I assume this is all 500 years-from-now-Titan-colony type speculation. Any first visit or indeed, first 'round' of visits - I wouldn't rely on ANYTHING other than that which I could take with me.

Doug

Why? Robots would already have constructed the habitation, the windfarm and the geothermal station - and the kettle would be on for tea.

'Tracking in' materials from outside might be complicated by some of the materials possibly formed outdoors not being particularly volatile below 0 C. Kerogen (or precursors) have been tenatively ID'd on asteroids, and might occur on Titan too. Polymerized Titanian 'gunk' might have to be carefully scrutinized by Huygen successors to assess the dangers. Additionally, our earthian environment is characterized by a polar solvent, water, and we are most skilled and experienced with that. Titan seems to have a 'hydrological' cycle driven by a non-polar fluid, and probe design will be challenging in regards to material properties and chemical effects.

Material properties and challenges of exploring a hydrocarbon environment have been done on Earth. There is a huge amount of experience designing probes for gas pipelines and hazardous chemical reactors that could be used. I don't think there are any chemical conditions that could exist on Titan that haven't already been dealt with somewhere in a chemical manufacturing process, save for the extreme cold.

Check out "pigging" of pipelines: http://en.wikipedia.org/wiki/Pigging
[EDIT: Could this be Doug's Next Big Robotic Project? ]

The basic amines that might be present would be a slight chemical challenge to some plastics and polymers due to their corrosive nature (gum rubber would be a bad idea). But Titan is in an overall reducing environment, so the rust and oxidation of metal components won't be a problem.

-Mike

What still concerns me about any operations on Titan (manned or unmanned) is the rather phenomenal temperature difference at which terrestrial machines and organisms (i.e., us) can operate versus Titan's natural environment.

Any terrestrial outpost or machinery is going to add *significant* amounts of heat to the Titanian environment. If ever there was a situation where observing a phenomenon affects that phenomenon, this is it.

We may have to figure out how to develop robots that can operate entirely at Titanian temperatures before we set out to study the place at close range, because the heat our current technology would be pumping into the local materials will change them in innumerable ways, and we won't see them as they've developed in situ.

-the other Doug

Exactly. But in fact Titan conditions could be quite benign for machines. Certainly there's no problem with electronics working at those temperatures (superconducting materials available), and a nitrogen atmosphere should be an advantage over a vacuum as far as moving parts are concerned. I haven't yet heard mention of anything mooted in Titan's surface chemistry that would attack metals. There could be a problem finding an insulating material that is flexible rather than brittle at those temperatures for cable sheathing, etc., but those chemists are very resourceful. (Give Juramike 20 minutes. )

The serious point behind my last post is that I don't ever envisage a manned visit in gung-ho Apollo style with people climbing down a ladder to the surface and bouncing around in boots. I think the first human visitors will arrive at a fully operational base station (not just VERY well insulated but with active heat pumping like an inside-out fridge) complete with rooftop docking system; a rover bay would be added later. Their main task will be to service and upgrade the robots.

The cold is going to be THE big problem facing probes, machines, and colonists on Titan. Compared to other moons, Titan's atmosphere is thick, cold, and windy. So there will more heat conducted away from warm objects on Titan compared to other moons where objects will be partially be isolated by vacuum.

[Compare keeping hot coffee in a Thermos to trying to keep a hot cup of coffee in a pan of cold water.]

A heavy methane rain would also do a really great job of sucking heat away from warm stuff on the surface as well, both from conductivity from the moving fluid but also from the instant evaporation of the methane rain drops when it hits the warm surface. Just like the first raindrops from a summer thunderstorm disappear when they hit a warm sidewalk here on Earth.

But think of the fun the colonists will have shattering roses, driving nails with bananas, and other fun low-temperature experiments.

-Mike

Odd how the analogies between Venus & Titan keep cropping up, even though sometimes 180 deg out of phase from one another. Dewar-type vessels have also been proposed for Venusian probes.

Correct me if I'm mistaken but it isn't Titan's surface composed of at least some proportion of ices? Meaning compounds which are liquid or gas at normal earthly temperatures. That raises the question of what would happen to that Titanian surface if it were subjected to earthly temperatures, especially over a prolonged period.

Wouldn't those ices soften, and eventually melt or subliminate?

If so wouldn't that lead (eventually) to objects (like landers, rovers, nuclear reactor modules) getting bogged in the Titanian surface, or even (given enough time) sinking into that surface in a more substantial fashion, whether in a more or less graceful way (albeit no doubt with various degrees of tilting) or via periodic subsidences (as the earthly temperatures caused the ices component to leach away from the silicate stuff, gradually undermining the integrity and load-bearing capacity of the Titanian surface).

=====
Stephen

Some of the surface materials may DETONATE on being warmed.
Take (I think) cryogenic nitrogen and methane ices mixed, irradiate with charged particles.... it turns yellow, and DETONATES on being warmed toward sublimation temperatures.

Does this require the presence of oxygen? If not, there could be some alarming things happening in cryovolcanic areas.

Do you have a reference for this? I poked around a little and couldn't find anything.

But it might be possible: Some possible culprits would be diazomethane (CH2N2) and even more hazardous cousins diazidomethane and triazidomethane (HC[N3]2). Diazomethane is yellowish and explodes when it crystallizes. (Chemists playing with this stuff had to use new joint-free glassware free from any surface defects. These days trimethylsilyl azide is a much safer alternative in recipes). The azidomethanes are exceptionally nastybad compounds that detonate at greater than 70% concentration. Many laboratory accidents occur when azidomethanes are accidentally generated. (I assume triazidomethane blows back to formamidine and 3 molecules of rapidly expanding nitrogen gas).

One described example: http://pubs.acs.org/cen/safety/19930419.html

All these detonations would NOT require the presence of oxygen.

(Azides are famously shock-sensitive. Sodium azide is used to make airbags inflate rapidly during collisions. Metal azides are even worse. IF (and it's a big if) light organic azides could be generated on Titan, these could be a bad thing.)

-Mike

Good grief... !!! Are you saying that there may be natural minefields on Titan? Do these compounds have an affinity for each other, or do they tend to disperse? (By that I mean in the "wild" state instead of under laboratory conditions, if the possible circumstances for natural formation are at all understood; assuming it doesn't happen naturally on Earth.)

IF azides can form on Titan. (I'm not sure if azides can form through photochemical or atmospheric means.) (It is comforting to note that Huygens didn't get blown up when it landed.)


Like anything else, concentration could occur through solvents reworking the surface or crust and concentrating compounds in ore deposits. Differential solubilities could cause selective deposition as sparingly soluble species ploop out of solution.

("If your are not part of the solution, you are part of the precipitate.")

-Mike

That's GENIUS.

Doug