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August 04, 2005
Between Google and eBay, you can get anything.
I was wondering about the Cassini spacecraft, launched in 1997, with much ado about it's three nuclear RTG power sources (radio isotope generators, containing between them 72 pounds of 238-Pu).
It's currently fairly close to Saturn's moon Titan, with the next flyby on the 22nd, as best as I can work it out, at around 4:52am.
What has this got to do with eBay and Google? Not much, until, curious about how long 72 pounds of fuel would last, I googled plutonium.
It was an advertisement too strange not to click. The closest thing they had was a detector that would show how many grams of fissile material you had on your hands and some Revlon lip gloss of the same name. Strange marketing idea, really. How many people want to smear something called plutonium on their lips? Or maybe that works for some people.
[The continued entry is just plain geeky and about atomic decay rates and approximate operational time of Cassini]
With a half life of about 85 years, the power produced from a lump of 238-Pu decays at 1-(.5)^(1/85), or about .81% per year. But it's not when it all decays, it's what power threshhold Cassini will stop working on. Eight years after lauch, the RTGs that originally provided 850 watts would now be kicking out closer to 796.5 watts [arrived at via 850-(.9919^8)]
Cassini specs mandate 600-700 watts as minimuim, this threshold should be crossed around the 43rd year of operation, so there should be another 35 years left in it.
Scrawled illegibly by Meathe at August 4, 2005 10:39 AM
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