Let me dive into the fringes of science fiction.
Many people, including my brother, who are for pushing into outer space, use the temptation of cheap fusion power. They say that the moon has supplies of Helium-3 which would make fusion power cheap and effective until we learn how to better do fusion power with what we have on Earth. As I understand it, there are two arguments: That a shallower learning curve will enable us to weed out the bad ideas which currently stymie us. Or that it is economically feasible to import Helium-3.
Helium-3 is not found plentifully on the Earth. It is both inert and light. It just floats away. That Helium – of any sort – which we have is found with natural gas trapped under salt domes. We get it as a byproduct of natural gas production. The amount of Helium-3 is truly saddening.
However, it is found on the moon. One idea is that Helium-3 ions from the solar wind are embedded in the moon and persist there. Especially in dark areas. This is an area of potential conflict. The Chinese are especially interested at present.
I have a different idea. Years ago Robert W. Bussard suggested a way to make an interstellar ramjet. Let’s divide the idea into two halves. There is a fusion jet. And before that, there is a large funnel shaped collector – mostly a magnetic field – which collects and concentrates charged nuclei from interstellar space. We do not know how to build a sufficiently large and robust collector field. it would be shockingly useful if we could.
What if we bypass the whole Moon thing, and build a collector at the L4 point? Just take the He-4 from the solar wind? once we have a narrow jet of solar wind concentrated, in the vacuum of space, we run that stream by a magnet and the stream will be separated by mass into a spectrum of mass. Direct the stream of Helium-3 into a grounded container and we have reconstituted Helium-3. At other locations we have Technetium, Oxygen, Nitrogen, Neon, Magnesium, even Titanium.
We can farm these things, rather than having to mine them. We also have a shadow of very good vacuum. We don’t have to go down to the Moon and bring them back up.
Also, while we are learning how to make a decent fusion reactor, we can learn to make a Bussard Collector. At the end of this process we have not only the Helium-3 which motivated us, but also a source of the supples we need for life in outer space. And as a pearl on a cushion, we just might have both halves of the Bussard Ramjet which opens up access to the nearer stars.