Is this process radiation hardened? If so, is that available in the open source PDK?

Radhard version of the pdk is under development

I'm curious how Radhard differs. Does it involve different manufacturing, or is it more conservaive design rules and changes in the sim models ot account for environment ?

Probably the latter. Rad hard designing is more so a change in circuit design and simulation workflow than a change to the PDK itself.

In the flowspace we extend ngspice to be able to simulate radiation effects and also we will provide some TRM to mitigate the effects at the circuit level.

I think having access to accurate TID models for each device will also be important

Good to know its under development. What sort of hardening levels are you targeting (500krads?). Also, this ngspice extension, since all this is under development I guess thats not included in the latest ngspice version (v.44)? When it is ready will it be rolled into a new general version or as some "flavor" of a current version?

it should follow the master branch of ngspice

Great. Thanks @Krzysztof Herman