Nasa Resumes Production Of Plutonium 238 Space Fuel After 25 Years
Our dangerously depleted supply of spacecraft fuel just got a little bump from the Department of Energy.

Looks Like Jell-O, Tastes Like Space Fuel A pellet of plutonium-238, the fuel source used in much of NASA's space exploration. Los Alamos National Laboratory. For the first time in more than two decades, the United States can put a "Made in the USA" stamp on non-weapons grade plutonium, Discovery News reports.

Plutonium-238 is an important fuel source for the radioisotope power systems that are used in spacecraft like the Mars Curiosity Rover and the New Horizon spacecraft that's on its way to Pluto. As plutonium-238 decays, it gives off enough heat to generate electricity and keep all the expensive parts of a spacecraft warm in the cold, dark nether regions of deep space.

For the rest of the story: http://www.popsci.com/science/article/2013-03/first-time-cold-war-us-making-plutonium-238