In response to the strategic needs of becoming a leading space power, and against the backdrop of hot topics such as "Airline-Flight-Based transportation of reusable rocket" and the successful in-situ recovery at launch tower during the fifth test flight of SpaceX's Super Heavy-Starship, this study benchmarks against world-class space launch sites, and combines the actual development of Chinese space launch site construction. It refines the basic characteristics that an "Airline-Flight-Mode" launch site should possess, including multi-station parallel operation, fast turnaround launch, high safety and reliability, and low-cost launch. The current gaps in China's space launch site in adapting to "Airline-Flight-Mode" launch are analyzed, and a demand system for building the "Airline-Flight-Mode" launch capability of China's launch site is proposed. At the organizational management level, China's launch site should develop from a single-mode construction and operation to a diversified mode involving national, civilian and commercial entities, while adhering to the concept of a large industrial ecosystem, integrated deployment and collaborative design of satellites, rockets and launch sites should be promoted to achieve "launch upon delivery and reuse upon recovery". At the key technology level, emphasis should be placed on the development of pre-launch rapid refueling, post-launch rapid recovery, special robots, in-situ recovery at launch towers, modular construction, etc., to achieve efficient turnaround, high-frequency launches, and multi-station implementation. The research can support the high-quality development of space launch site planning and construction.

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 response to the pressing demand for the large-scale and high-frequency development of space transportation, horizontal takeoff and horizontal landing-reusable launch vehicle (HTHL RLV) which does not rely on fixed launch sites and can operate as conveniently as aircraft, represents a crucial development direction for establishing a future scheduled space transportation system. The technical characteristics and developmental path of HTHL RLV are systematically elucidated, providing a comparative analysis of the strengths, weaknesses, and applicability of different technical approaches. On this basis, it focuses on key technical challenges and potential breakthroughs in the field, including multidisciplinary-coupled overall system design, wide-speed-range aerodynamic configuration, high-performance combined-cycle propulsion, lightweight structures, adaptive guidance and control, reusability, and intelligent operation and maintenance. Furthermore, prospective pathways for future technology development are also outlined.

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.

With the wide application of cognitive technology in the military field, cognitive Electronic Warfare (EW) has become the inevitable trend of future military war. Given the development of EW combat object in the cognitive direction leading to a decline in the operational effectiveness of traditional EW, an in-depth exploration and analysis of key technologies in cognitive electronic warfare are conducted, including cognitive reconnaissance, cognitive jamming, jamming evaluation, and dynamic knowledge base. Moreover, the basic concepts of cognitive EW are sorted out, by analyzing the numerous challenges to traditional EW. Then, the system architecture and composition of cognitive EW are studied. On this foundation, the key technologies of cognitive EW are summarized. Finally, based on the characteristics of cognitive EW, the development direction of cognitive EW has been prospected.

With the increasing frequency of human space activities, there are surviving debris of re-entry spacecraft and debris that impact the Earth's surface, causing typical damage cases and affecting the future technological development of spacecraft. Firstly typical re-entry damage cases and disposal methods of foreign spacecraft that have attracted significant social attention are analyzeds. Secondly the main international norms and standards for re-entry casualty risk are introduced. Then those assessment methods of re-entry casualty risk are studied together with re-entry risk analysis tools of NASA and ESA. Finally it's looked forward to the furture development and existing problems of major space powers in the technical directions of active deorbit, assisted deorbit, large-scale reentry, and reusable spacecraft. Research shows that although the re-entry casualty risk of spacecraft and debris is still difficult to predicte very accurately, it is expected to be moderately controlled by the design of risk-reduction measures along with technological development.

Nuclear thermal rockets, as a revolutionary potential space luanch vehicle, have the capability to significantly reduce the scale of space transportation missions or enhance transportation capacity. The historical research of nuclear thermal propulsion (NTP) technology in the United States and Russia (The Soviet Union) is reviewed, the development challenges of nuclear thermal rocket are analysed. By proposing feasible lunar return missions and manned Mars exploration transportation tasks for nuclear thermal rocket, the study examines key technological challenges form an engineering application perspective, including optimization of overall parameters, high-power thermal propulsion, nuclear safety design and protection. At the end of the research, it is suggested to strengthen the research and development of key nuclear thermal rocket technologies and promote the construction of non nuclear and nuclear testing capabilities.

For higher reliability, higher efficiency and easier maintenance, three TVC actuators for a hydrolox launch vehicle block are studied comparatively, in aspects of designs, models and testing performances, namely, a Servo-Valve Controlled Electro-Hydraulic Actuator (SHA), an Electro-Mechanical Actuator (EMA) and an Electro-Hydrostatic Actuator (EHA), each outputting a peak power of 3 kW. A fully packaged duplex EHA design is proposed, lightweight and compact by means of innovating indepth integrations in the actuator, Electro-Hydrostatic Module (EHM), Servo Motor Pumps (SMPs) and Electronic Control Units (ECUs). The weight of a TVC system with four EHAs is 85 kg, reduced by 37%, compared to the SHA counterpart of 135 kg. The dynamic capability of three TVC actuators is almost on a par, with the first-order frequency bandwidth of greater than 30 rad/s. As to the overall efficiency of energy conversion, it is one order of magnitude higher for an EMA or an EHA than a SHA. In an operation profile on ground with a duration of 1 200 s, the efficiency is lowest for an SHA, less than 1%, and heated quickly, with the temperature reaching over 100 ℃ at the hydraulic pump. In contrast, as to the EMA and EHA,the efficiency is remarkably upgraded to over 20%, with the temperature only slightly increasing by 5 ℃ at the pump or the electric motor. It demonstrates that an EHA embodies both the heavy loading, high reliability of a SHA, and the high efficiency, good maintenance of an EMA, at the same time overcoming the weak points in dynamics, power density, oil sealing, etc., providing an intriguing option for highly reliable and secure launch vehicles. The EHA has finished its maiden flight as the first one for launch vehicles.

Implementing the commercial space development strategy of China, the commercial space development posture over the world is analyzed. Meanwhile, the construction demand of the launch site of the commercial space is analyzed. A conception building a LOX-methane launch site in Jiuquan Satellite Launch Center is proposed. The launch site can meet the demand of dynamical system test run, test and launch of LOX-methane launch vehicle. A conceptual design program of the LOX-methane launch site is brought forward. The program includes assorted launch vehicles, general technical indexes, basic test-launch mode, site selection, general safety, and major constructions. The demonstration shows, the conceptual design program can meet the need of launch mission, and the construction scale is moderate. The conceptual design program can fulfill the demand of the programed LOX-methane launch vehicles in China. Using the launch site, a ZQ-2 launch vehicle is flying to the space in December 2023. The above demonstration can provide referential experience for the construction of analogues commercial LOX-methane launch site in China.

Trans-media aircraft refers to a new concept special aircraft with both air flight capabilities and underwater submarine capabilities, which includes submersible aircraft and submarine-launched drones. Aircraft that can span multiple domains is focused on. Through literature research, this study elaborates on trans-media aircraft and their characteristics and applications, introduces in detail the development status of trans-media aircraft at home and abroad, analyzes the technical difficulties of achieving trans-media flight, and summarizes the key technologies required for trans-media aircraft. Finally, based on the investigation and the current development at home and abroad, the prospects of the trans-media aircraft are prospected and development suggestions are put forward.