"Turn asteroids into space habitats!  Just use self-replicating robots." Says the blurb - and I immediately stop reading.  Because, unlike the author, I've actually given the concept of self-replicating robots some thought and have concluded they are distinctly non-trivial and not something humanity is likely to create in my lifetime.

In my case I was considering von-Neuman probes - inter-steller spacecraft which use the resources of the destination solar system to create replicas which are then sent out to other nearby solar systems.

The problem with self-replicating spacecraft (or robots) is they have to be capable of a huge number of industrial processes as everything which makes up the spacecraft, including the machinery etc used for the processes, must be manufactured by the spacecraft from the raw materials it can obtainThis means the spacecraft not only needs to be able to fabricate integrated circuits, but it needs to be able to manufacture the machinery used to fabricate the integrated circuits, and able to manufacture the machinery used to refine raw ores, etc. etc.

Once you start to think about what would be required, the idea of a self-replicating robot becomes laughable.  An inter-planetary spacecraft, certainly because size isn't as much of a factor.  One question is whether it would be possible to obtain or synthesize all of the necessary materials by mining asteroids and the inter-planetary medium to avoid the need to enter and exit planetary gravity wells & atmosphere.