Realization of the sound space environment for the radiation-tolerant space craft

In space, galactic cosmic rays and solar rays collide with integrated circuits. It causes a breakdown of LSI, namely a hardware failure. Due to the increasing requirements of spacecraft applications, it is important that radiation fault-tolerant techniques are improved. This paper describes an approach which realizes a dependable computing system using a reconfigurable device. Firstly, we decide a logical block, namely a "tile". A single tile is composed of several processing elements, such as Look Up Tables. A module is composed of several tiles. When a module does not work well for a hardware failure, circuits on a bad tile which has the hardware failure are reconfigured to a fine tile. In this approach, secondly, the size of a single tile is important. We can reduce void circuits when the size is very small. But, we must continually check whether all tiles are fine or not, and the computing cost will be very large. The approach requires the proper size of a single tile which a module is composed of so that efficiency and effectiveness with the system is in real use. Our experimental results show that our proposed approach can produce a prototype hardware system that is smaller when compared with a simple fault-tolerant implementation such as triple module redundancy. It is clear that our approach can implement larger circuits than current ones using the same device.