[jpollock]

Plutonium is manufactured in a reactor, not processed from ore. The dominant source for plutonium for deep space missions was the US government, and they dominant reason for producing it was bombs.

However, the US govt. doesn't need to produce bombs anymore - they've done enough work to know how to extend the life of the bombs they do have, as well as how to go about reprocessing the plutonium in warheads that are too old into new ones (I think). They are reducing the number of warheads in service, so the US has shut down domestic production.

The Russians seem to have caught up to the US in the warhead lifespan tech and they seem to have shut down their breeders too?

http://en.wikipedia.org/wiki/Plutonium-238