[handmodel]

I'm not going to pretend to be an expert but it seems like the hard/expensive part is probably building the underwater drone capable of taking the LIDAR?

I would imagine at some point getting overhead satellite imagery by plane of the entire world seemed impossible - as did street view coverage of the entire US - but not the craziest expense once you have the ability to do it once.

[chowells]

The really hard part is the combination of the very short range of light transmission underwater and the very large size of the oceans. How many centuries are you willing to spend on the project?

[roywiggins]

The MH370 search used sonar, which works well underwater but has quite short range so it involved driving ships around on the surface dragging sonar arrays backwards and forwards for years.

I think this is one of the systems used during the MH370 search, apparently it can scan 192km² per day.

There are 161,000,000 km² of ocean, so you'd need at least a million days or 3,000 years to scan the whole thing, give or take.

http://www.slhydrospheric.com/prosas60_spec.html

[narag]

There are 161,000,000 km² of ocean...

Sorry if you aren't the best choice, but I had to ask someone in the thread.

Why? I mean why all the ocean?

If the purpose is to find archeological sites, most will be on the continental platform.

[hetspookjee]

_what if_ you find remains of a truly ancient civilisation on the abyssal plains. Now that would get the films rolling!

[handmodel]

That sounds extremely slow but presumably now that they've built one the cost to build 100 or 1000 would be achievable if someone (or some government) had the interest.

I would think they would need a version that doesn't need the ship nearby to scale - but would still guess this is something that will be accomplished on the order of 30 years from now.

[ge96]

Would be curious if those gliders were helpful or not/how much smaller.

[bigDinosaur]

There's twice as much sea as land, and from a brief glance LIDAR penetrates to 300m (whereas google informs me the average depth of the ocean is ~3600m) as well as presumably some weird topology which might make for interesting challenges.

Certainly doesn't sound easy, but it'd be interesting to hear from anyone who works in this area.