Thread by @People_Of_Space

If you were to search for extra-terrestrial life in the Solar System and had a budget for let's say a medium-class/New Frontiers mission, where would you go? 🛰️

Not doing a poll; too many possible good answers!

For me, though, 🪐 moon Enceladus is (narrowly) the top choice.

There are other great options, of course!

Venus.
Mars.
Europa.
Titan.

Less likely other subsurface ocean-bearing moons or dwarf planets; we still know so little about them all!

Venus is great from the overall planetary science perspective. It's so frustrating that we still have little clue whether it had once possessed oceans, for how long, and when and how fast it changed into the current greenhouse hell!

Martian geology and chemistry shows many signs of liquid water activity long ago, perhaps around 3 billion years in the past. Transient periods with flowing water may have occurred later, and volcanic activity may still be keeping isolated subsurface regions habitable.

Europa is great! Large enough to have plenty of interior activity; tidally heated 'just right'; interesting chemistry from transport of Io-spewn compounds into the subsurface ocean... It's worth exploring much more, but likely very hard to get relatively pristine ocean samples.

Titan's got extremely interesting chemistry; a thick hazy atmosphere, hydrocarbon seas on the surface and likely water-ammonia ocean beneath the icy shell. Surface life would need to be exotic from our perspective, but many possibilities to investigate have been suggested.

Enceladus has one great advantage, though. The samples are right there, spewn out each time the moon gets farthest from Saturn.

From Cassini, we know the salinity is roughly similar to Earth's oceans; molecular hydrogen suggests low-heat hydrothermal activity; there's organics.