Good job--just a something you might be able to improve upon and/or consider for next time:
-The overall shape is a torus; I (IMHO) feel that it might be a little too plain, maybe try adding a few more details?; I see that you already have added many details to the model, but maybe try some smaller ones as well. (for example: possibly some wires, various capsules, solar panels, something along those lines.) I realize that many details will be added trough texturing, but the more modeled ones, the better--as long as you dont go completely overboard with it
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But overall, nice
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