When NASA's next Mars rover blasts off later this month, the car-sized robot will carry with it nearly eight pounds of a special kind of plutonium fuel that's in short supply.
NASA has relied on that fuel, called plutonium-238, to power robotic missions for five decades.
But with supplies running low, scientists who want the government to make more are finding that it sometimes seems easier to chart a course across the solar system than to navigate the budget process inside Washington, D.C.
Plutonium-238 gives off heat that can be converted to electricity in the cold, dark depths of space. It's not the same plutonium used for bombs. But during the Cold War, the United States did produce this highly toxic stuff in facilities that supported the nuclear weapons program — although those facilities stopped making it in the late 1980s.
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