These planets look as great in person as they do in these photos!
There are a few versions of this project out there, so I don't get any points for originality, but regardless, it's a great project and more importantly, the kids really seemed to like creating them.
The project took about 5-40 minute periods. On day 1 I showed everyone how to create the "waves" and blend them in an upward facing direction. On day 2 I set up a splatter paint station and demo'd how to start shading the planets. I flipped this lesson and used mostly video demo's which was incredibly useful because it took the kids 3 perios to complete the planets. So instead of having to demo the shading every period for my 5-5th grade groups, I just replayed the video and they saved on work and transition time. They had to make 5 or more planets. On the final day they cut and glued their planets, making sure all the shadows were on the same side. We discussed light sources and I explained that on a 2D surface, having a consistent light source would make their art look better even though they pointed out to me that in space there would most likely be multiple light sources ah, my 5th graders always thinkin!).