For session 2, I've made a MOON.
It has that moon-y effect in the sky just by being a large-ish object somewhat far away. Then I chopped and mostly flattened it for optimization, didn't change the look much.
And for a 3rd layer, I used inkscape to turn it into an svg.
(actually more data than the png, autotrace is not so effective)
I was going to make other things, but Blender was crashing on me (modifiers). Though I do think it ties the scene together (along with moon lighting and a green disk floating in the void for activities).