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Here's what I was thinking about today while looking out airplane windows: I was trying to figure out the economics of land and resources, then relate that to settling in space. Compare the two types of farm irrigation: circles and squares... 
2/ Where farmers irrigate crops in big circles, they are not using all of their land. They waste the edges. But the irrigation equipment is simple: a big pipe that rorates like the hand on a clock. This says something about the relative value of land and equipment...
3/ It says land is cheap, so irrigation is done in a way that minimizes equipment cost. But where land is expensive, like the land between these two rivers, they spend extra on equipment to irrigate all the corners of every square. No circles here.
4/ One more example before I tell why I think this is a parable about settling space. In this view there are no crops at all. But there are roads, and there are a few settlements of humans--not many humans though!
5/ I'm thinking that last picture is the transportation-dominant case, little use of resources. It is cheaper to bring food than to farm in a resource-poor area. That is how we currently do space exploration. All transportation, no industry. So few humans, and not much happening.
6/ The case with irrigation circles is the minimal infrastructure case. When we start industry on the Moon or Mars we try to minimize cost of equipment we have to ship from Earth. Resources are under-utilized. This is why we study steam hopping spacecraft. It is cheap equipment.
7/ Steam propulsion is not efficient. It wastes the water that we mine in space (like wasting the land in New Mexico, where I photographed the irrigation circles). But water is abundant in space, like the land, and steam propulsion uses cheaper equipment than LH2/LOX propulsion.
8/ The third phase is the square crop fields where the land is used maximally requiring more expensive equipment. There are lots of people there. More economic activity. So resources are valued higher and worth the cost of more complicated infrastructure. In space this will be...
9/...when we have a more fully developed economy in space, more expensive infrastructure on the Moon or Mars using the resources more optimally. So looking from the airplane today, I was thinking how we need to focus on the low tech solutions for space, first. Not high tech.
10/ As we move out of the transportation-dominant phase we need to move into a phase focused on simple, low-tech means of using resources to minimize technology costs. Steam propulsion. Simple mining. Simple regolith habitats. Later we build up high tech infrastructure.
11/11. I think we are mostly doing that already in the space resources utilization community. But I was reminding myself again that the way forward is the opposite of what most people think about space. We need resilient, cheap, maintainable tech, NOT high tech, to settle space.
