It's a really good and simple concept. Though not a truly original idea I do like how the moon's face is simple and cartoony in style plus the subtle, little details around the piece such as the light from earth and the stars give it a high quality feel.
My criticism of this work is very small but I would have liked to see more going on. I know it's space and nothing really happens out there but maybe having a rocket going around Earth or an asteroid somewhere would have broken the piece up better.
All said, it's great.