Now, we all know that Earth (EDZ), Io, Titan, and Nessus are destinations. Well, thankfully those aren't the only ones. Due to this being a demo version of the game, the empty slots above are... well empty. However, I do believe that each of those will contain other destinations. It is possible that the one in the middle could be an 8th destination. With this in mind, I can guess that the remaining destinations are as follows: top middle - Mercury middle - Venus left - Mars far left - Reef Who knows (besides Bungie) at this point?