L-5

Poul Anderson, Harvest Of Stars, 27.

The space habitat, L-5, has machines, nanotanks, crops and an orchard:

"L-5 produced wares for export, especially those that required low gravity or none in the making, but it also mostly fed and clothed itself. Were it cut off from trade with Earth it could soon be turning out everything it needed, deploying solar megamirrors for energy and obtaining raw materials from space." (p. 262)

That is what we need: self-sufficient colonies off Earth in nearby space. This one orbits sixty degrees behind the Moon, not far.

"She would not let herself consider how vulnerable to attack the colony was." (ibid.)

So, two things that L-5 needs:

defenses;

a just and peaceful interplanetary civilization with abundant solar energy where there is neither political nor psychological motivation for anyone to attack.