- 9 October 2009
- Reaction score
Via Slashdot: http://news.discovery.com/space/nasa-plutonium-production-space-fuel-130314.htm
After a 25-year hiatus, the Unites States has produced its first non-weapons grade plutonium needed to power space probes when solar energy won’t suffice.
NASA has been using a radioactive material called plutonium-238 to power its deep space probes since the 1970s.
The nuclear-powered spacecraft include the twin Voyager probes, now heading out of the solar system, the Mars Viking landers, the Galileo and Cassini missions at Jupiter and Saturn, respectively, and most recently the Mars Curiosity rover, which is seven months into a planned two-year mission.
The plutonium naturally radiates heat as it decays, which can be converted into electricity with a device known as a radioisotope thermoelectric generator, or RTG.
The U.S. produced its own supply of plutonium-238 until the late 1980s, when the Department of Energy’s reactors at the Savannah River Site in South Carolina, where the plutonium was generated, were shut down for safety and environmental issues. NASA then turned to Russia to purchase plutonium, but that supply line dried up in 2010.
Since then, the Department of Energy (DOE), working in collaboration with NASA, has been trying to restart domestic production of plutonium-238. Early results are promising.
After encapsulating the radioactive starter material neptunium, putting it into a reactor at Oak Ridge National Laboratory in Tennessee and radiating it for a month, the DOE did successfully generate plutonium, said Jim Green, chief of NASA’s planetary science division.
“This is a major step forward,” Green said at recent Mars exploration planning group meeting.
“We’re expecting reports from (the DOE) later this year on a complete schedule that would then put plutonium on track to be generated at about 1.5 kilograms (3.3 pounds) a year, so it’s going quite well,” Green said.
The fresh plutonium has the added benefit of reviving NASA's small and decaying supply of older plutonium still in storage.