# Tag Info

10

Well we don't yet have the actual proof that there's an "abundance" of 3He (Helium-3) embedded in the Lunar regolith that would make any "mining" worth our trouble. All we have so far is the indication that there might be, as shown by the trace amounts of 3He detected in the regolith samples extracted by the Apollo missions. Current estimates are that there ...

9

Two big ifs here. IF we achieved viable commercial fusion power (other than the sun) and IF He3 was an indispensable part of this process. But for the sake of argument, let's say He3 is the fusion fuel of the future. I'll quote John Schilling's comment from Rand Simberg's Transterrestrial Musings blog. Helium-3 mining on the moon simply does not pass ...

8

NASA [1] indicates that helium-3 can be assessed indirectly by measuring the presence of titanium dioxide and soil characteristics ("maturity"), the correlation having been derived from the study of Apollo lunar rock samples. The helium-3 is "detected" through remote analysis for these favorable mineral and soil characteristics. Using data on the titanium ...

8

This depends on your definition of "proven". What we know about Helium-3 is based on lunar soil samples collected at 9 different locations (6x Apollo, 3x Luna sample return missions). Extrapolation from that yields a figure of 2.47 million tons of Helium-3 stored in the surface layer of the Moon. However, we also know that the He-3 is at a very low and ...

7

On Earth, before a mineral or petroleum resource is mined/extracted, the deposit is delineated and evaluated. Briefly, the process involves sending a some geologists and some drill rigs and their operators to a deposit and drilling holes through the deposit on a predetermined grid pattern. The drill cuttings or core (depending on the type of drill used) ...

7

Lunar regolith may contain not only the lightest noble gas helium, but also hydrogen and other noble gases like neon, argon, krypton and xenon. The concentration of helium is much higher than that of the other noble gases. More than 99 % of lunar soil are oxides of silicon and some metals like iron and aluminum, see table 7.15 on page 62 of the Pdf. Source ...

7

The Moon would be a much better place most likely. As you said, 220 pounds of Helium-3 in a mass of many many tons of rock, makes it so that even a few tons of equipment to be dropped on the Moon would vastly reduce the price to return it home. Lifting 220 pounds from the Moon to return to Earth is relatively easy, all of the Apollo missions did it, and then ...

5

Interesting question! A quick check of Wikipedia's Helium-3 introduction says: The abundance of helium-3 is thought to be greater on the Moon than on Earth, having been embedded in the upper layer of regolith by the solar wind over billions of years, though still lower in abundance than in the solar system's gas giants. but let's not assume that ...

2

That is fairly obvious from the factoid you state yourself. In regions, of a celestial body, that are not shielded by an atmosphere and that are never lit by the sun, the temperatature can go down very, very low - actually close to the temperature of the Cosmic Background Radiation (2.725 K). So in permanently shadowed lunar craters the Helium-3 simply has ...

2

The appeal of 3He-D fusion is the lack of neutrons, which waste energy (being uncharged and all, you can't collect their energy) and when the neutrons collide with the reactor, they make the reactor itself radioactive (so 'easy' D-T fusion creates nuclear waste). Lunar 3He can be obtained essentially by scooping up the regolith and baking it to release ...

2

I've heard it said that IF we get fusion going, lunar regolith would have a specific energy less than low grade coal. Hobbe's answer gives some good cites so I'll use his numbers. 3GWh - that's 3 * 109 watts * 3600 seconds which is 1.08e13 joules. 1 to 15 billion kg of rock gives a specific energy of 10800 to 720 joules per kilogram. Wikipedia gives the ...

2

Although the exact value is not known, on various estimations (like in this paper), the local abundance of ${}^3\mathrm{He}$ is in the order of $10^{-5}$. There is also a more close experimental data. On this NASA paper, we get roughly a 1mg ${}^3\mathrm{He}$ by heating a ton of Lunar regolith to $700 ^\circ \mathrm{K}$. The paper also shows, a built up ...

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