Understanding the components of asteroids plays an important role in guiding research on the origin and evolution of asteroids, utilization of space resources, and asteroid defense. Siliceous asteroids are the main type of near-Earth and inner main belt asteroids and are also the most common parent bodies of ordinary chondrite. In order to improve our understanding of the mineral composition of siliceous asteroids, the mineral compositions of eight siliceous asteroids with high spectral signal-to-noise ratios were investigated. By deconvolving the mixed spectrum of asteroids, we have obtained the absorption characteristics of ferromagnesian minerals, including their magnesium olivine index (Fo#) and the proportion of high-calcium pyroxene and then we identified the corresponding meteorite analogues for these asteroids. The results indicate that Sr-type asteroids (3) Juno, (808) Merxia and S-type asteroid (4197) Morpheus have higher Fo# and lower high-calcium pyroxene content, with surface compositions similar to H chondrites. The Sq-type asteroid (433) Eros has a relatively low Fo# and a high proportion of high-calcium pyroxene, with surface compositions resembling L chondrites. Sv-type asteroid (5) Astraea and S-type asteroid (17) Thetis have surfaces almost devoid of olivine, while V-type asteroids (3908) Nyx and (4055) Magellan lack olivine altogether, with surface mineral compositions similar to basaltic achondrites. The results show that even if they are all siliceous asteroids, their types have mineral diversity, and their correspondence with meteorite types is also complex and diverse. This is related to the origin and evolution of the asteroid itself and its later transformations such as space weathering and impact metamorphism. It also shows that the existing asteroid spectral classification system needs to be improved, and caution is needed when interpreting the mineral composition and evolution of asteroids based on spectra.

Highly hazardous asteroids refer to asteroids that can enter the Hill radius of the Earth, which are the important objects for monitoring and warning tasks of planetary defense. Based on the latest near-Earth asteroid orbit/size distribution model, we applied a high-precision small body orbit propagation package to establish a simulated sample database of highly hazardous asteroids with diameters of more than 10 meters, which could be used to generate any user-required number of highly hazardous asteroids within any given duration. Through orbital deduction, populations including potentially hazardous asteroids undergoing close approaches, highly hazardous asteroids within 100 years were identified. The occurrence rates of each population in the near-Earth-asteroid and the initial potentially-hazardous-asteroid population were calculated, which confirm the effectiveness of potentially hazardous asteroids as key monitoring targets. Further more, by analyzing distributions of orbital elements and variation of occurrence rates relative to the orbital elements, it shows that the distributions of semi-major axes and eccentricities of two encounter populations mainly depend on initial distribution of near-Earth asteroid orbits, which may cause high-eccentricity orbits to account for a large proportion among the encounter populations.

Near-Earth asteroid impacts represent a significant potential threat faced by all of humanity. Monitoring and providing early warnings to identify near-Earth asteroids with a high impact probability, as well as conducting impact predictions, are essential prerequisites for planetary defense. According to the core requirements of short-term impact forecasting for near-Earth asteroid, National Space Science Center, CAS independently designed and developed the System for Hazardous Asteroids Risk Prediction (SHARP). The Imminent Impactor Scenario of SHARP (SHARP-IIS) performs orbit determination, orbit propagation, and impact prediction for near-Earth asteroids that reach a certain proximity to Earth based on observational data to provide critical references for planetary defense. This paper introduces the basic principles of each functional module of the SHARP-IIS system and demonstrates its performance through the impact events of asteroid 2024 RW1 and asteroid 2024 UQ with different observation arc lengths. In the scenario of asteroid 2024 RW1 with an observation arc of seven hours, the SHARP-IIS system achieved a relatively high-level prediction accuracy. Compared with the airburst data recorded by the Center for Near-Earth Object Studies (CNEOS), the calculated airburst location error by SHARP-IIS was less than 20 km, and the minimum airburst timing error was around 1 s.

