One theme that occurs frequently among subjects that I discuss is the matter of conservation and renewal of resources, including energy. The following essay urges the importance of development of energy storage on medium to large scales. Apart from the importance of various applications of energy storage, it is vitally important to the application of "renewable" or "sustainable" energy technology. In particular it renders the exploitation of intermittent sources of energy worth while, and secondly it permits drastic reduction of the scale of base load energy that utility companies must budget for. Short of the question of actual generation of energy, this is arguably the most important theme in a broad and vexed range of subjects.
If you find irritating errors of format and presentation, I apologise; this is my first attempt at using the blog facilities; forgive!
Practical options for Collection of Helium-3
This is not a document cast in stone, but a non-technical draft proposal. Anyone with doubts, queries, suggestions, objections, or corrections should please feel welcome to contact me.
Of all the prospects for power generation by nuclear fusion, Helium-3 (3He) has been touted by some as the best possible and most desirable nuclear fuel available. This is simplistic because the only clear advantages of 3He fusion are that, suitably burnt, it produces mainly energetic protons instead of neutrons. It thereby reduces problems of radioactivity, and also should permit direct generation of electricity by exploiting those protons as moving electric charges. This should be more efficient than generation of electricity from heat. Of course, any such process produces some heat as well, but the principles, as far as they go, seem sound and the advantages attractive.
However daunting the technical challenges of 3He fusion might prove, a far more serious problem for the foreseeable future is the disappointing shortage of accessible 3He for fuel. If the fuel is not available, it hardly matters how easily it could have been ignited if we had had enough to burn. On Earth 3He is present only in traces. Some of those traces came from the solar wind and some from tritium decay.
Obviously that ultimate source of 3He in our solar system is the sun. The sun emits a continuous though variable flow of charged particles. The solar wind is mainly a plasma of hydrogen, deuterium, and 4He, but it also contains some tritium and some 3He. From some points of view tritium is at least as good as 3He, because it is easier to store, and in any case it decays into 3He with a half-life of about 12 years. Accordingly, given a constant supply of enough tritium, we could rely on an adequate supply of 3He. Tritium of course has other uses as well, but those are not relevant in this context.
There are obvious attractions to the idea of stationing craft at various LaGrange points, of which the Earth's L1 point is the most seductive. However, the idea is questionable for several reasons. For one thing, as it approaches apogee, travelling in a highly prolate, narrow ellipse, the craft would be moving round the sun at a much lower velocity than the planet and its LaGrange points. It would require a great deal of fuel to match orbits.
Solar skimmer craft, unless they were stationed in circular orbit, would approach the sun on a highly eccentric, possibly even hyperbolic, trajectory that skims the chromosphere at perihelion. In any case the speed of the craft at perihelion should be of the order of a few hundred km/s. This is a large fraction of the speed of the solar wind itself. If the solar skimmer craft were in fact in more or less circular orbit, the same would apply, except that the craft would be permanently moving very fast, probably in retrograde orbit to maximise its speed relative to the solar wind.