cleveland61 writes "Space.com is reporting that an "undisclosed national security agency" is being assigned 7 Kg of NASA's 16 Kg supply of Pu 238. With a half life of 90 years Pu 238 is used mainly used in cases where batteries won't do here on earth. (Pacemakers, deep sea diving suits,etc.) It also provided the fuel for the Cassini Probe. My question is; Who is getting it and what are they using it for? Please tell me its Doc Brown looking for his 1.21 jigawatts!"