Not to be a downer, but if your PDC weapons can only reach Mars (for example), how would this contribute to alleviating unrest on Titan?
A better suggestion would be that unrest is decreased within the scope of the PDC's weapons.
It's not a suggestion, but an observation. I've made a test game, built a custom PDC as follows:
Weymouth class Planetary Defence Centre 15 350 tons 245 Crew 454 BP TCS 307 TH 0 EM 0
Armour 5-55 Sensors 1/0 Damage Control Rating 0 PPV 288
Intended Deployment Time: 3 months Spare Berths 1
Magazine 288
Fuel Capacity 250 000 Litres Range N/A
ICBM Silo (12) Missile Size 24 Rate of Fire 43200
This design is classed as a Planetary Defence Centre and can be pre-fabricated in 7 sections
added ten of them to Shipyard TG on Earth, made a colony of thirty million on Venus and according to the economic sheet, Venus demands 20 protection points and receives 2880, exactly the same amount as Earth, despite the fact that not only the base's armament can't reach Luna (much less Venus) it's not even armed. And yes, I run the game for several months and the unrest did not increase. Whether this is a bug or feature, I don't really know.