Snap, i've just come in having done the same. I'll scan and post it tomorrow. But this is about your sketch.
Really really good.
Excellent shading, I noted a difference in shade across the floor of the crater and you have captured that well. Overall it looks like a landscape, doesn't show any harsh lines that would make it look like a drawing or map. It's just really nice to look at.
Well done, keep em coming.