Mega-constellations of satellites are making a complex network in Low-Earth Orbit (LEO), which presents new legal and technical challenges. The widespread operation of mega-constellations necessitates a special technical and legal regulatory framework that is constantly evolving based on emerging technologies. Although it has not yet been completely established since it is fully dependent on the development of Space Traffic Management (STM), including the rules on space debris mitigation and collision avoidance systems, cyber security issues, environmental concerns, rules of registration, Radio Frequency Interferences (RFI), Space Surveillance & Tracking (SST), etc.
This paper addresses the legal issues of coordinating LEO mega-constellation operations within the framework of STM. The LEO mega-constellations creating the space environment congested necessitates the establishment of STM rules and standards to safeguard the safety, security, and sustainability of outer space activities. To do so, States and the private sector will have to develop effective, safe, and workable mechanisms that will allow space activities in the field of the deployment and operation of satellite constellations while ensuring the sustainability of all space activities on a long-term basis. Moreover, it needs the cooperation of related national and international organizations and other entities, including the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS), its Subcommittees, and Internation Telecommunication Union (ITU), to solve the legal and technical challenges of satellite constellations, especially mega-constellations, through the amendment of the current international legal regime, the implementation of a new international treaty, or the creation of soft law documents.

Since the official operation of the BeiDou Global Navigation Satellite System (BDS-3), it has played a vital role in the national economy, national defence and security, and to enhance the people’s productivity and life. Based upon the three main characteristics, route design inheritance and development, highly integrated services, and “spiraling” incremental development, this paper introduces the service composition of BeiDou Navigation Satellite System (BDS) and summarizes the evolution of four types of BDS services, that include Positioning, Navigation and Timing (PNT), message communications, navigation augmentation, and international Search and Rescue (SAR). Moreover, the design features and performance of each service are discussed in detail, and the development trend of BDS services is examined in the light of the latest round of changes in the Global Navigation Satellite System (GNSS). Finally, development proposals are proposed, namely, stable operation of the system, enhancement of service performance, and empowerment through integration of multiple means.

With the rapid development of intelligent connected vehicles, high-precision 3D navigation has become a key supporting technology. This article conducted a series of drive tests using the high-precision navigation technology of BeiDou and BeiDou+5G hybrid positioning technology, aiming to verify the positioning performance in complex highway traffic environments. The test was conducted on actual roads in Beijing and Hangzhou showed that the positioning accuracy of BeiDou high-precision navigation reached a real-time centimeter level, with a fixed rate of about 95% and a convergence time of less than 2 s. The elevation accuracy of BeiDou+5G hybrid positioning was better than 0.2 m. Combined with three-dimensional high-precision laser point cloud maps, the overlay verification showed that the model can support three-dimensional lane level navigation, verifying the application potential of BeiDou high-precision positioning and BeiDou+5G hybrid positioning technology in the fields of autonomous driving and intelligent connected vehicles.

This paper examines the interpretation and implementation of the “peaceful purposes” clause as it applies to military activities in outer space, analyzing its legal and political implications within the framework of international space law. The term “peaceful purposes” has long served as a cornerstone in treaties like the Outer Space Treaty (1967), designed to promote the peaceful use of outer space. However, ambiguities in its interpretation have led to diverging views among states, particularly as space activities increasingly intersect with military interests. This study investigates how the peaceful purposes principle has been interpreted in key legal instruments, evaluates how it applies to various military uses of outer space, and assesses the implications of these interpretations for international security and space governance. By examining recent state practices, doctrinal perspectives, and multilateral negotiations, the paper highlights the tension between the principle of non-aggression and the militarization of space, offering insights into potential pathways for legal reform and cooperation. The findings suggest that while the concept of “peaceful purposes” is rooted in non-hostile use, evolving geopolitical dynamics and technological advancements are challenging its application, necessitating clearer legal frameworks to balance national security interests with the pursuit of a sustainable and peaceful outer space environment.

Acknowledged as a highly versatile manufacturing technology, additive manufacturing holds the potential to transform traditional manufacturing practices in the future. This paper provides a comprehensive review of the latest processes for manufacturing multi-material structural components using additive manufacturing technologies. It discusses the most recent applications of these processes in the fields of automotive, aerospace, biomedical, and dental, and presents a systematic overview of commonly used methods in multi-material additive manufacturing.

In this paper, the technical specifications and characteristics of long-wave infrared payloads are summarized, and the main technical indicators are band, resolution, width, etc. The technical characteristics and initial in-orbit application of a new generation of advanced wide-width thermal infrared imager in China are emphatically introduced. Through analysis, it is concluded that the future development of long-wave load should meet the requirements of high radiation resolution, high calibration accuracy, high time resolution and high spatial resolution.

This paper proposes a multi-UAV cooperative exploration approach based on task-density space partition. In the research of multi-UAV cooperative exploration, it is a prevalent cooperative scheme to control robots to work independently in partitioned spaces. Nonetheless, only considering the position of robots during space partition cannot effectively ensure the overall cooperative efficiency. According to research on task density of current time points and positions of robots during exploration, robots with fewer task points are assigned to work in spaces with more tasks in the rolling horizon optimization planning mode, which can reduce the redundancy of multi-robot cooperative work. Comparative research suggests that the overall exploration efficiency is improved.

As the core of the rocket system, the performance and quality of rocket engines are of paramount importance. Currently, the production of aerospace model rocket engines does not differentiate the production and selection of motors according to the importance of the mission, which is insufficient to ensure the high reliability requirements of important launch missions. To select rocket engines with better performance quality for more critical launch missions, this paper uses fuzzy comprehensive evaluation and TOPSIS methods based on the test value or assessment information of evaluation indicators. The method scientifically and accurately ranks the performance quality of rocket engines, choosing the engines with better performance quality for more strategic missions, and providing technical support for national management decisions.

Aluminum alloy is widely used in military, automobile, aerospace, electronics, electric power and other industries. With the continuous development of industry, the demand for lightweight, topology structure and integration of functions and structures is becoming increasingly strong. Traditional technology has been unable to meet the demand. Additive manufacturing has significant advantages in the integrated forming of complex components due to its direct forming, strong adaptability, and short manufacturing cycle. This article comprehensively reviews the research progress of additive manufacturing of aluminum alloys in recent years, with a focus on three additive manufacturing technologies which are wire and arc additive manufacturing, laser metal deposition and selective laser melting. It reviews the principles of the three technologies and the progress in recent years and summarizes the challenges faced by the additive manufacturing of aluminum alloys and their solutions.

This paper introduces an integrated design and manufacturing technology for L-band spiral antennas based on modified polyetheretherketone (PEEK). Initially, PEEK granules are blended with a laser activator for granulation and filamentation, and the antenna structure is fabricated using a fused deposition modeling (FDM) forming device. Subsequently, a pulsed infrared laser with a wavelength of 1064 nm is employed to etch spiral microstrips and feed network board circuit functional patterns on the surface of the formed PEEK material structure. Combined with electroless plating technology, metallization of the spiral lines on the PEEK surface and the feed network board circuitare achieved. Test results demonstrate that the integrated spiral antenna exhibits a standing wave ratio of 1.46 at a frequency of 1.575 GHz, with a gain of ≥-2 dBi within a range of ±70°, and a gain of ≥-4 dBi within a range of ±85°, essentially meeting the antenna specifications. The study indicates that this method holds research and application value for integrated products such as antennas and structural circuits.