A quick idea for a sort of medical system, if feasible then how about a method of medical emergencies/plagues? At it's most basic this could work on a simple percentage calculator, each year a colony has X% to contract a medical emergency, the further out from the capital system the higher the change of such. To simulate contagious passengers and the like, have a modifier for systems with an existing emergency, so they get an increase in the chance to contract an emergency. To couteract this have a new installation that simply generates "medical points", if there is no current emergency then this installation reduces the chance of one happening by a set percentage per installation, and if an emergency if currently happening then there is a set percentage chance of curing the emergency per installation. As with construction brigades, have a ground unit capable of generating medical points so that you can cure emergencies on colonys with no installations etc. To prevent this being simply paying lip service to the medical services, make the Installations and ground units both expensive to create in the first place, and also consume a large amount of upkeep. This would mean most installations would end up being shutdown for much of the time unless a healthy supply of minerals is fed to them.
So if a colony develops an emergency then what? My thinking is to begin with an ever increasing reduction in population growth, say on a yearly basis. Also the same for unrest and construction. This way it will not instantly cripple a colony, but can be debilitating to new small colonies, and if left long enough can wipe out even a homeworld
Thinigs that come to mind on this that may or may not be doable.
1. Make the distance factor not due to just how many systems, but inside a system also. So an Earth based start would factor in colonies out on Titan as a higher risk factor than Earth.
2. If a colony is set to a destination of colonists then it gets an increase in the chance of emergency, this replicate possible lower standards of quarantine in various civillian shipping lines.
3. Have the emergency as something that is fixed to the planet itself. A colony with So if a colony contracted an emergency it will gain "disease points" each year. The medical installations will remove an amount of points equal to their combined rating for the number of installations/ground units. Once all the disease points are removed the eergency is over and cured. But assuming this did not happen and the colony got wiped out. The disease points would stay fixed onto the planet and then slowly dissipate in a way similar to current radiation and dust. This means you could not simply ship in a set of new colonists and start over without first curing the emergency. Doing so would just start up the disease point increase once more.
4. A database of various diseases, essentially they each act in the same way but can occur in multipe instances. Let us say colony A has plague A and colony B has plague B. On the next cycle colony A fails its check and contract plague B. This means it now has both plagues and suffers 2X the amount of penalties, as well ass generating 2X the number of disease points each year. Both plagues are logged seperately for the purpose of curing, and both now together contribute double the amount of check increases to neighbouring systems/colonies. In this way an unchecked emergency could cause devestation across an empire.
5. Allow for cross species contamination, to begin with I am not sure if genetically creating a new species means they are logged in the database as an entirely new species or a subspecies. However allow emergencies to cross into other empires that have made contact with each other. If they are at war then reduce the chance, if the have any kind of agreements then incrase the chance for each one. Have this start lower than the normal inter empire chance, and maybe go upto this basic rate once the two empires are both best of friends. As far as species go, if an entirely different species then say 1/4 of the spreading chance, and a subspecies 1/2 chance. This would simulate different physiologies etc.
6. A new research line in biology, this would work similar to the ones for research and construction and simply allow medical installations to generate more points per installation.
7. The obvious progression from the previous two points is a tech line of research to create new diseases for use in bio warfare. But I think this could get very complicated very fast.
Overall I think this could add a nice new dynamic of parts to keep an eye on in empire management, in addition it has the potential to create new "ruins" planets. Perhaps an NPR colony could get wiped out by some disease but never bother or be unable to claim back the colony. Another empire could then find a planet with what appeared as a ghost colony on the surface, perhaps still with a tiny amount of the contagion still left alive ready to spring back up should no precautions be taken. It would also mean carefully looking at potential new allies, sure those squid guys seem friendly enough, but they seem to be under developed and have tiny colonies. Would opening the trade lanes to them also open a doorway to tentacle diseases?