This paper presents the development of an FPGA-based automated testing simulator for Transmit/Receive (TR) modules deployed in next-generation Synthetic Aperture Radar (SAR) satellites. TR modules, which control antenna phase and gain for microwave signal transmission and reception, are core components that are required to operate reliably in harsh space conditions. Conventional testing methods rely on chamber-based testing, which is time-consuming, costly, and difficult to scale. Furthermore, environmental stress can induce anomalies, requiring hardware redesign and repeated testing and validation, significantly increasing development time and cost. To address these challenges, we propose an FPGA-based simulation platform that enables early design validation and automated performance testing under simulated environmental conditions. The system implements real-time anomaly detection and incorporates automated validation routines compliant with MIL-STD-883, a widely adopted standard for qualifying spaceborne components. Experimental verification confirms that the simulator significantly improves test efficiency and reliability while reducing development time and cost compared to traditional methods. The results demonstrate the practical effectiveness of the simulator as a tool for accelerating the design, verification, and qualification of space-grade TR modules.