One of the intriguing sessions at the DPS meeting was 4 papers outlining possible "flagship" outer planets missions. Apparently, these were in response to requests from NASA's space sciences directorate, which is looking for a new start on a major outer planets mission in the "near future". So, these four concepts probably are likely alternatives to be selected from.

The four were:

1. Europa Orbiter
2. Titan Orbiter/Lander
3. Jupiter System mission / Ganymede orbit
4. Enceladaus

These were only one paragraph blurbs, so no detail. The Europa Orbiter is clearly the latest version of that long-standing concept. The Titan mission (GSFC/JHU-APL joint proposal) would include an orbiter, lander, and balloon. Not much detail yet on engineering or costs, they conceede. The Jupiter mission would basically be Gallileo-on-steroids (and with a working antenna!), doing another multi-satellite tour, quite a lot of observation of Jupiter itself, finally ending up in Ganymede orbit. THe Enceladaus idea sounded pretty vague even for a one paragraph abstract -- but at least it indicates it's inthe running.

My question is this: if you only get one flagship outer planets mission in the next decade, which shall it be? Europa and Titan seem the top choices. Which would you pick?

Europa was on top of everyone's list five-ten years ago, but has Titan displaced it? On the one hand, Europa still seems more likely to be habitable by life as we know it, and the mission is much better defined already. On the other hand, estimates of the ice shell thickness are converging toward the thicker rather than thinner side, Titan is pretty fascinating(!), and in many ways is a more benign environment given the low radiation, the possibility of ballooning, etc.

Your call: where does the next major mission go?