100% with you there Gordon on the need to use self replicating robotic systems to prepare the way for humans.
Robert A Freitas Jnr wrote a report basically saying exactly this for NASA in about 1981. Unaware of his paper I wrote something similar in the Mensa journal Isolated M about 3 years later.
My fundamental question is – why waste mass terra-forming large balls of it with relatively small surface areas, when it is so much more efficient to make cylinders, spin them to simulate gravity, and live inside them? Put the spinning cylinder inside a non-spinning sleeve if you’re really worried about things hitting you from outside.
Just a few hundred feet of the surface of the far side of the moon would give us enough mass to give us a surface area equivalent to what we have here on earth.
Actually Bruce, when you start looking seriously at protection, placing a spinning habitat inside a rock sleeve beats a planet at every level I have looked at – which includes radiation shielding, gas loss, meteor impact, tectonic dangers, … etc.
Using a large ball of rock as a habitat is just so wasteful of mass, I suspect that earth will be the first and last one. We may never achieve a “General Products” hull, and we may be close enough soon enough that we never again consider the wasteful use of mass and energy involved in using planets.