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.

Research advances in fluid-structure interaction (FSI) during vehicle water entry, encompassing theoretical modeling, experimental testing, and numerical simulation are reviewed. The theoretical analysis systematically traces the evolution from classical potential flow theory to nonlinear multiphysics-coupled models, while critically analyzing their applicability and limitations in complex entry scenarios. Experimental investigations summarize measurement techniques for capturing transient parameters and revealing physical mechanisms, highlighting their crucial role in validating theoretical and numerical frameworks, with particular attention to instrumentation constraints and boundary condition effects. Numerical advancements are examined through grid-based and meshless methodologies, emphasizing their computational characteristics in resolving multiphase flow evolution and FSI dynamics. Finally, current technical bottlenecks are identified, followed by forward-looking perspectives on multiscale coupling modeling and intelligent algorithm integration.

The cryogenic exhaust valve is a key component of the liquid rocket propulsion system, and the main failure mode is the stuck guide. To improve its action reliability, a "metal-nonmetal" composite guiding structure is proposed. The non-metal hot pressing forming process is studied, and the theoretical calculation and simulation analysis of the guiding clearance variation under low temperature are carried out. An experimental system is built to verify the reliability of the forming process of the composite guiding structure and the rationality of the clearance calculation. The research results show that the nonmetal composite guiding structure of the cryogenic exhaust valve can adapt to the low temperature operating conditions, and has higher action reliability and tolerance to contaminants.

Permanent magnet synchronous motor (PMSM), owing to its high power factor, high efficiency, and high power density, have been widely employed in aerospace vehicles to enable high-dynamic servo motion. However, during long-term tracking control or attitude holding, PMSMs are prone to interturn short-circuit faults (ITSC). Under servo operating conditions, the fault signals exhibit non-periodic characteristics in the time domain, which poses considerable challenges for fault diagnosis. To address this issue, an ITSC diagnosis method is proposed based on the high-frequency negative-sequence current. First, a simplified analytical model of PMSM with ITSC faults is established to reveal the characteristic impacts of the fault on electrical quantities. Second, a high-frequency voltage signal is injected into the control system, and the high-frequency current response of the motor is extracted through a band-pass filters. Finally, the negative-sequence component of the high-frequency current is calculated as the diagnostic indicator, enabling real-time fault identification. By employing the high-frequency negative-sequence current as the fault feature, the proposed method can effectively distinguish healthy and faulty states of the motor under servo conditions, while improving both diagnostic speed and robustness. Simulation results demonstrate that the proposed method achieves reliable diagnosis under servo operating conditions with rapid variations in position, speed, and load, with a diagnostic time of less than one fundamental cycle, showing strong potential for engineering applications.

In the future reusable space transportation system, the plane-symmetric reusable launch vehicle has a high development priority, and the plane-symmetric launch vehicle control technology is one of the critical technologies. Firstly, the research significance and difficulties of plane-symmetric and liquid propellant rocket are analyzed according to the engineering requirements. Then, the research progress is summarized from four aspects, including attitude control, active load relief (LR) control, elastic vibration suppression and liquid sloshing suppression. Finally, in view of the unsolved problems in the existing research and the new problems brought by the special structure of liquid propellant plane-symmetrical rocket, prospecting its future development and putting forward several feasible research directions from the requirements of high-precision, high reliability and intelligent.

The airline-flight-mode launch capability is essential for future spaceports and a key indica-tor of their space launch capacity. Spaceports face challenges in improving this capability. These challenges include a lack of top-level planning, infrastructure pressure, an urgent need for technology upgrades, and management and safety risks. To tackle these issues, this anal-ysis proposes ten countermeasures. These strategies cover system architecture, overall lay-out, operation modes, rocket families, and testing and launch technologies. They provide valuable guidance for spaceports to enhance their airline-flight-mode launch capability.

The new generation of rocket-borne electrical system architecture fully embodies the characteristics of distributed information synthesis, which can realize the physical separation of rocket-borne electrical system, information sharing and dynamic resource allocation through appropriate unified real-time network design, reduce the impact of cross-domain information interaction, and improve the determinacy, reliability and fault-tolerant ability of system networking. Combined with the different real-time guarantee ability of real-time network flow control mechanisms, the information transmission requirements of rocket-borne integrated electronic system are analyzed, the time-sensitive flow control mechanisms are selected, the message and traffic type are matched, the time trigger window is designed through the joint optimization of path and scheduling, and the network simulation model is built using the OMNet++ to simulate and evaluate the performance of the network system. Through simulation, the matching relationship between all traffic and time-sensitive network flow control mechanisms in typical rocket-borne integrated electronic system are verified, and the feasibility of time-sensitive network application in rocket-borne integrated electronic system is demonstrated.

A primitive time synchronization method is proposed based on the FC-AE-1553 bus technology, aiming at the comprehensive development of onboard measurement systems and the background demand for real-time data sensitivity. This method enables each node in the FC-AE-1553 bus to have the same-time reference. On the basis of time synchronization, a scheduling timing based on time synchronization wasdesigned to collect real-time data from various NT nodes, meeting the requirements of real-time data for onboard measurement systems. The experimental results show that the FC-AE-1553 bus designed has nanosecond time synchronization, dual redundancy, and other functions, which meet the application requirements-of onboard measurement systems and improve the comprehensive level of onboard measurement systems.

Addressing challenges such as low data storage efficiency, weak real-time data retrieval responsiveness, and the separation between data storage and analysis in space missions, an integrated data-access-computation platform architecture is proposed. First, based on the characteristics of data acquisition and usage in the aerospace domain, a requirements analysis for the integrated platform is conducted. Subsequently, an overall architecture is constructed, outlining its core business processes and functional framework. The functional architecture comprises five layers: infrastructure, data acquisition, data storage, data computation, and data application, supporting multi-source heterogeneous data acquisition, operator invocation, task scheduling, and timed execution. Following this, a full-chain technical solution for real-time data acquisition, storage, retrieval, and computation is designed in detail, targeting the core functions of the integrated architecture. This solution provides decision-making support for space missions and lays a technical foundation for intelligent data analysis. Finally, key technologies are elaborated, including intelligent generation of aerospace test reports, data flow modeling, and visual analysis process orchestration.