It's nuclear. You can read about it here: http://en.wikipedia.org/wiki/Curiosity_(rover)#Specifications http://en.wikipedia.org/wiki/Curiosity_(rover)#Specifica

It's nuclear. You can read about it here: http://en.wikipedia.org/wiki/Curiosity_(rover)#Specifications http://en.wikipedia.org/wiki/Curiosity_(rover)#Specification... SAM (Sample Analysis at Mars) then uses this energy to heat the soil and analyze it. I recommend everyone to read about the SAM, it's a fascinating instrument. Arguably the most complicated instrument we've (humans) ever built. (If you're curious about the SAM, read this article: http://www.planetary.org/blogs/emily-lakdawalla/2012/curiosity-instrument-sam.html http://www.planetary.org/blogs/emily-lakdawalla/2012/curiosi...)