I totally LOVED the idea. I think it is really cool! It could be extended a lot, maybe mining different types of materials depending on what Earth needs at some moment, or giving the ship a fuel tank so you have to be coming back to Earth at some point.
To give some feedback, I'd say you absolutely need a tutorial, I spent like 5 minutes figuring out the controls and what I should do (and in a short game is a lot of time), and maybe adding some background, so you can feel when the ship is actually moving, because right now when there's nothing around it feels like you're not moving at all.
But otherwise, the idea is awesome and the game is great! I really liked it, good job!