NASA to start receiving plutonium for future space missions

Plutonium-238 emits a steady heat through natural radioactive decay.

Alex Bourque | Jan 25, 2016

Lost in all the shuffle of talk about a challenging manned mission to Mars is asking how to power the spacecraft for such a deep-space mission -- and NASA has produced an isotope of plutonium that is capable of doing that for the first time in 30 years.

The Department of Energy's Oak Ridge National Laboratory in Tennessee has produced a total of 50 grams of plutonium-238 for the first time since the 1980s, and it could be a step toward placing this energy source on the Mars 2020 rover and the Jupiter Europa Orbiter, according to a Space.com report.

Scientists are back to developing this isotop because only enough plutonium exists to power missions through 2030. Now, the DOE is planning on supply NASA with up to 400 grams of the stuff every year, eventually going up to 1.5 kilograms per year.

While most satellites and missions can rely on solar power or chemical batteries to stick around for years, but the sun becomes too faint to rely on once a spacecraft gets too far from Earth. That's where plutonium-238 comes in, which emits a steady heat through natural radioactive decay.

Only 35 kilograms of this isotope has so far been set aside for NASA missions, which would only be enough for two or three mission through the mid-2020s.

It's being used successfully today. The Mars Curiosity rover uses plutonium to stay on during the night, and Cassini relies on it to make maneuvers while orbiting Saturn.

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