Life & Temperatures on Titan

[DataPacRat]

Current musings: how much to draw on from 3e Vehicles to add options to 4e UltraTech's sonar-comms, to complicate whatever comm network exists in the subsurface ocean. Eg, VX1 suggests tight-beam and (very) sensitive, which could let somebody reach the 5,000 miles to talk halfway around the planet. (With a bit of delay, given sound's ~1.5 km/s speed in saltwater.) Or could make it easier/cheaper for someone at the top of the ocean chat with someone at the bottom.

(VLF radio doesn't seem to penetrate deeply enough, ELF needs miles-long antennas and has terrible bandwidth, and THS Under Pressure's notes on water transparency put the kibosh on lasercomms of more than half a mile or so. And I'm not using the sort of superscience that permits neutrino comms.)

VX1 also has some numbers for sonar GPS beacons and receivers, though neglects to mention their useful range, or how many should be planted in any given area.

I suspect one of the less-expectedly important factors is how much slower the sonarcomms are than radio, especially for AIs running at faster than realtime...

[DataPacRat]

Originally Posted by DataPacRat

I'm not using the sort of superscience that permits neutrino comms.

I've been re-reading some of my sources for the particular sort of superscience I'm using; and it turns out that it might, in fact, be the sort of superscience that permits neutrino comms. (Specifically, the replacement/tweak to relativity is compatible with a particular model of what keeps various subatomic particles together; one description I've read is that "photons can be modelled as ribbons of EM fields with a particular degree of twisting, neutrinos have different twists; and electrons can be modelled as photons circling round and round in tight circles, kept together by [technobabble about high accelerations]".)

However, to stay compatible with some plot points already established, I just have to make it infeasible for a SM+4 ship to carry a neutrino comm, especially an AU-range one. So I think I'm going to skip all the ones listed in 4e's Ultra-Tech p45 as being too small, and go back to Vehicles; I'm thinking of only allowing "extreme-range" neutrino-comms (and just maybe "very-long range" ones). Given how completely different the transmitting and receiving mechanisms are, I'm also thinking of having the base comm unit only be a transmitter, and having to separately buy receivers as both "receive-only" and "very sensitive".

(That would be: Transmitter: 15 tons, 600 cf, $600k, 40 kW; Reciever: 300 tons, 12,000 cf (23 feet cubed), $600k, 20 kW; effective range between the two: about 10 AU.)

Plot-wise, I've already noted that sonarcomm tech is good enough to relay messages through Titan's subsurface ocean, so whoever's hiding out down there won't be completely isolated, even if comms are limited to the speed of sound. At $1.2M a pop, it's not a system that's going to be found in every homestead, or even every city... and since the range is no better than a much-less-expensive lasercomm, the use-cases are pretty thin indeed.

In fact, about the only plausible use-case I've thought of is "megacorp or government has a self-contained secret lab buried (literally) too deep to be found by hostile spies". (Which certainly provides some interesting potential for future plot points...) Can you think of any other uses?