I don't know about other people's games but I cannot get planets to collide. They just circle around and around and around; most of the time, they even go through the planet it is suppose to hit (so half of the object is inside the other). Just an FYI. No big deal, still in beta. Also, the lander vehicle does the same thing. I think it is the distance. Basically, I built a map with 3 planets: an ice planet with a moon, and another planet in the far distance with its own orbit. When I travel to the distant planet it is fine, I get there no problem, but when I try to return, it just goes around and around, never landing. When I put the boosts on the distant planet, thats when it does the same thing. IDK, just FYI.