbit maintenance. Since most servicing tasks require observing the target, relative pose estimation is key for debris removal and satellite servicing. The complex orbital environment poses significant challenges for conventional feature extraction networks.. To address these challenges, this paper presents a multi-task convolutional neural network for space target pose estimation. The network uses a MobileNetV3-based encoder to extract image features and an Adaptively Spatial Feature Fusion (ASFF) module for adaptive multi-scale feature fusion. Although MobileNetV3 and ASFF have rarely been combined in the aerospace field, their combination offers significant advantages in low parameter count and reduced computational load, showing strong potential for spacecraft pose estimation. Two parallel prediction heads are employed: an EfficientPose head consisting of classification, bounding box regression, rotation matrix regression, and translation vector regression, together with a Heatmap head. This design leads to more robust and accurate pose estimation. The loss function follows a multi-prediction-head joint approach, where each component is weighted to form the final loss for multi-task optimization. The network is trained, validated, and tested on a simulation dataset of the DAWN satellite built with Unity. The dataset includes illumination variations, large distance changes, and multi-view target appearances, thus capturing the complex scenes typical of vision-based recognition tasks. Experimental results show that after 40 training epochs, the model achieves an average position error of about 0.05 m and a rotation error of about 0.8° on the test set. These results demonstrate the effectiveness and accuracy of the proposed network for space target pose estimation.
Wang, Wenzhi, Zhang, Zexu, Zhang, Fan, Song, Zhuo
Research on Testing Methods and Practices of on Board Data Handling Subsystem Based on Spacecraft2026-99-294710/19/2026
Subsystem testing, as a crucial engineering phase in the development process of the On Board Data Handling (OBDH) subsystem to ensure product quality, is increasingly valued by engineering organizations. The OBDH subsystem, apart from its characteristics of embedded software and FPGA with strong real-time performance and close hardware relations, also features multiple external interfaces, large communication data volumes, and frequent software changes. These factors highlight the significant challenges in testing the OBDH subsystem, making it essential to develop a theoretical framework and methods to guide the testing process. Following the principles of the Director’s Order No. 7 for full-cycle and multi-dimensional work, and based on the testing characteristics of the OBDH subsystem, a full-cycle testing model for the OBDH subsystem has been established. This paper presents comprehensive research and practical implementation of OBDH subsystem testing from three aspects: test environment establishment, test method implementation, and test experience summarization.
Ye, Zhiling, Zhang, Tao
Transformer-Based Short-Arc Relative Motion Pattern Recognition for Non-Cooperative Space Objects2026-99-295310/19/2026
To meet the demands of on-orbit monitoring and space situational awareness, this study proposes a Transformer-based relative motion pattern recognition method based on the self-attention mechanism, addressing the issues of difficulty in accurately characterizing the relative motion patterns of non-cooperative space targets under short-arc observation conditions, strong dependence on prior knowledge in traditional methods, and insufficient stability under noise interference. Firstly, this study constructes a non-cooperative spacecraft motion pattern action data set based on the Clohessy–Wiltshire (C-W) relative motion equation. By designing typical initial conditions of relative motion, trajectory samples including fixed-point following, hovering following, oscillating following, coplanar circling, non-coplanar circling, approaching and receding, etc. of multiple motion patterns are generated, and the relative position and relative velocity sequences in the local orbital coordinate system are used as model inputs. Subsequently, an motion pattern recognition network composed of an input representation module, a Transformer encoding module, and a classification output module is constructed. The trajectory sequence representation is achieved through linear embedding and position encoding, and the multi-head self-attention mechanism is used to capture the global dependencies and key dynamic features between different time steps, thereby completing the discrimination of the target motion pattern category. Finally, model training and testing are carried out based on the constructed data set, and experimental analysis is conducted from three aspects: training convergence, classification performance in the absence of noise, and robustness in the presence of noisy observations. The results show that the proposed method can effectively learn the discriminative features in short arc segment relative motion, and performs well in terms of accuracy, Macro-F1, and confusion matrix; in the presence of Gaussian noise interference, it outperforms the Multi-Layer Perceptron (MLP) baseline model while still maintaining clear category boundaries and high recognition stability.
Mao, Yicheng, Zhang, Zexu, Li, Yingshuo, Song, Zhuo, Zhang, Fan, Liang, Jintang
Methodological Study on Fluid-Structure Interaction Dynamics of Spacecraft in Martian Rarefied Atmosphere Aerobraking2026-99-293210/19/2026
During aerobraking, spacecraft deploy large flexible solar arrays to obtain enough aerodynamic drag. In the rarefied Martian atmosphere, rapidly varying dynamic pressure causes low-frequency elastic vibrations of these appendages, leading to coupled translation-rotation-vibration fluid-structure interaction (FSI) that affects both aerodynamic characteristics and attitude stability. Traditional high precision methods such as DSMC are difficult to apply to long-duration simulations owing to their high computational cost. To solve this problem, this paper proposes a one-way FSI framework, which conbines a cross-regime panel method for aerodynamic calculation with a reduced-order multibody dynamic model. The simulation results show that the framework can reduce the computational burden while retaining the main physical characteristics required for the analysis. The aeroelastic response of a representative spacecraft configuration is analyzed, and the results can support configuration design, aerobraking corridor constraints, and control system development.
Zhou, Tianhao, Cui, Hutao
Pose Tracking and Formation Keeping Control of Spacecraft Formations under High-Order Control Barrier Functions2026-99-297610/19/2026
Aiming at the constraint issues of adjacent spacecraft solar panel collision avoidance and formation keeping in the pose tracking control of spacecraft formation, this paper proposes a distributed relative position and attitude cooperative control strategy on the basis of high-order control barrier functions. First, nominal control strategies for relative position and attitude tracking using the sliding mode control method to achieve high-precision tracking of relative motion are de-signed. Then, high-order control barrier functions suitable for solar panel collision avoidance and spacecraft formation keeping constraints are constructed. The control strategy constraints satisfying safety specifications are derived based on the forward invariant set theory. Finally, a quadratic programming optimization framework is established by combining the nominal control strategies and constraint conditions and then we obtain the optimal control strategy by solving this framework. Numerical simulations verify that the designed control scheme achieves precise tracking of relative position and attitude for spacecraft formation, avoids collisions between solar panels of adjacent spacecraft and prevents excessive loosening of the formation configuration.
Zhu, Ziqi, Qin, Wenyu, Lyu, Yueyong
Adaptive Optimization of Fault Diagnosis Models Based on Reinforcement Learning and Robustness Quantification Feedback2026-99-299510/19/2026
Spacecraft operate in a highly complex in-orbit environment. Telemetry data from power systems is often plagued by multi-source disturbances such as plasma noise, electromagnetic interference, and communication packet loss, which places very strict demands on fault diagnosis model reliability. Using dynamic disturbance test manifolds and the comprehensive robustness quantification index (RQI) for evaluation, we found a critical vulnerability: baseline models such as the joint loss enhanced global sparse attention transformer (JLE-GSA-Transformer) perform well in resisting continuous signal disturbances, but their performance drops sharply when temporal structures are disrupted due to data missingness. This finding highlights that static diagnostic models have fragile robustness boundaries when operating under extreme non-stationary conditions. To solve this problem, this paper puts forward an adaptive optimization method that combines deep reinforcement learning (RL) with quantitative robustness feedback. By making use of the dynamic disturbance manifold, this method embeds the RQI into the reward function of the RL algorithm. Through continuous updates to the agent’s policy, it drives the adaptive adjustment of key parameters in the JLE-GSA-Transformer, mainly including the coding structure of global sparse attention (GSA) and the discriminative boundaries of temporal cosine-center joint loss. This closed-loop mechanism can significantly improve the stability, adaptability, and long-term reliability of the model when it works in complex environments with multi-source disturbances.
