I have been doing a lot of space themed lessons recently. This is my first grade space project. Basically, my students used a black crayon to draw planets, stars, moons, suns, aliens, etc. Next all of these things were colored with oil pastels. I emphasize the importance of coloring neatly and dark, since the paint will stick to all things that are left as plain white paper. Finally, I gave my students blue and black watercolor paints to paint the sky.
I think adding a little blue in the background, makes these space pictures look more authentic.