[@Sophrus] Have you read the star wars books about the Chiss? I personally love the book where they are first introduced. They built a base inside an asteroid. A lone asteroid. Nobody managed to detect it. A well hidden refueling station inside a low albedo asteroid shouldn't be underestimated. Add a few dozen more rocks and you've got a recipe for success. Surely not strong if found, but locating it is the hard part.