Tried this out for a bit and I'm definitely gonna keep it on my phone! Comparing to other similar games I find it more interesting and fun to play. It also does not heat my phone up very much at all which most other games tend to do after just a little while. Below is some purely constructive criticism and thoughts that came to me while playing that I think could improve the game if you were to look into this and update it. But even if you don't, as said, a well made game! This should be on Featured if you ask me.
I do have some trouble single selecting small planets (dragging over works fine). I can of course zoom in, but that is really sub-optimal as it decreases my ability to interact with the entire map at once. This I find makes the orbital maps pretty difficult/annoying to play.
One thing I thought of that would make commanding ones forces easier, would be if no ships from one planet would land on another planet that itself were sending ships in the same move. This would make it a bit easier to manage multiple small planets vs one large.
Furthermore, the AI currently seems to only ever focus to capture one planet (if it is the closest one to their main forces or something I do not know), and does not ever try to capture planets that would be worth considerably more to them, even if they have the opportunity to do so.