I've almost finished assembling the random bits of junk on this. I'm just working on the asteroid bit itself, which is quite awkward as it's always going to be contrived and abstract. Various bits of blue foam have been glued together and have been drying overnight prior to being filled to create the edges of the partial crater. The look is inspired by the Star Wars Rebels episodes on the abandoned clone asteroid base (just getting in to this with my 3 year old!).
No photos yet as i) bad light and ii) it still looks kind of infant school project

I'm hoping this will improve with paint!