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How has plutonium-238 provided electrical power for space missions?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — actinoid element Modern version of the periodic table of the elements (printable).

Plutonium-238 has been instrumental in providing electrical power for space missions through the use of radioisotope thermoelectric generators (RTGs).12

Because plutonium-238 is an alpha-emitting isotope with a relatively long half-life of 87.74 years, it serves as a reliable, long-lived heat source. In these generators, the heat produced by the isotope's radioactive decay is converted into electricity. This process is highly advantageous for space exploration because the resulting power units are small, lightweight, and capable of operating in remote, unattended environments where traditional power sources are impractical.1234

These power sources have been utilized in various capacities, including providing heat for batteries on spacecraft like the Curiosity rover, powering missions to the outer planets to enable the transmission of data back to Earth, and even being deployed on the Moon.12