The gauging accuracy of propellant filling system is critical to the success of aerospace launch. Because of the defects of the calibration method for the flowmeter of launch site filling system, the deviation for the liquid level I value calculated by the filling system flowmeter and the theoretical value of the rocket tank liquid level I is quite large. An online calibration method is proposed for the flowmeter of filling system by which K coefficient of flowmeter is corrected by the rocket tank liquid level I. The result is shown that gauging accuracy of propellant filling system in launch site is enhanced, which is of great importance for the success of rocket launch.

The gas-liquid combined rapid erection hydraulic system is a new type of large flow hydraulic system which is driven by gas and motor pump, and can greatly increase the erection speed. The fault analysis and the reliability analysis of a rigid erecting hydraulic system with combined gas-liquid oil is carried out. Then the fault tree analysis is carried out by taking the fault of excessive vibration in the erection position as an example. The simulation analysis of typical faults of the system is carried out by means of co-simulation, and the relationship between fault causes and fault phenomena is studied and the effects and hazards of the fault are discovered. Some improvement measures are put forward to improve the reliability of the system.

Torque limiter is a physical protection device that ensures mechanical equipment operates under safe load conditions. Conventional engineering design typically employs static design and verification methods, with optimization and iteration carried out through physical prototypes, resulting in long development cycles and high costs. The design simulation and combination parameter optimization of a miniaturized torque limiter for a specific model are focused on. Firstly, based on the principle and elements of the steel ball's inclined surface disengagement, some mathematical formulas are established and a three-dimensional structure is designed, identifying the key parameters affecting the performance of the torque limiter. Secondly, the torque transmission characteristics and structural strength of the torque limiter are simulated, and the accuracy of some strength simulation results is verified by using Hertz contact theory. Thirdly, the main structural parameters are optimized and evaluated by using the orthogonal experiment method, obtaining the best parameter combination. Finally, two principle prototypes are produced based on the models before and after optimization, and static disengagement experiments are conducted to verify the accuracy of the disengagement torque under static load.

High-speed centrifugal pumps are widely used in industry and aerospace, and their performance is affected by the matching of the number of inducer and impeller blades. In order to study the effect of different matching relationships on the pump performance, numerical simulations based on the RNG k-ε model are carried out using ANSYS-CFX software, and the accuracy of numerical calculations is verified by external characteristic tests. By analyzing six matching relationships of inducer blades with 3 and 4, and impeller blades with 5, 6, and 7, the results indicate that when the number of impeller blades is fixed, the head is improved at small flow rates but reduced at large flow rates while increasing the number of inducer blades. Keeping the number of inducer blades unchanged, the head is improved while increasing the number of impeller blades, especially at large flow rates. Increasing the number of inducer blades expands the range of vacuole distribution, while changing the number of impeller blades has less effect on cavitation performance.

In response to the application background of satellites passing over or observing a ground target within a specific time, the Walker constellation scheme design is carried out for meeting the revisiting time requirements. The models of a satellite coveraging a ground target are constructed. The methods for calculating the time-windows of a satellite passing over a ground target, and onboard circle/rectangular-field-of-view sensor observing a ground target are designed. On this basis, a Walker constellation scheme design algorithm which satisfies the revisiting time requirement with the minimum satellite number is developed. The simulations and analyses are provided for three simulation scenarios. The results of the developed algorithm are compared with STK, and the average error of revisiting times is less than 1.1 s, which verifies the accuracy and rationality of the models and the algorithm. The relevant research results can provide reference for the design of Earth observation constellation schemes.

In response to the pressing demand for the large-scale and high-frequency development of space transportation, horizontal takeoff and horizontal landing-reusable launch vehicle (HTHL RLV) which does not rely on fixed launch sites and can operate as conveniently as aircraft, represents a crucial development direction for establishing a future scheduled space transportation system. The technical characteristics and developmental path of HTHL RLV are systematically elucidated, providing a comparative analysis of the strengths, weaknesses, and applicability of different technical approaches. On this basis, it focuses on key technical challenges and potential breakthroughs in the field, including multidisciplinary-coupled overall system design, wide-speed-range aerodynamic configuration, high-performance combined-cycle propulsion, lightweight structures, adaptive guidance and control, reusability, and intelligent operation and maintenance. Furthermore, prospective pathways for future technology development are also outlined.

The wide-velocity-range (WVR) reusable flight vehicle, due to its extensive flight airspace and broad Mach number range, is challenging to select a fixed working state as the design point. Moreover, due to a large number of factors affecting the overall performance of the vehicle, as well as the varying impact and sensitivity of these factors in integrated air-launch system design, it has brought considerable difficulty to the integrated optimization design. A single-stage-to-orbit (SSTO) reference trajectory for the WVR reusable flight vehicle is established, conducting sensitivity analysis on key parameters from three major aspects of design: aerodynamics, propulsion, and structures. Through perturbation analysis of the reference design parameters, the impact of different parameters on the overall performance of the flight vehicle under varying operating conditions is comparatively analyzed. This successfully identifies several design parameters that significantly influence the vehicle's performance. Finally, based on the sensitivity analysis results, the study makes reasonable recommendations on subsequent optimization directions for the wide-speed-domain reusable flight vehicle from four aspects: schematic design, aerodynamics, propulsion, and structures.

In order to meet diverse mission requirements and reduce design and production costs, modular design has become an important development direction for flight vehicle system design. For modular flight vehicle, general components are key components and also the primary prerequisite and important foundation for carrying out modular design. To address the problem of poor module universality in traditional flight vehicle design, a general component construction method based on self-organizing mapping neural network is proposed. Firstly, the characteristics and content of modular flight vehicle design are introduced. Secondly, in response to the problem of long computation time and easily getting in the local optimization in self-organizing mapping algorithm, the calculation process for the general component construction method combining self-organizing mapping and neural network is proposed. Finally, simulation experiments are conducted using a modular flight vehicle design example to validate the proposed general component construction method. The results show that the method can effectively meet the requirements of modular flight vehiclegeneral component construction, and significantly improve computation time and solution accuracy compared to a single self-organizing mapping algorithm.

Initiating explosive devices on rockets are disposable products. Test items on the ground are rarely, and directly related telemetry data are little in flight. By means of data correlation, the present telemetry data can be fully utilized to analyse the performance of initiating explosive devices. Several portion of flight telemetry data closely related to the initiating explosive devices is selected, a analysis on its performance is made, and the result with performance indicators and the test dates on ground are contrasted. The analytical method is verified to be right.

High-speed underwater vehicles are critical carriers for underwater high-speed penetration. To address their higher drag reduction demands, higher-performance underwater drag reduction technologies and more precise control techniques are required. Supercavitation drag reduction is primarily explored, which holds significant development potential, discussing its drag reduction mechanisms, component functions, and cavitation morphology changes. The current status and development level of supercavitation drag reduction technology theory, experimental validation techniques, and typical equipment are analyzed both domestically and internationally. Further, key issues in motion control for high-speed underwater vehicles are examined, researching control techniques such as linear feedback, robust pole placement, sliding mode variable structure, H-infinity robust control, and intelligent control, conducting research and application analysis on motion control methods. Areas requiring further research in current supercavitation drag reduction are also analyzed, including cavity stability issues, flow field simulation and validation for complex force-thermal physical processes, multiphase flow complex thermophysical process modeling, and robust stability design in highly nonlinear environments. Finally, from a future development perspective, it identifies unresolved problems such as perfecting fundamental mechanisms, intelligent control, algorithm innovation, structural innovation and interdisciplinary integration, and engineering validation. References for research on drag reduction and control technologies for high-speed underwater vehicles can be provided.