Liu, He, Wei, Cheng, Zhang, Zexu
Study of On-Orbit Rigid-Flexible-Thermal Coupling Dynamic Response and Attitude Control of Large Spaceborne Deployable Parabolic Truss Antenna2026-99-290910/19/2026
Modern space exploration relies more and more on vehicles that carry expansive antenna arrays, a trend driven by steady progress in the field of space engineering. The study centers on constructing a coupled model that accounts for structural rigidity, flexibility, and thermal effects in a sizable orbital unfurling parabolic antenna, along with designing its orientation regulation system. A blended coordinate formulation and a heat-based discretization approach are employed to derive the motion and temperature-governing equations of the assembly. A unified pointing control method is then developed by merging classical feedback control principles with torque compensation control. Computational experiments involving a spacecraft fitted with such a dish antenna are executed. The findings reveal that sudden heat fluctuations, exemplified by the transition out of Earth’s umbra, trigger oscillatory behavior in the antenna framework and disrupt the satellite’s angular position. The designed orientation regulator successfully counteracts these thermally driven perturbations, even when the system representation contains inaccuracies.
Zhou, Shijie, Liu, Xiang, Cai, Guoping
Move Blocking Event Triggered Model Predictive Control of Spacecraft Formation2026-99-295610/19/2026
This paper addresses the problem of formation reconfiguration for deputy spacecraft flying in a spatial circular formation around a chief spacecraft. To improve the real-time applicability of formation control under onboard computational limitations, a reconfiguration method is proposed by integrating Tschauner–Hempel (T-H) relative dynamics, Event-Triggered Model Predictive Control (ET-MPC), and a Move Blocking strategy, while explicitly considering collision-avoidance constraints. Based on the T-H relative dynamic model, an MPC framework is established to generate control inputs for the reconfiguration process. To reduce the computational burden of conventional MPC, an event-triggering mechanism is introduced so that the optimization problem is solved only when necessary, rather than at every sampling instant. Meanwhile, a Move Blocking strategy is employed to reduce the number of online decision variables by constraining successive control moves over predefined intervals. In addition, to simultaneously address inter-spacecraft collision avoidance and limited-thrust constraints, an optimization model with binary variables is formulated. To evaluate the proposed approach, four simulation cases, namely MPC, ET-MPC, MB-MPC, and MBET-MPC, are conducted under the same reconfiguration scenario. Simulation results show that all four methods can successfully accomplish the formation reconfiguration task while satisfying the minimum safe-distance requirement. Moreover, the methods incorporating Move Blocking reduce the computation time required for solving each individual optimization problem, while the event-triggered schemes significantly reduce the number of optimization updates compared with the corresponding time-triggered methods, thereby further lowering the overall computational cost. The results demonstrate that the proposed method provides an effective and feasible solution for real-time formation reconfiguration and control on resource-constrained spacecraft platforms.
Zhang, Yuning, Zhang, Zexu, Liang, Jintang
Coupled Vibration Analysis and Vibration Suppression for Spacecraft Multi-Panel Structures by Stiffness-Tunable Hinges2026-99-292410/19/2026
Spacecraft hinged-panel structures feature a multi-hinged configuration, substantial dimensions, low stiffness, and low damping, making them susceptible to sustaining low-frequency vibrations under multi-source excitations. To address this challenge, a novel stiffness-tunable hinge is proposed for low frequency vibration attenuation. Firstly, the hinge structural geometry and stiffness-tunable principle are presented. Subsequently, FEM models of multi-panel structures incorporating stiffness-tunable hinges are developed. The natural frequencies and mode shapes of the system are investigated. Simulation results indicated that the multi-panel structures reveal bending vibrations, torsional vibrations, and coupled bending–torsional vibrations of the hinge-panel structure. Finally, a microgravity experimental platform was developed, this experimental platform offers several advantages, including extremely low friction, unconstrained horizontal motion, a compact structure, a small footprint, and robust reliability. The gravitational load of the hinged-panel is nearly counterbalanced, thereby enabling its unrestricted, omnidirectional translation across the horizontal plane. The experimental results rigorously validated the link between hinge stiffness-tuning and system eigen-frequency migration. Furthermore, vibration suppression at low frequencies of 0.29 Hz (for three-panel) and 0.31 Hz (for four-panel) was realized using non-contact magnetic excitation. This approach achieved amplitude reductions of approximately 9.70 dB at 0.29 Hz and 12.53 dB at 0.31 Hz. These findings demonstrate a novel strategy for suppressing low-frequency vibrations in spacecraft structures.
Bi, Zhiwei, Lin, Hui, Hu, Wei, Wang, Yufeng, Zhang, Ce, Yu, Ruijiang
Rapid Trajectory Optimization for Mars Aerobraking Campaigns2026-99-294010/19/2026
Aerobraking is a key technology for reducing propellant consumption in deep space exploration missions. Targeting the Mars aerobraking trajectory optimization problem, this paper proposes a rapid trajectory optimization method based on a high-precision analytical approximate solution. First, a Mars aerobraking dynamics model is established. Based on the assumptions of a linear flight path angle and a linear altitude rate, a high-precision analytical approximate solution for Mars aerobraking trajectories is derived. Simulation results verify that the proposed analytical solution satisfies the accuracy requirements for Mars aerobraking trajectory optimization. Based on this analytical solution, the state transition function of the aerobraking trajectory optimization problem is reconstructed, and the Sequential Quadratic Programming (SQP) algorithm is employed for the optimization. Numerical simulation results demonstrate that the proposed method requires less than one minute to optimize an aerobraking campaign consisting of 80 atmospheric passes. Compared with traditional optimization methods, it exhibits significant advantages in computational efficiency when dealing with aerobraking trajectory optimization problems characterized by long durations and multiple velocity pulses.
Ding, Yuancheng, Dong, Jie, Cui, Hutao, Chen, Zheng
Performance Prediction of Hall Thrusters with Deep Learning Algorithms2026-99-298810/19/2026
Accurate performance prediction is essential for improving the reliability and service life of Hall thrusters in space applications. Because conventional scaling-based prediction methods are often limited when the operating state and magnetic-field structure become complex, this study develops a deep-learning framework for rapid prediction of key Hall-thruster performance indicators. Three representative neural-network architectures, namely Multi-Layer Perceptron (MLP), Convolutional Neural Network (CNN), and Bidirectional Long Short-Term Memory (BiLSTM), are constructed and comparatively evaluated. Among them, BiLSTM achieves the best overall performance, with a Mean Absolute Percentage Error (MAPE) of 6.44% on the test set. Additional validation based on real Hall-thruster experimental data gives a MAPE of 3.884%, indicating that the proposed model has good generalization ability and can provide an effective data-driven tool for Hall-thruster performance prediction.
