I appreciate that science cannot operate in isolation of the rest of the world, what with all the economic and political realities and such.  However, learning that politics was the reason to use an inferior power source for Philae makes me sad.<p>Can anyone shed more light on what type of political problems would using RTG create?  Something about weapons grade plutonium, perhaps?  Or this being an European project, and we cannot possibly source the materials from the US?  Or (and I hope this is not it) green “solar good, nuclear bad” dogma?