WASHINGTON New demands from the U.S. national security community have cut into the supply of Plutonium 238 available to be used for upcoming space science missions, a Department of Energy official said.
NASA has relied on Plutonium-fueled radioisotope thermal generators (RTGs) for decades to provide certain interplanetary spacecraft with a long lasting source of electricity. NASAs Saturn-bound Cassini spacecraft has multiple RTGs on board and the U.S. space agencys current plans for a mission to Pluto call for at least one of the Plutonium-packed batteries.
Earl Wahlquist, associate director of the Department of Energys Space and Defense Power Systems Office, said July 23 that 7 kilograms of Plutonium 238 slightly more than half of the U.S. inventory is being reassigned for use by an undisclosed national security agency.
The 7-kilogram parcel of Plutonium is due to be removed from a spare RTG the Department of Energy built for NASA as part of the Cassini and Galileo programs.
Wahlquist said the transfer will leave 9 kilograms in inventory for space science missions. But the nations supply of Plutonium 238 is due to increase the months and years ahead.
Speaking at a conference for potential bidders on projects in NASAs planned series of New Frontiers missions to the outer planets, Wahlquist said that the Department of Energy is forecasting the need for as much as 29 kilograms of Plutonium 238 through 2010.
NASAs plans account for at least part of the demand. NASA intends to include some type of Plutonium-fueled RTGs on the Mars Smart Lander slated to launch in 2009. NASAs proposed 2006 mission to Pluto and the Kuiper Belt also calls for an RTG.
As a result of the forecast for increased demand for plutonium, the Department of Energy announced in January 2001 that it planned to resume production of the radioactive material this decade. But re-establishing a production capability at U.S. nuclear laboratories will take five to six years, according to Wahlquist.
In the meantime, the Department of Energy will continue to buy Plutonium 238 from Russia. Wahlquist said the Department of Energy will buy 1 kilogram of the non-weapons grade Plutonium from the Russian government this year. The U.S. plans to buy another 5 kilograms of the material from Russia in 2003 and additional quantities in 2004 and beyond.
Wahlquist also told the U.S. industry, academia, and government officials attending the New Frontiers bidders conference here that the Department of Energy is pursuing the development of new RTGs on NASAs behalf.
The Department of Energy recently contracted with Denver-based Lockheed Martin Space Systems to build a prototype of a new nuclear-powered battery dubbed the Stirling Radioisotope Generator. The new design is expected to be more efficient than todays RTGs.
Later this year the Department of Energy expects to award a contract for developing another new RTG design, dubbed the Multi Mission RTG. The Multi Mission RTG, Wahlquist said, will use about 4 kilograms of
Plutonium 238 to produce about 110 watts of electricity. The RTGs aboard Cassini generate about 300 watts of electricity too much juice for the smaller spacecraft NASA tends to build today.
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