[X] My Assistant

[Del Palmer]

The mission flyby description is now up.

975 km altitude, focusing on the southern hemisphere, lots of RADAR observations including a bit of SAR...

[edstrick]

The radar data frustrates the <expletive deleted> out of me, cause it's clear you really need much better than 100 meter resolution to really see the important geological details in most terrains. A future orbiter should plan to map all of Titan at 100 meter resolution, at worst, with sample capability <and the ability to build up local high-rez maps -- the whole return ultimately bandwidth-to-earth limited> at better than 25 meter resolution.

Of course, the CCD imaging frustrates me more, as we need a framing color camera with the same resolution in the 1.5 to 5 micrometer middle infrared. Impossible when Cassini was being built, possible now. We just can't see Titan's surface well enough, but we can see enough to make agonized progress and with swear-buckets full of qualifications. We're gonna have to make do for now. It's just that simple.

[JRehling]

The radar data frustrates the <expletive deleted> out of me, cause it's clear you really need much better than 100 meter resolution to really see the important geological details in most terrains. A future orbiter should plan to map all of Titan at 100 meter resolution, at worst, with sample capability <and the ability to build up local high-rez maps -- the whole return ultimately bandwidth-to-earth limited> at better than 25 meter resolution.

Maybe tough to do, given that the thick atmosphere and huge scale height forces any orbiter to stay at a fairly high altitude.

Given the funding parameters, I don't think we'll see a Titan orbiter as the next mission there. I think it'll be an aerobot that observes from altitude along a long ground track (thousands of km), then sets down once on the terrain of choice and performs surface studies. Even better would be an aerobot that could make two or more surface stops, flying downwind each time. But that would be pricier.

That would provide very limited coverage, but very high resolution, with the hope that the track would cover representative terrains. Unfortunately, the northern lakes and the equatorial sand seas seem to be difficult to connect in one "trajectory" with the east-west Titanian winds.

If a single terrain had to be chosen for the next touchdown, it would probably be any sediment-rich area near the northern lakes that is not currently below the fluid line.

The cheapest mission plans for Titan run up estimates of approximately $1.6B, so any landed mission arriving also with an orbiter would run close to $3B.

Nothing's going to be cheap where Titan exploration is concerned. Drat it.

[rlorenz]

Given the funding parameters, I don't think we'll see a Titan orbiter as the next mission there. I think it'll be an aerobot that observes from altitude along a long ground track (thousands of km), then sets down once on the terrain of choice and performs surface studies. Even better would be an aerobot that could make two or more surface stops, flying downwind each time. But that would be pricier.

One word to you : bandwidth. An orbiter is the key element in any architecture - since Titan has
so much to explore, there is no single question to be posed to which there is a 1 bit, or 1 Gb answer -
you want to send Tb back, and that is hard without an orbiter as a relay. So you start with an orbiter
(which can, over 4 years, attain global coverage at 100m by SAR and at 2 microns) and add cool bits
from there.

I am pretty warmed-up on these questions - we (the APL/JPL/etc team) had our site visit from the
NASA review panel for the Flagship study - I myself got grilled for 3 hours.....

Flagship study reports should be released in the next month or so - that should explain everything.

[JRehling]

One word to you : bandwidth. An orbiter is the key element in any architecture - since Titan has
so much to explore, there is no single question to be posed to which there is a 1 bit, or 1 Gb answer -
you want to send Tb back, and that is hard without an orbiter as a relay. So you start with an orbiter
(which can, over 4 years, attain global coverage at 100m by SAR and at 2 microns) and add cool bits
from there.

I am pretty warmed-up on these questions - we (the APL/JPL/etc team) had our site visit from the
NASA review panel for the Flagship study - I myself got grilled for 3 hours.....

Flagship study reports should be released in the next month or so - that should explain everything.

I'll be excited to see those reports.

My fear is that a Titan orbiter will be the right plan but struggle with the planning and funding stage the way Europa Orbiter did. Of course, that worry isn't any less with other possible missions, so we have to pick the right mission first and then fight the good fight to get it aloft.

Using a Titan orbiter as a data relay seems to offer some new headaches. If the follow-on mission (aerobot, lander) is designed after data starts coming back from the orbiter, then it'll be one heck of a delay between the arrival of the orbiter and the arrival of the follow-on. The orbiter will have to have a very long lifespan to still be on the job.

On the other hand, if the follow-on is launched relatively soon after the orbiter, it makes it impossible to redesign the follow-on to accomodate new science. That's a minor concern -- a larger one is that we would have to fund two gigadollar missions to the same target in short order, and even Mars barely musters that level of funding (spread out over more missions).

The Titan program is going to have to be a Big Commitment from on high and win a second flagship mission against the field of other priorities in the outer solar system. It could be a battle royale between the tremendous interest inspired by Titan and the administrative inertia that makes such huge efforts difficult to undertake.

[rlorenz]

If the follow-on mission (aerobot, lander) is designed after data starts coming back from the orbiter, then it'll be one heck of a delay between the arrival of the orbiter and the arrival of the follow-on. The orbiter will have to have a very long lifespan to still be on the job.

On the other hand, if the follow-on is launched relatively soon after the orbiter, it makes it impossible to redesign the follow-on to accomodate new science. That's a minor concern -- a larger one is that we would have to fund two gigadollar missions to the same target in short order, and even Mars barely musters that level of funding (spread out over more missions).

All three elements (Orbiter, Lander, Balloon) can fit on a single Atlas V