SpaceX's SuperHeavy Starship interstellar transportation system project is developing rapidly and has now entered the orbital-level test flight stage, which may become another powerful launch vehicle to change the world's aerospace landscape. The different stages of the design iteration of the SuperHeavy Starship system are sorted out. The main technical changes and improvement motivations in each stage are summarized. The technical characteristics and the future application direction of SuperHeavy Starship are analyzed. It is hoped to provide enlightenment for the development of China's space launch vehicles.

A concept design method for the return of the first sub-stage of a launch vehicle is proposed. It provides a solution for the overall design of a recoverable Launch vehicle. Firstly, a motion model for return of first stage is built. In order to calculate the thrust and its adjustment range, two parameters that named thrust ratio and thrust adjustment factor are defined in the model. Secondly, relation between recovery thrust and left propellant is discussed. A constraint of left propellant is introduced. Finally, a return scheme of a first stage is planned through a simulation example. The method proposed answers such questions as how much propellant should be reserved to realize the return of the first stage, how much thrust should be used, what is the adjustment range of thrust during the return process, the landing point of the stage, the max velocity during the return, and height and velocity before the stage enters the landing phase. The example shows that this method can be used to plan a complete return scheme for the first stage of a launch vehicle.

The low orbit internet constellation represented by "Starlink" is a hot topic in the current development of the aerospace field. Multi-satellite stack technology can significantly improve the utilization rate of fairing space, thereby accelerating the construction speed of low orbit constellations, and is one of the important directions of future multi-satellite launching technology. This article analyzes the requirements and significance of multi-satellite stack technology, summarizes the existing connection forms of multi-satellite stack, and then points out the suitable connection forms for large-scale constellation construction through comparative analysis. The mature connection schemes of multi-satellite stack are interpreted, and the composition principle and technical characteristics of this technology are obtained. Finally, the difficulties and challenges in the stucture design and connection technology of multi-satellite stack are analyzed and prospects are proposed, providing reference for future multi-satellite stack structure design.

This article focuses on the dynamic model of air rudder rotation around the rudder shaft, considering a dry friction model with rotational clearance and Stribeck effect, and establishing the forced vibration equation of air rudder rotation with clearance and dry friction. The average method is applied to analyze the amplitude frequency characteristics of the rotational direction. The influence of different friction torque coefficients and external excitation frequencies on the amplitude frequency response of axial vibration is studied. The results show that when the external excitation frequency changes, the amplitude frequency curve of the vibration around the axis exhibits hysteresis nonlinear characteristics of different softness and hardness. Multiple solution frequency bands appear in the frequency domain, and the frequency domain multiple solution frequency bands increase with the increase of the friction torque coefficient.

Aiming at solving the SBIRS three satellites detection trajectory estimation problem, a data fusion trajectory estimation algorithm based on the GEO satellite and the HEO satellite detection is proposed. According to the SBIRS constellation composition and detection mechanism, the STK is used to analyze the SBIRS coverage capability to a certain area, calculation shows that over three satellites can fully cover it in about 43% of the simulation time. Establishing the three satellites detection data fusion estimation algorithm model to estimate the missile target motion state in real time, the current statistical model is adopted to describe the missile motion state, the centralized structure is adopted to achieve detection data fusion, in addition, the unscented Kalman filter is used as trajectory estimation filter. Simulation results show that, compared with the binary detection trajectory estimation error, the three satellites detection trajectory estimation error is significantly reduced.

In order to enhance the delivery and survival capability of unmanned aerial vehicle group in specific areas in long-range mission scenarios, and effectively complete various missions, a missile borne unmanned aerial vehicle group delivery scheme is proposed. The unmanned aerial vehicle group is delivered to the mission area through missile carriers, utilizing the rapid reentry advantage of the missile to improve the delivery and survival capability of the missile borne unmanned aerial vehicle group. Taking the end interception system "Dense Array" as a scenario, the survival capability of the unmanned aerial vehicle group is simulated and analyzed under two schemes of missile based delivery and parachute based delivery. The effectiveness of the proposed scheme is verified, meeting the requirement of the unmanned aerial vehicle group entering the mission area with a high survival probability in actual mission scenarios.

