Comment 2VR1 Re: Nuclear power battery

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New Horizons spacecraft prepares to study Pluto after 9-year voyage

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Nuclear power battery (Score: 1)

by tanuki64@pipedot.org on 2014-12-07 15:36 (#2VPF)

I am happy to read that New Horizons has a nuclear power battery: http://en.wikipedia.org/wiki/New_Horizons#Power
Ok, hard to go without one in that kind of mission, but when I read this:
Less than the original design goal was produced, due to delays at the United States Department of Energy, including security activities, which held up production.
I am sure the uneducated mobocracy tried its best to throw a monkey wrench into the works.

Re: Nuclear power battery (Score: 1)

by evilviper@pipedot.org on 2014-12-08 20:05 (#2VQW)

I am sure the uneducated mobocracy tried its best to throw a monkey wrench into the works.
The WP article says there were only about 30 protesters, far less than previous missions. The DoE just isn't churning out Pu-238 in mass quantities like it used-to, and it's much more expensive as a result, too.

My question is, why isn't NASA getting more efficient (so that it only needs a fraction as much Pu) since the "T" in RTG is only 5-8% efficient?

They've been extensively developing SRGs to replace RTGs for quite a few decades, requiring only 1/4 as much Pu for the power, yet haven't ever put a single one in space.

Re: Nuclear power battery (Score: 1)

by tanuki64@pipedot.org on 2014-12-08 20:49 (#2VQY)

I am certainly not an expert, but from a gut feeling I would say RTGs are more robust than SRGs. A moving piston? Over years? Yes, maybe for manned missions, where repairs or exchanges are possible. But for something like New Horizons? I would think something without moving parts would be superior.

Re: Nuclear power battery (Score: 1)

by evilviper@pipedot.org on 2014-12-08 21:17 (#2VR1)

I would think something without moving parts would be superior.
Try hitting a computer chip with a hammer. Then try the same thing with your car's engine. Still think solid-state is always superior?

Both SRGs and RTGs are designed (and tested) with the same lifetimes in-mind. The SRGs even lose less capacity over time (thermo-electric materials decay). And NASA has done the testing to prove that SRGs can operate continuously for the necessary lifetimes.

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