When the US Department of Energy halted Plutonium 238 production as far back as 1988, things looked grim for the future of space exploration. On Monday, March 18th, NASA's planetary science division head Jim Green announced that production has been restarted, and is currently in the test phases leading up to a restart at full scale.
Steven Aftergood at the Federation of American Scientists presents Fifty Years of Space Nuclear Power "A plutonium fueled RTG that was deployed in 1965 by the CIA not in space but on a mountaintop in the Himalayas (to help monitor Chinese nuclear tests) continues to generate anxiety, not electricity, more than four decades after it was lost in place. See, most recently, "River Deep Mountain High" by Vinod K. Jose, The Caravan magazine, December 1, 2010." (MeFi previously)