NASA relies on pu-238 to power long-lasting spacecraft batteries that transform heat into electricity. With foreign and domestic supplies dwindling, NASA officials are worried the shortage will prevent the agency from sending spacecraft to the outer planets and other destinations where sunlight is scarce. Thorium reactors produce PU-238 as a “free” byproduct. In 2009 Congress denied a request to produce more Pu-238 by traditional means, instead relying on Russia to sell us the plutonium. (Remember the Russian reset?) Russia made their last delivery in 2010. PU-238 production has since been restarted by converting Ne-237 to Pu-238 at a cost of over 8 million dollars per kilogram. The Ceres-Dawn spacecraft used over 22 Kg of Pu-238 as electricity generator.
To get the best efficiency of generating Pu-238 out of a molten salt Liquid Fluoride Thorium Reactor, the excess U-233 and TRansUranium products have to be extracted continuously while the reactor is running, and this technology is not yet implemented, but is necessary to implement before we can also have Thorium power on the moon, and Thorium Power is the only viable solution if we are ever going to have a moon colony, so we should get to it.