Manned Landing On Titan, Issues & Answers? Options

[nprev]

Just got to thinking about some of the problems that may have to be addressed if & when we ever try to visit Titan in person.

The first thing that comes to mind is what might happen if some Titanian air gets inside an oxygen-rich manned spacecraft, say from minor airlock residue. I imagine that the explosive potential of some of the trace gasses is pretty high, and there's probably also a significant risk of poisonous compounds as well. So, here are some tenative requirements:

1. REALLY efficient air-scavenging airlocks.
2. Surface suits that can't trap external gasses in creases, folds, etc.
3. Spark-proof electrical/electronic everything.
4. Smoking is strictly forbidden (with apologies to the entire 1950s SF movie genre!)

Gotta be more...any ideas?

[nprev]

Oh, okay; so maybe the pressure differential isn't a big deal, then. Thanks!

I have no idea how efficiently Titanian air could be scrubbed from an airlock, nor how long it would take. However, if pressure turns out not to be too big an issue physiologically, then keeping the lander cabin at a slightly higher pressure than the outside as you'd suggested before should stop most unwanted influx.

Here's another issue: How will they generate electricity? Solar cells are out, obviously. Would a whole bunch of RTGs do the trick, or would they need a somewhat larger nuclear power plant? (Of course, by the time we're actually able to do this we may well have compact fusion power sources...here's hoping! )

Come to that, would it be worthwhile to haul in a bunch of oxygen & run fuel cells? Are there some easy ways to liberate H2 from Titan's surface compounds? Or, would it be simpler to "burn" some of the simpler CH compounds as conventional fuels using our oxygen cache?

[JonClarke]

I have no idea how efficiently Titanian air could be scrubbed from an airlock, nor how long it would take. However, if pressure turns out not to be too big an issue physiologically, then keeping the lander cabin at a slightly higher pressure than the outside as you'd suggested before should stop most unwanted influx.

I have done some reading on particulate removal, which can be very fast and efficient, but don't know much about organic gases, which is why I asked. It would be interesting to find out how much pressure differential is required. Labs and factories that use hazardous materials run an\t lower pressures than the outside world, warships and some military vehicles operating under NBC conditions have higher internal presures to keep nasties in and out respectivively, this could serve as a guide for what would be required on Titan.

Here's another issue: How will they generate electricity? Solar cells are out, obviously. Would a whole bunch of RTGs do the trick, or would they need a somewhat larger nuclear power plant? (Of course, by the time we're actually able to do this we may well have compact fusion power sources...here's hoping! )

RTGs probably don't deliver enough power for a crewed mission. Failing compact fusion I think a fission reactor is the best option, at least initially. The high atmospheric density makes it easier to dispose of waste heat from a reactor on Titan than on the Moon or Mars, rather than relying on passive radiators (remember for every kW of electricity a reactor typically generates about 10 kW of waste heat), cooling fans would greatly increase the effectiveness of convection in dumping heat. Heat pads or rods into the ground would be another option, but you would not want to over do it.

For a permanant station, a wind farm might be an attractive supplement, given the low gravity, high atmospheric density, and presence of locally strong winds (there are lots of dunes on Titan). Titan has an internal heat source so geothermal (titanothermal?) power is another alternative.

Come to that, would it be worthwhile to haul in a bunch of oxygen & run fuel cells? Are there some easy ways to liberate H2 from Titan's surface compounds? Or, would it be simpler to "burn" some of the simpler CH compounds as conventional fuels using our oxygen cache?

Well the rocks appear to be water ice and ice clathrates, so with the waste heat you could melt the ice and electrolyse the water to oxygen. Methane and hydrogen could be recovered if needed, or simply dumped. The amount of methane in the Titanian atmosphere will support combusition with the addition of sufficient oxygen. So you could simply run reverse combustion engine, drawing ambient atmosphere into a combustion chamber, injecting oxygen, and igniting the mixture for example with a diesel engine or gas turbine. This makes long range ground vehicles and aircraft a much easier proposition than on Mars, for example. Methane and oxygen would be an ideal propellant combination for ascent and descent vehicles, although again, with sufficient plant and abundant atmospheric nitrogen, methane and a source of oxygen you could also manufacture storable hypergolics like hydrazine and nitrogen tetroxide, if you needed to.

Jon