Explore the vast range of titles available.

The capture of a target spacecraft by a chaser is an on-orbit docking operation that requires an accurate, reliable, and robust object recognition algorithm. Vision-based guided spacecraft relative motion during close-proximity maneuvers has been consecutively applied using dynamic modeling as a spacecraft on-orbit service system. This research constructs a vision-based pose estimation model that performs image processing via a deep convolutional neural network. The pose estimation model was constructed by repurposing a modified pretrained GoogLeNet model with the available Unreal Engine 4 rendered dataset of the Soyuz spacecraft. In the implementation, the convolutional neural network learns from the data samples to create correlations between the images and the spacecraft’s six degrees-of-freedom parameters. The experiment has compared an exponential-based loss function and a weighted Euclidean-based loss function. Using the weighted Euclidean-based loss function, the implemented pose estimation model achieved moderately high performance with a position accuracy of 92.53 percent and an error of 1.2 m. The in-attitude prediction accuracy can reach 87.93 percent, and the errors in the three Euler angles do not exceed 7.6 degrees. This research can contribute to spacecraft detection and tracking problems. Although the finished vision-based model is specific to the environment of synthetic dataset, the model could be trained further to address actual docking operations in the future.

In spacecraft rendezvous and docking, traditional methods that rely on inertial navigation and sensor data face challenges due to sensor inaccuracies, noise, and a lack of multi-approach assurance. Focusing on exploring a new approach as assistance, this study marks the first application of deep learning-based image feature matching in spacecraft docking tasks, introducing the Class-Tuned Invariant Feature Transformer (CtIFT) algorithm. CtIFT incorporates an improved cross-attention mechanism and a custom-designed feature classification module. By using symmetric multi-layer cross-attention, it gradually strengthens inter-feature relationships perception. And, in the feature matcher, it employs feature classification to reduce computational load, thereby achieving high-precision matching. The model is trained on multi-source datasets to enhance its adaptability in complex environments. The method demonstrates outstanding performance across experiments on four spacecraft docking video scenes, with CtIFT being the only feasible solution compared to SIFT and eight state-of-the-art network methods: D2-Net, SuperPoint, SuperGlue, LightGlue, ALIKED, LoFTR, ASpanFormer, and TopicFM+. The number of successfully matched feature points per frame consistently reaches the hundreds, the successful rate remains 100%, and the average processing time is maintained below 0.18 s per frame, an overall performance which far exceeds other methods. The results indicate that this approach achieves strong matching accuracy and robustness in optical docking imaging, supports real-time processing, and provides new technical support for assistance of spacecraft rendezvous and docking tasks.

In the assembly missions of spacecraft, the cabins docking are the final part of the product assembly to form the probe into a whole, which is one of the most critical parts of the assembly task. The spacecraft of Insertion and Containment in cabin docking faces difficulties such as eccentricity of mass, small safety spacing, and non-visibility. In this paper, interference detection method based on reverse engineering non-contact virtual assembly and precision docking process method with tiny spacing of cabin eccentricity were proposed, and a large eccentric inline cabin docking device was developed to solve the problem of inline cabin precision docking. The above-mentioned method was applied to achieve nearly 100 successful dockings during the AIT process, which ensured the success of the spacecraft mission.

To ensure the successful completion of the manned spacecraft flight missions during China Space Station phase, an analysis of the mission characteristics was conducted. In response to the challenges posed by extended in-orbit flight duration, complex and variable external thermal flux, docking at different ports of the space station, new emergency rescue missions, high precision landing requirements, and efficient earth-to-space transportation, the following coping strategies were proposed, including: implementing long-life design to accommodate extended missions, actively temperature controlling and passive thermal insulation for temperature-sensitive equipment, developing all-directional rendezvous and docking designs, adding emergency rescue spacecraft on the ground, upgrading the re-entry guidance and control methods, and adopting autonomous rapid rendezvous and rapid return technologies. These strategies have been successfully implemented during the space station phase, ensuring the successful completion of the Shenzhou-12 to Shenzhou-18 crewed spacecraft missions. The results demonstrate that the analysis of the mission characteristics was accurate, and the proposed countermeasures are reasonable and feasible, effectively ensuring the safety and reliability of the crewed spaceflight missions for China Space Station.

This study focuses on the 6-DOF (six degrees of freedom) relative translation-rotation coupled control problem for spacecraft autonomous rendezvous and docking. The impacts of unknown inertial characters, space perturbation forces, and moments are considered. First, the integrated 6-DOF position-attitude coupled motion model is built up in the body-fixed frame of the active spacecraft. Then, an adaptive fuzzy control approach is developed by using the backstepping method, which estimates the lumped perturbation of the dynamics model uncertainties through the fuzzy approximation principle. Meanwhile, the norm approximation technique is utilized to decrease the consumption of computational resources caused by excessive online parameters in traditional fuzzy approximation methods. This method uses norm-mapped parameters to replace the adaptive parameters in traditional fuzzy logic systems, thereby approximating the total system disturbances with a reduced number of parameters. The results of the simulation experiment show that the developed method can achieve the rendezvous and docking objective disturbances and uncertainties.