Sun, Chang-You, Tian, Bin, Yu, Yun-Chao, Wang, Ke, Li, Shu-Feng, Xie, Kan, Yang, Su-Lan
A Health State Assessment Method Based on Autoencoder and Analytic Hierarchy Process for Spacecraft Components2026-99-297310/19/2026
Health assessment of complex systems mainly relies on expert experience or a data-driven health assessment model trained by a large volume of historical condition monitoring data. However, only relying on expert experience to handle the health information contained in a large amount of telemetry data is very time-consuming and labor-intensive for spacecraft, and it does not make full use of a large amount of historical data. Moreover, due to limitations such as space-ground data transmission resources, it is also difficult to obtain all the condition monitoring parameters at each system level for different health states. In response to these challenges, this paper proposes a health assessment framework combining expert experience and data-driven strategy to achieve a multi-level quantitative assessment for spacecraft components. Specifically, a deep autoencoder is trained to construct the state change curves of the key condition monitoring parameters, and the quantitative score map is constructed for each parameter. Then, by analyzing the matrix of pairwise importance for parameters based on expert experience, the health status change curve at a second level of the component is constructed. Finally, a quantitative score map of the component status is provided using the health status change curve to realize the multi-level quantitative health assessment. A case study on health assessment for an attitude control actuator is conducted to show the overall procedure and effectiveness of the health assessment framework. The results demonstrate that the proposed method can effectively integrate expert knowledge and data characteristics, providing a feasible framework for the multi-level health assessment of spacecraft components.
Dong, Yunjia, Li, Yuqing
Nonlinear Dynamic Modeling and Active Control of a Large-Scale Two-Dimensional Planar Phased Array Antenna2026-99-290110/19/2026
A new method for dynamic modeling and active control of the large-scale, on-orbit assembled two-dimensional planar phased array antenna is proposed in this study. As the demand for high imaging accuracy and scanning coverage in satellite antennas increases, there is a shift toward larger apertures. However, large-scale phased array antennas face challenges such as low rigidity and significant nonlinear vibration during attitude maneuvers, which can degrade pointing accuracy and shape precision. To address these issues, this study proposes a dynamic modeling framework that incorporates geometric nonlinearity, employing finite element method (FEM) and a polynomial fitting-based model order reduction technique. A rigid-flexible coupling dynamic model is then developed based on the velocity variation principle. In control design, the paper integrates an active vibration control law using cable actuators with a computation torque algorithm based on control moment gyroscopes (CMGs) to design an integrated attitude-vibration control system. This system aims to suppress nonlinear vibration while achieving high-precision attitude control. Simulation results demonstrate the effectiveness of the proposed integrated control approach in both vibration suppression and attitude maneuvering, offering valuable insights for its practical application in future space missions.
Ma, Yihao, Liu, Xiang, Jin, Chaochen, Cai, Guoping
NGO-Based Orbits Optimization for Impulsive Transfers between DRO and Halo Orbits2026-99-293910/19/2026
This research investigates the design of fuel-saving orbital transfer trajectories for spacecraft departing from distant retrograde orbits (DRO) toward Halo orbits around the Earth-Moon L2 libration point. Relevant trajectory designs hold practical value for future lunar space station projects and deep space exploration undertakings. Previous research commonly adopted indirect modeling methods or classic evolutionary algorithms to acquire transfer solutions, yet these techniques show limited performance in multi-body dynamic systems, particularly unsatisfactory convergence efficiency. To address this defect, this paper proposes an improved direct optimization strategy based on the Northern Goshawk Optimization (NGO) algorithm. All numerical analyses are conducted within the circular restricted three-body problem (CR3BP) framework, which accurately reflects gravitational features in cislunar space while avoiding overly complicated calculation processes. The departing and target orbits are discretized mathematically, and the whole transfer mission is defined as a constrained nonlinear optimization problem aiming to minimize total velocity variation. The adopted algorithm balances global exploration and local exploitation rather than prioritizing a single search mode. This balanced mechanism effectively lowers the risk of falling into local optimal solutions, a prevalent flaw of conventional optimization methods. Precise dynamic modeling is also implemented: canonical transformation is applied to reorganize dynamic governing equations for simpler computation, and differential correction technology is utilized to optimize preliminary trajectory results generated by NGO iteration. Multiple tests with diverse initial values and mission constraints are carried out to verify the method’s stability. Simulation results prove that the proposed strategy maintains steady performance under external interference and stably yields qualified feasible trajectories. Overall, the Northern Goshawk Optimization algorithm proves applicable for high-precision orbital transfer optimization. This study also provides valuable references for low-energy trajectory planning in cislunar space.
Huang, Jiaxin, Zhang, Zexu, Liang, Jintang, Wang, Yiyu
2026 International Symposium on Aerospace Information and Industry Innovation2026-99-290010/19/2026
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Tobolski, Sue
Research on Interconnection Technology of Spacecraft in Cislunar Space2026-99-294310/19/2026
Communication interconnection and interoperability in cislunar space have become an important development direction for low earth orbit satellite internet to extend into outer space. To address the challenges such as the difficulty in cross-domain interconnection of heterogeneous spacecraft, insufficient compatibility of protocols and architectures in the ground station,earth orbit, lunar orbit, lunar surface and extended networks, this paper reviews the current development situation of the US and China’s cislunar space networks, and summarizes six challenges in the aspects of link layer and network layer protocol standardization, addressing and routing, gateway design, information security, and multi-system integration. Based on this, this paper proposes constructing a cislunar space network centered on IP protocols based on the USLP link-layer protocol, which adopts a combination of two-layer switching and three-layer routing addressing mechanism, multi-gateway interconnection, hybrid security architecture, and multi-protocol stack compatibility, and clarifies four key technologies: network protocol architecture, standardized routing gateway, electronic data sheet, and network digital modeling and simulation. An integrated network system covering the five domains is constructed, achieving unified standards, fault tolerance, safe and efficient interconnection and interoperability for cislunar space spacecraft, which can provide core support for human lunar exploration, deep space exploration, and the perception and development of the cislunar space.
Jia, Weisong, Wang, Xiang, Liu, Yusheng, Wang, Luyuan, Sun, Yong, He, Xiongwen, Zhao, Kanglian, Xu, Ke
Active Control of Attitude-Maneuvering-Induced Vibration of Membrane Antenna Based on Reinforcement Learning2026-99-290810/19/2026
Space membrane structures, prized for their lightness, affordability, and ability to fold and unfold, hold immense promise for missions like deep space exploration, high-definition Earth observation, and advanced satellite communications. However, these structures are typically large-size, ultra-lightweight, highly flexible, and have very low damping. This leads to complex dynamic behavior featuring significant geometric nonlinearity, strong coupling between rigid and flexible motions, and uncertain parameters. Consequently, creating accurate yet simple mathematical models for designing controllers is exceptionally difficult, and traditional control methods that rely on such models often fall short. To tackle this problem, this study focuses on a membrane antenna spacecraft equipped with cable actuators, aiming to suppress its vibrations during attitude maneuvers. Using the Deep Deterministic Policy Gradient (DDPG) algorithm, an intelligent vibration controller based on the Actor-Critic architecture is designed. This approach is data-driven, meaning it learns effective control strategies directly through interaction with the system’s environment, bypassing the need for a precise pre-defined mathematical model. Simulation results show that the controller demonstrated superior vibration suppression and strong adaptability across several key scenarios.
