In view of the key engineering and technical issues in the development of cislunar space, studies are carried out from the perspectives of cislunar space transportation, resources of the Moon and small celestial bodies, lunar robots, and the cislunar space economic system. Cislunar space transportation can be divided into phases such as round-trip between the Earth and the orbit, Earth-Moon transfer, and lunar landing and ascent. It is necessary to develop different vehicles, transportation modes and reuse schemes according to the environmental characteristics of different phases, and consider the integrated design of the space station near the Earth and manned lunar exploration. The abundant resources of the Moon and small near-Earth objects are the material basis for the development of cislunar space. The geostationary orbit is an ideal industrial park in cislunar space. The vacuum, low gravity, low temperature and sufficient solar energy in lunar space facilitate the development of electrification transportation such as magnetic levitation, space elevator and skyhook. Facing the harsh lunar environment and scarce human resources, the lunar robot will play a leading and main role in infrastructure construction, astronaut accompaniment and assistance, human-machine cooperation. The development of cislunar space is not only for manned landing on the Moon, but also for the establishment of cislunar economic system. It will promote the national interests to extend from the land and the sea to cislunar space, promote the development of space industry from the earth to cislunar space, and accelerate the progress of human society from the earth civilization to the solar system civilization.

The development of the Long March 8 (LM-8) series of launch vehicles is reviewed, which is designed to fill the gap of the payload capability of 3 to 4.5 tons to the sun-synchronous orbits (SSO), and to derive the no-side-booster configuration covering the payload capability of less than 3 tons, thus taking the main role of the madium-lift launchers in the launch market to constitute China’s next-generation of launch vehicles. On this basis, research and development of the LM-8 variants is being carried out to further improve the performance and shorten the launch period. The key technologies of the LM-8 with fundamental configurations are introduced, and the innovations of the upgraded version being developed are discussed, including the closed-loop self-pressurization for the hydrogen tank, the hydrogen and oxygen common bottom tank with a diameter of 3.35 meter and PMI sandwiches, etc. In line with the construction of the Wenchang commercial launch site, the future development of Long March 8 series is prospected.

Manned lunar exploration missions require thousands of tons of launch vehicles to deliver astronauts and a small amount of payload to the lunar surface. To improve the overall performance of manned lunar exploration missions, a systematic analysis is conducted at the overall level, including the design concepts, design methods, model optimization, and data correction. The proposed overall technologies include probability-based overall design, integrated design of spacecraft and rocket, optimization design based on digital models, and overall performance improvement based on measured data correction. Based on the practice of the overall design of manned lunar exploration missions, the application effects of these technologies are summarized, and the direction for future research is pointed out. These technologies play an important role in improving the overall performance of manned lunar exploration and maximizing the efficiency.

Aiming at the problem of improving the flight reliability of the space transportation system based on the reliability limit of products, a technical approach of breaking through the application of intelligent flight technology to support the higher-quality development of space transportation system is proposed. The four stages of intelligent flight technology development across the world are summarized, and the development gap of the technology is analyzed. Based on this, the intelligent flight technology development framework of China’s space transportation system is formulated, a functional layer composed of “perception and monitoring”,“evaluation and decision” and “implementation and disposal” is constructed, and corresponding key technologies are defined. The influence of the intelligent flight technology on the overall design criteria and process of the top layer is analyzed. Finally, the development of China’s intelligent flight technology is prospected.

Focusing on cutting-edge scientific issues related to lunar exploration and applications, 9 overarching goals and 38 specific objectives for manned lunar exploration program have been proposed, leveraging China’s technical capabilities in manned spaceflight and lunar exploration, as well as its expertise in lunar and planetary science, the objectives center on scientific research, lunar-based scientific research, and resource exploration and utilization. Based on these scientific goals and trends in domestic and international manned lunar exploration landing site selection, basic principles and processes for selecting landing sites have been established. Thirty prime landing sites have been identified, and relevant factors considered in the further selection of landing sites are given, taking into account scientific value and engineering implementation conditions. These scientific objectives and landing site selection recommendations will serve as important guidance and top-level input for the design and implementation of manned lunar exploration program.

Aiming at the problems of iterative design inefficiency, performance limitation and the design redundancy that are caused by the independent traditional satellite overall design of control process, an integrated optimization design method of satellite overall system and the attitude control is proposed. Based on the traditional satellite multidisciplinary design optimization (MDO) model considering the orbit, structure, power and propulsion subsystems, the satellite attitude control simulation in the application mission is incorporated into the satellite multidisciplinary analysis process in order to implement an accurate analysis of coupling effects between satellite overall design and attitude control, and perform a comprehensive evaluation on the complete mission pay-back. In this way, the integrated optimization of the satellite overall system and control process can be accomplished. Finally, by taking one agile Earth observing satellite for application research, it is demonstrated the attitude control process has a great influence on the final satellite overall design solution. Besides, the integrated optimization method generates better overall design solution with better design performance and less design redundancy than the traditional MDO method, which verifies the feasibility and effectiveness of the proposed integrated optimization design method.

