[dylan604]

we're attempting to search for life and the thing you want to do is use radioactive heaters? we deliberately crashed a satellite into the planet to avoid having it potentially contaminate the moons we are curious about, and yet you're thinking they'd just irradiate everything like this? it's really just not logical

[sandworm101]

In the outer solar system, under miles of ice, in total darkness and cold .. it is nuclear or nothing. Short of antimatter batteries, there is no other source of power that would be even theoretically suitable.

[ceejayoz]

The concern is more spreading Earth life. NASA's Planetary Protection team (which is a delightful job title) is largely concerned with sterilizing stuff we send out so any discovery of microbes on Mars doesn't turn out to be hitchhikers.

Even a fully fleged nuclear reactor isn't gonna do much damage to Europa and potential life. Swimming in a nuclear reactor's fuel pool is quite safe; water's some of the best shielding we have. https://what-if.xkcd.com/29/