A Study on Standardization of Ammunition Stockpile Test Procedure (ASTP) for Improving the Reliability of Thermal Batteries for Missiles

Purpose: This study aims to identify the technical limitations of the current Ammunition Stockpile Test Procedure (ASTP) for thermal batteries used in guided weapon systems, and to propose a standardization framework to improve the reproducibility of evaluations in a multi-center testing environment.<br/>Methods: A multi-center round robin test involving four evaluation institutions was conducted to investigate the effects of environmental conditions, equipment configuration, and wiring methods on data consistency. Major electrical characteristic tests, including insulation resistance, continuity, and polarity tests, were comparatively analyzed to identify key sources of measurement variation.<br/>Results: The results confirmed that qualitative criteria used in non-functional inspections may cause differences in interpretation between agencies, while environmental conditions and equipment configurations were found to significantly affect data reproducibility, even within acceptable specification ranges. In particular, insulation resistance measurements showed noticeable variability depending on temperature, humidity, and characteristics of the measurement system. Based on these findings, standardized environmental conditions, equipment performance requirements, wiring procedures and quantitative interpretation criteria were proposed. Additionally, a dual-document framework consisting of a common defense standard and a modular ASTP structure was established to enhance the consistency and scalability of the evaluation system.<br/>Conclusion: The proposed framework provides a practical approach to transforming the existing experience-based evaluation system into a standardized, data-driven reliability assessment system. The results of this study are expected to improve the reproducibility of thermal battery evaluations and strengthen the technical reliability of defense quality assurance systems.