Mapping Underground Caves/Tunnels on the Moon/Mars

[sanman]

Here's an interesting article on the first 'skylight' - opening to a possible underground lava tube or cavern - discovered on the Moon:

http://www.newscientist.com/article/dn18030-found-first-skylight-on-the-moon.html

I'm wondering how it might be possible to map out underground caverns and lava tubes on the Moon, without having to look for openings. Shouldn't there be a way to use cavern-sensing radar, or something like that, to spot underground cavities from an orbiting satellite or from a surface rover?

What's the most accurate way to map such underground cavities, without having to rely on chance discovery of openings? What's the best sensory/instrumentation for this purpose?

My understanding is that to scan through rock, you need to use very low frequency radio waves at high power, but their long wavelengths would limit the resolution of the features being scanned for.

Here's a recent article I read about hyperlensing - could this be the answer?

http://www.physorg.com/news175702307.html

Clever physical manipulation of the imaging sound waves enables the hyperlens to resolve details smaller than one sixth the length of the waves themselves, bringing into view much smaller objects and features than can be detected using today's technologies.
So this is with sound, but you know the same principles apply to EM waves.

Perhaps this could be a useful approach to mapping out underground cavities with high precision.

Could hyperlensing be useful for planetary exploration and underground mapping?
What do you all think?

 

[rathat]

Watch this! this guy is incredible, he developed underground and underwater mapping robots, he even talks about sending it to Europa and using a nuclear powered heated drill to get under the miles of ice to get to the liquid ocean and map out under water caves this is INCREDIBLE http://www.ted.com/talks/view/id/141

 

[LURCH]

Good video! However, the first explorations should be done by ground-penetrating sonar. Seismic charges set off on or just below the surface and the soundwaves measured at stations throughout.