Advances in Astronautics Science and Technology最新文献

The LS-DYNA simulation software was used to study the overload characteristics of a projectile penetrating a layered protective structure at high velocity. Firstly, the simulation data were compared with experimental data to verify the accuracy of the finite element model. The process of projectiles penetrating two different protective structures was analyzed, and the overload characteristics of the projectile under different working conditions were studied. Results show that the peak overload of the projectile penetrating the light protective structure at 1200 m/s and 1700 m/s can exceed 80,000 g and 130,000 g, respectively, and the peak overload of the projectile penetrating the heavy protective structure at 1200 m/s and 1700 m/s can exceed 40,000 g and 70,000 g, respectively. When the projectile penetrates a lightweight protective structure with different material shielding layers at the same velocity, the overload peak value of penetrating the shielding layer material of reinforced concrete is greater than that of penetrating the shielding layer material of granite. The deceleration peak value of the projectile penetrating a light protective structure is larger than that of a projectile penetrating a heavy protective structure at the same velocity mainly due to the good buffering effect of the thick soil layer of the heavy protective structure.

Liquid rocket engines are fault-prone parts on launch vehicles. Due to its complex working environment and strict performance requirements, liquid rocket engines often face many kinds of failure risks during actual commissioning and operation. In view of the high risk of liquid rocket engine failure and the scarcity of abnormal video data in the actual commissioning process, the traditional fault monitoring methods are faced with many challenges. In response, this paper proposes a fault simulation testing methodology specifically for liquid rocket engines under complex interference conditions. A semi-physical model has been developed to mimic the abnormal states that liquid rocket engines may experience during debugging or operational activities. This model enables the collection and generation of a series of video data that closely resemble real-life fault scenarios, enhancing the effectiveness of fault monitoring and analysis. Finally, by comparing with the data of the actual test run, the simulation test data achieved a high degree of similarity, indicating that the designed simulation test can effectively simulate the actual physical process during the actual test run. Through the innovative fault simulation test method, this study successfully solved the problem of abnormal video data scarcity, and provided support for the research of liquid rocket engine video anomaly monitoring.

Surveillance and anti-surveillance are currently the dominant forms of orbital game of spacecraft. Based on the maneuver capabilities and surveil strategies of typical surveillance satellites, an evasion strategy as well as a defend strategy using an escort satellite are proposed. The maneuver capabilities of a typical geostationary earth orbit (GEO) satellite are first demonstrated, followed by a detailed demonstration of the evasion abilities against the approaching surveillance satellite. Then a high-maneuvering escort satellite is proposed as another way to cope with the surveillance satellite and the corresponding defend strategies are analyzed. Simulation results demonstrate that a normal satellite can hardly escape the approach and detection of a smart surveillance satellite. However, a high-maneuvering escort satellite can maintain precise sight tracking of the surveillance satellite, which means with certain protective payloads installed, the escort satellite can successfully drive the surveillance satellite away from our high-valued GEO satellite.

A fixed-time orbital rendezvous guidance strategy was proposed to meet the requirements of the time-sensitive pursuit-capture game mission. A key problem of fixed-time orbit rendezvous is the design of deceleration guidance strategy and the choice of transfer time. In order to solve the deceleration guidance problem under limited thrust, a displacement formula under constant rocket thrust is proposed. Basing on the formula, a deceleration guidance strategy of "pulse correction, deceleration condition, inverse-relative-velocity deceleration" was designed so that the spacecraft can meet the terminal position constraint. Basing on the formula, a deceleration guidance strategy of "pulse correction, deceleration condition, inverse-relative-velocity deceleration" was designed so that the spacecraft can meet the terminal position constraint. For the mission time delay caused by deceleration process, a differential correction method was designed based on the displacement formula, which can obtain the Lambert transfer time corresponding to a given mission time. With the proposed method, the mission time error is reduced less than 1 s.

