very good but
i don't like the diagonal bottom spikes
the sphere need some work in my opinion, on the textures mainly, i don't like them, probably some less "casual" texture may be better, for example a texture with mostly horizontal lines and with some "elements" on it (for example little rings with windows/lights, bespin style, or maybe an "hydroponic garden" if you want a civilian structure )
i like the yellow tech parts hidden in the rock, but i find them too "regular", maybe a secondary docking bay(with maybe the possibility to fly INSIDE the asteroid

;7), a couple of panoramic windows, some little structures could improove the whole thing
A docking platform could be used also at the base of the sphere: make the sphere diameter little smaller so to create a little horizontal area between the sphere and the vertical area, and work on this area to make a little platform
Overall vote so far: 7,5/8
can become easily an 8,5 or probably more with little work:) when you will finish it we also may use it in the starwars mod for some missions:)