Michael already mentioned it. You can click on nearly every star in the background - and in the describtion over there is stated that it should be possible to visit each system. Anyway i have the impression that under such conditions i need a new rack with some harddiscs and a further rack with CPUs to play this game - although the demovideos are done on a halfway good PC nowadays^^
Lets hope this game wont become that much resource killing as vista was it^^