"Physics equation question
2D 3He --> 4He 1H or 2D + 3He --> 4He + 1H "Someone keeps anonymously removing the '+' signs" Whoever it is, please would you explain why. We will revert the edits until an explanation is provided as we cannot figure out if it is vandalism or not. Thanks. Charles F. Radley 15:03, 1 July 2007 (UTC)
current uses for He3
What are the current uses for He3, other than fussion power research? What potential markets open up if the price begins to fall?
Davew 11:48, 24 December 2006 (PST)
Application - Medical lung imaging
According to Wikipedia:
Medical lung imaging is an interesting new experimental application of He3.
Charles F. Radley 12:35, 7 January 2007 (PST)
He3 Fusion Works!
The opening statement is incorrect: "even though He3 fusion is not yet demonstrated". Gerald Kulcinski's group at the Fusion Technology Institute of the University of Wisconsin-Madison has had a working He3 fusion reactor operational for some time now on a non-governmental research budget. See the article: http://www.thespacereview.com/article/536/1 which describes his research program. Answers to many questions regarding He3 and mining it on the Moon can be found in Jack Schmitt's book: "Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space", Harrison H. Schmitt, Praxis Publishing (Springer, New York, 2006), a very detailed analysis of the problems, costs, and benefits of setting up a lunar He3 mining colony. This work should form the core of the discussion of this article since there is no other major work on the topic available.18.104.22.168 12:33, 31 December 2006 (PST)
Greetings thanks for the link. I will correct the Lunarpedia article accordingly.
Yes I am well aware of the work of Schmitt and his colleagues at Wisconsin-Madison, although I had missed the part about the experimental reactor. We should note, however, that the reactor they have does not achieve break-even, that is it consumes more energy than it creates. They acknowledge that it will be at least 20 years before break-even of He3 can be demonstrated.
- The fact also remains that De-Tr and De-De fusion are easier to achieve than He3 fusion, and we are nowhere near break even on the other fusion methods. For the past 40 year scientists have claimed that we are 10 to 20 years away from fusion break even. In other words, no measurable progress has been achieved, and there are no credible predictions of how long it will take. When Schmitt and his team claim that He3 is 20 years away, I would says that we could multiply that number by 5 or more.
- Therefore, for all practical purposes, commercial fusion (of any kind, He3 or other) is vaporware. I discount it at a basis for lunar development in my lifetime. My focus is on more near term goals.
Well, yes, of course. But break-even was not the point in suggesting the above correction (for which thanks for the alteration). To have achieved He3 fusion at all was remarkable, given that Kulcinski's operating budget is from two private sources amounting to less than 6 figures, while on the other hand billions of government monies have been poured into the international tokamak reactor (ITER). A larger research budget and more personnel for Kulcinski's group would alter the projected time to break-even considerably. As for the De-Tr cycle, problems with that were also discussed in the Kulcinski interview cited above which make those processes less favorable. 22.214.171.124 15:01, 31 December 2006 (PST)
Direct Solar Heating
Has anyone done the calculations on the required diameter of a fresnel lens that could be effectively used to heat the regolith in the recovery of He3 and other volatiles?
Davew 12:38, 30 January 2007 (PST)
Hi Dave, I previously posted some numbers. It makes no difference whether it is a Fresnel lens versus a reflector, the diameter is the same. At large apertures, lenses have greater losses than mirrors, so reflectors are normally used. In Astronomy, for example the break point is generally around 25 cm aperture. There are very few refractors with diameters greater than 25 cm Charles F. Radley 13:15, 30 January 2007 (PST)
Tritium decay produces He3. Tritium is produced by bombarding an isotope of lithium with neutrons in a fission reactor. Why can't lithium be mined from regolith, bombarded, the tritium stored and the Helium3 slowly be drawn off? could there be any advantage of this over collecting the He3 from the regolith directly? And what about other gases produced by heating regolith? What use could they be of? T.Neo 10:28, 31 July 2008 (UTC)
Direct Solar vs RTGs
Echo 2 was a 0.0127mm thick 41.1 meter diameter spherical mylar balloon launched in 1964. The total weight of the system was 256kg and included the inflation system and some solar panels:
If a parabolic version of Echo 2 were half silvered this size of reflector would concentrate more than a 1.5 megawatt of sunlight if used outside of the earth’s atmosphere. Optimized cylindrical solar concentrators designed for cooking basalt could weigh less than this. Solar tracking is an easier problem on the moon since the solar cycle is 28 earth days long. The distillation system and material handling would be the heaviest part of any He3 lunar activity.