In view of the major constraints of high costs of round-trip transportation in the large-scale space application of the space station and the the manned deep space exploration program, during the development of China’s next generation of manned spacecraft, in order to reduce operating costs and improve economic benefits, relevant designs are carried out according to the reusability. The reusable modes of China’s next-generation manned spacecraft are proposed, the technical difficulties of reusable spacecraft are analyzed, and the technical approaches to solve the problems are given from four dimensions: reusable condition design, product reusable performance design, reusable maintenance support design and autonomous health detection and diagnosis design. Thus formed a architecture for reusable technologies of the next-generation manned spacecraft. This study defines the reusable technology roadmap and realization direction of the next-generation manned spacecraft, which can be used to guide the development of future reusable spacecraft and lay the foundation for large-scale space development.

Aiming at the requirements of top-level mission planning for manned lunar exploration, an integrated mission planning and design method is proposed for manned lunar exploration. By combing and decomposing the whole flight profile, an integrated method based on the circumlunar perturbation is proposed, and three key design constraints for the mission planning have been identified. Then, the constraints for illumination, lunar orbit and return landing sites are analyzed. According to different time scale constraints, the mission monthly window, daily window and hourly window are gradually selected to meet the engineering requirements. Finally, the planning results are verified by simulation on the integrated platform. The proposed method can solve the comprehensive window design problem for standard and deferred mission, and also provides an effective pathway for rapid planning in a large time scale.

The safety of astronauts is of utmost importance in any manned space mission. That’s why the launch abort system (LAS) of China’s next-generation manned spacecraft has been designed with meticulous attention to detail. From entering the cabin to entering the orbit, every step has been analyzed using the MBSE method to ensure the system meets the highest safety standards. This system is specifically aimed at manned lunar exploration and low-Earth-orbit space station missions, making it a crucial component of any manned space program. The launch abort mode and system design have been studied and determined, with special research conducted in various aspects such as trajectory and control, structure and separation, aerodynamics, power, and information. The identified technical difficulties have been overcome with proposed solutions, and the development of key technologies has been summarized. LAS will undergo full assessment and verification in subsequent development to ensure stable and reliable operation during formal flight missions. With this new launch abort system, the safety of manned spaceflight missions can be further enhanced and improved.

To cope with the potential thrust-drop malfunction of the manned lunar exploration launch vehicle, a parking orbit re-planning method is proposed based on the evaluation of the residual carrying capacity of the launcher. By analyzing the constraints of the whole flight profile and the characteristics of the Earth-Moon transfer trajectory systematically, the off-line trajectory planning algorithm improves convergence performance, and thus can be used to evaluate the residual carrying capacity as thrust-drop happens. For the situations that the launcher is not capable for injecting the transfer orbit, a sequential orbit/trajectory re-planning method is designed to guarantee the safety of the astronauts. On the premise of ensuring the altitude of the parking orbit, the elements about the orbital plane are further optimized to provide a favorable initial state for the subsequent rescue actions. Meanwhile, the nonlinearity of the terminal constraints is alleviated by the injection point forecast, and the initial reference is generated by convex optimization method with well convergence, thus, the solving efficiency of the sequential re-planning algorithm can be improved. Simulation results show the proposed method can generate the trajectory that transporting the spacecraft to the optimal parking orbit under the thrust-drop malfunction situation.

The concept of ‘system reconfiguration’ have been widely applied in various walks of life, however there are no unified understanding about its definition, objectives and methods. Based on the definitions from some industry organized in this paper, the concept of system reconfiguration is discussed along with the concept of system. Then the concept of reconfigurable launch vehicle is discussed. The objectives of reconfigurable launch vehicle are proposed. The characteristics of reconfigurable launch vehicle are summarized. The evaluation method of launch vehicle reconfigurability is also proposed and the effectiveness of the method is validated by simulation. Finally, suggestions for follow-up work of reconfigurable launch vehicle are proposed.

In order to improve the launch coefficient as the goal, a systems engineering technology is proposed. Combined with the design object, the overall multi-level design process and optimization object are sorted out from the four aspects of design concept, constraint boundary, design method, and identification return, to build the overall system of technologies. Taking the system as the traction, combined with the development practice of the new generation of launch vehicles, the research process and application effects of some of the technologies such as safety margin shooting, active environmental control, multi-disciplinary joint optimization, and propellant residue identification are summarized. At the same time, the direction of follow-up and continuous research is pointed out, which is of great significance to support the improvement of the launch coefficient.

