H3 on the moon

[TimeDog]

is there really H3 there like i herd, or can it be made out of the regolith or something?

 

[Shpaget]

I suppose you mean tritium which would be 3H (H3 is triatomic hydrogen which is something entirely different).
Tritium is formed whenever a deuterium captures one more neutron, but since deuterium is scarce itself it doesn't happen often in nature. In fact tritium is extremely rare on Earth (in nature).
It is also radioactive (it has a half-life of approx. 12.5 years) which further decreases its occurrence in nature.

So, I would say that 3H can not be made out of moon regolith (as depicted in the movie Moon), it wouldn't be economical.
It is usually produced in nuclear reactors.

 

[origin]

is there really H3 there like i herd, or can it be made out of the regolith or something?

I believe he is refering to helium-3 which is more correctly written He3. It is an isotope of helium. I assume it is 2 protons and a neutron in the nucleus. This is an excellent fuel for fusion reactors, because the reaction produces almost on neutrons. Neutrons are the problem because neutrons produce ratioactive isotopes in the structual material of the reactor. There is an (relative) abundance of it on the moon.

Problems:

1. We don't have fusion reactors.
2. We don't have a space ship (or even a design) to go to the moon to get it.
3. We have no way to mine it.

 

[Shpaget]

Don't wish to split hairs here, but Helium with atomic mass 3 would be He-3 while He3 would be a molecule with three He atoms, however without subscript and superscript I guess we can't be sure of anything

Lets wait for OP to clarify things up.

 

[origin]

Don't wish to split hairs here, but Helium with atomic mass 3 would be He-3 while He3 would be a molecule with three He atoms, however without subscript and superscript I guess we can't be sure of anything

Lets wait for OP to clarify things up.

Freaking hair splitter!

 

[Astro_Robert]

Clearly the OP must be referring to He-3, whether it is a typo or he just heard something in passing, Tritium is usually written as T rather than H3 or H-3 I believe.

He-3 IS abundant on the lunar surface and, if I recall correctly, it is deposited there by the solar wind. Many people have thought about mining the lunar surface for this isotope for Fusion reactors. Using this element in a fusion reactor is desirable because it is 'easier'. That is the fusion reactions can take place at lower plasma temperatures and pressures, thus requiring more modest (but still rather huge) magnetic and other containment as well as radio-frequency (think big microwave) plasma heaters.

In fact there was a drama/thriller out last year in limited release called 'Moon' about this activity. It was actually quite good and I recommend renting it if you missed the theatrical release.

 

[Astro_Robert]

Although we are not now in a position to do any Moon mining, the long pole in the tent is clearly having a fusion power plant (let alone and industry) that would require meaningfull quantities of this isotope. Also in my earlier post I mentioned that He-3 fusion is 'easier'. I meant in comparison to trying to fuse regular Hydrogen or even Deuterium.

Assuming Obama does not success in killing NASA, we will have the lift capacity to design and deliver some sort of mining equipment in 5-10 years. It is unlikely that we will have viable fusion prior to that, although I am not aware if anyone has worked out the detailed mechanics of what mining would actually require assuming we would make the effort.

But economically, fusion produces so much energy per unit mass that mining would be feasible using any technology other than the ultra expensive space shuttle.

 

[a_lost_packet_]

..however without subscript and superscript I guess we can't be sure of anything ...

Subscript and Superscript are available when posting. The tag macros, if needed, are at the right-hand side of the top formatting bar.

But, yeah, if one doesn't use them when making a reference then it is a bit difficult to determine what they're talking about.

 

[Shpaget]

Yeah, I was referring to the original post
(and later consciously decided not to use them to make the point) :twisted:

 

[vaxheadroom]

OK boys and girls, let's review our basic chemistry regarding noble gasses.
1) They don't form compounds with anything!

So He3 and He-3 are unambiguous because they CAN'T refer to a tri-helium molecule!

Now that being said:
1) There's quite a bit of He-3 on the moon and you can get it out of the regolith by just heating it up and capturing the resulting gas.
2) There's WAY more He-3 on Uranus and Neptune, and if we had a nuclear thermal rocket motor we could go get it!
3) Yep, He-3 fusion is way out in the future, but if we had tons of He-3 available, it'd be here way sooner!
4) He-3 is SO expensive, you can almost assuredly make a business case now for mining the moon for it!

 

[Shpaget]

Let's split more hair. :twisted:
When one atom bonds with another atom of the same element it's not a compound. It is element.
Noble gases can form compounds.

I was also referring to standard nomenclature in which numbers behind the element symbol mean the number of atoms. When used in front of the symbol, numbers usually refer to the atomic mass.
The fact that triatomic helium does not occur in nature is irrelevant when trying to decipher what the OP meant when he wrote H3 and I asked if he meant tritium.

 

[TimeDog]

i meant He-3. and no i havent seen this 'Moon' movie. but im definately gonna check it out

 

[neilsox]

Possibly, these two and other isotopes in the regloth of the moon are useful, but they are parts per million, some parts per billion, so extraction is not easy. Worse the hydrogen and helium isotopes leak from the container, contaminating the vehicle that returns them to Earth. When we have bases on the Moon perhaps stuff separated from regloth will be useful. It is sort of like extracting useful stuff from the road sweepings from our roads = as far as I know that is not done, probably because it is not cost effective. Neil