And are you ready for this - it would be called the JIMO! :-)

The key thing here is "$8 billion".

Compare with the RTG powered missions at
http://centauri.larc.nasa.gov/newfrontiers/ for $700 million a pop.

Other links on JIMO:

http://www.sfgate.com/cgi-bin/articl...NGON3J5RN1.DTL
http://www.jpl.nasa.gov/jimo/