Zhang, Hua, Chen, Cheng, Liu, Xiang
Modeling and Analysis of Mechanical-Electrical Coupling in Flywheel Systems Considering Faults2026-99-292310/19/2026
Spacecraft flywheel systems are critical actuators for attitude control and stability maintenance, and their operating reliability is strongly affected by the health state of the supporting bearings. When local defects occur on the bearing raceway or rolling elements, the rolling contact state changes abruptly, which leads to time varying contact deformation, fluctuating support reaction force, and additional rotational resistance. Unlike many ground based rotating machines, spacecraft flywheel systems usually operate in compact and highly integrated configurations, where direct vibration measurement is difficult in practice. In contrast, motor current, voltage, and speed signals are easier to acquire and are therefore more suitable for condition monitoring. To describe how bearing defects propagate from the mechanical domain to electrical responses, a simplified electromechanical coupling model is developed for a flywheel rotor motor system with local bearing defects. First, a rolling element contact model is established using the defect induced deformation relation and Hertzian contact theory to derive the time varying bearing support force. Second, the fluctuating support force is mapped to an equivalent time varying load torque to represent the dominant pathway through which bearing defects influence the motor side. Third, the derived load torque disturbance is coupled with the transverse rotor dynamic equations, the rotational motion equation, and the motor dq axis model to obtain a simplified electromechanical coupling equation set. The proposed model preserves the main physical transmission chain from bearing defect to electrical response. The model provides a clear theoretical basis for analyzing fault propagation mechanisms and for developing current based diagnostic methods for spacecraft flywheel systems.
Wu, Haolong, Li, Yuqing
Adaptive Slicing and High-Reliability Transmission Method for Spacecraft On-Orbit Data2026-99-292210/19/2026
Spacecraft On-orbit data are characterized by large volumes, stringent timeliness requirements, and heterogeneous data values, posing significant challenges to traditional satellite-ground transmission systems. To improve transmission efficiency and reliability under dynamic link conditions, this paper proposes an adaptive data slicing and collaborative reliability enhancement method. First, a joint evaluation model integrating Data Impact and Link Health is developed to evaluate data importance and transmission conditions. Based on the evaluation results, the slice size, priority allocation, and redundancy configuration are dynamically optimized. Second, a distributed collaborative verification mechanism combining Reed–Solomon erasure coding and multi-node arbitration is introduced to enhance data integrity and recovery capability. Furthermore, a mission-driven elastic scheduling strategy is designed to facilitate efficient resource allocation in multi-user transmission scenarios. Experiments were conducted on 100 telemetry files with a total volume of 1.9 GB in a simulated satellite-ground communication environment. Experimental results demonstrate that the proposed method improves average throughput by 25.3% and achieves a reconstruction success rate of 99.7% across 1,000 packet-loss reconstruction trials.
Li, Cheng, Liu, Peng, Chen, Xi, Cui, Yan, Li, Han, Li, Xian, Wang, Zhihui, Yi, Xiu
Effect of Space Radiation on the Properties of Methyl Phenyl Vinyl Silicone Rubber (MPVQ) Compound2026-99-14249/11/2026
In this study, the influence of space radiation on the properties of methyl phenyl vinyl silicone rubber (MPVQ) compounds is systematically investigated. The results reveal that with increasing radiation dose, the appearance of MPVQ compounds changes from white to pale yellow and then to grayish-yellow, while their hardness continuously increases. Both the tensile strength and tear strength of the samples exhibit the S-shaped variation curves with radiation dose. At a radiation dose of 1 × 10^6 Gy (Si), the tensile strength, elongation at break, and tear strength decrease by 20%, 89%, and 69%, respectively. When the radiation dose exceeds 1 × 10^6 Gy (Si), both the tensile strength and tear strength rebound moderately. However, further increases in the dose cause both properties to decline again. By contrast, the elongation at break decreases consistently throughout the dose range. Besides, the samples are non-flammable in the presence of open flames. According to these experimental results, the MPVQ products can meet the 15-year service lifetime requirement for the static spacecraft, although their elasticity and load-bearing capacity could be substantially diminished, leading to increased brittleness and susceptibility to fracture under stress. However, some physical or chemical modification of the MPVQ materials is definitely needed for their further application in the dynamic mechanism for the long-life spacecraft that are directly exposed to the space environment. In our opinion, the results shown in this work could provide some necessary guidance for the further development of the related materials in the related field.
Wang, Peng, Chen, Yacan, Li, Jiaxin, Wang, Nan, Zhao, Tianqi, Liu, Hanliang, Huang, Zhipeng, Huo, Xiubing, Sun, Wei
A Computing Method of Splitting Factor for 3D Non-Compatible Generalised Mixed Hexahedral Element2026-99-12119/4/2026
With the rapid development of the aerospace industry, FEM has been widely applied as a key tool. However, the high complexity of aircraft and spacecraft geometries and structures often leads to unavoidable distorted meshes in FEM, which significantly degrades the accuracy of analysis results. Both the splitting factor and the mesh distortion significantly affect the accuracy of the generalised mixed elements. The coefficient matrix deviation between the distorted element and the standard element was quantified. Thus, the computing equation for a three-dimensional (3D) hexahedral distorted element’s splitting factor was constructed. Examples were used to validate the proposed method. For distorted meshes, the accuracy of NCGME has been improved.
Shen, Ao, Qing, Guanghui
Optimization and Control of Mechanical Testing for Batch-Produced Manned Spacecraft2026-99-03128/14/2026
To safely, efficiently, and high-quality complete the mechanical testing of batch-produced manned spacecraft during the China Space Station (CSS) phase, a series of optimization measures were proposed based on system engineering principles. These measures cover the entire mechanical testing process from preparation to implementation, including: establishing a standardized mechanical testing documentation system; reducing the number of mechanical sensors that do not affect result evaluation; pre-identifying and measuring background noise; digitizing test notching and evaluation methods; and standardizing and automating testing procedures. Additionally, targeted measures for test safety and quality control were implemented, including regular inspections of reusable spacecraft components, strict control of test hazards and operational risks, and standardized management of ground support equipment (GSE) through regular inspections. The proposed optimization and control measures have been validated through applications in batch-produced manned spacecraft during the CSS phase. The results show that: the generalization rate of mechanical testing documentation exceeds 80%; the number of mechanical sensors has been reduced by more than 10%; the test preparation period has been shortened by over 4 days; test efficiency has been improved by 30%; the single-direction test duration has been reduced by more than 50%; and the total test cycle has been shortened by 25%. These results indicate that the proposed optimization and control measures are reasonable and feasible, which effectively reduces redundant test operations and items, lowers potential test risks, improves test efficiency, shortens the overall test cycle, enhances test safety, and ensures the high-quality completion of mechanical testing for batch-produced manned spacecraft.
Peng, Huakang, Wang, Mengchen
Design of Adaptive Overtorsion Sliding Mode Observer Based on Logarithmic Gain Law and Estimation of Satellite Disturbance Torque2026-99-03158/14/2026
The vigorous rate of new spacecraft being launched has made the accurate estimation of in-orbit environmental disturbances torques paramount to reducing attitude control performance corrosion. Leveraging telemetry from an asset in low-earth-orbit, we present a novel Adaptive Super-Twisting Sliding-Mode Observer, which interlinks three techniques heretofore decoupled: 1) saturation-constrained angular-acceleration adaptation; 2) Kalman-filter preconditioning of angular velocity; and 3) state-weighted logarithmic gain with dual leakage. Denoising of raw Euler angle sequences and detection of quasi-steady epochs are achieved with a customized Kalman update, while an adaptive band-pass stage isolates the torque-related acceleration signature. Casting these filtered data into the super-twisting form, we update the log gain on-the-fly, and twin leakage terms remove excess energy with accompanying chatter rejection—without compromising bandwidth. Head-to-head telemetry tests show a positive margin headroom on noise attenuation that has to be compared with the power-gain type counterpart and that increases with the signal roughness, thereby validating the fact that this technique refines environment torque estimates and hence strengthens robustness design envelopes in next-generation attitude-control systems.
