Bob Shaw 
Orbitsville Departure [EPUB ebook] 
Orbitsville Book 2

Two hundred years ago mankind found Orbitsville, a vast sphere whose habitable inner surface comprised living space equivalent to five billion Earths. The resulting migration was enthusiastic — and nearly total.Earth itself is a backwater now, a place with which the people of Orbitsville maintain only marginal contact. But just because it’s backward doesn’t mean it isn’t dangerous.