Wednesday, August 31, 2011

Thinking big

In previous posts, I discussed how to make a lunar colony self supporting. After all, it makes little sense to spend a lot of money just to subsidize an uneconomical activity. We do that pretty well already right here on the ground.

So, just exactly what can a lunar colony produce for the Earth?

It struck me that a big energy project could be built on the moon and beam the energy back to Earth. Yes, I've discussed this before. I ruled it out, now I am thinking it over again.  It occurred to me that the basic infrastructure would enable additional infrastructure to be built, which could earn an income.

I think I ruled it out previously because energy is only worth about 40 bucks per megawatt hour, at wholesale rates. So, let's see. If a gigawatt plant running continuously, should be able to produce 40,000 dollars in income per hour. That's 350 million dollars of output per year. If it lasted 30 years, it would generate 10,512,000,000 ( 10.5 billion) in revenues. If one plant could be built thusly, it would need to be considerably less than this cost in order for it to be profitable.

A lunar water cracking facility was priced at 88 billion or so.  It would not appear to be profitable, if the projects were comparable in complexity and cost.  But, let me forge ahead anyway.  Note: All of this is speculative, as I don't have the details of an actual design.

Could you build such a structure on the moon? It would be large, I would think. For such a project would require a large workforce and a considerable amount of material being put into position in order to bring this facility into being.

You would need to supply the fuel from the moon. You probably want to build it out of materials readily at hand on the lunar surface. This would require mining facilities. It would be a complex undertaking. Impossible? Perhaps.

Now, if you were to build some supporting infrastructure first, this may be a bit more feasible.  I covered that in a previous post.

You do not need water for a LFTR.  It is an inherently safe design and may not need much in the way of operational costs to run it.

How big would a LFTR design need to be?  Hard to say.  From the link above, it would take 1 ton of thorium per year to run it.  That means 30 tons of thorium need to be mined and processed on the moon.  Thirty tons sounds like a lot, but is only slightly less than twice what the lunar landers weighed on the launch pad during the Apollo era.

It would not require heavy shielding nor containment facilities, as it would not be under pressure.  So, the construction should be simpler than with a uranium fueled reactor.  If it would be possible to make it as simple as possible, it would help matters a lot.  Don't know if it needs to be covered, because I don't know if the salts would evaporate in the lunar vacuum.  If it does evaporate, then it will have to be fully enclosed.  That would make it more complex.

It is an ambitious project, but if you are going to do something, why not think big and go all the way?

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