There were rad-hard versions of the 1802.
Many a geek earned their wings coding the 1802.
The problems of maintaining remote embedded systems like the Hubble are similar to maintaining implanted medical devices. They are expensive and hard to access physically so you design in failsafes, watchdogs and massive redundancy where you can. OCD afflicted coders are the sort that are needed for such work... they cannot abide any possibility of a failure and cover every contingency.