In this paper, the development history of the attitude control technologies for China’s liquid-propellant launch vehicles is systematically reviewed from three aspects of dynamic modeling, attitude controller designing and simulation technology. In addition, the current problems and challenges faced by the attitude control technology are summarized. According to the development trend of attitude control technology for the launch vehicles abroad and the technical requirements for the development of launch vehicles in China, the future development of the attitude control technology is prospected, and five key research directions for the next phase are put forward.

The launch vehicle separation technology at home and abroad is systematically studied, including booster separation, interstage separation, fairing separation and payload separation. Combined with the technical development needs of non-pyrotechnic separation mechanism, the technology of separation mechanism is comprehensively analyzed from two aspects of the connection form and driving energy. The technical characteristics of each mechanism are compared and analyzed, and the development trend of non-pyrotechnic separation mechanism product is researched and prospected, aiming at providing reference for the technological innovation and product systemic development of non-pyrotechnic separation mechanisms of launch vehicle.

China’s next-generation manned spacecraft need to take into account both near earth and lunar exploration missions, so it is required that the reentry capsule has the ability to re-enter and return at the second cosmic speed. To meet the second cosmic velocity reentry and return as the main goal, aerodynamic shape optimization design of the next-generation manned spacecraft reentry capsule is carried out. Firstly, the requirements of the reentry capsule of the new generation manned spacecraft are sorted out, and the preliminary shape selection analysis of the reentry capsule is carried out. Secondly, an approximate model is established based on the results of engineering calculation and CFD software numerical simulation, and the aerodynamic shape of the reentry capsule is optimized by multi-objective optimization method. Finally, the effective verification of aerodynamic shape is completed through flight test.

SpaceX’s two-stage fully reusable space transportation system, the Starship spacecraft and Super Heavy rocket, lifts off on its first full-stack test flight in April 2023. During the flight, a number of engines appeared abnormal operation, and the speed and height seriously deviated from the flight profile, and finally exploded and disintegrated in the first-stage flight phase. In this paper, combined with various characteristic parameters obtained from the investigation, the prediction and inversion design of the maiden flight profile of the Starship system are firstly carried out, then various abnormal events in the actual flight are sorted out, and the working conditions and typical processes of each system are reproduced, and the failure causes are analyzed and judged.

The lightweight design methods of aerospace structures in recent years are reviewed and summarized, and the lightweight design of the thin-walled structure and connecting structure is discussed. For thin-walled structures, the development trends of lightweight design for post-buckling behavior, robust design considering imperfections, and innovative thin-walled configuration are analyzed. For connecting structures, two design methods are introduced from the load path and regional stress regulation. In addition, the common key problems such as high-precision experiment methods of lightweight structure and digital twin model are reviewed, and the development prospect of lightweight design methods for aerospace structure in the future are prospected, which could provide reference for future research work and equipment development.

To address the challenges of low computational efficiency and poor reliability in the transfer trajectory design and mission cost assessment for manned lunar exploration, a novel method based on pesudostate theory and dynamic weight strategy is proposed. Firstly, a trajectory optimization model of manned lunar exploration is built using pesudostate technique to improve the efficiency and accuracy of solving the Earth-Moon free return trajectory and Moon-Earth return trajectory. Then, a dynamic weight strategy is utilized to quantify the mission efficiency factors such as mission period, lunch window and velocity increment, and the actual engineering constraints such as mission solar elevation angle and reentry condition. A comprehensive evaluation criterion for the manned lunar exploration program is established, and the ranges of dynamic weights are given through vast numerical simulations. Finally, the numerical simulation results for the candidate landing regions of future manned lunar exploration missions show that the proposed method realizes efficient mission trajectory design and comprehensive evaluation ranking of candidate landing regions.

The recent achievement of on-orbit spacecraft swarm manipulation missions and plans are reviewed, and the key technologies for on-orbit swarm control are focused on such as spacecraft swarm serialization design, swarm behavior modeling and intelligent emergence mechanism, swarm ad-hoc networking, swarm intelligent perception, swarm autonomous task planning and distributed autonomous cooperative control. These technologies are systematically summarized and categorized. On this basis, their development trends are stated, and a set of swarm manipulation system capabilities for the on-orbit construction of large space facilities is proposed. It is expected to provide reference for the future on-orbit construction of large space facilities and the development of spacecraft swarm manipulation.

Aiming at the manned deep space exploration mission of the Starship spacecraft, the basic facts of the system is outlined, and the preliminary plan of SpaceX for the system to support future manned lunar and Mars exploration missions is introduced. The capability and performance requirements of the Starship spacecraft in the flight phase and during its stay on the surface of other celestial bodies are analyzed respectively. The scale of the mission is estimated considering the actual engineering situation and key technologies are summarized. Finally, some thoughts and suggestions are put forward for manned deep space exploration, which can provide reference for subsequent project planning and program demonstration.