Recently, a two part study and interview was posted regarding the economic feasibility of lunar mining for ice. The study is somewhat older, being originally published in 2002, but the basic assumptions appear to have improved in general regarding the RoIC prospects, specifically with regards to the quality and quantity of the ice in certain lunar locations, which would somewhat smooth the initial mining costs.
The study forms an integrated whole, covering all details from the launch from Earth’s surface to the mining, to the aerobraking return flights necessary to bring the lunar resources to final destination. As such, it is the first of its type that I have seen regarding mining, and while some of the assumptions are in need of updating with more accurate information, it goes to show that there are commercially viable cases for economic exploitation of space.
Space economics form something of a circular loop, for the more work that occurs in space, the more efficient it is to do other work in space. The basic analogy is a fuel station (propellant depot in aerospace terms). If there is only one or two cars that comes past regularly, unless the price they are willing to pay is very high, the delivery and fixed costs are greater than the revenue being realized and the fuel station is a money loser. But if there are more customers, then the revenue rises until it is economically viable.
This particular study would seem to fall into that category, given that it focuses on the exploitation of lunar ice, which, when broken down through electrolysis, forms two of the primary fuel components for chemical rocket propulsion. If there are not enough space-only operations, this would prove to be a fuel supply with no consumers. This is why the study pushes heavily for the deployment of a LEO to GEO tug system (what it calls an OTV or Orbital Transfer Vehicle) that can be used to transfer satellites and other cargo at a fraction of the cost of a single unit from Earth.
There was another study that was conducted around using propellant depots and space tugs to service Iridium’s satellite constellation, in three parts here, here and here. Likewise, there is also this collection of studies on in-space operations, all of which could rely on fuel provided from a mining infrastructure such as this. Each of these studies show that there exist viable cases for RoIC in space, although it is likely that at best only 10% of these ventures would succeed in surviving through the start-up phase. However, that success percentage has long ago been deemed acceptable for Earth-bound businesses, and so should suffice for space.
It is only a matter of time before the slow creep of humanity outwards from our blue planet renders profitable operations conducted solely in the deep of space and on other bodies.