Yep, and before that there was JIMO, the Jupiter Icy Moons Orbiter, which was to be powered by a nuclear fission reactor (not an RTG). It lost funding in 2005.

Yep, and before that there was JIMO, the Jupiter Icy Moons Orbiter, which was to be powered by a nuclear fission reactor (not an RTG). It lost funding in 2005. ESA continues work on JUICE, the Jupiter Icy Moon Explorer. No doubt there are more I'm forgetting. JIMO: https://en.wikipedia.org/wiki/Jupiter_Icy_Moons_Orbiter https://en.wikipedia.org/wiki/Jupiter_Icy_Moons_Orbiter JUICE: https://en.wikipedia.org/wiki/Jupiter_Icy_Moon_Explorer https://en.wikipedia.org/wiki/Jupiter_Icy_Moon_Explorer