“Without a restart of plutonium-238 production, it will be impossible for the United States, or any other country, to conduct certain important types of planetary missions after this decade,” – US National Research Council report in 2011.
Stores of plutonium have been slowly running out since the late 80s. Promising scientific research over the past year could lead to starting up plutonium production again. This means explorations of intergalactic space can continue in the future!
Read more here: http://bit.ly/144QjUZ
-Image of Plutonium is By the U.S. Department of Energy [Public domain] via Wikimedia Commons