Comment by geomark
6 days ago
I sure wish they would talk about the hardware. I spent a few years developing a radiation hardened fault tolerant computer back in the day. Adding redundancy at multiple levels was the usual solution. But there is another clever check on transient errors during process execution that we implemented that didn't involve any redundancy. Doesn't seem like they did anything like that. But can't tell since they don't mention the processor(s) they used.
One of the things I loved about the Shuttle is that all five computers were mounted not only in different locations but in different orientations in the shuttle. Providing some additional hardening against radiation by providing different cross sections to any incident event.
NASA actually publishes these things on their NTRS page. The Primary flight controller is rocking Green Hills INTEGRITY RTOS on BAE RAD750s in a quad redundant config, with a VxWorks backup on a Frontgrade Gaisler LEON4 (SPARC V8). This allowed for parts of the ARINC653 spec regarding time and space partitioning of the RTOS scheduler to be used.
You can read more about it below (when the server throwing errors). https://ntrs.nasa.gov/api/citations/20190000011/downloads/20... https://ntrs.nasa.gov/api/citations/20230002185/downloads/FS...
I read, for probe missions, that one technique is to get a bunch of consumer chips and irradiate the hell out of them. Now take the winner model and get a bunch of those. Irradiate them. The winner goes to Mars.
The claim was that some plain old chips are exquisitely radiation resisitant, and it's not clear why.