At the moment, i just program it for singleplayer. But it's planned to get it multiplayer in the future.
No, don't do that and forget the multiplayer idea completely. Make it a nice singleplayer game and you're fine.
Then, I suggest you create a better planet/ sun, it looks horrible even for testing.
Just open MED and add a sphere with a high polygon count, you can adjust the number of faces/ edges after you have clicked the sphere button. Then use atlas or regular mapping for a simple texture and better don't use normalmapping for planets/ suns.
The ship is a little too dark, I would at least add some glowing parts. Where is its engine?
