For anyone like me with no Nature subscrition - I just rechecked the OPAG link in post 1 of this thread and was pleased to find some news about the Titan proposal, including a handy factsheet.

"...But it will be hard to justify going to the same place as Huygens."


Excuse me? Did someone not get the memo about Titan having diverse environments on it's surface?

Straight clip from the T38 Mission Description (here):

"...wind, rain, volcanism, tectonic activity, as well as river channels, and drainage patterns all seem to contribute in shaping Titan’s surface. ...
impact craters...lobate flows... volcanic structures....Dunes ...large bodies of liquid."...etc.

Not even CLOSE to boring.

The problem is that when it reaches the high levels of bureaucracy, those things go out the door. Bean counters will see it and wonder why we are going to Titan since we have just had Cassini/Huygens explore it.

The Titan Explorer with Orbiter (based on the limited explanations given in the OPAG Titan Explorer Fact Sheet and Nature Comparison Table) really seems to be a capable explorer that would bring our understanding of Titan to the next level. The Orbiter+Lander+Balloon combination would give a very detailed study of one of the most dynamic solid ground bodies in the solar system. To put in perspective how much Titan science could be accomplished, "the 4-year orbital mission returns orders of magnitude more data about Titan than Cassini – this mission will spend more time at Titan in its first 3 days in orbit than the nominal and extended Cassini missions" [as quoted from the OPAG sheet].

Then again, the Titan Explorer has a price tag to match it complexity. At $4 billion, it costs nearly 25% more than JSO and nearly 20% more than EE. These are real differences that could hamper its funding. Some of this could presumably deferred to ESA, but TANDEM is a broader proposal that includes Enceladus science that doesn't exactly mesh with Titan Explorer with Orbiter.

The report also states that a $2 billion "orbiter only" mission could also be proposed, but this would return much less "surface truth" constraints. Is it also possible to send only the Orbiter+Balloon or Orbiter+Lander for an intermediate price tag? The Orbiter+Balloon would still cover a lot of ground and give great camera-radar comparisons over larger areas of the moon.

I'm looking forward to the full OPAG report.


On a related note, how long could we expect to keep the balloon floating around Titan? I suspect that the dense air and cold temperatures should keep it there for a long time, but I have never seen official estimates.

I'm willing to put on my prophet hat, and predict that NASA will try Europa, while ESA returns to Titan with a long visit to Enceladus.
With both agencies contributing partly to the other's mission.
Just a hunch.

I'm not sure that ESA has the budget to fly solo to the outer planets. Last I heard, they were considering EUR 650 million for spacecraft (not including launch) funding. I don't think that TANDEM or Laplace will get off the ground without international cooperation.

This is what I like about the Titan Explorer proposal - it splits into international components beautifully. NASA can't afford all of it? Fine - ESA does the lander, JAXA does the balloon - let's go. It's not quite that simple - but it's a princple that worked with C-H, and it saved C-H from cancellation (if you read 'The Titans of Saturn') because of a mutual responsibility once you split a mission like that.

Doug

I agree that Titan is probably the most interesting moon out there. Sometimes I wish that a scaled down Jupiter orbiter could be sent as a "mini-flagship" - $1-1.5 billion, perhaps sooner than the JSO concept, and then a Titan (or advanced Europa) mission could follow sooner than if it had been a full flagship.

One could even imagine a New Frontiers scale Jupiter orbiter - maybe go for huge solar arrays instead of RTG. It should fit I'd have thought.


Oops.

Just a wild thought and well OT I know.
Could there be a way of harvesting power from Jupiter's huge magnetic field and radiation belts, thus turning a nuisance into a resource? It sometimes seems that all the Jupiter proposals are working against the grain of the Jovian environment.

Edit: Chemist, I hope you're right.

An idea like that was explored a few years ago...I can't remember where I saw it. However, the complexity of the system proved prohibitive.

"One could even imagine a New Frontiers scale Jupiter orbiter - maybe go for huge solar arrays instead of RTG."

The JSO report stated that another orbital tour without orbiting a moon wouldn't be worth it. I have my doubts about this statement. That's like saying there's no point to MRO since Viking orbited Mars. Galileo and Viking orbiter's instruments are from the same era. And Galileo had the communications bandwidth of Mariner 4, as I recall.

However, consider that the very simple Juno orbiter is ~$900M. It has a short life and avoids the radiation fields. I suspect that a 3-axis orbiter with a high communications rate and capable of living through a Galileo-level radiation load would probably be $1.5-2.0B Given that the descoped JSO orbiter is $2.3B, saving the extra few hundred million may not be a good tradeoff. It's probably as hard to sell a $1.5B mission as a $2.3B mission.

"I'm not sure that ESA has the budget to fly solo to the outer planets. Last I heard, they were considering EUR 650 million for spacecraft (not including launch) funding. I don't think that TANDEM or Laplace will get off the ground without international cooperation."

With Juno at ~$900M, I don't see how a mission to Titan could fit into the budget. There has been talk that a flyby Saturn probe mission would fit within that kind of a budget, so if ESA were willing to drop simple, short-lived landers on Titan and have the carrier simply flyby, that might fit in.

I was being sarcastic. Such a mission is already in work - Juno.

Doug

Yes, intermediate options are O+L+L, O+B+B, O+B, O+L.......


No official estimate in the sense that no-one can think of a reason it wouldnt be practically forever - hot air
balloons do not suffer from leaks by small tears (and at Titan no UV damage, packing/inflation fatigue as on terrestrial
hot air balloons)
Flagship study said 1 year, just to put a bound on operations cost.

I finally had the time on a plane flight to read over the EE and JSO reports in detail. The attached chart gives cost comparisons, launch cost comparisons, and instrument complement comparisons. One of the key differences between the full up proposals and the descope missions is reducing weight to enable the use of a cheaper launch vehicle.

One note on the instrument descope for EE: cutting the narrow angle camera as part of the descope would be one of the last cuts implemented to save money (second from the bottom of the list).

I am beginning to favor implementing the EE descope mission with the narrow angle camera restored to the instrument list. For the ~$900M cost difference, NASA could fly an additional New Frontiers mission. I think that the return from being able to fly an additional New Frontiers mission might be more valuable than the additional science returned from the full EE or JSO mission.

An the Titan side of the equation, there is a cost estimate in the feasibility study of $1 billion Titan and Enceladus missions ( http://www.lpi.usra.edu/opag/TitanEnceladu...onDollarBox.pdf ) for a mission that would just drop off a lander or balloon, by itself, at Titan: $1.4 billion. And that's with the main craft being a cruise stage -- a carrier spacecraft that would do any significant science studies of its own would add about $600 million. There is simply no way to do any such mission within the New Frontiers cost band, or anything close to it. But, of course, there is still both enormous flexibility in what kind and scale of Titan mission to do, and great capability for NASA/ESA collaboration in it -- once we decide how much we actually want to spend. ESA's contribution plus the savings from implementing a descope mission at Jupiter would pay for such a mission.

However, I am finding myself more drawn to a full up Titan mission. It is simply too exciting of a world.