The fission based RTG system used on Cassini weighed 56kg and produced about 900 watts of electricity from about 13,000 Watts of heat.
I see in the volatiles article that hydrogen is the most bundant volatile on the Moon. Is this in regoltih alone or mostly in ice at the poles? If so, is it available in the regolith to be viable for use as rocket fuel? T.Neo 13:04, 1 August 2008 (UTC)
Just the regolith alone. Harvesting regolithic hydrogen for use as rocket fuel is likely to be much less economical than using it to compensate for the small but gradual leakage of atmosphere during oxygen production as well as that from pressurized habitats. The ice at the poles is another question entirely. There is disagreement as to how that hydrogen should be utilized. Personally, I would prefer to keep it on the moon while shipping oxygen back to LEO for a propellant depot. Probably cheaper to ship hydrogen to LEO than to ship it to the moon to make up for a future shortage. - Jarogers2001 19:30, 1 August 2008 (UTC)
So if you ship O2 to LEO to use as propellant, where does the fuel come from? Is it shipped from Earth? How do you get hold of H2 or any other fuel on the Moon? T.Neo 08:21, 2 August 2008 (UTC)
It could be shipped from earth at first, but eventually it could be shipped from NEOs and the moons of Mars. H2 is much lighter than H20 due to the fact that Oxygen is 8/9ths of the mass of each water molecule. The first H2 would need to be shipped to the moon, but it could also be recycled, scavenged from regolith, or harvested from the poles. However, whether I think it's a good long term idea or not, polar hydrogen will likely be used as rocket fuel in the beginning. It works in the short term. - Jarogers2001 08:36, 2 August 2008 (UTC)
I hope that there is water on the moons of Mars, because it will be useful as propellant for spacecraft. NEOs, however, I am not too sure about. Wouldn't millions of years under the huge spotlight sun strip them of their volatiles as has happened to the Moon? This lack of "fuel" will lead to some interesting rockets and propellants, etc. T.Neo 15:53, 3 August 2008 (UTC)
The lack of water on the moon is due (we believe) to the way that it formed. A very large collision in which most of its mass was either converted to plasma, vaporized, melted, or shattered and was sprayed out into space where accretion took place sans volatiles. On the other hand, NEOs, Phobos, and Deimos are asteroids which contain hydrous minerals within their internal structure. Like the moon, they are also subject to the same space weathering that will embed helium 3 and other volatiles into their surface regolith. The really interesting part is that recent discoveries (I don't remember where I read them offhand) have begun to blur the line between cometary bodies and asteroids, suggesting that many asteroids may be dead cometary cores which may contain internal ice deposits insulated by the highly refractory surface regolith. - Jarogers2001 17:20, 3 August 2008 (UTC)
So, if some asteroids (the ones that are not extinct comets) are similar in composition to the lunar regolith, could techniques developed on the moon be used for asteroid mining? Could the moon be the place to build asteroid mining devices? And water in NEOs might be a lifesaver. I thought you had to get beyond the frost line to get to large amounts of water. Is there any advantage of mining He3 from asteroids instead of the Moon? Do the Martian moons hold large He3 reserves? T.Neo 16:23, 4 August 2008 (UTC)
You are absolutely correct in the thought that techniques learned on the moon will be useful for asteroid mining. The same weathering processes responsible for the abrasive lunar regolith are also responsible for the surface regolith layer of asteroides. It would also be easier to launch an asteroid mining device from the lower gravity well of the moon than to launch it from earth. "I thought you had to get beyond the frost line to get to large amounts of water." So did I. The amount of He3 available on bodies will need to be determined on a case by case basis due to changing asteroid orbits, etc. The farther away from the sun you get, the less He3 you will receive as the solar wind spreads out in the same way as sunlight.. - Jarogers2001 16:38, 4 August 2008 (UTC)
- I really with MediaWiki had a merge feature. It's not a legal issue with us, just a nuisance. It's arguable that Wikipedia violates its own licence every time it does a merge that loses contributor information, though, which is every time... I've been pondering the workload needed to export and import a combined article. Needs a test... -- Strangelv 11:26, 5 August 2008 (UTC)
- If you want to try some kind of merger test, I recommending exporting the two articles, merging them, then importing them under a test name to avoid problems. What I would do is to simply copy your work and mine from Helium, move the Helium3 article to that location, then add our information at the top and proceed with cleanup/editing. I would hope to be able to do this within a week of featuring Volatiles so that Helium can then be featured on the front page. All contributor information from this article would be moved to that location. - Jarogers2001 11:35, 5 August 2008 (UTC)