Satellite and Ariel imaging systems are located at high altitudes. Thus, they are more vulnerable to Soft errors than similar systems operating at sea level. This paper studies the effect of transient faults on microprocessor based imaging systems. The paper studies the ability of different watchdog timer systems to recover the system from failure. A new improved watchdog timer system design is introduced. This new design solves the problems of both the standard and windowed watchdog timers. The watchdog timers are tested by injecting a fault while a processor is reading an image from RAM and sending it to the VGA RAM for display. This method is implemented on FPGA, and visually demonstrates the existence of fast watchdog resets, which can not be detected by standard watchdog timers, and faulty resets which occur undetected within the safe window of the windowed watchdog timers.