This paper summarizes three definitions of the solar system boundary, i. e., planetary orbit boundary, heliospheric boundary and solar gravitational boundary, presents the difference between interplanetary space and interstellar space, and discusses the scientific objectives and key scientific problems of the solar system boundary exploration, which includes four missions,namely, exploration of no man's land, panoramic view of the heliosphere, sweeping of major planets, and archaeology of the solar system.

The oversea researches on human health and safety in space exploration have been focused on the physiological effects of weightlessness and their internal mechanisms for decades. A series of breakthroughs have been made in physiological effects and the mechanisms of diseases, including cardiovascular dysfunction, bone loss, muscle atrophy, space motion diseases, and microgravity enviroment. China's researches in this field started relatively late, however relevant researches have begn to accelerate gradually with the vigorous development of China's space exploration and manned spaceflight. Some gratifying progresses are made in some aspects such as space gravity physiology, astronaut medical supervision and medical insurance, physical and chemical regenerative environmental control and medical insurance, as well as space life science and biotechnology, which relate to space human safety and development. The special researches in molecular medicine are carried out for weightlessness bone loss. The therapeutic drugs are innovated for small nucleic acid molecules of microRNA-214, which successfully slow down the decline of osteogenic capacity and bone-loss rate caused by simulated weightlessness and aging. These breakthroughs provide important medical support for the human space exploration.

Development of outer space resources has great economic, technological and political significance. As a resourceconsuming country, a big mining country and an aerospace country, China should actively participate in outer space resources development and its international governance. This paper uses normative analysis, law, economics and political science methods to analyze the current situation of outer space resource development, points out the problems in current multilateral and unilateral governance mechanisms. Based on China's current economic development, industry interests and future strategic needs and by learning from similar resource development systems, the paper puts forward China's propositions on the outer space resource development, including actively participating in and leading international governance and timely promulgating relevant domestic policies and laws.

As a space power, China hasn't launched a large-size mission driven by scientific objectives yet. For a case study, the paper investigates the development of NASA's next-generation astrophysics mission-wide field infrared survey telescope (WFISRT), a flagship/large-size mission. Despite that WFIRST has been confronted with cancellation in NASA FY budgets during the past few years, the project passed a critical programmatic and technical milestone in March 2020, and was given the official green light to begin hardware development and testing (Phase C). In the following May, NASA renamed the telescope after Nancy Grace Roman, i.e., Nancy Grace Roman Space Telescope, which shows the mission's strong vitality. Roman Space Telescope aims to conduct dark energy research, exoplanet search and near-infrared survey, while demonstrating the coronagraph's technology for direct imaging of Earth-like exoplanets. WFIRST fits for the NASA's Vision and Mission, and will strengthen US leadership in space science, and its development somehow provides lessons learned about flagship missions.

According to space launch and transportation systems of the world, history and current development are studied in this research. Comparisons of rockets, rocket engines and satellite launch centers are carried out, which yield the future development trend. Some perspectives are also brought forward. Entering the space with extreme-low cost will totally change the centennial development of the aerial transport. Remote and cross-domain transportation will break the transportation efficiency of the aerial transport over the world. Reusable earth-space transportation system will become a necessary choice to maintain space environment, such as cleaning space debris. Multiple orbit requirement of spacecraft will expedite diversity and multi-domain launch capacity of the space launch system. Domains where conventional space propulsion systems, e.g., hydrogen/oxygen, lox/methane, and LO2/RP-1 based engines, are applied will inevitably witness an revolution. The development trend and future perspectives of the space launch and transportation system will benefit researches in our country, such as choosing technical route, tackling critical techniques, engineering and so on.

Hypersonic vehicle technology, as a symbol of aerospace technology in the new century, has become a focus of attention in military and aerospace fields at home and abroad. This paper introduces the classification of hypersonic vehicles, analyzes the development route, overall plan and performance parameters of the mainstream hypersonic aircraft, and summarizes its technological characteristics. The characteristics and direction of technology development are analyzed in terms of aerodynamic design technology, hypersonic propulsion technology, hypersonic structure thermal protection technology and hypersonic guidance and control technology, which have important influences on the development of hypersonic vehicles. In addition, based on the model development and investment direction of foreign hypersonic vehicles, the development trend of hypersonic vehicle in the future is predicted, so as to provide guidance and reference for the related development research.

Human resource has long been recognized as a key element in national economic and social development. Despite several rounds of western-imposed sanctions, Russia maintains global leadership in space industry by relying on strong scientific and technological strength accumulated during the Soviet era, continuous investment and support from government, especially the dedicated and high-quality engineer teams. Russia partly inherites an advanced training mode of aerospace human resource from the Soviet era, by rationally arranging higher education, building colleges with aerospace characteristics, promoting combined training mode of aerospace colleges and enterprises, and continuously improving the in-service education and training system. The establishment of a relatively mature and unique aerospace human resource training mode has laid a foundation for Russia to make continuous breakthroughs in aerospace.

Meteorological satellite is an important national basic and strategic space system. Especially in recent years, environmental problems have become increasingly severe, natural disasters have occurred frequently, and modern wars have put forward higher requirements for meteorological satellites in terms of accurate measurement of cloud conditions, ocean waves, atmospheric temperature, pressure, wind speed and other parameters. Although the polar-orbiting weather satellite system of the United States has achieved continuous global all-weather coverage by integrating the respective polar-orbiting weather satellite systems of DOD, NOAA, and EUMET, NOAA has been exploring the transformation and development of meteorological satellites, and has carried out a variety of transformation explorations such as new generation of satellite architecture research, pilot procurement of commercial meteorological satellite data, and research on key technologies of meteorological small satellites. This article reviews these transformation explorations to provide reference for the development of China's meteorological satellites.

The European project of search for disruptive space technology has attracted attention because of its systematic advantages. From the perspective of methodology the experience of this project can provide reference for the systematic study of disruptive technology in China. This paper studies the primary search and evaluation process of disruptive space technology in Europe, analyzes the theoretical basis, evaluation criteria and evaluation methods based on STEP framework, and introduces the technology roadmap of disruptive space technology. Through summarizing the experience of European disruptive space technology method system in theory, method and implementation, this paper draws enlightenment for China to promote its disruptive technology innovation, such as paying attention to the analysis of technology application scenarios, establishing expert resume information platform, constructing multi-source information support system, and strengthening the management of technology development planning.