Posted by tourdemars to Technology at March 15, 2013 11:19 PMAfter a quarter-century hiatus, the United States has begun producing plutonium-238 once more. The decision was made to ensure that future NASA projects would have access to the valuable fuel. As US stocks dwindled, NASA began buying plutonium-238 from Russia, but that agreement came to an end in 2010. When most people think of plutonium, they think of nuclear weapons — but that’s not what plutonium-238 is used for. If you need a power source that can last for decades, plutonium-238 is fantastically useful stuff. It’s got a half life of nearly 88 years and it emits 560 watts of heat per kilogram of material. It’s a vital component of the radioisotope thermoelectric generators (RTGs) used on Curiosity and in a number of space probes, including Cassini. One of the best features of plutonium-238 is that, while it’s radioactive as hell (275 times more so than plutonium-239, it takes a minimal amount of shielding to protect spacecraft or humans from contamination. Plutonium-powered pacemakers (yes, that was a thing for a little while) have operated as long as 25 years without running out of power.
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