Very cool! I really enjoyed arranging the planets to guide the ship, and it was a fun amount of trial and error getting the right placements along with the right ship launch direction and speed. That last level was very tricky! It's an awesome concept, and it really fits the simulation theme well.
One thing I would have liked is the ability to remove planets, since I found myself in an unwinnable situation on level 6 and had to reload. I'm glad you included a level select!