Interstage thermal separation is one of the core technologies in the flight process of solid rocket. The traditional "three in one" test usually includes three main subsystems: upper stage motor, servomechanism and separation system. For practical engineering development, it is costly, expensive and long cycle. It can only be used for system level performance verification test, and is not suitable for exploratory developmental test. Based on the new ground test method of cold air simulated rocket interstage separation test, combined with theoretical model, numerical simulation and ground test verification, the internal flow field in the initial pressure holding stage of interstage separation is simulated, the law of gas pressure change in interstage section is revealed, and the test mechanism of cold air simulated rocket interstage separation is expounded; Through numerical simulation analysis, the effects of different initial pressure of pressure accumulator, different volume of pressure accumulator, different pipe area and different volume of interstage section on the change of gas pressure are studied, which provides a solution for the design of interstage separation test of cold air simulation.

In order to study the mixing and explosion characteristics of liquid oxygen and kerosene, a partial confined space test system is established to simulate the application scenarios of the launch site and the tests are carried out. It is demonstrated that when liquid oxygen and kerosene are discharged and mixed at the same time, the concentration of kerosene and oxygen increases at first and then decreases. When kerosene temperature is ${65}^{\circ}\mathrm{C}$ and ignition excitation is ${5.9}\mathrm{\;J}$, even if liquid oxygen leaks, the ignition and explosion condition are still not reached at the measuring points arranged above the liquid level. In the test when the kerosene temperature is raised to ${80}^{\circ}\mathrm{C}$, explosion occurs when liquid oxygen is released only for about 20 seconds. At ignition time, the concentration of kerosene, oxygen, and nitrogen are ${1.31}\%,{40.05}\%$ and ${58.64}\%$ respectively, and the ratio of kerosene concentration to oxygen concentration is 0.033 .

For solid-engine aircraft, closed-loop guidance methods with energy matching or angle constraints are generally used in the powered flight segment, which have high control accuracy. However, its accuracy is greatly affected by engine performance deviations. Therefore, a zero-range Orientation closed-loop guidance method based on neural network is proposed to reduce the impact of engine performance deviation on the guidance accuracy. Firstly, the motion model of the powered flight segment of the aircraft is established, and the closed-loop guidance of the zero-range Orientation is analyzed and deduced. Secondly, a multi-input neural network algorithm is designed, the input and output parameters are determined, the residual energy, the velocityto be increased and the angle of the zero-range Orientation are trained. Then, the training results of the above neural network with the zero-range Orientation closed-loop guidance are combined. This method enables feedback of different zero-range Orientation angles under different engine deviations. Finally, different deviation states for simulation verification are chosen. The simulation results show that this method can effectively reduce the influence of engine deviation on the guidance accuracy, and has strong anti-bias ability and high guidance accuracy.

To study the safety of a tower slewing platform structure, a three dimensional numerical model is established with actual sizes and operating conditions. The structural force, pressure margin of hydraulic system with different wind loads, and the influence of lift platforms’ amount are researched which are concerned closely in use. In working condition, the maximum stress of structure is ${223.98}\mathrm{{MPa}}$, and the structure safety factor is 1.58 . The pressure margin of hydraulic system is calculated with the worst wind direction and the maximum windward area. When the platform is opened with permitted wind speed, the hydraulic system pressure can not be lower than ${5.40}\mathrm{{MPa}}$, and the pressure margin is 2.96. The structure safety factor is 1.35 when the number of lift platforms is 9. According to the results of simulating calculation, the security of the slewing platform can be confirmed. The simulating model can provide a reference for the slewing platform’s application.

Thermal protection is a regional protection measure covering the outer surface of the launch pad to prevent the bearing structure of the launch pad from being eroded by the rocket launch gas flow. It is a key link to ensure that the launch pad can reliably carry the rocket safely. In recent years, as the launch frequency of the conventional liquid carrier rocket represented by the Long March 2C rocket has increased year by year, the recovery time of the launch pad after the launch of the rocket has also been greatly reduced. Therefore, a rapid recovery scheme for thermal protection of the launch pad is proposed, which combines the ablation type heat protection technology with the absorption type heat protection technology, and the modular thermal protection components are designed to realize rapid replacement through simulation, test and use. The results show that the repair time of the new thermal protection is shortened from 3 days to 1 day, and the protection effect is good, which can meet the needs of high-density rocket launch.