Yin, Xu, Deng, Yuhui, Chi, Dongxiang
Research on Optimizing Mars Atmospheric Capture Approach Trajectories Based on the Adaptive Differential Evolution Algorithm2026-99-03078/14/2026
To strictly balance orbital insertion precision with engineering constraints during Mars aerocapture, we present an angle-of-attack (AoA) trajectory optimization framework based on adaptive differential evolution. First, a three-degree-of-freedom flight dynamics model was established utilizing the Mars-GRAM 2024 atmospheric standard. Subsequently, we formulated a penalty function centered on apoapsis altitude deviation to enable constraint-oriented dynamic optimization. Within this framework, we introduced an adaptive, direction-guided mutation strategy that integrates global optimal individuals with elite solutions. Furthermore, a parameter update mechanism driven by mutation success rates was developed to significantly enhance algorithmic robustness and computational efficiency. The AoA command sequence for the capture phase was parameterized using a piecewise constant formulation. Comparative simulations under ±30% atmospheric uncertainty demonstrate that, within critical velocity ranges, our improved algorithm elevates the trajectory altitude by approximately 36 km compared to fixed AoA methods. Notably, it reduces convergence time by 50% while strictly adhering to spacecraft physical performance boundaries. These results underscore the method's capability to provide robust, high-precision orbital adjustment support for aerocapture missions in uncertain atmospheric environments.
Tao, Kemeng
Charting the Flight Path of the Aerospace & Defense Industry with Digitalization26AERP08_028/1/2026
New technologies, advanced materials, evolving mission profiles and fast-changing requirements are forcing the aerospace and defense (A&D) industry to dramatically increase the speed of engineering. Companies must design, validate and bring more complex products to market faster than ever, even as software, electronics and autonomy continue to reshape what aircraft, spacecraft and defense systems can do. At the same time, a growing production challenge is emerging. Workforce shortages, supply chain disruption and pressure to reduce cost and cycle time are converging with new demands for greater volume and flexibility. Defense programs are seeing increasing need for larger quantities of lower-cost systems such as drones, while commercial aerospace companies continue to work through backlogs and reinforce their fleets. To keep pace, the industry must accelerate innovation while also scaling production with greater speed, resilience and adaptability.
Resilience Evaluation of HVAC Outdoor Units Against Typhoons Using Finite Element Method2026-99-01067/31/2026
In view of the practical problem that the air-conditioner outdoor units in the spacecraft test workshops of coastal launch sites are severely damaged under the influence of super typhoon, this paper employs the finite-element simulation method to establish a finite-element model of the outdoor units. The implicit Euler solution method is used to calculate the stress conditions of each component of the unit under the influence of typhoons with wind speeds of 50.9 m/s and 61.2 m/s respectively. By combining with the material yield strength, the weak links in the design are identified, and targeted improvement measures are proposed. The simulation results demonstrate good agreement with the actual impact of the typhoon, which can effectively guide the typhoon-resistance optimization design of subsequent air-conditioning units.
Gu, Yufei, Chen, Shaojiang, Shi, YunShan, Fu, Yuanming, Chen, Xi, Yang, Degang
Engineering Practice of Sealing Design and Testing Technology for the Solar Array Drive Assembly of Tianhe Core Module2026-99-02437/31/2026
The Core Module of the space station is the first module of China’s Space Station, responsible for controlling the key parameters such as orbit, speed, and pressure of the entire space station, and serving as the control center of the assembly. The Solar Array Drive Assembly is a part of the Core Module. It needs to participate in the functional requirements of the whole cabin sealing of the cabin body, so it adopts the design scheme of semi-sealed. By adjusting the compression ratio and volume fraction of the sealing ring, and the roughness of the sealing surface, the overall sealing performance is improved. A small cavity leak detection hole is added to realize the sealing effect of detecting the second-layer seal separately. The real leakage rate of the drive mechanism is detected effectively by using multiple calibration schemes in the leak detection process, and the semi-sealing technology of the Solar Array Drive Assembly is verified, which has guidance and reference significance for the subsequent spacecraft design requiring a sealing function.
Dai, Fei, Zhu, Jiahao, Huang, Mengzhe, Qian, Zhiyuan
Design and Dynamic Analysis of Deployable Support Mechanism for Cylindrical Sunshield2026-99-02267/31/2026
With the deepening of space exploration, deep space exploration missions face formidable challenges. Among these, intense solar radiation and high-temperature environments pose severe threats to precision instruments and equipment in space. Stray light suppression and protection against external heat flow inputs have emerged as critical technical requirements in the design of modern spacecraft over recent years. To address the demand of space applications, this paper proposes a cylindrical deployable sunshield with axial deployment capability. First, drawing on the 6UU/3UPU/3UKU mechanism as a foundational reference, the basic module was defined through in-depth analysis of the multi-layer Kresling origami pattern. Guided by the modular composition principle, these basic modules were further assembled into an integrated deployable support mechanism. Secondly, the overall kinetic and potential energy of the full mechanism system were computed and incorporated into the second-type Lagrange equation. To verify both the correctness of the established dynamic model and the reliability of follow-up simulation studies, an integrated validation strategy was implemented: SolidWorks was used for three-dimensional modeling and kinematic simulation of the mechanism, while Matlab was employed for numerical solving and result analysis of the dynamic model, with consistent outcomes from both tools confirming the model’s correctness.
Liu, Yongyu, Chang, Boyan
Development and Technical Verification of A Lunar Dust Environment Simulation Mechanism2026-99-01757/31/2026
Lunar dust consists of extremely fine particles and exhibits electrostatic charging properties and electrostatic adhesion. These characteristics cause lunar dust to be highly susceptible to mobilization during lander touchdowns, rover traversals, and human activities, forming widely distributed dust clouds. Lunar dust contamination not only abrades spacecraft and equipment to impair their performance but also poses a threat to astronauts’ safety. To verify the impact of the lunar dust environment on exploration equipment components, a simulation mechanism adaptable to the thermal vacuum test environment was designed. This mechanism is integrated into the lunar environment simulation system and uses a vacuum stepper motor to drive a ratchet mechanism, enabling precise vibrational injection of simulated lunar dust. It mainly consists of a pretreatment mechanism, a particle sedimentation mechanism, a shielding mechanism, and an ultraviolet (UV) irradiation system. Considering the vacuum operating environment, alternating high and low temperature conditions, as well as the strict requirements for the mechanism’s compact size and high reliability, this paper analyzes in detail a series of problems encountered during the development of the mechanism and their corresponding solutions. Stainless steel and polytetrafluoroethylene (PTFE) were selected as the main materials for the mechanism. Meanwhile, active temperature control measures were adopted to actively regulate the temperature of components such as the motor. Ultimately, the mechanism can withstand alternating high and low temperatures ranging from -150°C to 150°C and a vacuum environment of 5 × 10^–6 Pa. Under this environment, the mechanism can achieve vibration frequency adjustment within the range of 1-5 Hz, and realize the sedimentation of simulated lunar dust particles with a particle size of less than 200 μm over an area of 150 mm × 150 mm. After sedimentation, the simulated lunar dust particles can be charged through the photoelectric effect.
