This sketch transitioned nicely into a drawing, with conflicting feelings. I started in pencil and wanted to do watercolor only. Due to limited time I decided to ink it. I liked the ink so much I was afraid coloring it (in any form) would ruin it. I went along with it anyway. Then I decided to not color the sky and smoke, and I am glad I did.
The only minor issue is that the lower part of the booster rocket is not in line with the perspective of the rest of the picture, but oh well.
I did like how the sky turned out. My wife insisted on using masking tape to fixate the paper I am glad she did, because the paper warped significantly with the amount of water on it.
The spaceshuttle and rocket are touched up with my Sakura grey brushes. The rest is watercolor.
Here is the original sketch I based this on. It was a one-off attempt and I stuck with it.