The first thing you will want to do is create a type-system for your industry, which is a list of common types of things in your industry. In the private space industry, that might include things such as companies, space vehicles, and astronauts. You want to be as complete as you can be. While you can add or change your mind later, doing so may invalidate some of the annotations you made previously and force you to do a lot of rework.
Fortunately, many industries have been creating data models that represent their industries for decades, so you may find one already done for yours as well. Check the Industry Standards Organizations for your domain.
If you don't find one, IBM has curated a general type system from analysis ...
