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it says: "nuclear battery". it looks small. can someone point me to some more details? Obviously if they decided its fine to shoot this thing into the space (go

it says: "nuclear battery". it looks small. can someone point me to some more details? Obviously if they decided its fine to shoot this thing into the space (go through Earth atmosphere) - it should mean that there was no environmental danger for this thing to go bad?

deleted 14y ago
[deleted]
warfangle 14y ago
It uses a radioisotope thermoelectric generator (RTG). Many spacecraft use them. The Apollo 13 RTG is currently at rest on the ocean floor. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen...
jlgreco 14y ago
Nuclear batteries are unlike what we normally think of as "nuclear reactors". They both use heat, but nuclear batteries do not bring the fuel to criticality (in other words, no chain reaction). This limits their power output obviously, but they are pretty damn reliable in return. The one in Curiosity seems to have 5kg of Plutonium 238. I don't know what kind of containment it has to protect it during launch, but I assume it is fairly substantial. Nuclear batteries are not something NASA is new to, they have used them many times before, including in the Voyager probes. Interestingly, nuclear reactors have been put into space too, by both the US and the Soviets. There have been incidents but nothing that I would really call a disaster. http://en.wikipedia.org/wiki/RORSAT http://en.wikipedia.org/wiki/RORSAT
InclinedPlane 14y ago
It's an RTG, it uses the heat created by decay of radioactive isotopes to drive a thermocouple. These things have been designed to be incredibly safe, capable of surviving an explosion of their launch vehicle and remaining intact, for example. But even should their protective capsule be breached the radioactive material is in a ceramic (oxidized) form in spheres. If you cracked open an RTG and threw the insides into a very hot fire nothing would happen, you could just come by and collect the intact ceramic spheres after they'd cooled.
- tocomment 14y ago
  So ignoring the safety issues, would there be enough radioactive isotopes on Earth for every house to have it's own RTG? Imagine unlimited energy, and heat your home with the waste heat?
  - jlgreco 14y ago
    Plutonium 238 would be your best bet for such devices, if only because it's halflife is 87.7 years. Strontium 90 might also work, with a halflife of 28.8 years. However plutonium would not be easy to put in every house since you have to make it in nuclear reactors. You get about half a kilowatt per kilogram of it, I don't think production of it could scale that high. Strontium is naturally occurring and relatively common. Sr 90 is a trace isotope though. Off the top of my head I would suspect you would be facing similar challenges that separation of Uranium isotopes face.
    - adestefan 14y ago
      Sr-90 is not naturally occurring because of its short half-life. Any Sr-90 found today is either from weapons testing or made in a reactor.
  - InclinedPlane 14y ago
    Probably not. The problem with isotopes needed for things like this is that they tend to have short half-lives (short half-lives = high decay rate = lots of heat generated), which means they pretty much don't exist naturally at all. So they will need to be produced artificially as fission fragments or through neutron irradiation of other isotopes. It's easy enough to produce large quantities of "hot" isotopes in a fission reactor which could be used for RTGs (ignoring safety) but the problem there is that if you're operating a nuclear reactor anyway why not use the heat production from the isotopes to produce energy there instead of going the roundabout, and unsafe, route of packaging things up in RTGs?
    - outworlder 14y ago

deleted 14y ago

[deleted]

warfangle 14y ago

It uses a radioisotope thermoelectric generator (RTG). Many spacecraft use them. The Apollo 13 RTG is currently at rest on the ocean floor. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen...

jlgreco 14y ago

Nuclear batteries are unlike what we normally think of as "nuclear reactors". They both use heat, but nuclear batteries do not bring the fuel to criticality (in other words, no chain reaction). This limits their power output obviously, but they are pretty damn reliable in return. The one in Curiosity seems to have 5kg of Plutonium 238. I don't know what kind of containment it has to protect it during launch, but I assume it is fairly substantial. Nuclear batteries are not something NASA is new to, they have used them many times before, including in the Voyager probes. Interestingly, nuclear reactors have been put into space too, by both the US and the Soviets. There have been incidents but nothing that I would really call a disaster. http://en.wikipedia.org/wiki/RORSAT http://en.wikipedia.org/wiki/RORSAT

InclinedPlane 14y ago

It's an RTG, it uses the heat created by decay of radioactive isotopes to drive a thermocouple. These things have been designed to be incredibly safe, capable of surviving an explosion of their launch vehicle and remaining intact, for example. But even should their protective capsule be breached the radioactive material is in a ceramic (oxidized) form in spheres. If you cracked open an RTG and threw the insides into a very hot fire nothing would happen, you could just come by and collect the intact ceramic spheres after they'd cooled.

tocomment 14y ago
So ignoring the safety issues, would there be enough radioactive isotopes on Earth for every house to have it's own RTG? Imagine unlimited energy, and heat your home with the waste heat?
- jlgreco 14y ago
  Plutonium 238 would be your best bet for such devices, if only because it's halflife is 87.7 years. Strontium 90 might also work, with a halflife of 28.8 years. However plutonium would not be easy to put in every house since you have to make it in nuclear reactors. You get about half a kilowatt per kilogram of it, I don't think production of it could scale that high. Strontium is naturally occurring and relatively common. Sr 90 is a trace isotope though. Off the top of my head I would suspect you would be facing similar challenges that separation of Uranium isotopes face.
  - adestefan 14y ago
    Sr-90 is not naturally occurring because of its short half-life. Any Sr-90 found today is either from weapons testing or made in a reactor.
- InclinedPlane 14y ago
  Probably not. The problem with isotopes needed for things like this is that they tend to have short half-lives (short half-lives = high decay rate = lots of heat generated), which means they pretty much don't exist naturally at all. So they will need to be produced artificially as fission fragments or through neutron irradiation of other isotopes. It's easy enough to produce large quantities of "hot" isotopes in a fission reactor which could be used for RTGs (ignoring safety) but the problem there is that if you're operating a nuclear reactor anyway why not use the heat production from the isotopes to produce energy there instead of going the roundabout, and unsafe, route of packaging things up in RTGs?
  - outworlder 14y ago