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#PowerOk, 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.
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.
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.
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.