NASA faces plutonium fuel shortage for space exploration

Wired : Voyager 1, which recently passed into interstellar space, has been traveling for 36 years and is expected to remain powered for another 12. Such endurance is possible because the probe is powered by a battery that generates electricity from the radioactive decay of plutonium-238. The Curiosity rover exploring Mars, the Cassini probe taking pictures of Saturn and its moons, and most of the rest of NASA’s planetary exploration craft are powered the same way. Plutonium-238 is used because it’s a safe, slowly decaying material. Other power sources, such as solar, chemical, and fission are less effective, shorter lived, or too heavy. But NASA’s supply, which is controlled by the Department of Energy, is down to around 36 lbs (16.3 kg) and most of that is already allotted to future missions. Plans are being put into place to restart ²³⁸Pu production, but NASA has to rely on DOE to manage the production, which is a multiyear project to obtain enough fuel for a single battery. NASA is working to develop more efficient batteries, but even with significant improvements, DOE’s production will likely not keep up with NASA’s consumption. Wired‘s article looks in-depth at many of the options that NASA is pursuing, and the potential future for planetary and deep-space exploration.