Hey ! That's symetrical ! *flame*
I gather this is supposed to be on the moon ? Maybe a lunar lander in the center, some rocky outcrops. And for heaven's sake, remember that the moon is
white, so making the ground green is a tad silly.
I don't know, maybe a little more substanance in the bottom. You didn't give any reference pics (e.g. of a gostek), so I'm just guessing, but you'd be able to see the other side of the ground. Unless that's the style you're lookn' for (floating green moon base), I suggest you make the ground a wee bit more thick