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: 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. You just want thermal decay.” Perseverance is only the second Mars rover to use nuclear power as its main source of electrical energy. The agency’s first three rovers—Sojourner, Spirit, and Opportunity—all used solar power, but this meant they ran the risk of losing power completely when enough dust accumulated on the panels. Starting with Curiosity, which arrived on the Red Planet in 2012, NASA engineers switched to nuclear power as the rover’s main source of energy. It was a bold choice considering that, at the time, the US stockpile of nuclear fuel for space missions was dwindling and there wasn’t a single facility in the US capable of making more.