This paper provides a comprehensive survey of the security challenges and countermeasures in Satellite Communication Systems (SCSs). The authors, Minjae Kang, Sungbin Park, and Yeonjoon Lee, from Hanyang University, highlight the rapid development of SCSs due to advancements in space launch technologies, which has also led to significant security vulnerabilities. Real-world attacks like AcidRain and AcidPour have demonstrated the need for robust security measures. The paper categorizes and analyzes attacks and defenses within the framework of confidentiality, integrity, and availability, focusing on specific threats to SCSs. It evaluates existing countermeasures and offers insights into the security policies of different nations, recognizing the strategic importance of satellite communications. The authors also present future security challenges and solutions, including full quantum communication, AI-integrated SCSs, and standardized protocols for next-generation terrestrial-space communication. The paper is structured into sections covering the background of SCSs, security attacks, defense methods, security policies, and future research directions. It aims to provide a systematic view of the landscape, addressing the limitations of existing surveys and contributing to the comprehensive understanding of SCS security.This paper provides a comprehensive survey of the security challenges and countermeasures in Satellite Communication Systems (SCSs). The authors, Minjae Kang, Sungbin Park, and Yeonjoon Lee, from Hanyang University, highlight the rapid development of SCSs due to advancements in space launch technologies, which has also led to significant security vulnerabilities. Real-world attacks like AcidRain and AcidPour have demonstrated the need for robust security measures. The paper categorizes and analyzes attacks and defenses within the framework of confidentiality, integrity, and availability, focusing on specific threats to SCSs. It evaluates existing countermeasures and offers insights into the security policies of different nations, recognizing the strategic importance of satellite communications. The authors also present future security challenges and solutions, including full quantum communication, AI-integrated SCSs, and standardized protocols for next-generation terrestrial-space communication. The paper is structured into sections covering the background of SCSs, security attacks, defense methods, security policies, and future research directions. It aims to provide a systematic view of the landscape, addressing the limitations of existing surveys and contributing to the comprehensive understanding of SCS security.