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The energy density of nuclear batteries is astounding. Per the linked spec sheet, at 2.8W/kg and 17y mission duration, that's about 417,000Wh/kg. By comparison
by dweekly 5y ago
The energy density of nuclear batteries is astounding. Per the linked spec sheet, at 2.8W/kg and 17y mission duration, that's about 417,000Wh/kg. By comparison a lithium ion battery has 250Wh/kg.
- acidburnNSA 5y agoNuclear fission reactors are even crazier. With breeding you get 22,500,000,000 Wh/kg. Good old E=MC^2.
- dheera 5y agoTechnically all batteries are E=mc^2, it's just that nuclear fission converts more of the mass, but still, not all of it. Lithium batteries do get ever so slightly heavier when charged, but it's basically undetectable.
- kuprel 5y agoHow do lithium ion batteries convert mass to energy?
- dheera 5y agoThe principle of E=mc^2 is of mass-energy equivalence. Any form of stored energy has mass, including the binding energy between atoms in a molecule, and lithium ions convert those chemical bonds to electric currents when a load is applied. The mass associated with those chemical bonds is miniscule compared to the protons, electrons, and neutrons, but it is not zero.
- ben_w 5y agoAll (confined?) energy is equivalent to mass, even when that mass isn’t in the form of elections and quarks.
- samplatt 5y agoThere's a really good joke about Ferengi political situations here, but I'm no economist.
- ben_w 5y agoI think quark jokes are a bit cheesy myself. ;)
- 12ian34 5y agoI find them strange and charming
- mynegation 5y agoHey it is not Reddit, but at least these are not off-color jokes.
- varjag 5y agoFission is not anywhere near E=MC^2. That would be matter/antimatter annihilation.
- willis936 5y agoIt is E=MC^2 though. 0.1% of the mass is converted into energy.
- varjag 5y agoNo, it's E=(0.001M)C^2
- willis936 5y agoThat is absurd. It is E=MC^2 where M is 0.1% of the total mass of the reactants. 100% of the mass difference is converted into energy.
- varjag 5y agoThe GP was talking in relation to W/Kg, and the output per Kg is definitely not e=mc^2. It helps reading things in the context.
- StavrosK 5y agoYou are correct, though it would help to clarify that you're correcting the GP on the "per kilo" part, and not the "energy" part. I agree, if you're deploying 1 kg of fissile material, only 0.1% of that will be converted to energy. We should talk about energy per mass of fissile material, not energy per mass of "mass difference".
- whatshisface 5y agoWindup toy cars are also E=mc^2.
- 5y ago
- The_rationalist 5y agoSo with a nuclear fission reactor NASA could make an immortal space probe! It's very sad that this isn't a project.
- dheera 5y agoNuclear fission reactors have a lot of moving parts, and creating something that lasts 50 years without one of those moving parts failing, unmanned, and subject to the harshness of space, isn't trivial. Nuclear batteries are extremely reliable though, as they are fully solid state. A Pu-238 battery can emit useful amounts of power for upwards of a century, and there is virtually nothing to break.
- f00zz 5y agoThe Russians have a few of those: https://en.wikipedia.org/wiki/BES-5 https://en.wikipedia.org/wiki/BES-5
- sundvor 5y agoIt appears to be holding up well at 27 years past the age spec too. It is astonishing how something sent out when I was a toddler is still working till this date; kudos to the engineers.