[Colonel]

I was thinking about this for awhile to figure it perfectly. Corruption-Your Home planets would have little amounts of Corruption but the farther you got away from a Homeworld the more corruption. The only way to decrease this is by either stationing troops or ships\bases on or near the planets in question. Distance would be determined by movement cost. also as you got more advanced your Empire would expierce less corruption-so long as you implament the new facilties.