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Variable Output RPG
Hello,
Is it possible to design a RTG so that the daughter products release more heat at a later date than when it is first assembled. I am thinking of missions where the early flybys are in the inner system and heat rejection may be a problem, but once you reach the outer planets the extra heat and power can be put to good use. Earl Colby Pottinger -- I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos, SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to the time? http://webhome.idirect.com/~earlcp |
#2
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Variable Output RPG
JRS: In article , seen in
news:sci.space.tech, Earl Colby Pottinger posted at Fri, 26 Mar 2004 10:55:27 :- Is it possible to design a RTG so that the daughter products release more heat at a later date than when it is first assembled. I am thinking of missions where the early flybys are in the inner system and heat rejection may be a problem, but once you reach the outer planets the extra heat and power can be put to good use. In theory, it may be. Start the RTG with a supply of Isotope X, which has a twenty-year half- life and decays into Isotope Y without depositing noticeable energy nearby; but Isotope Y, also with a 20-year half-life, decays violently. AFAICS without algebra, that starts out with a zero heating-rate, and subsequently has a larger heating-rate, thereby doing what you want. However, ISTM that the chances of finding a decay chain with that property, and fulfilling all the other conditions, will be rather small. -- © John Stockton, Surrey, UK. Turnpike v4.00 MIME. © URL:http://www.merlyn.demon.co.uk/ TP/BP/Delphi/&c., FAQqy topics & links; URL:http://www.merlyn.demon.co.uk/clpb-faq.txt RAH Prins : c.l.p.b mFAQ; URL:ftp://garbo.uwasa.fi/pc/link/tsfaqp.zip Timo Salmi's Turbo Pascal FAQ. |
#3
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Variable Output RPG
In article ,
Earl Colby Pottinger wrote: Is it possible to design a RTG so that the daughter products release more heat at a later date than when it is first assembled... It's not unthinkable, but it strikes me as a major extra complication in an already rather constrained choice of isotopes. (This wouldn't be primarily a matter of the RTG's design, but of what isotope you use.) thinking of missions where the early flybys are in the inner system and heat rejection may be a problem, but once you reach the outer planets the extra heat and power can be put to good use. It's probably easier to go with an orthodox RTG design and use some variable way of getting rid of the extra heat. (I recall one non-RTG design which faced the same problem -- the electronics box was heavily insulated for operation out in the Kuiper Belt, but this obviously made it prone to overheating early on -- and incorporated a clever no-moving-parts solution: the innards were cooled by a heat pipe running out to a radiator, and around the time the bird passed the orbit of Mars, the heat-pipe fluid froze in the radiator, shutting down the heat pipe.) -- MOST launched 30 June; science observations running | Henry Spencer since Oct; first surprises seen; papers pending. | |
#4
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Variable Output RPG
Earl Colby Pottinger wrote in message ...
Hello, Is it possible to design a RTG so that the daughter products release more heat at a later date than when it is first assembled. I am thinking of missions where the early flybys are in the inner system and heat rejection may be a problem, but once you reach the outer planets the extra heat and power can be put to good use. There are isotopes which decay as you say, but I don't know if any would have the combination of properties which would make for a good RTG... How about engineering a "baby reactor" which weigh less than 100 pounds? Using tricks like insulated and heat pump cooled moderator, which would "cool" part of the neutron flux in order to decrease the fissile fuel mass... The thermally insulated hot core would be the energy source. Charles Pooley |
#5
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Variable Output RPG
Earl Colby Pottinger wrote in message ...
Hello, Is it possible to design a RTG so that the daughter products release more heat at a later date than when it is first assembled. I am thinking of missions where the early flybys are in the inner system and heat rejection may be a problem, but once you reach the outer planets the extra heat and power can be put to good use. Yes! http://groups.google.com/groups?selm...news.dfncis.de Someday I'll finish the full paper ... eventually. |
#6
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Variable Output RPG
Abrigon Gusiq wrote:
Anyway to store the energy you get from the heat in the inner system, but then you release it when you get to the outer system? Photosynthesis or better yet heat instead of light? snip quoted message incorrectly placed at bottom If you could do that, while remaining light enough, then you wouldn't bother with the RTG, and just use the energy storage device. In short, no. Batteries top out somewhere around 500Wh/Kg (not for current ones), which a RTG will beat in under a days output, and there is no storage system that's much better. |
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