Titan exploration beyond Cassini Options

[titanicrivers]

Beyond Cassini
Two proposed future Titan missions to be presented at the 2017 LPSC conference http://www.hou.usra.edu/meetings/lpsc2017/pdf/1958.pdf and http://www.hou.usra.edu/meetings/lpsc2017/pdf/2306.pdf
promise to extend and enhance Cassini’s discoveries concerning this marvelous world.

[TheAnt]

I really like the Dragonfly proposal, but I am afraid the chance of seeing it happen is very small indeed.
It's similar to the drones most of us are familiar with now.
Now constructing a multipropeller drone that will have to function in that temperature range and environment is both difficult and risky in several ways.
Some metals have brittle 'ductile-to-brittle-transition'. and what substance to use as lubricant in the bearings?
(Copper might be used in wiring and bearings though - if I remember correctly it's a metal that don't have the BDT transition.)
Anyway I think NASA and ESA are a bit to risk aware to seriously consider this one, and for the other agencies, it's outside their capability.

[rlorenz]

I really like the Dragonfly proposal,......

I'm glad you like it, it has been a lot of fun to work on.

I'm not going to get into a to-and-fro on a competitive proposal, but your metallurgy risk comment is not well-founded. Engineering systems operate in Titan-like
conditions all the time in the liquefied natural gas industry (and in launch vehicles with cryogenic propellants like liquid oxygen) The relevant materials are well-understood - Huygens didn't smash into pieces.

As for rotors, they don't need gearboxes so the lubrication is a much simpler problem than for rovers, for example.

Of course, all these and other technical challenges will receive close scrutiny during the review process, which I am not going to prejudice with further discussion in this forum.

Over the years I have formulated an aphorism of planetary vehicle design :
"It is possible to contrive a pathological planetary scenario that will defeat any finite-cost space system".
So reductio ad absurdam, to avoid risk altogether, you stay at home. I hope that is not NASA's posture.

[TheAnt]

I'm glad you like it, it has been a lot of fun to work on.

I'm not going to get into a to-and-fro on a competitive proposal, but your metallurgy risk comment is not well-founded. Engineering systems operate in Titan-like
conditions all the time in the liquefied natural gas industry (and in launch vehicles with cryogenic propellants like liquid oxygen) The relevant materials are well-understood - Huygens didn't smash into pieces.

Thank you for the reply, Rlorenz.
No I never expected Huygens to shatter on impact - hehe. And a good aphorism there also.
But I did wonder if fast moving propellers and their vibrations might be at risk in one way of other, all happy to be told my fears were wrong.

The following posts seem to have addressed the other problem I had in the back of my head - the need to land at a safe place for the RTG to charge up the batteries for next flight.
For whatever it's worth the Dragonfly get my thumbs up - for whatever it's worth. Quite more data and information can be gathered from a moving platform.
So let's hold thumbs that the idea might get a serious consideration. =)