[dlvfdfoa] 3 space colonization targets

Moon, Mars, more space stations.

Moon: closer than Mars, easier to travel to and fro, more solar power.  Mars: (probably) more water, more gravity, atmosphere shield against radiation and meteorites.

Space stations: even easier travel.  If we are to become a K2 civilization, we need to practice building space stations.  Prefer to leave Moon and Mars uninhabited because we may eventually disassemble them for raw materials to make many space stations.

We have yet to build a space station with a radiation shield that reduces space radiation down to levels seen at the surface of the earth.  Also yet to build one with artificial gravity (via centrifuge) equal to earth.  We'll want both to prevent human evolution from diverging relative to earth.