Source: | Dave Mosher | January 13 ,2019

  • (ORNL)

    NASA relies on plutonium-238 (Pu-238), a human-made radioactive element, to power its longest-operating and farthest-flying spacecraft.

  • Nearly all Pu-238 was made during the Cold War, and supplies are running low. The shortage threatens to limit deep-space exploration.
  • The Department of Energy is now making new Pu-238 and recently achieved an eight-fold increase in production with a new robot.
  • Oak Ridge National Laboratory says its robot is “the next key step” in making enough plutonium to perpetually meet the needs of NASA.

The US government says a new robot is poised to help it create a reliable, long-term supply chain of plutonium-238 (Pu-238): a radioactive material NASA requires to explore deep space.

NASA uses Pu-238 to power its most epic space missions — among them New Horizons (now beyond Pluto), the Voyagers (now in interstellar space), and Cassini (now part of Saturn).

As Pu-238 radioactively decays and generates heat, devices called radioisotope power sources convert some of that energy into electricity. Because Pu-238 takes centuries to cool down, the contraptions can keep a robot humming for decades.

But Pu-238 is human-made and one of the rarest and most valuable materials on Earth. In fact, the last time anyone manufactured it in earnest was during Cold War-era nuclear weapons production. Today, NASA has perhaps three missions’ worth of the stuff left before the supply runs out.

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