Interesting NASA presentation on the Mars rover flight software. It looks like they use radiation hardened PowerPC chips. They also use GCC 4.1.2 as one of their compilers. https://github.com/CppCon/CppCon2014/blob/master/Presentations/C%2B%2B%20on%20Mars%20-%20Incorporating%20C%2B%2B%20into%20Mars%20Rover%20Flight%20Software/C%2B%2B%20On%20Mars%20-%20Mark%20Maimone%20-%20CppCon%202014.pdf