“It takes a radiation dose of about 5 Sv to cause death to most people. Diodes and computer chips will show very little functional detriment up to about 50 to 100 Sv“.
It's to note that "little functional detriment" contributes to a catastrophic failure in a digital system. A flip of a single bit can fell the thing you're trying to operate. Humans respond with much more delay and can usually complete most any mission, even if they die of complications later.