Moon helium deal is biggest purchase of natural resources from space
washingtonpost.com
washingtonpost.com
Would be interesting to see the economics of the various hypothetical business models.
https://en.wikipedia.org/wiki/Breeding_blanket#Tritium_breed...
The current method is neutron capture of deuterium, but you'd get much larger amounts, fast, using lithium; particularly if it's isotopically enriched. Either way you get radioactive tritium, which decays to helium-3 over a 14-year half-life. The tritium is what fusion reactors want.
It's regrettable we've let China establish a world monopoly over lithium enrichment. This is yet another thing they could have a large starting advantage on, with their immediate access to lithium-6 at scale.
First, am I understanding correctly that you aren't talking about DT fuel, but are instead suggesting that we use the tritium to produce helium-3 by letting it decay? This sounds extremely inefficient, and it also seems like it would cause supply chain issues where power production relies on helium-3 that we started producing decades ago. This would mean that the infrastructure we set up wouldn't be useful for decades, and that if production stopped for a few months there would be a helium-3 shortage decades later. Lunar helium-3 extraction would have a shorter feedback delay, making it less vulnerable to latent shortages and more useful as a medium-term power source.
Second, isn't lithium-6 a rare material? Lithium is abundant, but brine and rock deposits that are cheap and easy to extract are quite limited. Also IIRC something like 92% of it is lithium-7 which is much less useful in enrichment. And that's not even considering the geopolitical factors you mentioned. I'm obviously not saying that tapping into harder-to-access deposits and filtering for lithium-6 would be more difficult than sifting lunar regolith for helium-3, but it still sounds extremely difficult.
> "there would be a helium-3 shortage decades later"
There's a conceptual misunderstanding: radioactive decay is continuous—there's no latency of waiting. You get a stream of decay product right from the start.
> "economically infeasible"
It's the sole source of helium-3 today.