JIMO
Jupiter Icy Moon Orbiter will be the flagship of the promethus project. This sounds like an extremely cool mission and could even answer the question of life on Europa. The power from the fission reactor onboard will allow JIMO to actually go into orbit around Callisto, Ganymede and Europa, instead of the flybys Galileo did. Also the additional power allows for much more powerful instruments to examine in detail those moons and the rest of the jovian system.
Make it so.