Happily, Pu-238 is being manufactured again: http://news.discovery.com/space/nasa-plutonium-production-space-fuel-130314.htm http://news.discovery.com/space/nas

Happily, Pu-238 is being manufactured again: http://news.discovery.com/space/nasa-plutonium-production-space-fuel-130314.htm http://news.discovery.com/space/nasa-plutonium-production-sp... Another source I read at the time of the announcement said it will take a while to spin up, so there are some mission constraints over the next ten years. A Europa mission would wipe out existing supplies.