Atomic batteries aren't really controversial or politically sensitive and have been used to great effect by many nations involved in space travel.

There's some problem with Tritium expose if the craft exploded on launch but those haven't really stopped it usage.

It's been developed for spacecraft use by Russia, China and the US, that's it. It IS politically sensitive in Europe.

The issue is getting the plutonium.

nasa almost used up the last bits of our reserves of it for the last mars lander.

Thankfully it appears that the united states department of energy is re-visiting generating plutonium-238 for NASA:

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

Yet another reason to build thorium reactors since the "waste product" is PU-238.

4) Rare and are designed to last ages, whereas this thing will burn up far earlier, wasting the rare ingredients.