Since the 1990s, the United States, Europe, Japan and China have successively implemented and planned their own asteroid exploration and defense missions, and asteroids have become a new hot spot for deep space exploration after the Moon and Mars. Looking at the development history of asteroid missions, the application of CubeSats and landers can play an important role in different types of asteroid missions, such as asteroid sampling return and near-Earth asteroid defense. Hayabusa 2 deployed two types of Micro/Nano-landers, MINERVA and MASCOT, in the mission to obtain high-precision in-situ detection data on the asteroid surface, which supplemented and enhanced the scientific discoveries of Hayabusa 2. DART observed the kinetic impact process and ejecta morphology by releasing the CubeSat LICIACube. The HERA mission will use two CubeSats, Milani and Juventas, to accurately measure the surface composition, internal structure and gravity field of the Dimorphos asteroid. This paper will analyze the application cases of CubeSats and landers in different asteroid missions, and propose some ideas for using CubeSats and landers in the mission based on the mission objectives and mission forms of my country's first asteroid defense mission.

The method of a low-cost verifiable in-orbit laser ablation experiment was given in this paper. With this method, a meteorite ball which was be releasing actively was ablated by multi-pulse continuous laser beams which were generated by a mall pulse laser with low energy. Through a combination of laser rangefinder, micro-propulsion module, and attitude control system, as well as acceleration curve measurement and integration, effective tracking and convenient measurement of velocity increment of the target meteorite ball have been achieved. Finally, specific design with specific experimental scenarios was provided, and preliminary simulation of the test effect was given. This work will provide a experimental idea for the impulse coupling coefficient in-orbit measurement which is the key parameter to evaluate the effect of laser ablation for asteroid orbit deflection with the real scene of asteroid defense.

Based on the observation data from the Sanya Incoherent Scatter Radar during the 2020 Geminid meteor shower, this study analyzed the flux of micrometeoroids in near-Earth space. From December 13th to 14th, 2020, a total of 9,500 micrometeoroid events were detected over a continuous 24-hour observation period, with an average rate of approximately 400 events per hour. Considering the radar beam width and duty cycle, the flux of micrometeoroids in near-Earth space was estimated to be 4.3 events per day per 100 square meters. Given the radar's observational mode and sensitivity limitations, this estimated value is likely lower than the actual micrometeoroid flux. The diurnal distribution of micrometeoroid flux showed significant variation, with a peak occurring around 07:00 Beijing Time and a minimum around 19:00. The micrometeoroid flux density obtained by the Long Duration Exposure Facility (LDEF) in the United States through impact craters is three times higher than that obtained by the Sanya radar. In addition to differences in the spatial height and duration of measurements between the two methods, the local time distribution of micrometeoroid flux may also be one of the main reasons for the discrepancy between the two measured values. This study provides a reference for establishing an independent micrometeoroid flux model in China.

In 2023, the Space Commerce Office under the National Oceanic and Atmospheric Administration (NOAA) of the United States Department of Commerce launched the "Traffic Coordination System for Space" (TraCSS) project, based on the previous open database architecture. It is anticipated to offer fundamental space situational awareness data and services to civilian and commercial space operators, sending alert messages to spacecraft that might face collision risks, in order to achieve safe space flights, space sustainability, and the coordination of international space activities. This article, in accordance with the project information released by Space Commerce Office and relevant open-source information, combs and analyzes the system construction path, framework design, and the functions of each component of the system. TraCSS adopts a cloud-based containerized microservice architecture, achieving the integration and governance of US military, civilian, and commercial space situational awareness data. We analyzed the development process, system design, and possible influences of TraCSS. Also, we combined the characteristics of TraCSS to provide insights and recommendations for the development path and system construction of China's space traffic management.

