The idea of having a Space Station hollowed out of a NEO (Near Earth Object) or NEA (Near Earth Asteroid) is not a matter of science fiction, but an issue of logistics and finance.
We already have the technology available to reach space, the ability to navigate to an asteroid, harness it with the intention of dragging it into a closer, lower orbit and then mining the metals, frozen gases and water out of it until its an empty husk.
It makes sense then that the materials mined could be used to manufacture products in space into something that could be utilised by mankind to build a gravity-based station that would then be able to provide a working and living habitat to thousands of people.
Asteroids contain virtually all of the essential ingredients needed to house and maintain humans in a sustainable environment. We would be able to extract oxygen from the rock, water, hydrogen and even grow things in the rich dust that coats the asteroids.
The ability to rotate the rock wouldn't be difficult, although largely unnecessary. Also, placing the NEO in a position where it achieves plenty of energy, power, heat and light via solar collectors would ensure our ability to cultivate a reasonable habitat inside such an object.
Whilst the inside could house humanity in experimental, or commercial/industrial groups. The outside could handle defences, or even powered engines to move the asteroid station to new orbits. The hydrogen that is locked up in the rock would provide more than adequate fuel for such an exercise, making it very economical and cost effective.
We would even be able to manufacture deep-space vehicles and use the Station as an interim transit point for other missions. It would be cheaper to produce and maintain than shipping the finished products by expensive rockets from Earth's surface.
Multiple Stations orbiting Earth could provide important functionality in the observation of weather or climate change, it would be advantageous to have the mobility of working in an environment so close to outer space without the existing gravity and atmospheric restrictions that surround us now.
So, the plausibility of Alpha Station as outlined in the book is a wholly realistic exercise and one that we could well see becoming reality in the first half of this century.
More information can be gleaned from the following sites.