Here's something interesting. All previous NASA radioisotope thermoelectric generators (RTGs) were based on plutonium cores and generated electricity by using thermocouples combined to form a thermoelectric generator. But NASA's got two problems with the current generation of RTGs: the Department of Energy is getting stingy about handing out plutonium; and thermocouples are only 5-10% efficient, making the units heavier than they'd like.

Enter the Advanced Stirling Radioisotope Generator. That prior Wikipedia link shows the ground-based prototype, while this news article has pretty pictures and video of the final design. It uses uranium, which is more easily available and also not as dangerous in case of a problem.[1] Intriguingly, it generates the electricity with Stirling engines, which are piston and cylinder technology invented in the early 1800s as an offshoot of steam engines. The great thing about the old RTGs was the total lack of moving parts, making them very durable; the new ASRG has a moving control rod in the center of the uranium, and the Stirling generators have pistons and flywheels and whatnot chugging back and forth, meaning lots of moving parts to get stuck or broken. I guess NASA is confident they will keep working as long as necessary.

Anyway, I just think the whole thing is very cool, and I wanted to let my nerd flag fly.

Video of the whole thing, copied from the news link above:



[1] Environmentalists have been complaining for years about the potential hazards of plutonium being released into the atmosphere by an old-style RTG if it exploded during launch. With uranium, there is already a huge quantity of it in the atmosphere, because uranium is found in trace quantities in coal and thus goes up the smokestack in every factory and power plant that burns coal. Note that I don't expect this to calm down certain environmental groups, specifically those that don't realize that a typical large coal plant releases more atmospheric radiation than did the Three Mile Island power plant during its accident.

Posted by: Boviate at 03:31 PM | Comments (1) | Add Comment
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