Looks great man! I like the detail and texture in the nebula as well as the little space ships. It reminds me of *JoeJesus' earlier works. I just think the color saturation and contrast is a little intense, so it's not really easy on the eyes. Contrast can really boost the appeal of your images, but you have to use it carefully as well not to overdo it. The planet texture is very nice, too. I think I'd increase the intensity and size of the planet's shadow cause it seems to be lit from almost every direction (which would be fairly unrealistic in a space setting, but of course you can do whatever you like!).
I like the way the shading on the planets is done. It reminds me of the traditionally-painted space art that was done before digital tools became good enough for it, or the kind of space scene you would see in an anime perhaps