However big the GM says it is? The ranges are somewhat abstract compared to games like D&D. Using the battle-mat from ‘Had my Mystic Mountain battle mat printed’, I’ll tell you what I would rule the areas as.
If your ship is placed on the exact center, where the dot is in the middle, then the 4 ‘pie’ shaped sections surrounding it would be considered close range. The next section out would be Medium, next circle would be long range, and the final circle would be extreme.
Alternately, the 4 wedges in the center could be considered as ‘contact’ with the ship, and the 8 blocks surrounding it would be close, then medium, and long being the final circle. As I said at the beginning, it depends on how the GM is viewing it and how they want it to work.