This is a bit of a break-away from what you normally do, but that's not a bad thing; it means you gettin' bettah
I like teh neb-stars. Their brightness is low which imo gives it that sense of distance; it feels like those stars are really far away because of their low brightness around them.
now this is just me being picky: asteroids really are smooth rocks not usually so craggy and crusty. They are mostly smooth and have small holes in 'em as if there were space worms that lived in 'em. But it doesn't matter, cuz craggy asteroids look good anyways
other than that, dark pieces are okay, but overall, I think you leave too much dark 'black' area on the sides. If you like dark pieces, that's great, but try to refrain from leaving large borders of blackness.