## 1 Introduction
Furthermore, research has identified vulnerabilities in satellite communication networks, focusing on the use of automated security analyzers to strengthen satellite communication interfaces [20]. However, several key challenges remain underexplored, including distributed attacks across multiple segments, vulnerability interdependencies, and the absence of standardized quantitative risk assessments. Although existing models provide valuable insights, they often fail to fully capture attack propagation between segments and the cascading impact of vulnerabilities. Moreover, most studies rely on qualitative assessments, limiting their capacity to systematically evaluate security risks and compare mitigation strategies. Additionally, much of the existing research focuses on satellite communication systems, leaving a gap in the broader satellite network security landscape. A structured security assessment framework is crucial for addressing these gaps and enhancing the overall understanding of satellite network security risks. To overcome these limitations, this study systematically analyzes vulnerabilities in the satellite network and employs threat-modeling techniquesto quantitatively assess the overall security posture of the network [21]. Specifically, the Threat Vector-Hierarchical Attack Representation Model (TV-HARM) [22] is utilized to systematically analyze the multilayered architecture and diverse attack vectors. TV-HARM, an enhanced model that integrates the concept of a threat vector with the widely used Hierarchical Attack Representation Model (HARM) [23], enables the structured and precise analysis of network attack paths [24; 25]. Furthermore, this study extends the TV-HARM-based security framework to reflect the distinct characteristics of satellite networks and refines security evaluation metrics to align with their operational constraints. The improved framework provides a systematic methodology for assessing satellite network security. By modeling multisegment attack propagation, it enables a detailed evaluation of inter-segment attack paths and incorporates vulnerability interdependencies by analyzing interactions among operating systems, communication protocols, and hardware platforms. By leveraging this security framework, threat modeling and integrated countermeasure analysis are conducted to evaluate security risks. This approach ultimately enhances the overall security posture of satellite networks [26; 27]. The structure of this article is as follows: Section 2 reviews prior research on satellite network security and highlights its limitations. Section 3 examines security threats to satellite networks and defines attack scenarios. This section also describes the application of TV-HARM and the redefinition of security metrics for quantitative evaluation. Section 4 presents the experimental results, discussing the effectiveness of mitigation strategies based on the analyzed metrics. This section also includes a discussion of the findings and highlights future work to address remaining challenges. Section 5 concludes the article with a summary of the key findings, emphasizing their implications for satellite network security.