Xu, Menglong, Lv, Shizeng, Li, Guohua, Gong, Jie
Research on Integrated Design and Optimization Method of High Speed Shuttle UUV Rudder and Propeller2026-99-08647/30/2026
Along with the advancement of the maritime power strategy, the research, development, and application of deep-sea space stations are becoming increasingly important. However, since deep-sea space stations mainly rely on acoustic communication, they cannot exchange information with ground stations quickly and accurately. To improve data transmission efficiency, this paper proposes using a high-speed shuttle UUV instead of acoustic communication. In this context, an efficient propulsion system is critical as it enables the UUV to achieve high speed and maintain stability. A propeller meeting the 110.9 N thrust requirement is designed using the chart design method, and the 110BL230-630 brushless DC motor is selected based on motor–propeller matching. This motor has a rated speed of 3000 rpm, rated power of 3000 W, and torque of 9.6 Nm. The performance curve of the NACA0012 airfoil is analyzed to select an appropriate rudder surface. The rudder area (4067 mm^2) is designed in accordance with DNV rules, with the following parameters: tip chord length 40 mm, root chord length 40 mm, and half-span 70 mm. CFD analysis is conducted on the designed propeller and the UUV equipped with the integrated propulsion system. The predicted performance of the P4119 propeller (hydrodynamic parameter deviation ≤ 1%) and the SUBOFF hull (resistance relative error ≤ 3.04%) confirms the accuracy of the CFD method for calculating propeller open-water performance and UUV drag. Through comparative analysis, the optimal rudder–propeller spacing is determined to be 60 mm, as this spacing yields the highest propulsion efficiency.
Wei, Jiaguang, Feng, Xiaowei, Zhao, Fuchen, Wang, Xingke, Xu, Shanzhi, He, Wenxuan
Study on Fuel Sloshing in Launch Vehicle Tanks and Response of Anti-Sloshing Plates2026-99-08437/30/2026
Violent shaking induced by motion excitation in a dynamic environment can generate significant additional forces and moments in liquid propellants, affecting spacecraft stability and attitude control. This study employs the CEL method to establish a fluid-structure interaction model for a launch vehicle fuel tank. The penalty function approach addresses FSI and hinged contact behavior, while the control volume method quantifies liquid pressure on anti-sloshing plates and propellant volume changes. Initial filling angles were used to simulate motion excitation equivalently. For partial filling conditions, the effects of equivalent filling height, initial filling angle, and anti-shake plate thickness on impact resistance were analyzed. Results indicate that at a fixed initial liquid filling angle, increasing the equivalent liquid filling height elevates both the maximum pressure and displacement of the anti-sloshing plate, though the rate of increase diminishes with greater plate thickness. At a fixed equivalent liquid filling height, increasing the initial liquid filling angle raises the maximum pressure, while the enlarged liquid-solid contact volume suppresses propellant sloshing, thereby reducing the displacement of the anti-sloshing plate. This study provides theoretical support for the structural design of anti-sloshing plates in rocket tanks.
Jiang, Longxuan, Le, Guigao
Research on Multi-Physical Field Accelerated Life Test for Long-Life Rotary Mechanism for Space Applications2026-99-08147/30/2026
The coupled multi-physical field environment in space, including vacuum, high-low temperature cycles, and temperature gradients, is the key factor affecting the life of the spacecraft’s rotary mechanism. Aiming at the use requirements of long-life space rotary mechanisms, this paper designs a multi-physical field accelerated life test scheme. This scheme simulates the vacuum environment, high-low temperature cycles, and temperature gradient conditions encountered during on-orbit operation. Ground-based accelerated life tests were conducted based on this scheme to verify the life of the mechanism under a comprehensive environment. Taking a certain type of space rotary mechanism as the test object, an integrated test platform was constructed, incorporating a vacuum simulation system, a temperature gradient control system, and a mechanism performance test system. Corresponding test procedures and failure criteria were established. Test results verified that after accumulating 130,000 ±7° small-angle reciprocating swings, the mechanism’s lifespan indicators met expectations. Post-test, the overall performance of the mechanism still satisfied the design requirements, with key moving components remaining in good condition. This study provides important experimental evidence for the on-orbit application of this mechanism type and offers valuable engineering reference for the design and evaluation of life tests for space mechanisms under multi-physical field coupling conditions.
Wang, Haomiao, Du, Yuefei, Huang, Mengzhe, Yang, Jinping
Research on Long-Life Solid-Liquid Hybrid Lubrication Technology for Large Drive Mechanisms of Survey Platform2026-99-08267/30/2026
For the large drive mechanisms of the survey platform, aiming to achieve long-life in-orbit rotation lubrication, a study was conducted on the tribological characteristics of a lubrication solution combining molybdenum disulfide (MoS2) coating with the application of perfluoropolyether (PFPE) greases. Validation tests were carried out under vacuum and high-low temperature environments to evaluate the equivalent in-orbit service life of solid lubrication coatings when used in conjunction with vacuum greases. Additionally, the physical properties of the friction pairs under solid-liquid hybrid lubrication conditions were investigated. Using life components equivalent to the actual product state, vacuum high-low temperature life tests under solid-liquid lubrication conditions have been completed to validate long-life lubrication technology. This holds significant guiding and reference value for the design of subsequent long-life spacecraft.
Fu, Zhibin, Zhang, Kai, Yang, Siqi, Zhu, Jiahao, Qian, Zhiyuan, Ji, Ming, Zhang, Lei, Wang, Zhiyi, Ma, Zhifei
Research on the Inter-Stage Energy Transfer System of Launch Vehicles Based on Multi-Channel Coupling Mechanisms2026-99-16197/24/2026
In the paper, a novel non-contact high-power energy transfer system based on a layered coupling structure is designed to meet the demand for reliable energy transmission during the inter-stage separation process of launch vehicles. The system adopts the upper four-coil transmitting array and the lower single-coil receiving structure and combines the innovative design of a 6:1 step-down transformer topology. Through the optimization of the multi-channel magnetic field coupling mechanism, the system realizes the safe transmission of more than 2 kW of power in close interstage under the difficult problem of transmission loss under the scenario of low input voltage and high output current, which effectively solves the problem of the system. Experimental findings can demonstrate that with a specified input voltage, the system could keep its output voltage of about 28 V under a given input voltage, and the maximum output current reaches about 85 A. The transmission efficiency is significantly higher than the traditional single-coil structure, and the measured data verify the applicability of the scheme in the core indexes of voltage stability, power capacity, and transmission distance. The design breaks through the reliability limitation of traditional contact connections under extreme working conditions and provides an innovative solution for continuous energy supply during the dynamic separation process of the carrier.
