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How does plutonium-238 provide electrical power to spacecraft?
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transuranium element
Modern version of the periodic table of the elements (printable).
Plutonium-238 provides electrical power to spacecraft primarily through its use in radioisotope thermoelectric generators (RTGs).12
The process functions as follows:
- Heat Generation: Plutonium-238 is an alpha-emitting isotope with a half-life of 87.7 years. As it undergoes alpha decay, it releases a significant amount of thermal energy—approximately 0.57 watts per gram.123
- Energy Conversion: This heat is harnessed by thermoelectric devices, which convert the thermal energy directly into electricity. Because these generators have no moving parts and are highly reliable, they are ideal for long-duration space missions, such as powering the Curiosity rover or missions to the outer planets.142
- Advantages: Plutonium-238 is specifically chosen for these applications because it emits a negligible amount of gamma rays, which minimizes the need for heavy shielding that would otherwise be required for other radioactive isotopes.12