I beat expansion 5! It took a couple tries over 15-20 minutes or so. I like how there is potential to calculate and optimize production, but I sometimes just bought stuff with high numbers and hoped it was enough (I played Balatro this way).
I have some suggestions if you decide to work on this game further. I do agree that the orbiting speed can ramp up pretty fast. I think the player should control the speed so they can play as fast as they want. My other suggestion would be to have some other way to sell or get rid of the planets. I don't really want to spend suns keeping a cold planet that gives 4 earths every rotation. There is some fun in managing the little space you have though, not sure if it's intended. I could have also used extra suns at the end to move planets I didn't want into the hot orbit.
The art is really nice, sound fx are pretty good, and the minimal music is a nice choice given the setting. This game is a pretty polished experience overall. :)