Buildings

Buildings and wonders in Interstellar Space: Genesis can be constructed in colonies once the prerequisite technology is discovered by placing them the construction queue. Each requires an open building slot (even ) and a per-turn maintenance cost in.

Planetary Buildings can be built in all colonies; Empire Buildings can only be constructed once by each faction; and Wonders are unique to the galaxy.

The total number of in a colony is determined by the colony's, which in turn is limited by. This makes large or huge worlds best suited for Empire Buildings and Wonders.

When a better version of a building type is researched all existing instances are automatically upgraded--for instance, all instantly become.

Planetary Buildings
Planetary buildings can be built in every colony subject to constraints and the limits of your. Due to these limits, it can make sense to scrap some buildings important for the early growth of a colony such as a in favor of other buildings once the colony is fully developed. For the same reason, you may want to be selective about what you build in a colony depending on its specialization and exposure to enemy forces--an may make sense in a border colony but not one deep in your empire's interior, and a  might be limited to colonies devoted to ship production.

Empire Buildings
Empire buildings can only be built once in each empire. Some provide empire-wide benefits while others (Capitals) provide a bonus only to the colony itself. The latter should only be built in colonies that are going to produce a lot of whatever that bonus applies to--ideally large or huge planets with high and other buildings benefiting the same resource.

Wonders
Wonders can be built only once in the galaxy. Each requires reaching tier 3 in one of the trees. All provide some empire-wide benefit, while some also provide a benefit to their home colony as well. The is particularly powerful if you are missing any type of  as it immediately grants one of each, opening up the corresponding technologies for research.

Orbital Modules
(Star Bases, Battle Stations, and Star Fortresses) are necessary to build ships larger than destroyers and will also defend the system against any invaders. Orbital Module techs apply an immediately bonus to all existing and future Orbital Stations--the modules themselves require no additional construction. Many provide a bonus that scales with diplomatic treaties.