The Russian government also has dwindling supplies after halting production of Pu-278, so they are pursuing a more lucrative contract with NASA - the cause of the dispute.
If Congress denies domestic production and the Russian deadlock continues, there appears to be only one answer to the plutonium deficit: ESA.
"To see see ourselves as a serious planetary science partner on the world stage with the United States, we're building up our nuclear capability for European-built RTGs," David Southwood, ESA's director of science and robotic exploration, said in an interview with Spaceflight Now. "We are building for a pretty major capability being available in Europe in the 2020s."
Southwood also hinted that Pu-238 isn't necessarily the only fuel that can be used with RTGs. Americium-241 has the advantage of a longer half-life, meaning these pellets will fuel RTGs for longer, but at a reduced energy output. Another big drawback with swapping americium for plutonium is that americium is more hazardous.
"Plutonium-238 is an alpha emitter, and you can shield alpha particles with a piece of paper," Adams said. "It's neutrons that damage people, and americium is more a neutron emitter than plutonium-238."
Regardless of the fuel Europe decides to produce, the commencement of a nuclear energy program for space missions will have to wait for approval from ESA Council meetings in 2011 or 2014.
Whatever the outcome, it is good to see strengthening collaboration between ESA and NASA.
"Our target is to have an independent capability, which may help our American friends," Southwood added.
Images from top: A pellet of Pu-238 (DoE), NASA New Horizons Pluto mission with RTG attached (NASA).
Source: Spaceflight Now