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The RTGs on the Voyager spacecraft weigh 38kg. They initially produced 160 Watts. That sounds like a no-go to me.
by alejohausner 2y ago
The RTGs on the Voyager spacecraft weigh 38kg. They initially produced 160 Watts. That sounds like a no-go to me.
- FredPret 2y agoIt might not have great power density but boy does that thing keep going for decades
- jaggederest 2y agoFull power for ~10,000 years, give or take.
- fragmede 2y agoNo. You're thinking of nuclear waste. Voyager's RTG lasted "only" a few decades.
- jaggederest 2y agoDesign choice, not an inherent constraint. Plutonium has a half life in excess of 25000 years
- chickenbig 2y ago> Design choice Presumably this is why Pu-238 is used for RTGs where power density matters; a half life of 87.7 years means a reasonably long working life using with only 1/3% of the mass compared to Pu-239.
- jaggederest 2y agoOh yeah you're probably right, I didn't think about it being a different isotope. I figured they just kept it near-critical to keep it toasty instead of a shorter half life.
- mlindner 2y agoLong half life also means low energy output.
- Gibbon1 2y agoI think you need 1 hp per 10-15 lbs of weight to fly. I think that's around 130 W/kg. I checked a piper cub is something like 100. Other hand Pu-238 produces 570 W/kg. A piper cub with it's 48kw engine would need 87kg of Pu-238 to produce the same energy. I looked up the cost, $1968/g. So 48kw would cost $171 million. Interesting idea but doubt.
- Gibbon1 2y agoForgot the efficiency of an RTG is at most 10%. So you'd need 870kg of Pu-238. Which is twice what a Piper Cub weighs.
- brnt 2y agoI wish Toshiba would have actually sold that RTG laptop battery. Imagine never having to charge!
- hypercube33 2y agoNot just Voyager but the mars robots as well.
- beefman 2y agoDragonfly is NASA's RTG-powered octocopter. It launches for Titan in 2028 https://dragonfly.jhuapl.edu/ https://dragonfly.jhuapl.edu/ https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe) https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe)