Title: NASA’s Mars Rover Will Be Powered by US-Made Plutonium | WIRED
Headings: NASA’s Mars Rover Will Be Powered by US-Made Plutonium
NASA’s Mars Rover Will Be Powered by US-Made Plutonium
In 2015, Oak Ridge National Laboratory produced the first plutonium fuel in the US in nearly 30 years. Now it’s headed to another planet.
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Content: NASA/JPL-Caltech
On Thursday, NASA is expected to launch its new Mars rover, Perseverance, on a mission to search for signs of ancient life on the Red Planet. It’s the agency’s largest and most autonomous Martian explorer yet. It’s also the first to be powered entirely with American plutonium. At the heart of Perseverance is a small “ nuclear battery ” the size of a beer keg called a radioisotope thermoelectric generator, or RTG. Unlike the nuclear reactors that create electricity on Earth, RTGs don’t have to initiate or sustain a fission reaction to generate power. They don’t even have any moving parts. Instead, they passively harvest the natural heat produced by the decay of plutonium-238 and convert it into electricity. They can reliably provide energy and heat to a spacecraft for decades—the two plutonium-powered Voyager probes launched in the late 1970s are still transmitting from interstellar space —and have been NASA’s go-to power source for more than two dozen deep-space missions. “Plutonium-238 is a unique isotope of plutonium that principally decays by alpha radiation, and because of that, it generates a lot of heat,” says Robert Wham, the plutonium supply program manager at Oak Ridge National Laboratory, which is now responsible for making the stuff for NASA. “ For a small spacecraft like Perseverance, you don’t want fission power.