The pursuit-evasion game of orbital satellite is an important research problem in the field of space security. In this pursuit-evasion game, intercepting the target usually requires superior maneuvering capabilities. To address this issue, a method is proposed in this paper to use multiple small satellites with weaker maneuvering capabilities to encircle and capture larger targets with stronger maneuvering abilities. Firstly, based on Tsiolkovsky’s formula, the planar interception problem is derived and a one-on-one planar interception strategy is designed. Next, the existence of solutions for planar mission is analyzed, and a multi-satellite encirclement configuration is designed based on elliptical passive flyby theory. Finally, simulation analysis is conducted on the impact of various design parameters of the planar interception configuration on the encirclement task. The results indicate that the initial distance between interceptor and target significantly affects interception time. Simulation results validate that the proposed interception strategy and encirclement configuration can achieve rapid interception of close-range targets effectively.

With the increasing number and capabilities of orbital satellites and their onboard sensors, satellites scheduling plays an important role in growing demands for Earth observation tasks. A conflict-priority-based variable neighborhood tabu search method is proposed in this paper. By analyzing the flexibility of resources, the conflict-priority of tasks, and the visible time window features, the indicators of the impact, the conflict, the flexibility, and the bad impact are first established. On this basis, a first-come first-served greedy algorithm and a minimum bad impact greedy algorithm are designed for the generation of the initial solution. some rule-based heuristic strategies are also adopted for optimizing. Additionally, the algorithm incorporates three types of neighborhood structures including insertion, swapping and rearrangement, and deletion, using a tabu list to avoid local optima. Experimental results indicate the validity and efficiency of the proposed method. All solutions are within 10% of the optimal solution, with some even within 5%.The proposed method is effective for obtaining optimum solutions or solutions with a very good quality in various multi-satellite scheduling scenarios of realistic planning.

The properties of control allocation for attitude takeover of a failed spacecraft using nanosatellites are investigated in this paper. Since each nanosatellite with thrusters can only provide a two-axis torque on the combined system, multi-nanosatellites are distributed on different positions of the failed spacecraft to achieve three-axis attitude control. Considering there is no centralized node to calculate the allocation torque, a distributed optimization algorithm is developed. The proposed method can provide each nanosatellite with the optimal torque through communication with its neighbors, leading to energy consumption balance. The communication load is reduced using an event-triggering detector without Zeno Effect. Compared with the other two methods, the effectiveness of the proposed method is demonstrated using attitude maneuver examples.

This paper proposes an optimization strategy using competitive particle swarm algorithm for the anti-reconnaissance problem in the near-range game scenario of spacecraft. Firstly, the constraint analysis is carried out for the anti-reconnaissance game scenario, and game model are designed. Then, an adaptive sliding mode pointing controller is designed, and the effectiveness of the controller is verified through simulation examples. For the survival game, the two-point boundary value problem is derived. To facilitate the solution, it is further transformed into a single-objective optimization problem, and solved by using competitive particle swarm optimization algorithm. The simulation results verify the effectiveness of the solution method.

Aiming at the problem of non-cooperative spacecraft interception under the many-to-many pursuit-evasion game scenario with complete information, this paper establishes a multi-round interception model based on the theory of matrix game, and elaborates the practical significance of the Nash equilibrium mixed strategy in this scenario. Aiming at the demand of model solving, a model solver based on genetic algorithm is designed. Finally, the optimized strategies for many-to-many space interception game is analyzed based on the given scenario and control requirements, and the effectiveness of the established model and its solver is verified by numerical simulation.

Focusing on cutting-edge scientific issues related to lunar exploration and applications, 9 overarching goals and 38 specific objectives for China's manned lunar exploration program have been proposed. Leveraging China's technical capabilities in manned spaceflight and lunar exploration, as well as its expertise in lunar and planetary science, the objectives center on scientific research, lunar-based scientific research, and resource exploration and utilization. Based on these scientific goals and trends in domestic and international manned lunar exploration landing site selection, China's basic principles and processes for selecting landing sites have been established. Thirty prime landing sites have been identified, including 11 low-latitude regions and 1 mid-latitude region, taking into account scientific value and engineering implementation conditions. These scientific objectives and landing site selection recommendations will serve as important guidance and top-level input for the design and implementation of China's manned lunar exploration program.