Guo, Xinwen, Jing, Xiaorong, Xu, Pengfei
Design and Application of A Pressure Measurement System Based on Spacecraft Chemical Propellant Engine Plume Test2026-99-16237/24/2026
Spacecraft with chemical propellant engines, especially spacecraft for exploring extraterrestrial objects, need to carry out plume tests on the ground in order to determine the influence of engine plumes on spacecraft. An important purpose of the plume test is to accurately measure the pressure field in key parts of the spacecraft. In this paper, according to the pressure measurement requirements of the spacecraft plume test, the design of a pressure measurement system is carried out, which mainly includes a pressure measurement sensor, a pressure difference measurement sensor, a pipeline, a cable, a measuring instrument, a data acquisition instrument, upper measurement software, and so on. The designed pressure measurement system was successfully applied to the plume impact test of Chang'e VII, which provided important technical support for the development of the spacecraft.
Wu, Yue, Guo, Qinliang, Wu, Dongliang, Liu, Xiaoning, Tao, Dongxing, Lin, Boying, Xie, Zheng, Wei, Xi, Niu, Tong
Lubrication Design and Experimental Verification of Long-Lifespan Ball Screw for Space Environment2026-99-16357/24/2026
Ball screws, as classic high-precision transmission structures, are widely used in various linear motion mechanisms. To meet the needs of space applications, it is necessary to address issues such as microgravity and long lifespan to enhance the in-orbit lifespan and reliability of ball screws. Traditional oil or grease lubrication methods are often unsuitable for space environments due to microgravity and vacuum evaporation problems. This paper conducts relevant research on lubrication design, friction pair design, and friction and wear verification to solve the lubrication and lifespan issues of long-lifespan ball screws for space applications.
Xie, Wen, Zhao, Jian, Gong, Kang, Hu, Xiaonan, Guo, Menglei, Jiao, Hanyu
Analysis and Experimental Research on The Impact of the BangBang Valve Switch on the Flow Rate of the Storage and Supply System2026-99-16157/24/2026
This article focuses on a wide range of high-precision storage and supply systems. Under the rated flow rate of 2.928 mg / s of the proportional flow controller, the instantaneous flow fluctuation range of the BangBang valve reaches 2.963 mg / s, exceeding the control accuracy requirement of 1% for the proportional flow controller. By establishing mathematical models of the BangBang valve, proportional valve, and proportional flow controller for simulation analysis, the trend of the simulation results is consistent with the experimental results. Furthermore, considering the spatial layout and weight of the storage and supply system, this paper proposes a method to improve the accuracy of flow output by adding 180 mL of air capacity between the proportional valve and the proportional flow controller. Ultimately, the maximum flow fluctuation of the proportional flow controller at the moment of the BangBang valve opening and closing is 2.941 mg / s, which meets the control accuracy of the proportional flow controller. Moreover, the error between the output flow rate of the proportional flow controller and the rated working flow rate is minor after increasing the air capacity.
Li, Zhong, Li, Zongliang, Yan, Zelong, Huang, Tiankun
Experimental Analysis of Human Head Dynamic Response and Injury under High-G Landing Shock2026-99-18617/17/2026
This study looks at how the human head reacts and gets injured during high-G landing impacts in spacecraft return capsules. We used a vertical drop tower system for the experiments. A standard crash test dummy, called the Hybrid III 50th, was used to imitate how astronauts sit during landing. We applied two common safety standards—the Head Injury Criterion (HIC) and the 3 ms cumulative acceleration rule—to measure head response under high-G impacts. The results show several things. First, head acceleration increases linearly as seat acceleration increases. Second, the peak total acceleration of the head is much higher than the seat acceleration. In particular, acceleration in the X and Z directions is much stronger than in the Y direction. Third, when seat acceleration went over 47.71 g, HIC exceeded the safe limit of 700, and the 3 ms head acceleration also passed the 80 g limit. This suggests that 40 g should be considered a safe upper limit for seat acceleration. This work provides experimental support for improving landing systems to protect astronauts’ heads during high-G impacts.
An, Hao, Wang, Yafeng, Guo, Yazhou
Analysis of Structural Stiffness Indicators of Manned Lunar Vehicles2026-99-18277/17/2026
The structural stiffness of a manned lunar vehicle is a core indicator ensuring its stable operation in the complex lunar environment. The vehicle’s body structure must meet multiple requirements, including high stiffness, lightweight design, and adaptability to lunar surface conditions. Since lunar gravity is only 1/6 of Earth’s and the terrain is rugged and dusty, the body structure must employ a high-stiffness design to withstand driving impacts and resist deformation, thereby preventing mechanical failures or safety hazards for crew members caused by excessive structural distortion. However, excessive structural stiffness would result in an overweight vehicle body, conflicting with the spacecraft’s lightweight requirements. Thus, the structural stiffness index should be optimized to a lower value while ensuring safe operation during lunar surface driving without compromising performance. This paper calculates and determines the structural bending and torsional stiffness indicators for the manned lunar vehicle’s body through simplified model calculation and the FEA method.
Shen, Zhenghui, Wu, Yingjia, Yang, Jianfeng, Wang, Weijun, Zhang, Chongfeng, Han, Liangliang
A Method for On-Orbit Testing of Long-Term Docking of Manned Spacecraft at the Space Station2026-99-18487/17/2026
To ensure the successful implementation of the separation, evacuation, and return processes of manned spacecraft after long-term docking at the space station, regular on-orbit health assessments must be conducted. Based on this requirement, a technical method for evaluation through autonomous on-orbit testing is proposed. First, the docking status and characteristics of the manned spacecraft’s systems, such as information management, crew environmental control, thermal control, power management, docking function, attitude, and orbit control function, are described. Then, the functional requirements for the separation, evacuation, and return of the manned spacecraft, such as the relative measurement, the relay communication, TT&C and data transmission, image and voice, instrument display and alarm, and the attitude measurement, are analyzed. Subsequently, the on-orbit testing system, test items, test procedures, and test methods for health assessment are detailed. It also provides the design of TT&C support, the design of energy support, and the main principle explanation for autonomous on-orbit testing of the system.
Cheng, Wei, Nan, Hongtao, Tian, Ye, Zhao, Zheng
Multi-Frame Centroid Extraction Method for Optical Navigation During the Approach Phase of Small Body2026-99-18517/17/2026
Autonomous optical navigation is one of the important navigation methods for the small bodies approach phase. To improve optical navigation performance during the approach phase to a small body, this paper presents a method for extracting the target centroid from sequential optical images. The process begins with fitting a minimum enclosing ellipse to the detected contours in each frame to obtain an initial estimate of the centroid. Building upon this, edge corner points across adjacent images are matched using normalized cross-correlation, and their displacement is tracked using optical flow techniques. The observed pixel trajectories are analyzed, and a predictive model of pixel motion is formulated based on the geometric relationship between the detector and the small body. By combining the directly extracted centroids with the predicted motion of key pixels, a fusion strategy is developed to improve the reliability of the centroid estimation. Finally, numerical simulation results demonstrate that the method significantly improves the accuracy of centroid extraction, thereby enhancing the overall performance of optical navigation during approach operations.
Liu, Jing, Zhu, Shengying
Asteroid Landing Navigation Based on Invariant Extended Kalman Filter2026-99-18567/17/2026
Optical navigation serves as a critical modality for autonomous guidance during small celestial body landing missions. To address the inherent strong nonlinearities in both the lander’s dynamic model and optical observation model, this paper investigates an invariant extended Kalman filter algorithm based on Lie group structures. First, we establish the state model and optical observation model on the special Euclidean group. Subsequently, a linearized right-invariant error dynamics equation is derived using invariance theory, along with the formulation of state prediction models. Furthermore, the feature vector observation model is modified into a right-invariant observation form, enabling state correction through exponential mapping of innovation vectors. Numerical simulations using asteroid Eros 433 demonstrate that the proposed invariant extended Kalman filter (InEKF) outperforms the conventional extended Kalman filter (EKF) in both estimation accuracy and convergence speed. Notably, the algorithm eliminates the need for online Jacobian matrix computations, satisfying the stringent navigation requirements for autonomous landing operations. The results validate the effectiveness of Lie group-based filtering in handling the nonlinear geometry of pose estimation for irregular celestial bodies.
