One of my favorite books on writing (aptly named “On Writing“) is written by Stephen King and in that book he regurgitates and then chews on one of the most common rules for writing; write what you know.
First time I read it it made a helluva lot of sense. I mean, it does sound damn difficult to write about space when you have spent all of your life with your feet planted firmly on the ground. Yet, if you can’t write about what you like, doesn’t it take away the fun of it? The reason you write is because it’s fun, right? Then it doesn’t make sense to write about accounting or plumbing (because honestly that doesn’t sound very exciting for a plot).