From Introduction in the beginning of the book:
The Orbit game system (fully explained in this one book) covers individual characters, items, armies, starship battles, planets, weapons, governments, and galaxies.
Then, there's a long list of different alien races, creatures, androids, and pirates & other assorted rogues. Although, unlike other science-fiction adventure, or "space opera" roleplay games, your character may meet any of them, or even be any of them, too.
That's just one thing which makes Orbit different from the rest. Added to that, the system itself is easy to understand and flexible.
No level-limits on careers.
No penalties based on gender.
No boundaries on your imagination.
Welcome to Orbit, roleplaying the way it was meant to be.