Liu, Zhengdong, ZHU, Shengying
Cooperative Spacecraft Orbit Design for Small Body Exploration2026-99-18637/17/2026
To address the orbital design problem for cooperative observations with multiple spacecraft in small bodies exploration, this paper proposes an orbital design method that accounts for cooperative observation effectiveness, given the primary spacecraft’s orbital parameters and observation schedule. First, to accurately compute the visible regions on the small body surface, we develop a polyhedral equal-solid-angle resampling scheme based on the Hierarchical Equal Area iso-Latitude Pixelization (HEALPix), thereby constructing a pixel-based surface grid of the small body. Then, by taking the cooperative observed area ratio and the mean instantaneous field-of-view overlap ratio as effectiveness metrics, and the maneuver ΔV as a constraint, we formulate an optimization-based search strategy to solve for the optimal orbital configuration parameters within the search space. Numerical simulations show that the proposed method produces near-circular, non-coplanar configurations that satisfy both propellant use constraints and cooperative observation requirements, providing a useful reference for engineering design.
Cao, Yilin, Zhu, Shengying
Effect of Micro-Morphology on Thermal Radiation Properties of TC4 Alloy2026-99-05127/10/2026
With the development of manned spaceflight and deep space exploration, TC4 alloy has been used for the structure design of aircraft due to its excellent characteristics. Thermal radiation properties (solar absorptance and hemispheric emittance) of TC4 alloy are becoming important design indices. We investigated TC4 alloys with different surface morphologies and the effect of micro-morphology on thermal radiation properties. The results show that the solar absorptance of the alloys is sensitive to surface roughness and microstructure. As the surface roughness or crack increases, solar absorptance increases. Hemispheric emittance of the alloys increases as surface roughness is added, but it is insensitive to the micro-nanostructure of the alloys.
Liu, Yang, Zhu, Xiaoxi, Ren, Chaolong, Li, Dasong, Wan, Lei, Huang, Feiyu
Lunar Lander Landing Dynamic Model and App Development in Simscape®2026-01-60026/10/2026
With the recent renewed interest in manned lunar exploration, it is critical to revisit the Apollo Moon landings with new analysis tools. Modeling the Moon landings of the past can help guide the development of new landing vehicles for the present and the future. One of the critical subsystems to model is the vehicle’s landing gear. During a landing event, structural loading, energy absorption, and toppling stability are important factors that drive the design of landing gear subsystems. These aspects can be studied using models and simulations in addition to physical testing. This study explores one recent modeling tool for modeling the landing gear and uses the Apollo 11 Moon landing as a use case. A generic model was built using MATLAB®, Simulink®, and Simscape® Multibody to model the dynamics of a landing event. The landing gear structure comprising the primary strut, secondary struts, footpads, and joints was modeled in Simscape® Multibody. Various energy absorption mechanisms in the struts were modeled based on the relative motions of the inner and outer cylinders of the leg. Touchdown contact forces, when the footpads strike the lunar surface, were modeled considering the soil mechanical properties. Slosh dynamics were modeled using a mechanical pendulum module, and tip-over controllers were developed using Simulink®. However, neither was applied in the presented analysis relating to the Apollo lunar module. After developing the generic landing dynamic model, the Apollo 11 landing was simulated for validation purposes with results closely matching the historical measured data. A MATLAB® Graphical User Interface application (app) also was developed based on this model for usability and better accessibility of the landing simulation by non-experts on landing dynamics. It offered the opportunity for landing stability study with and without control, i.e., the max slope a lander can land without tipping over in 3D realistic landing situations.
Arndt, Grant, Wu, Wei, Butzman, Noah
Influence of Boundary Conditions on Dynamic Characterization of Launch Vehicle Structures with Closely Spaced Modes2026-26-07306/1/2026
Dynamic characterization tests play a critical role in launch vehicle applications, as they provide the frequencies and mode shapes required for refining Finite Element Models (FEM) and ensuring structural integrity. While such tests are often routine when mode shapes in orthogonal planes are well separated, practical challenges arise when modes are closely spaced. In these cases, careful test planning and execution become essential to obtain reliable results. A key factor influencing test outcomes is the boundary condition of the test article. Although free-free suspension, achieved through very low-frequency support, is theoretically ideal, it is often impractical. As a result, most dynamic characterization tests are performed with a base-fixed condition, where the properties of the supporting structure can influence the measured response. For structures with asymmetry limited to a single axis, mode shapes are typically expected to align along that axis; however, deviations may occur when boundary effects are significant. This paper presents a case study of a structure in which the first bending modes in orthogonal directions were separated by only 0.1 Hz. The hardware, with a mass of less than 4 tons, was mounted on a 110-ton rectangular platform without strong ground fixity. Although initially expected to have negligible influence, the base altered the bending mode orientations by up to 30 degrees, even though frequencies and mode shapes remained largely unchanged. Through carefully designed experiments, these closely spaced modes were extracted, and the base influence was identified. A repeat test on a rigid, concrete-embedded platform confirmed the true orientations. The results underscore the importance of accounting for boundary condition effects in dynamic characterization tests and provide practical guidance for test engineers to mitigate uncertainties in future launch vehicle applications.
Panda, Ajay Kumar, Avirah, Nohin K, Shaikh, Altafhusen
Augmented Reality and Multimodal Interfaces for Astronaut Training and In-Orbit Operations2026-26-07966/1/2026
Augmented Reality (AR) and multimodal human–machine interfaces (MMI)— combining visual overlays, voice, gesture, eye- tracking, and biometric sensing—are maturing into flight-relevant technologies capable of transforming astronaut training and in-orbit operations. These interfaces can reduce task time, lower procedural errors, and mitigate cognitive workload, thereby strengthening crew autonomy and mission safety. Global operational experiences from International Space Station (ISS) augmented- reality trials and related international programs are synthesized to inform the proposed system architecture and validation framework: (i) an overview of India’s current AR/MMI-related ecosystem relevant to human spaceflight, including astronaut training pipelines and research collaborations; (ii) a mission-grade AR/MMI system architecture and multimodal fusion/decision logic suitable for human-rated operations; (iii) algorithms and programming examples for AR-driven finite-state-machine (FSM) procedures and workload-sensitive adaptation; and (iv) simulation-backed datasets across representative procedures indicating approximately 20 to 30 percent task-time reduction and approximately 40 to 50 percent error- rate reduction under controlled conditions (based on ten procedures and twenty-four simulated sessions for workload analysis). The findings reinforce that AR/MMI deployment can improve training throughput, reduce crew fatigue, and increase safety margins when designed with evidence gating, conservative confidence thresholds, and robust fallback modes. Recommendations include establishing a Human Space Flight Centre (HSFC) AR/MMI laboratory, conducting structured A/B validation trials, and committing resources for progressive demonstrations aligned with future in-orbit operations.
Yadav, Anoop Singh
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