[johnwalkr]

I wouldn't call it the standard, it's just used in designs with legacy to avoid the huge cost of re-qualification of hardware and software. It's infeasible a lot of times due to cost and power consumption. I work in the private sector in space (lunar exploration actually) and everyone is qualifying normal/automotive grade stuff, or using space-grade microcontrollers for in-house designs, with everything from 8-32bit, [1] and ready-made cpu boards[2] for more complex use cases. I'm sharing just 2 examples but there are hundreds, with variations on redundancy implemented in all kinds of ways too, such as in software, on multiple cores, on multiple chips, or on multiple soft-cpu cores on a single or multiple FPGAs.

[1] Example: https://www.militaryaerospace.com/computers/article/16726923...

[2] Example: https://xiphos.com/product-details/q8