I see that many websites and magazines with physics thematic are pretty excited about mining Helium 3 isotope on the Moon. But this seems to be a very hard-to-get resource. For more than one reason:
- There is not too much of it on the moon. It actually seems to be 0.007% of the moon soil.
- Transport to earth would be also very VERY complicated in my opinion.
- People would be required to take care of the harvesters.
Deuterium can be found in the seas as "heavy water". No spaceships needed.
Now even when we get the Helium-3, I have a strong suspicion that it contains less energy than Deuterium but it will require more energy to start the fusion.
Why I think it needs more initial energy to start the fusion?
- Deuterium contains one proton and one neutron. That makes a +1e core.
- Helium 3 has 2 protons and one neutron - That's +2 core.
Now the worst problem with fusion reaction is, that once you pull the atoms so close, that the electron shells no longer shield the polarity of the protons they start repelling with electric force. Now if you're trying to pull +1 and +1 together it seems much easier than pulling +2 and +2 together. Just think about the standard equation:
$F_e = k*\frac{|Q_1*Q_2|}{r^2}$ where $k$ is the permittivity constant and $Q_{1,2}$ are the proton charges. Repelling force must be 4 times as large.
Why I think it contains less energy?
This is even simpler to explain. In the fusion process we merge smaller cores to create larger. We normally start with hydrogen and create helium. Now when we already have Helium fused, it means that we missed one step in the fusion. Why would we do that?
Can't actually Helium 3 core be one of cores that are created in Hydrogen fusion?
cold-fusion
because cold fusion is most likely to be used as fusion power source. $\endgroup$