http://www.zmescience.com/space/nasa-plu...is-034243/
EXCERPT: According to the Department of Energy, the plutonium-238 stockpile is enough to make only three more nuclear batteries. These are used to power long-term space missions, like Curiosity rover now studying Mars on site, the Voyager probes which were launched in the 1970s and are now almost out of the solar system or New Horizon which is close to making the first Pluto flyby in history. [...] All these remarkable achievements were made possible thanks to plutonium-238 and the technology developed to harness its heat. [...] The only fix is to make more plutonium-238, of course, but this might take a while....
EXCERPT: According to the Department of Energy, the plutonium-238 stockpile is enough to make only three more nuclear batteries. These are used to power long-term space missions, like Curiosity rover now studying Mars on site, the Voyager probes which were launched in the 1970s and are now almost out of the solar system or New Horizon which is close to making the first Pluto flyby in history. [...] All these remarkable achievements were made possible thanks to plutonium-238 and the technology developed to harness its heat. [...] The only fix is to make more plutonium-238, of course, but this might take a while....