Significance With the rapid development of space technology in the 21st century, the frequency of deep space scientific exploration and manned space missions continues to increase. There is an urgent need to establish a highspeed integrated information network. Highly reliable connectivity between space - based satellite networks and ground - based networks is urgently needed. A large number of high-value satellite on - orbit experiment data will be returned to ensure the smooth progress of scientific research missions. Satellite laser communication has the advantages of high speed, good safety, small size, light weight and no electromagnetic spectrum constraint. Satellite laser communication has gradually stepped out of the laboratory to complete the technical verification between satellite and Earth and between satellites. It is expected to solve the bottleneck of data transmission in the current space information network and meet the growing business needs of aviation and aerospace. Institutions from Europe, the United States, and Japan carried out satellite laser communication research earlier. At the beginning of this century, the on - orbit technology verification of point - to - point inter - satellite/satellite - based acquisition, tracking and pointing, and long distance relayless communication modulation and demodulation has been completed. Space communication technology has been gradually moving towards the practical stage. China has achieved rapid development in the field of satellite laser communication technology in the past 20 years. The original verification was completed, the key technical problems were solved, and the technological level of related devices was greatly improved. Under the traction of engineering missions such as HY - 2, Mozi and BD - 3, various key technologies of satellite laser communication have been verified in orbit. At present, it is developing towards high - speed networking applications. Progress This paper focuses on the development status of satellite laser communication in Europe, the United States, Japan and China. By combing through the technical expertise and research priorities of the above regions, we can discover their future development directions. Then the current status and challenges of satellite laser communication technology in target acquisition and tracking, modulation and demodulation, atmospheric turbulence suppression and anti - interference link maintenance are analyzed. Those mainly include the robustness of the mechanical structure of the communication terminal, the adaptability of the platform, the anti - interference, the asymmetry of the upstream and downstream of the satellite and the ground communication, and the low availability in the harsh environment. In view of the above problems, we give a possible solution to the future development according to the current research status of the corresponding technology, so as to provide a certain reference for scientific researchers in related fields, and then promote the development of China ' s space field. Finally, according to the needs of space engineering and social development, the development trend of satellite laser communication technology in the future is predicted. Conclusions and Prospects Satellite laser communication technology has been studied since the 1970s. After several rounds of technological innovation, technological breakthrough of the components, and systematic on - orbit verification, it has become one of the important means of high - speed satellite communication. This paper systematically describes the difficulty existing in the application of satellite laser communication. According to the requirements of space exploration and engineering applications, the development trend of satellite laser communication technology is forecasted. With the coming of the era of high - speed information networking, satellite laser communication technology will play an irreplaceable role.
