If you want to fly to deep space, you need some way to stay warm and get power. For many spacecraft, that means carrying solar panels. But if you want to fly far from the sun, or rove around on a planet’s surface, you need more power than solar panels can provide. And that means nuclear power.
But there’s just one problem: NASA uses the radioactive isotope plutonium-238 to power deep-space missions, and the agency is worried about running out. There is only so much Pu238 available, and the Department of Energy stopped making the isotope in the waning days of the Cold war.
I recently traveled to the Oak Ridge National Laboratory, in Tennessee, to see where nuclear technicians are building a plutonium production line. They aim to manufacture 1.5 kilograms of plutonium oxide, all for NASA, by the year 2021. As I report in my latest feature for Nature, that’s not an easy task.