Here's one of the better ones from my long series of space pictures that I did in September of 1990. It depicts an asteroid field and what would now be called a "dwarf planet," which is really a planet populated by dwarfs. I managed to get a nice three-dimensional look to the piece. It was mostly done with airbrush. I have had the same airbrush rig since 1980, changing only the metal airbrush nozzle and trigger. I have just dragged the contraption out and set it up again, because I'm going to do airbrush work for a new space abstraction picture.
I'm kind of spoiled by digital "painting" where you can get airbrush textures and overlays easily, that would take hours to create in real paint. However, your client doesn't get anything that he can frame and put on his wall, unless you have it printed large size by an expensive process. And even then, it's not quite the same. Airbrush painting is probably going towards obsolescence anyway, except for things like T-shirts and graffiti. There has always been something "cheap" about airbrush painting, and very few "fine" artists (if any) use it.
I painted the asteroids and planetoid on this picture with a regular brush. 14 years later, I ask myself, why did I paint all those rocks lined up? They are all roughly oval, and they're all floating with their longer axes sort of parallel. They should be randomly posed. Maybe the dwarfs on the planet had too much time on their hands and put the rocks in order.
"Blue Thoroughfare with Asteroids," acrylic on illustration board, 7" x 10", September 1990.