71–80 of 116 posts
put it in a car
1kW isn't driving you anywhere though(even if we ignore all the dangers of having a nuclear reactor in a car). A typical automotive engine produces 100-300kW.
But apparently the 10 kW is modeled to weigh about 1800 kg, so no need to worry about one in a car any time soon.
Earlier quoted context omitted.
The problem with Stirling engines is they have moving parts. It's highly unlikely a Stirling cycle generator on the Voyagers would have operated for 40+ years as their RTGs have.
The 40+ years the Voyager probes have stuck around for is impressive... but the actual primary mission duration was about 12 years (for Voyager 2), and that was with two (planned but not guaranteed) extensions for Uranus and Neptune. The RTGs on both probes have decayed A fair amount at this point and are producing a lot less power. 10 years may seem short, but combined with an electrically powered thruster there is…
There must be some way to directly turn radioactivity (or heat) into thrust with sufficiently high exhaust velocity!?
This is similar to the "Stirling radioisotope generator" [1] but it is an actual nuclear reactor (albeit a small one). Both systems are a response to the same fundamental problem, the dwindling supply of Plutonium-238 [2]. The Stirling radioisotope generator uses Pu-238 more efficiently than thermoelectric RTGs, and the nuclear reactor from the article dispenses with Pu-238 altogether. [1] https://en.wikipedia.org/wi…
The problem with Stirling engines is they have moving parts. It's highly unlikely a Stirling cycle generator on the Voyagers would have operated for 40+ years as their RTGs have.
You get around 15 years of useful work and 15% efficiency with current day technology.
It has no moving parts as RTG, has better power to weight than RTG, and has efficiency comparable to simple Stirling
the cold of space and the heat of a nuclear reactor would be the perfect combination for a peltier reaction. not very good for a rover though.
cold of space? Unfortunately, no - space is an extremely effective insulator, so it's extremely difficult to get rid of heat. You need large heat sinks (which adds weight) and they have piss-poor efficiency in space. So your cold side would get hot very quickly
Earlier quoted context omitted.
"It also solves the 'base load' problem on deep space missions which would like to use more power for radio communications." Not really, since "moving parts" ...
One of the primary uses are deep space probes. The stirling engine has exactly two moving parts and uses non contact seals. In theory the lifetime should be limited by the deformation of the piston at elevated temperatures. Still, you’re right. They certainly have to do a lot of reliability testing to be able to show that these stirling engines will last 10+ years before they use them in a mission. They have several…
Voyager 1 is going for 50 years ...
This is similar to the "Stirling radioisotope generator" [1] but it is an actual nuclear reactor (albeit a small one). Both systems are a response to the same fundamental problem, the dwindling supply of Plutonium-238 [2]. The Stirling radioisotope generator uses Pu-238 more efficiently than thermoelectric RTGs, and the nuclear reactor from the article dispenses with Pu-238 altogether. [1] https://en.wikipedia.org/wi…
The problem with Stirling engines is they have moving parts. It's highly unlikely a Stirling cycle generator on the Voyagers would have operated for 40+ years as their RTGs have.
https://en.wikipedia.org/wiki/Optoelectric_nuclear_battery
Its major, still undressed downsides are the requirement of expensive beta emitters, and synthetic diamond PV cells (everything else will die to beta particles)
Earlier quoted context omitted.
The problem with Stirling engines is they have moving parts. It's highly unlikely a Stirling cycle generator on the Voyagers would have operated for 40+ years as their RTGs have.
Yup, I wonder how they can guarantee the engine will keep turning for 10 years even. Maybe if everything is sealed in a (very long) lived lubricant that stands the harshness of space? Still hard to imagine
As a heuristic, the less mechanical parts in any system, the more efficient it is over time.
Ideally, everything that's built is engineered like a spacecraft, because to some extent it is, and is onboard one.
This is similar to the "Stirling radioisotope generator" [1] but it is an actual nuclear reactor (albeit a small one). Both systems are a response to the same fundamental problem, the dwindling supply of Plutonium-238 [2]. The Stirling radioisotope generator uses Pu-238 more efficiently than thermoelectric RTGs, and the nuclear reactor from the article dispenses with Pu-238 altogether. [1] https://en.wikipedia.org/wi…
For anyone else wondering why Pu-238 is dwindling, from the linked wikipedia: “The United States stopped producing bulk Pu-238 with the closure of the Savannah River Site reactors in 1988.[12][13][14] Since 1993, all of the Pu-238 used in American spacecraft has been purchased from Russia. In total, 16.5 kilograms (36 lb) has been purchased but Russia is no longer producing Pu-238 and their own supply is reportedly r…
In light of the current geopolitical climate, it's probably better that NASA's (et al) plutonium should come from Canada vs. Russia.
Earlier quoted context omitted.
1kW isn't driving you anywhere though(even if we ignore all the dangers of having a nuclear reactor in a car). A typical automotive engine produces 100-300kW.
But it would be perfect for a well isolated home wouldn't it?
This is similar to the "Stirling radioisotope generator" [1] but it is an actual nuclear reactor (albeit a small one). Both systems are a response to the same fundamental problem, the dwindling supply of Plutonium-238 [2]. The Stirling radioisotope generator uses Pu-238 more efficiently than thermoelectric RTGs, and the nuclear reactor from the article dispenses with Pu-238 altogether. [1] https://en.wikipedia.org/wi…
For anyone else wondering why Pu-238 is dwindling, from the linked wikipedia: “The United States stopped producing bulk Pu-238 with the closure of the Savannah River Site reactors in 1988.[12][13][14] Since 1993, all of the Pu-238 used in American spacecraft has been purchased from Russia. In total, 16.5 kilograms (36 lb) has been purchased but Russia is no longer producing Pu-238 and their own supply is reportedly r…
As an aside: There are some people who are very skeptical of both atoms and space exploration. I'm not sure what their motives are but given the amount of steel necessary to produce wind turbines, I'm unconvinced that "renewable" is actually "greener."