What would a moon have to be made of to make it worth mining?

This. It would have to be something consumable to prevent destroying it’s own market.

Diamonds are just carbon. We have plenty of that here on Earth.

I have heard that He 3 is the only material that we have currently found/know of that is economically worth going extra-terrestrial to mine and return.

Actually, I’m misremembering. When I asked the question, I got a ballpark figure of 20,000 tons, which is considerably less than the load of a large container ship these days.

(Bolding mine). Well, that’s the multi-trillion dollar question.

Truffles?

Unobtainium? You know, some sort of wonder material? If it had applications in space travel, we could mine it using conventional materials, until we could construct unobtainium mining equipment which would greatly increase productivity.

Printer cartridges then. That’s where the real money is.

That would be my guess.
We’re running out of the stuff. Someday it may just be worth it.

Give your wife earrings with charcoal studs and let us know how it goes.

What about Phosphorus? The Master Speaks.

I think you meant to say we are running out of He-4, which is the ballon stuff - and we are not really running out of it, just that demand is outstripping supply.

He-3 is different stuff, a product of the solar winds that the moon appears to collect. In theory in may be a way of clean nuke fusion. Also containing tremendous energy per volume, I’ve heard a estimate that a fuel tank the size of the external storage tank of the Space Shuttle filled with liquid He3 could supply the US’s peak current demand for electrical power continuously for a year.

Deposits of hydrogen and oxygen be to start with. That way you can create, water and oxygen for the miners, and rocket fuel to get whatever else you can scrape up back to earth.

My point is, if we really need diamonds, it would probably be more cost effective to spend a few billion dollars on developing techniques for making artificial diamonds, than to go to space to find them.

That’s not completely correct. He3 would be used with hydrogen in a fusion reaction. It’s the creation of He4 and the released energy that’s impressive, not the inherent energy content of He3 itself.

Magnetic monopoles? I have no idea what they’re good for, and they’re only theoretical at the moment, but Niven’s belters hunted for them greedily.

I’d love to have time travel, just so I could bring this thread back to the science fiction writers of the 40s and 50s.

They were, shall we say, innocent of any economic knowledge. They couldn’t do a cost-benefit analysis if their typing fingers were about to be chopped off. What I get out of reading the work and the histories of the field, though, is that it never occurred to them that such analysis would ever be necessary.

They should have known better. The fuel needs of rockets had been completely worked out in technical detail, and done so over and over by various people in various countries at various times. They had watched the various amateur rocket groups play around with their tiny rockets and get exactly nowhere. Robert Goddard, now retroactively legendary, had the best funding and never got a rocket up 2 miles. The Germans spent almost as much on the V-2 programs as we did on the atomic bomb, a number over a billion marks. Americans knew that bought them much less than what had been predicted. (Expectations were for 5-15 tons of explosive, but the reality was one ton, far smaller than conventional bombs of the day.) So they knew that a moon rocket would have to be an order of magnitude bigger. At least they should have known because every newspaper and magazine in 1944 carried full details.

Yet they all acted as if the economic returns were obvious. I’d like to give them the excuse that none of it mattered for fiction, but from what I can determine they said the same things in private and in their nonfiction. The 1953 Complete Book of Outer Space, a collection of articles intended for the popular reader by technical experts also includes “Exploitation of the Moon” by Hugo Gernsback, still crazy after all those years. It’s a serious proposal to put mines on the moon because there might be veins of gold and silver and possibly veins of pure metal that doesn’t even need smelting. A picture caption, undoubtedly written by the book’s editor, states that “Scientists are agreed that apparently wasted surface of moon may cover a gigantic wealth of mineral deposits and deduct this from type of rocky terrain.” Solar power would be cheap and always available on one side or the other. The moon colony will be a miner’s camp. Transportation to and from the moon “will be as routine as today’s air freight.” This was not for some hazy future. A moon landing was predicted “no later than 1977.”

Today’s writers use similarly optimistic numbers about the moon. kanicbird is probably referring to this proposal from the Artemis Project which takes unconfirmed estimates of He-3, imaginary mining and collecting of it, and the unknown technology to make it a fusion power source and uses it to pay for itself by universal use for all power generation on earth.

It won’t happen. The moon is not Deadwood. You can’t make the numbers work. You couldn’t then and nothing has changed since. That’s counterintuitive, but so is everything else in science these days.

This sort of makes more sense, though He3-He3 fusion should be ‘clean’, the energy released when I ran the numbers was not spectacular and one would be better going with good ol’ H-H dirty fusion for max energy. I have not look at He3-H fusion, well not lately.

I don’t think better rockets are going to cut it. We’re not that far away from the efficiency limit for chemical rockets, and atomic rockets score pretty low politically (NIMA - Not In My Atmosphere). I mean, maybe we’ll get rockets that are twice as efficient, or ten times, but they’d need to be like 10,000 times more efficient to make mining a remotely economical prospect.

Maybe if we manage a space elevator. Or a maglev catapult (more reasonable an engineering prospect on the airless moon, but it would be pretty reckless to entrust such a device to a bunch of criminals at the top of our gravity well).

They’ll score higher as soon as China starts building them.

Data?