Please correct me if I am wrong
But my understanding is that the chips chosen when building a space probe are usually several generations behind the cutting edge because Rad-proof chips lag behind the off the shelf chips. This means that when the probe is launched it is launched with chips MANY generations behind the cutting edge.
What does it take to 'Radiation harden' a chip? I remember that a sapphire substrate helps (but I could be remembering wrong)
Anyone have any inside knowledge?