Based on the introduction to theresearch status and trend of international space-based laser debris removal technology, the existing problems of space-based laser debris removal technology are systematically analyzed. 
In view of the existing problems, the work and research progress of the Beijing Institute of Spacecraft Environment Engineering in this field are introduced from several aspects, such as dynamic behavior of laser-driven debris, orbit transfer model, ground simulation system, space-based removal system scheme and target selection strategy. The main research methods include laser-driven micro-impulse measurement experiment, surface triangulation three-dimensional reconstruction calculation method based on laser-material interaction theory, simulation calculation based on orbital dynamics, etc. It also looks forward to the future research direction in the field of this technology.

BeiDou navigation satellite system (the BeiDou system) is the only PNT (Positioning, Navigation and Timing) resource in China that has coverage of the globe and near-Earth space and provides continuous high-precision, low-cost positioning, navigation and timing solutions for users in a unified spatio-temporal benchmark. As an important spatio-temporal benchmark transmission system, the BeiDou system is the most important resource for the national PNT system to provide a PNT capability under a unified spatial-temporal benchmark. This paper proposes the concept, composition and development model of the space-based PNT system design based on the BeiDou system with all its space characteristics, as well as the advantages of the system. It opens up a new direction for the construction of China’s PNT system and expands a new horizon in the research of a PNT system in China.

Heavy launch vehicles represent the ability of a country to enter space and utilize space resources. In recent years, with the growth in human space exploration, the major aerospace powers and companies in the world are planning to develop heavy launch vehicles. This study analyzes the development of heavy launch vehicles in the world, reviews the characteristics of China’s heavy launch vehicle serial configuration, and then proposes common points and development trends of future heavy launch vehicles in the world.

 Ocean sound speed profile (SSP) is the key factor affecting acoustic propagation. The acquisition of SSPs in real time with high precision is meaningful for underwater activities. By means of the remote sensing method, the sea surface data could be obtained in near-real time. Typically, the subsurface fields are correlated with the sea surface parameters. Thus, the SSPs could be obtained by means of satellite remote sensing. In this paper, the history as well as the current research over the reconstruction of subsurface fields by means of sea surface data is introduced. Then two methods to reconstruct the SSPs with sea surface data, including the linear regression method using the empirical orthogonal function, and the self-organizing method based on the big data theory, are described in detail in the paper.