US To Run Out Of Power Source For Deep-Space Missions In 10 Years


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Andrew Follett Energy and Science Reporter
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America will run out of the essential nuclear power source for deep-space exploration, called plutonium-238, in 10 years, according to a profile.

Plutonium-238 (Pu-238) is a radioactive byproduct of producing nuclear weapons, and is an irreplaceable source of power for deep-space missions. After the end of the Cold War, America stopped making new Pu-238 and only has enough left to fulfill NASA’s mission schedule until 2026.

Pu-238 is an incredibly stable power source that can act like a battery for spacecraft, as it has a radioactive half-life of almost 90 years. Every NASA probe, from Voyager to the latest Curiosity Mars Rover, has used Pu-238 and future planned missions would require more Pu-328. Right now, there is only 77 pounds of Pu-238 left in America, and only half of that is in usable condition. That’s only enough for three or four missions — based on the Curiosity rover’s use of roughly 10 pounds of the power source.

“Current radioisotope thermonuclear generators use Pu-238,” Texas Republican Rep. Lamar Smith, chairman of the House Committee on Science, Space, and Technology, told The Daily Caller News Foundation. “While NASA and DOE are making progress reconstituting the nation’s ability to produce Pu-238, it remains to be seen whether this progress will be sufficient to supply future mission needs in a cost effective manner. The committee will continue to track the progress of Pu-238 production, as well as the development of alternative power sources for outer planet exploration.”

This simply isn’t a good substitute for Pu-238 either. Solar simply cannot provided enough energy to power a spacecraft as it gets further away from the sun. Chemical batteries don’t last long enough to be useful, while nuclear fission power systems are too heavy and alternative radioactive isotopes have other issues.

“Radioisotope power systems are critical to the exploration of outer space,” Smith continued. “From the surface of Mars to Pluto and beyond, they provide power where chemical or solar power systems are not practicable. NASA must maintain its ability to explore – either using radioisotope power systems, or some other way.”

Restarting Pu-238 production is likely to be incredibly difficult and expensive. The general cost estimates are around $125 million over the next ten years. A team at Oak Ridge National Lab took three years to make about 0.44 pounds, less than 5 percent of what would be needed for a single mission. Currently, the U.S. is buying Pu-238 from Russia, but even that source may run out because the country stopped producing it in 1993.

The Russians sold 36 pounds of Pu-238 to the U.S. in 1993 for more than $45,000 per ounce, but reneged on a deal to sell 22 pounds to the U.S. in 2009.The U.S. government approved spending about $10 million a year in 2013 to produce more Pu-238, but little has come of this.

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