Satellite communication systems (SatCom) is a brand-new network that uses artificial Earth satellites as relay stations to provide communication services such as broadband Internet access to various users on land, sea, air and in space. It features wide coverage, relatively high transmission rates and strong anti-interference capabilities. Security authentication is of crucial significance for the stable operation and widespread application of satellite communication systems. It can effectively prevent unauthorized access, ensuring that only users and devices that pass security authentication can access the satellite network. It also ensures the confidentiality, integrity, and availability of data during transmission and storage, preventing data from being stolen, tampered with, or damaged. By means of literature research and comparative analysis, this paper carries out on a comprehensive survey towards the security authentication methods used by SatCom. This paper first summarizes the existing SatCom authentication methods as five categories, namely, those based on cryptography, Blockchain, satellite orbital information, the AKA protocol and physical hardware respectively. Subsequently, a comprehensive comparative analysis is carried out on the above-mentioned five categories of security authentication methods from four dimensions, i.e., security, implementation difficulty and cost, applicable scenarios and real-time performance, and the final comparison results are following obtained. Finally, prospects are made for several important future research directions of security authentication methods for SatCom, laying a well foundation for further carrying on the related research works. learn more on arXiv