Aiming at the docking requirements of small satellites in orbit service, an axial, radial double-locking satellite docking mechanism was designed to realize the docking and separation of small satellites. Capture docking using the butt bar and the groove. The mechanism possesses multiple advantages, such as simple structure and fast response. A dynamic model considering contact, collision, buffering, and friction was established, and ADAMS software simulated the docking process. Apart from that, the dynamics and motion data of the mechanism were obtained. As revealed by the results, under the initial conditions of the general light and small docking mechanism, the mechanism can achieve the set task and complete the docking with a small collision force. What’s more, the buffer device can absorb 85.5% of the energy of the satellite, and the mechanism has a certain attitude correction ability. Altogether, this exploration can provide a reference for designing satellite docking mechanisms and formulating a docking strategy in the future.

The zero-gravity unloading method is a process method commonly used in the spacecraft field. It has been widely used in the docking installation and ground deployment test of load equipment such as solar wing and antenna, and it is used according to the situation of solar wing, antenna or other load equipment. Different gravity unloading tooling. This article analyzes and compares various unloading methods according to the installation requirements of a certain model of large parts in the zero-gravity state. On the basis of analysis, it is concluded that the traditional five methods of uninstallation are not suitable for the installation and uninstallation of large-scale equipment modules of this model. It is necessary to carry out targeted design according to the configuration characteristics, main structure characteristics and installation requirements of large-scale equipment to realize large-scale modules. Stress-free assembly in zero-gravity state. As a result, a method for installing large parts of spacecraft based on zero-gravity unloading was proposed, which formed a large-scale component docking technology and realized the smooth assembly of the product.

This paper addresses the relative position and attitude tracking control in the framework of geometric mechanics for autonomous rendezvous and docking of two spacecraft where the relative motion of the leader and follower spacecraft tracks a desired time-varying trajectory. Using exponential coordinates on the Lie group SE ( 3 ) , which is the set of positions and orientations in three-dimensional Euclidean space, and the adjoint operator on the Lie algebra se ( 3 ) , the relative coupled translational and rotational dynamics is modeled. Based on the terminal sliding mode, a robust adaptive terminal sliding mode control scheme on SE ( 3 ) is proposed to ensure the finite-time convergence of the relative motion tracking errors using limited control inputs despite the presence of unknown disturbances and moment of inertia uncertainty. The control scheme is then applied to a situation where the follower spacecraft synchronizes its attitude motion with the leader, while maintaining a constant relative position with respect to the leader. The robustness of the controller is established using Lyapunov stability theory. Simulation results of close range rendezvous and docking verify that the proposed control scheme can achieve faster and more accurate tracking performance while consuming less control energy than the conventional terminal sliding mode control method.

The study presents the laser shock processed (LSP) aluminum–graphene composite development and performance evaluation as a solution for spacecraft docking systems that require high tribological reliability under vacuum and extreme thermal conditions. Hot extrusion produced a 0.02 wt% single-layer graphene composite that received LSP treatment using 3J energy with 70% pulse coverage degree. Post-LSP treatment showed both good graphene distribution across the material and refined grains throughout the surface. The treatment of LSP raised the Vickers hardness levels of the composite by 28% above the untreated sample’s outcome. The wear rate diminished by 42% under 60 N force and 0.15 m/s sliding speed in vacuum conditions. An improvement of 33% occurred in the sliding performance after LSP treatment because the COF reduced from 0.30 to 0.20. The constructed Python-based digital twin model employed multi-variable regression analysis for 30 experimental trials yielding an R² value of 0.91 and an RMSE value of 0.026 mm³/N·m. The predictive model results matched up with experimental data points within 5–8 percent ranges. Surface integrity along with wear resistance in aluminum alloys improves substantially through the application of LSP with graphene reinforcement which makes them appealing for space docking system mechanical components.

A robust nonlinear control strategy is presented for a cooperative spacecraft rendezvous and docking maneuver, where the pursuer spacecraft is subject to input saturation and actuator faults. The nonlinear coupled models for relative attitude and relative position dynamics are expressed in the pursuer body-fixed frame. A novel control strategy based on feedback linearization framework is developed, and a second-order disturbance observer is employed to estimate and compensate all uncertainties including parametric uncertainties, external disturbances, input saturation and actuator faults. It is proved that the closed-loop systems are uniformly ultimately bounded by using Lyapunov theory. Numerical simulations are given to illustrate effectiveness of the proposed control strategy.