Super Heavy-Starship is a two-stage fully reusable heavy-lift launch vehicle proposed by Space Exploration Technologies Corp. (SpaceX). In Super Heavy-Starship, mechanisms are widely utilized to implement various functions of the launch vehicle, such as connection, separation, aerodynamic control and landing shock absorption. In addition, traditional pyrotechnics are replaced by high-pressure cold air as power source of mechanisms. Focusing on the landing shock absorption mechanism, grid rudder mechanism, flap rudder mechanism, stage separation mechanism, and pneumatic mechanism of Super Heavy-Starship, the mechanism composition, working principle, design ideas, merits and demerits are clarified. The innovation points of SpaceX's mechanisms are summarized. Furthermore, the gaps and deficiencies in the development and application of launch vehicle mechanisms in China are analyzed, and corresponding suggestions are put forward as well.

In response to the multiple ignition requirement of the expander cycle hydrogen-oxygen engine, research on the torch ignition system scheme is conducted, and a relatively reasonable low-pressure torch ignition system scheme is identified. The results show that the mixing ratio of the torch igniter fluctuated greatly when opening the hydrogen main valve, which may cause structural ablation. The scheme of introducing hydrogen from the inlet of the hydrogen turbine and liquid oxygen from the outlet of the liquid oxygen pump has a lower ablation risk, but it has a certain impact on the engine's start-up and steady-state characteristics. The low-pressure torch ignition start-up tests of liquid rocket engine are carried out for the first time in China. The experimental results verify the simulation results, and indicating the feasibility of the scheme.

In order to solve the possible problems of filling accuracy and kerosene quality in the drainage process of the closed filling pipeline at the end of the kerosene, the pipeline deformation caused by the change of pressure and temperature is discussed by analyzing the influencing factors that affect the change of kerosene in the pipeline. The thermodynamic calculation model of temperature, pipe diameter and deformation pressure is constructed, and the accuracy of the model calculation is verified by experiments. According to the numerical calculation results of the model, the optimization measures for the drainage process are proposed to ensure the reliability of the drainage process of the filling pipeline.

In the fault-tolerant control of polyphase motors, hysteresis control is generally adopted for the more complex non-sinusoidal fault-tolerant current obtained by multi-constraint solving. Compared with hysteresis control, voltage space vector control has the advantages of low torque ripple and low energy consumption, which is more common in the control of polyphase motors. In order to solve the problem that the non-sinusoidal fault-tolerant current cannot be decoupled directly for voltage space vector control, Fourier transform is introduced and the non-sinusoidal fault-tolerant current is decomposed into fundamental current and third harmonic current to realize the decoupling transformation of the non-sinusoidal fault-tolerant current. Based on this, the decoupling transformation matrix is derived and the correctness of the processing method is verified by simulation analysis. The results show that this method can solve the problem that the non-sinusoidal fault-tolerant current under open fault-tolerant control of polyphase permanent magnet synchronous motor cannot be directly applied to voltage space vector control, so as to reduce the torque ripple and improve the motor current stability.

The stability of shipborne platform in complex sea surface wind and wave environments is an important foundation for the operation of shipborne equipment. Attitude stability control for shipborne platform, an active disturbance rejection controller is designed, which improves the tracking accuracy of the shipborne platform to the target angle, ensures the rapid response of the system, and suppresses the influence of uncertain factors such as wind wave disturbance and load disturbance. In order to further improve the control effect of the controller, the particle swarm optimization algorithm is used to optimize the intelligent parameters of the controller. The simulation results show that the ADRC can improve the tracking speed, accuracy and robustness of the system.

The safety of solid rocket launch vehicles under the abnormal side tumbling condition in the process of railway transportation is studied. Based on investigation and analysis of various vibration absorption schemes, the technical scheme of energy absorption system with the combination of cushion airbag and honeycomb is put forward. The side-rolling simulation analysis is carried out using Hypermesh and LS-DYNA software. The results show that the acceleration of the rocket's side-rolling down decreases from 27g to 8.91g, and the contact collision force between the launcher and the carriage decreases from 382.59kN to non-contact by using the above technical scheme. Meanwhile, it can obviously improve the safety of solid rocket launch vehicles under abnormal conditions such as railway transport rollover. Finally, it provides important guidance for the design of special solid rocket launch vehicles.

