This study investigates the combustion performance of gas-oxygen and gas-methane pintle injectors, which discusses the influence of pintle injector structure design parameters and thrust chamber combustion design parameters on the combustion performance. Theoretical analysis is carried out by numerical simulation and other methods. The simulation results show that the oxidizer central pintle injector has a higher combustion performance. A larger angle of the pintle head and a smaller distance of the intermediate sleeve have a higher combustion performance. A smaller pintle head radius can significantly play a role in cooling the pintle head, but there is a certain loss of combustion performance. When the speed ratio is about 1.1, the combustion performance is higher, and the temperature of the pintle head is lower. When the mixing ratio of oxygen and methane is around 3, the combustion performance is higher.

As a critical component of the space transportation system, solid launch vehicle has advantages such as full-vehicle storage, versatility for sea-based and land-based launch, rapid response, and low requirements for launch support. The development process and overall technical scheme of Smart Dragon-3 solid rocket are introduced. In addition, the practical experience in the development of solid launch vehicles is drawn as a brief summery. Furthermore, the series development of solid launch vehicles is claimed, based on the analysis of the future positioning of solid rocket development. The carrying capacity of medium-sized solid launch vehicle needs to be improved, through research innovation, scale development and optimization of comprehensive cost. In this case, the demands of various launch orbits can be satisfied by the style of offhand sea launch.

Selective laser melting (SLM) technology is a key technology for parts manufacturing in the aerospace field. With integrating the overall structural optimization design and SLM technology, the overall lightweight manufacturing of complex components can be achieved. In view of the high-performance manufacturing requirements of parts in the aerospace field, the progress in the manufacturing of complex integral components and lightweight structures in the aerospace field by SLM technology in recent years is introduced, and the future development direction is pointed out.

To address the issues of penetration and precision attacking for air-to-air missiles, an analytical solution for the miss distance of a non-zero-order guidance system is derived. The solution is then extended to advanced guidance laws beyond proportional navigation guidance. Based on these results, the effectiveness of evasion under different maneuvering strategies is analyzed which theoretically explaining the typical characteristics of miss distances in step and serpentine maneuvers and factors influencing the optimal maneuvering strategy are studied. Through reasonable adjustment of maneuver timing and direction, the effectiveness of evasion is improved. Furthermore, considering the integration of penetration and attacking through intelligent guidance laws, an adaptive-stepsize sparsified sampling prior model theory infusion remedial training agent learning (ASTRAL) is introduced. Simulation results show that the missile agent trained with the ASTRAL can effectively evade defender while maintaining its attacking capability during penetration. In addition, the generated guidance law demonstrates good engineering feasibility.

With the rapid development of technology, digital technology has become a key force driving innovation and development in various industries. Based on extensive research on the current state of digital applications in the aerospace industry both domestically and internationally, this research focuses on summarizing the achievements and experiences of the implementation of digital technology in the engineering development of the SD-3 commercial rocket. The aim is to delve into the current application status of digital technology in the commercial space industry and through typical case studies to analyze its specific implementation strategies, and to provide valuable references and insights for innovation in related fields.

To ensure the reliability of dynamic seal performance of low temperature valve in liquid rocket engine, the sealing pressure and performance of a new type of labyrinth packing dynamic seal structure are simulated and tested. Firstly, the structure of traditional packing dynamic seal is optimized, and a new PTFE-Graphite-Metal labyrinth composite seal is designed. Then, based on the thermal stress coupling method, the influence of the working condition on the dynamic sealing performance is analyzed, and two empirical models for PTFE and Graphite are proposed to represent the dependence of contact stress on both the loading pressure and temperature. Finally, the sealing performance of the new labyrinth dynamic seal is tested at room and low temperature. The results show that the new labyrinth dynamic seal can achieve good sealing performance at room and low temperature, which is consistent with the simulation results.

For Falcon 9 rocket launch missions in 2024 and before, a reuse indicator system has been initially established. Statistical analysis is conducted in the time dimension and status dimension, and the development rules of Falcon 9 rocket one-stage reuse technology are initially obtained. By the analysis of the rules, the development and evolution process of Falcon 9 rocket recovery and reuse technology is divided into three stages. Finally, a preliminary prediction is made on the development of China's reusable rockets.

In the process of rocket engine development, the test work is very important, and the main result of the test is a large number of data measured in the test, so the measurement is very important. The rocket engine has a harsh working environment, high test cost, high test risk, many measuring points, high precision and large scale, and requires wide measuring range and frequency to ensure high accuracy of steady-state parameter measurement and no distortion of transient process measurement. Therefore, special requirements are also proposed for the test system. In order to meet the new requirements of rocket engine test, a digital filter is proposed for optimizing the performance of rocket engine test system, which can optimize the dynamic characteristics of the test system on the basis of not changing the original equipment hardware, and meet the requirements of high accuracy of steady-state parameters an no distortion of transient parameters. The experimental results show that the proposed method can obviously improve the performance of rocket engine test system.

The intelligent upgrade of the aircraft has put forward new requirements for guidance capabilities, and traditional algorithms perform poorly in tracking spatial three-dimensional trajectories under biased conditions. An aircraft trajectory tracking guidance method is designed based on the TD3 reinforcement learning algorithm. Through the action space in the form of deviation, the penalty term in the reward function and the guidance of the rate of change of distance, problems such as difficult convergence of algorithm training, large fluctuations in control quantity, and large cumulative deviation at the middle and final shift points are solved. Compared with the traditional LQR algorithm, the reinforcement learning guidance algorithm has significantly improved guidance accuracy and deviation adaptability, and has good versatility, which can be applied to small-scale formation maintenance issues.

In order to solve the problem of vulnerability of the missile-loaded motor shaft and bearing in the high overload environment of 23 000g guided artillery projectile, the anti-high overload brushless DC motor using a combination of disc spring and special steel ball for buffering and vibration damping is designed. Firstly, the acceleration load curve of the missile-borne motor is obtained by calculation. The bearing and shaft of the brushless DC motor are analyzed to be the failure prone parts. Secondly, according to the energy absorption characteristics of dish spring and steel ball, a composite damping structure of brushless DC motor combining dish spring and special steel ball is designed in the case of limited structural space. And based on this structure, a high speed and fast response anti-high overload motor is designed. Finally, the simulation and experimental analysis of the designed motor show that the design of the composite buffer structure can effectively reduce the stress and deformation of the motor shafting parts under the high overload environment. The structure of the anti-high overload motor has no obvious damage after the Marshall's drop hammer test, and the working performance meets the requirements of precision guidance control.