Simple but fun game. I agree with the other commenters in that the lighting and planets look stellar (*inter*-stellar perhaps? Hoho), though at the moment it's a bit too easy to get some early income and start cranking out Frigates to make you untouchable. I'd also say the game is in dire need of a tutorial, it took me a few tries to realize what clicking the buttons did (I thought you had to place buildings down after selecting the button and was clicking everywhere on screen to no effect)
Overall though, great theme, I'd love to see this be developed further.