The usual stuff, I have some names for certain things and I don't like these too much and look for better ones
The ones I look for to replace are inside " ". Also, these should coexist well with others.
The theme is an old bureaucratic space empire.
"planetary defences" - it's a set of installations on planet surface capable of enganging ships (so it takes part in the spece battle that takes place on the orbir rather than defend the planet from ground invasion
"militia" (actually that one is probably perfect, but I will list it for consistency) - civilians that defend the planet from the ground invasion
"imperial infantry" - ground forces (infantry mostly, maybe some heavier stuff too) that defend the planet from the ground invasion (so kind like a territorial army)
"storm troopers/shock troopers" - ground forces used for attacking an enemy planet after your fleet has taken control of the orbit (planetary defence installations are down) (so kind like an expeditionary army), it's a bit of an elite formation (definitelly better equipped than the territorial army)