The space textures are made by me in PS. They are just placecard textures. I'll do better later on. Nebulae are easily done using the existing textures with an edge out button click.
Placecard textures? New term for me. But if they're just normal textures, they're a bit more limited in scope than what I was after myself anyway; ZH is limited to 1024x1024 textures, so I'm instead building overlays up to fifty/sixty times the size and importing them through worldbuilder hacks - not the easy way round, but it's working, slowly, I just need to get the detail up.
The nebulae will be impassable terrain. But advanced ships will have locomotors that will allow you to travel through them later in the game.
Sounds familiar to what I'm up to; although for nebulae effects, I modified water, which you can animate nicely *hint* ;)2!!