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Power SystemWhat are possible power sources for satellites? |
A "fuel" for a radioisotope thermoelectric generator is a kind of unstable element. As that unstable element decays, it produces heat, which the RTG can use to make electricity.
The table below summarizes which kinds of fuel are used. Note that when we talk about watts, we're talking about a unit of power, and that we're referring to how many watts of power are generated in terms of heat. There is some loss of wattage when converting from heat to electricity through thermocouples.
| Element | Half-life (years) | Watts/g (thermal) | $/Watt (thermal) |
| Polonium-210 | 0.378 | 141 | 570 |
| Plutonium-238 | 86.8 | 0.55 | 3000 |
| Cesium-144 | 0.781 | 25 | 15 |
| Strontium-90 | 28.0 | 0.93 | 250 |
| Curium-242 | 0.445 | 120 | 495 |
DS1 does not use RTGs.
Are radioisotope thermoelectric generators safe?
