Now, of course, the great thing about the solar system as a frontier is that there are no Indians, so you can have all the glory of the myth of the American westward expansion without any of the guilt.
All of this got me thinking about the history of the westward expansion, and got me to wondering how the exploration of the Solar System would be changed if there were an indigenous presence out there.
I think people enjoy a series. When you like a story, many readers want more of the same, which is dandy, if the author and the characters have more to say.
Then, I realized that there is an indigenous presence in the Solar System. It's us. So, then, I got to wondering what would happen if a more technologically advanced society moved next door to us, the way we moved next door to the American Indians.
So, one of the things I was doing with the aliens in The Quiet Invasion was creating that advanced society which had ideas about morality and proper use of natural resources that were radically different from ours, as the Europeans were from the American Indians.