[X] My Assistant

[JRehling]

http://www.lpi.usra.edu/opag/announcements.html

That's one little URL with a lifetime's worth of reading material.

Three detailed studies are available in PDF format. The missing body is Titan, which will be the subject of a forthcoming report.

The three focus missions are:
Europa Explorer: Fairly detailed description of a mission that is pretty much what Europa Orbiter would have been.

Jupiter System Observer: Basically, Galileo 2 (without the antenna mishap!). The craft would start with a 3-year tour of all the Galileans, then spend 1 year in an elliptical Ganymede orbit, then the rest of the mission in a tight, polar Ganymede orbit (like MGS at Mars). That would map the heck out of Ganymede, but also be close enough to the rest of the system to make long-range observations for years. Note that Ganymede would thereby provide a lot of radiation shielding.

Enceladus: where three profiles are examined in depth: Enceladus Orbiter only; Enceladus Orbiter with soft lander; Saturn orbiter with Enceladus soft lander.

There's more to chew on here than I have had (or may ever have) time for, but I'll throw in my two cents' worth:

Seems like a Europa-only mission would only benefit from coming after a JSO. EE would explore Europa much better than JSO would; why even have JSO observations at Europa if EE came first? In many ways, these two missions are competitive. EE would have the big payoff, but JSO seems like basic recon that would prime EE, especially giving specs on radar performance. But if we waited til JSO was 4 years into its mission before completing design of EE, then put EE sometime mid-century.

If an Enceladus mission included a Saturn orbiter, then maybe the same orbiter could provide data relay for separate Titan elements. However, a lot of the Enceladus science goals would require an Enceladus orbiter, so I don't think a Saturn orbiter for Enceladus/Titan will win out.

Note that Enceladus orbital velocity is low enough that the craft could manage to take lots of hits from ice pellets and survive. Put a bulletproof vest on the craft and let it soar through the plumes endlessly.

[nprev]

Looks more & more like we're not going to reach a consensus here, which is interesting. It's very clear now that there are numerous science objectives of great interest in the Jovian system, and one mission probably won't cut it even for the questions we know to ask, much less the ones we don't know yet.

Redirecting a bit if I may, should OPAG then derive an integrated mission campaign for the Jovian system as a whole, similar to that for Mars? Understand that we can't do the same launch rate, but perhaps a NASA/ESA/JAXA collaborative planning effort could cover all the essential bases over a reasonable time-frame. We could do considerably more working in parallel, especially right now when we have both specific Europa objectives and a number of things to find out about the other moons.

[djellison]

. It's very clear now that there are numerous science objectives of great interest in the Jovian system,

Just to totally screw things - I'd rather we went back to Titan than any of the Jovians...but maybe that's just me

Doug

[centsworth_II]

Just to totally screw things - I'd rather we went back to Titan than any of the Jovians...but maybe that's just me
Doug

But that's, as you would say, jumping the queue.

[djellison]

jumping the queue.

Post-Voyager score (if you include Juno)

Jupiter. Two orbiters, One probe, Two flypasts
Saturn. One orbiter, One lander.

If you ask me, Saturn's owed an orbiter and some flypasts - another mission to the Jovian system really WOULD be queue jumping.

Like I said - just throwing in a vote for somewhere else. I'd pick Titan over any of the other suggestions. An ideal world, we'd do all of them, but if I had to pick one, just to me, Titan seems the most exciting, interesting and intriguing.

Doug