One approach is to use powerful and cost efficient COTS hardware for generating the outputs, and then you can have a much simpler rad hard computer take those i

One approach is to use powerful and cost efficient COTS hardware for generating the outputs, and then you can have a much simpler rad hard computer take those in to generate the final decision. You also need all kinds of watchdogs to make sure you can reboot if something shits the bed, and you have to be careful about how things communicate to make sure that one faulty computer won't spam the others into uselessness