As well as the private sector, government organizations, and military units use satellite systems strategically. The on-board computer is one of the essential components of a satellite system. It is costly and challenging to encounter hardware failure in an on-board computer after launch. STM Defense Technologies Engineering Inc. has developed a low cost, high-performance national on-board computer for satellites. In this study, we described a test software designed for MICROSATPRO, the national on-board computer. MICROSATPRO performs tests through this software during the space-mission where it is an experimental load. The purpose of the software is to detect the hardware failure that may occur in the electronics on the compelling environmental conditions and to eliminate these errors if possible.