Alternative Energy
News Archives | Strange Ideas
Return to News Index | Strange Index
Vehicles | Flywheels | Fossil Fuels | Free Energy | Fusion | MagLev
New Sources | Radiothermal | Scams | Shortages/Outages | Superconductors
Hydrogen Economy | Thermoelectric | ZPE
5/25/2005 Alt Energy. The Amazing Voyager Power Supplies.
"... Still operating in remote, cold and dark conditions 27 years later, the Voyagers owe their longevity to these Department of Energy-provided generators, which produce electricity from the heat generated by the natural decay of plutonium dioxide."
Read more about the Voyager power sources here. Plutonium isotope 238 in the from of plutonium oxide is the best choice for radioisotope thermoelectric generators due to a half-life of 87.7 years, a reasonable energy density and exceptionally low gamma and neutron radiation levels. It needs less then 1/10 of a inch of lead shielding. Due to decay, I think the Voyager power outputs started at about 470 Watts and dropped from there. So, 23 years after production the output dropped to 390 Watts, and by 2001, just above 300 W. We know that the power output of P238 is 0.567 watts per gram, so Voyagers may have had about 267 grams ( a little over 1/2 lb.) each. Interesting. Too bad the stuff is so toxic to life. Plutonium is a neat power source because 1/2 lb can run a laser printer, a reading light, and a laptop computer continuously for over 20 years. More here. Why not just bury tons of this stuff deep underground and tap the energy?
Diagram of a radiothermal generator used on the Cassini probe. From NASA (JPL) http://saturn.jpl.nasa.gov/spacecraft/safety.cfm
"Unfortunately, Pu-238 is difficult to manufacture, making it extremely expensive. An accurate price is difficult to determine because of the lack of an open market, but the recent estimates by experts in the field indicate that the material costs several thousand dollars per gram in kilogram sized lots - if it is available at all. Since RTG conversion efficiency is on the order of six to eight percent, this puts the price of a 50 W power supply at close to a million dollars."
Ah, that's why.
Return to News Index | Strange Index
CLICK THESE BANNERS TO SEE THE TOP SPORKING UVULAS
