Distant Worlds is a vast, pausable real-time, 4X space strategy game which models a "living galaxy" with incredible options for replayability and customizability. Experience the full depth and detail of large turn-based strategy games, but with the simplicity and ease of real-time, and on the scale of a massively-multiplayer online game. Now greatly enhanced with the new Universe release, which includes all four previous releases as well as the new Universe expansion!
In this science fiction universe, I think other race are accepted to land on a planet, except in rare case where the alien race is xenophobic and don't allow other races to come.
But in that case, some plastic surgery, holographic device or simply the furtivity would help.