I know this is a really broad net. But since my last search ended up so close to a total bust I figured I'd toss one out easy to find results for. Unfortunately its not the easiest to google for without being repeatedly more specific for each different space possibility.
So the results this time are for any and all fics where the Amazons in Ranma 1/2 are descended from people who had to travel through space to get to Earth. Be it from other planets in this solar system to time travelers that happen to have needed to travel in space to make it to Earth as their destination. As long as they had to travel outside of Earth's atmosphere before getting to Earth it counts.