I spent a couple of hours creating a system with the system designer only to have it all be for naught. There are a couple of factors that contributed to this effort being wasted, and here I will propose improvements to the System Designer based on my experiences. So, what happened to my hard work you ask? I saved the system and went to play it, but some planets that had been orbiting the sun were now orbiting another planet. I believe since the two planets were relatively close together, the game chooses what to orbit "Automatically". I propose the coordinate system be changed to a polar system. It makes more sense, allows planets to be spaced out azimuthally, and goes a long way to emphasizing orbits that are not perfect circles. Polar coordinates could be implemented along side of the current Cartesian system, or it could be an option. Planets tend to move when you click on them to select them. This is especially true when zoomed out in the editor. This can cause orbits of moons or nearby planets to change in addition to resetting the orbit of whatever you were trying to select. This is very frustrating and annoying. Please, change the editor so that planets cannot move from the same action that selects them. A recap of all suggestions , in no particular order. Add a field to each planet to select what it orbits to ensure it does not change, "Automatically". Switch to a Polar Coordinate System. Allow a planet to keep the same velocity vector (if it still results in a valid orbit) when moved. Prevent planets from moving on selection. Allow the selection and movement of more than one object at a time. Add a checkbox for each planet to "Lock" the settings preventing any accidental (or intentional) change while the box is checked. Thank you for listening. EDIT: 9-10-14 Additional suggestion: Make the center of the polar grid whatever the currently selected planet/moon is orbiting and default to the sun when nothing is selected.