FUNDING
- how will we pay for space development and settlement? -

Yes, we can always be looking at how we can increase revenue thereby paying for space settlement and development. But there are a number of approaches to greatly reduce expenses thereby making develop don't and settlement that much more easy to achieve and sustain.

EXTENDING CREW STAY
A certain percent of the cost of maintaining a permanent base will be in the rotating of crew. For the ISS, this is (currently) being done by the Russians at over $80 million per seat. For a permanent lunar base heading towards settlement, if crew stay can be doubled then the cost of crew rotation can be approximately halved. For settlers intending to remain off Earth indefinitely, the cost of rotations may not be an issue.

RECYCLING
An often overlooked secret to reducing the cost of maintaining a permanent base or settlement is to develop ever-increasing levels of recycling. For example, on the ISS, water is being recycled at the 93% level. So, each liter of water can be recycled thereby effectively providing the equivalent of 14.3 liters. Recycling works best for consumables and not as much for durable items.

IN-SITU RESOURCE UTILIZATION
It is fairly obvious that using local resources could result in a large savings by not having to ship them. Mars has the largest quantity of resources, but the Moon has all of the resources needed to support a large, growing settlement. Between different types of asteroids, one can pull together what one needs for in-space settlement. It's just that one has to do extra work importing the asteroids resources. As for free space such as low Earth orbit (LEO) there are essentially no material resources and so one has to import everything.

The good news is that the development of a few items (water, organics, and metals) and processed into usable forms can result in a dramatic reduction in shipping costs. The Space Development Network believes that it is possible in the relatively near-term (e.g. within a few years from when the first permanent habitat is established.

And recycling and ISRU work together in that, the more one recycled, the less materials one has to produce from local resources.

So, advocates for commercial space development need to pay equal attention to the reduction of expenses and not only on what the source of revenue might be.