Mobile Launcher (ML) is one of the critical ground supporting systems, which is going to be in service for Space Launch System (SLS). The function of ML includes stacking, assembly, process checkouts and launch support for the SLS rocket and Orion spacecraft. The structure layouts, operations and functions from Apollo and Saturn V are valued and baselined. The ground support equipment like umbilicals and accessories are researched and renewed. Besides, ML is aimed to be possessed of strong applicability and generality for different heavy-lift rockets, including SLS. The generality design is then performed, and modules and equipment are borrowed from previous launchers. Comprehensive tests of function, security and reliability are carried on. The research in the paper will provide reference for the launcher of heavy-lift rocket in China.

C/SiC composite material for hypersonic vehicle structure has a broad application in near-space area. The active / passive ablation performance of the C/SiC composite is studied numerically. An approach for active sublimation ablation performance up the ${2000}^{\circ}\mathrm{C}$ of $\mathrm{C}/\mathrm{{SiC}}$ composite materials is proposed and some wind tunnel experiments have been designed and completed. The results show that the ablation performance proposed has good accuracy compared with the wind tunnel results. The results can provide a reference for the structure and thermal protection design and safety assessment of the hypersonic vehicles based on C/SiC composite material.

Aerodynamic heating is a key issue in the research of hypersonic vehicles flying in near-space. It has an important influence on the aerodynamic, thermal environment and safety of the aircraft. Due to the limitation of experimental methods, wind tunnel experiments cannot simulate real flight conditions accurately. CFD is an important tool for studying aerothermodynamics problems. The format dissipativeness and grid are two important factors that affect aerothermodynamics simulation. The smaller the format dissipation, the better the CFD performance, but low dissipation will cause shock instability phenomena. A hybrid HLLCE format which has both the HLLE format stability and the low dissipativity of the HLLC format is constructed. This format exhibits the low dissipation properties of HLLC at a lower Mach number and can overcome shock instability phenomena at high speed. The thickness of the linear bottom layer of the boundary layer is used as the reference scale, and 1/10 of the thickness of the linear bottom layer calculated by the feature length is taken as the minimum grid scale for thermal environment calculation. The performance of low dissipation scheme is verified by hypersonic sphere example with the proposed grid scale

As an important component of aircraft guidance system, non-metal radomes have multiple functions such as heat protection, wave transmission and load bearing. It is connected to the aircraft body through high-temperature resistant adhesive agent. Radome is frequently subjected to harsh mechanical and thermal loads during the period of service, and the joint structure is often the weakness of strength design. Therefore, accurate simulation for mechanical behavior of the joint structure and achieving accurate prediction of load-carrying capacity are crucial for the structural design and optimization of radome. Based on bilinear cohesive model, the failure behavior of radome adhesive interface is numerically described by ABAQUS. And then the damage evolution of adhesive layer is simulated, and the accurate prediction of bearing performance of radome joint structure under flight thermo-mechanical environment is achieved. The corresponding experimental study is carried out. The experimental results are in good agreement with the simulated ones, verifying the validity of numerical method. It provides an effective way to solve bearing problem of aircraft-level radome joint structure.

Currently, in fuze two levels of environmental force arming, high dynamic overload is often used as one insurance element. Generally, one arming method is used of the inertia mass block's movement trip under trajectory overload. Mass blocks are limited by mechanical movement and are difficult to integrate in fuze systems, and is poor in testability. A scheme based on MEMS sensor technology is proposed and designed to arm the fuze. The principle, composition, function of the system, software workflow and the test and verify situation are introduced. This method has a wide scope of use can improve the flexibility of fuze systems and is easy to system integration.

The optics window is usually faced with severe aerodynamic heating, and there is a prominent image saturation problem because of high temperature. Therefore, researchers often use film cooling to isolate the direct heat convection from the outflow. A tangential high-density cooling film generation structure is designed which is used for high pressure and heat flux. Through reasonable ground test, numerical simulation and engineering calculation, the main factors affecting the cooling efficiency are studied. The preliminary results show that tangential high density gas film can reliably reduce the surface heat at high pressure and high heat flux. The research effectively adapts to the increasingly harsh optical observation environment.