Lunokhod and the Dead Russian Spy

There's a big brouhaha right now in Great Britain regarding the mysterious death of a former Russian spy, who was discovered to have been poisoned with polonium-210. Interestingly, polonium-210, which is highly radioactive, was used by the Russian space program in the 1970s - primarily to power the Lunokhod rover that went to the moon. According to this article, a half-gram of polonium can generate 140 watts of energy by just decaying.