Frankly, i find the planets lacking slightly and i think it may be down to not knowing how to operate gravity on a planet made out of cubes. My answer is simple, make the planet a cube. Gravity always acts down onto a cube face. If you were to jump off the edge of a surface of a planet, you would fall down relative to the face you were previously on, and you would fall onto the other surface and gravity would change directions. One problem is ships and the gravity boundary between faces of the cube. One solution i can think of right now is to have gravity effect the ship and those inside it differently, they are always attracted to the centre. What do people think?