Although distances can be fractional, the locations of systems are always located at integer coordinates. Each system has certain characteristics that make it valuable or not. Each system has an environment , which determines what kinds of species from compatible environments will find it easy to live there. Colonies are created in systems by colony ships which are given explicit colonize orders while already present in the system. Colonies contain some population , measured in population units , which grows over time, according to the population growth rate , which is dependent on the habitability of the system.
Production is budgeted and spent every turn on colony and technology spending.
Resources are used to build ships. A system which has an income greater than its overhead is profitable . At that point the remaining income is divided between technology and colony spending. Each technology has a technology efficiency , which determines how many technology units are gained by spending one production unit on investment in that particular technology. It is an unfortunate fact that we can secure peace only by preparing for war.