[Frontiers] Icy ocean worlds represent some of the most compelling targets in the search for extraterrestrial life, yet their exploration is constrained by significant logistical challenges including long transit times, limited solar power availability, and demanding radiation environments.

Nuclear power and propulsion systems can offer a transformative capability by providing high specific impulse, continuous high-power availability, and mission flexibility.

Here, we review the fundamentals of key nuclear technologies, their histories, and evaluate three mission concepts: (1) a 44 kWe nuclear electric propulsion-enabled combined Enceladus sample-return and Saturnian moon tour mission, (2) a 43 kWth nuclear-powered Europa Tunnelbot enabling ocean access, and (3) Nuclear thermal propulsion-enabled orbiters to the Uranus and Neptune systems with significantly reduced cruise times or increased payload.

These concepts demonstrate that nuclear systems can increase payload mass, enable complex multi-moon tours, provide continuous high-power in situ operations, and make distant ice-giant missions feasible within realistic programmatic timelines.