I liked this game a lot!

One thing I noticed is that I found the game to be pretty hard if I just tried to tap based on where I thought was a good "launching point". But then I realized I could use the dashed lines in the orbit circle as basically "arrows" pointing to where the ship would go if launched at that point in the orbit, and I instantly got much better if my strategy was (a) pick the dash in the orbit circle that points to the next planet, and (b) just then only focus on tapping when the ship hits that dash in the circle.

I think a "hard mode" would be to get rid of the dashes in the orbit circle and just make it a solid line.