I just see it in my head and wonder if I can do it. Even if I'm drawing a person I may look at a picture but actually draw a different angle or pose. I just need the picture to remind me of them. It helps for reminding me of spacing of eyes or why the structure of their face makes this or that expression. If a scene and scenario is something I have in my head then I may start out with that and change mid drawing if I find I like another idea better. I'm the opposite of structured. I'm whimsical. But I do lose myself in what I'm doing. Drawing in pencil helps. Once I get used to all proportion and angle and perspective I may switch to pen. I used to favor that. Each medium has it's own quirks though. Each has it's own cheats and tricks. You can't carry what you learned doing in pen over to watercolor or watercolor to acrylic. And you learn as much by accident as on purpose.
Mostly I just want to have fun with it. Here is one I started and thought I would let sit till I decide how to do the details like stars and sun angle. It's not high art anyway.
I may try to add a refection of a woman in the capsule pointing at him or just move on to something else. It's silly anyway.
P.S. I would like to see your ceramics, zacharias.