The MIC69303RT they are referencing in that article is a computerized on off switch.
Radiation hardened means fewer, larger transistors, and lower clock speed. On a 386 processor if it gets hit by an ionized particle it might flip 100 transistors between 1 and 0, that can be recoverable. On a modern AMD Threadripper it might flip over a million transistors since so many are packed into the same area, that is unrecoverable. Furthermore, the L1, L2 cache on processors is only vulnerable to ionized Radiation during something called a latching window. An old 30 MHz 386 might have 1000 per second, a new 5 GHz 20 core processor might have several million per second. We had a fascinating course in computer lab on this
Here is a NASA article from 2022, where they discuss that they hope that their future computer processor platform might be 100 times faster then the 30 year old processor tech that is used on Mars Curiosity Rover, which has roughly the performance of a Pentium II.
https://www.nasa.gov/news-release/n...ion-spaceflight-computing-processor-contract/
For comparison: An Intel Pentium did 188 MIPS in 1994, an AMD Threadripper 3990X (which is a 2020 processor) does 2,356,230 MIPS.