Electrical connectors, as the basic components of space equipment for in-orbit servicing and maintenance, have extensive assembly and disassembly access requirements. The automatic access technology involves key technologies such as force sensing, visual recognition and positioning, and compliance control of manipulators. It has important research significance and promotion value. Based on a 6-DOF manipulator, a binocular structured-light camera, and its control software, a test platform for automatic access of different types of electrical connectors was constructed. The template point cloud was precisely aligned using key-point extraction, RANSAC course registration, and ICP fine registration algorithms. The high-reliability identification of different types of electrical connectors in the access state was completed. The impedance control of robotic arm was used to achieve a series of manipulations, including grasping and positioning, aligning, screwing, plugging and disassembly. The feasibility of the platform system and method was verified by testing the automatic access operation of Y27 and J30 electrical connectors as typical cases.

This paper discusses the forms and characteristics of Thermal Protection Structures (TPS) for Reusable Launch Vehicles as well as the importance of health monitoring and maintenance. TPS play a crucial role in the operation of aerospace vehicles. They not only have to withstand extreme temperatures and pressures but also ensure the safety of the vehicle. The monitoring objects of TPS cover their service status and possible damages. We reviewed the technical means of health monitoring for TPS. Among them, optical fiber sensing technology has the advantages of high precision and anti-interference, and can monitor the temperature and strain of TPS in real time. Acoustic emission technology can effectively detect the occurrence of structural damage. Ultrasonic guided wave technology can perform rapid detection on large-area structures. Finally, taking the space shuttle as an example, the maintenance technology of thermal protection structures was introduced, including the repair of damaged parts, etc., to ensure that the TPS is always in a good working condition and provide strong guarantee for the safe operation of aerospace vehicles.

During the process of accurate measurement and identification of space objects, space searching camera must overcome complex space environment, such as the noise of massive star background, the deficiency of features within single visible images, rapidly relative orbital maneuvering of the spacecraft. In this paper, far range area target detection and close range feature recognition were proposed to extraction, matching and tracking of target feature parts in real-time and accurately. Using feature detection, shape analysis and deep learning methods, centroid of target feature parts could be measured or calculated. Base on the design of space searching camera with dual-band common aperture system, simulation and experiment of high resolution images were promoted. The resolution show that the resolution of image details has been improved by 10%~30%. At the same time, function of feature detection, centroid localization and match recognition was realized.

Space debris poses a growing threat to the safety of space activities and the development of the aerospace industry in various countries, as its number increases annually. Addressing the challenges associated with space debris, such as its small size, high dynamics, and difficulty in long-distance detection. We proposed the application of distributed aperture radar in the field of space debris perception,and summarized the key technologies for realizing space-based distributed aperture radar from three aspects:high-precision formation flying, space-time-frequency synchronization, and beam forming. Additionally, recommendations and outlooks for future research were provided.

The efficient and stable transmission of the charged beams is of great significance in space technology's cutting-edge fields. In applications such as space high-energy physics and the charged beam irradiation studies, precise control of beam characteristics is essential for high-quality applications. However, during the charged beam transmission, issues like increased electron transverse displacement and decreased beam spot flux density have emerged, limiting its application and development. Traditional design methods struggle with the complexity of the charged beam-expanding magnet assemblies' numerous parameters, failing to achieve a global optimal solution and meet the demand for high-precision beam transmission. An intelligent optimization design method for these magnet assemblies was presented. Using a genetic algorithm-based design process, We first analyzed the phase space coordinates of electrons from the front-end accelerator. Then, based on charged particle beam optics and quadrupole magnet field theories, combined with beam component distribution, the beam transmission matrix was calculated to obtain the electron phase space vector at the device's end. Considering processing capabilities and actual conditions, the geometric parameters and relative positions of magnets were determined using a neural network-modified magnet field theory. Finally, the optimal beam-expanding mode and parameters were found through the genetic algorithm, achieving efficient optimization of the magnet assemblies, increasing the beam spot's transverse size, reducing Coulomb repulsion, and compressing the divergence angle. These research achievements are significant for the charged beam transmission technology. They help break through existing technical bottlenecks, enhance equipment performance and application effects, provide a foundation for further the charged beam manipulation research, and expand the innovative application prospects of the charged beams in more fields.