The ARM processor has come a long way from an obscure British microprocessor of the 1980's to being the dominant basis for the current generation of smart phones, and tablet computers, as well as its use in space. There are already several rad-hard Arduino architectures available, and a rad-hard Pi coming along in a few years. An exciting approach would be to build a rad-hard cluster computer, using the Beowulf software. Actually, this was done and is still operating in Earth orbit. As H-P says aboout its supercomputer on the International Space Station, "...bring the computer to the data."