To analyze the correlation characteristics between visible-infrared spectrum and infrared radiation of photonic crystal films, three kinds of Ge/ZnS photonic crystal films with different visible reflectance and the same infrared emissivity are designed. By simulating the infrared radiation characteristics of photonic crystal structures, the influence of solar illumination and reflection spectrum on the infrared radiation characteristics of the films in vacuum and atmospheric environments is discussed. The simulated results show that the difference of visible reflectance will lead to the discrepancy of surface temperature in the presence of sunlight. For infrared radiation, the high reflection surface will reflect solar radiation at low temperature for $3 \sim {5\mu}\mathrm{m}$ waveband, which has a negative impact on infrared camouflage. For $8 \sim {14\mu}\mathrm{m}$ waveband, when the infrared emissivity is low enough, the infrared radiation emittance of the photonic crystal structures is close. The fabrication of samples and the measurement of reflection spectrum and infrared thermography are carried out. The test results show the consistency with the simulation, and verify the infrared camouflage performance of three films. The research results are helpful to understand the visible-infrared spectrum and infrared radiation correlation characteristics of photonic crystal films, and provide reference for the spectral design and application scheme of visible-infrared camouflage materials compatible with microwave camouflage.

In order to control the riveting interference and minimize the damage of GFRP composite caused by riveting, it is necessary to study the influence trend of riveting squeeze force on the interference of ${\Phi4}\mathrm{\;{mm}}2\mathrm{A}{10}$ rivet. The dynamic riveting process and the interference of the rivet have been simulated by ABAQUS on the effects of diameter of pre-drilled hole and riveting squeeze force of ${\Phi4}\mathrm{\;{mm}}2\mathrm{A}{10}$ aluminum alloy rivet on GFRP composite and aluminum alloy layers. On the basis of the simulation the experimental investigations are performed. The Interference test and metallographic analysis of the specimens are conducted. Results indicate that the interference of the same measurement location in the rivet increases with the increase of the riveting squeeze force and the interference with the same riveting squeeze force decreases through-the-thickness. ${\Phi4.2}\mathrm{\;{mm}}$ diameter of pre-drilled hole and ${18.3}\sim {18.7}\mathrm{{kN}}$ riveting squeeze force can achieve the optimum interference and the GFRP composite has no apparent injuries.

In order to improve test efficiency of launch vehicle and optimize the process of prelaunch testing, and to alter the traditional method of disconnecting electric cables manually for leakage monitoring, based on maintaining the original power supply circuit, a leakage monitoring technology research for the medium frequency alternating current supply circuit is proposed and developed. At the same time, the precision of leakage monitoring circuit is analyzed and the self-detection method is used to advance the reliability and safety of the system. The test results show that the system realized online leakage monitoring lasting no less than 24hours, and the range of leakage monitoring is 500 kΩ~50 kΩ with the precision better than ±10%, satisfying the monitoring requirements. Finally, the system experiment is carried out in the prelaunch testing of large cryogenic launch vehicle with high-reliability, high-precision and high-efficiency, and has significance of improving the level of automated testing and realizing unattended fore-end of launch vehicle.

A modular hierarchical power supply and distribution method is proposed for electrical system of launch vehicles in order to avoid large scale power supply cable, complex topology and potential path. Each stage of electrical system is planned as an independent power supply and distribution unit, and the integrated power supply and distribution framework is realized in the unit. Electrical isolation is designed among different power supply and distribution units and ground equipment to prevent the electrical coupling and potential circle path and reduce the system complexity. The power and distribution system has the advantage of modularization in system level and the plug and play with units, which provides a technical basis for the standardized design of the power supply and distribution structure of the future electrical system and hierarchical test of the launch vehicle.