Going Underground on Other Planets?

That is pretty much all speculation and hypothesis (scientific guessing). We will never really know until we get there.



Evaporated to space.

I'm wondering what the soil of the Moon is like, I'd guess rocks, smaller rocks, pebbles then powder. I don't think it would be much like the soil on Earth but it might be possible to tunnel into the side of a crater say at the north or south pole and make a small five to ten acre community. We would be close to (hopefully) a water source and would be able to establish a somewhat self sustaining colony.

If the soil can support itself when dug out that would be great. If it's rock that would hold up better. With the Moons lesser gravity that might be easier to support the ceiling. I'm thinking the soil at the craters edge might be very loose and need a chemical added to it to increase stability.

<pedant mode> I think its been heavily suggested and is probably true that that some water was split into H2 and O and the O oxidised iron hence the red planet so evaporated into space is only 2/3 true by no atoms and about 1/8 by mass </pedant mode>

And i think more recent studies suggest that quite a bit of water has gone subterranean and maybe trapped in permafrost in both the polar regions.

There were lots of samples brought back by the Apollo missions so it is possible to look up its consistency and IIRC i think NASA or some other entity actually sells moon dust/rock substitute of a similar consistency for experiments to be done on down here on earth just in case we ever do go back and need the knowledge for localised building mining etc.

I think that some cracked open lava tubes have already been spotted not sure if they are near the poles so an inflatable system might be good there or also on the surface if in an area with lots fine dust an inflatable with open honeycomb surface could easily be filled up with dust to have a foot or more of radiation shielding.

That is that speculation and hypothesis. There is no concrete evidence that is what has happened. People want so hard to believe that Mars was wet and Earth-like that they interpret information to support that. Keep that in mind.

Given Mars' mass, even after the late bombardment and outgassing period it wouldn't have had enough pressure to retain much liquid water, it wouldn't have been around for very long, when water evaporated it would never come back as rain and all the free O2 from dissociation quickly made it's escape without being able bind with anything. On Earth, despite having extensive stable oceans of water, the iron didn't oxidize out until life provided the free oxygen (Oxygen catastrophe).

Mars' apparent red color comes from it's CO2 atmosphere. If you could strip it away, it would look brownish gray.

Color corrected MSL Curiosity landscape:




More optimistic speculation. There is water on Mars, but it's a solid mineral there.

In order to sustain the investment necessary to populate another world, there has to be profit, probably the first ventures that would be capable of breaking even would be Mining, then colonists could be moved into the voids dug out of the Regolith, or whatever.

I wouldn't go for direct illumination through transparent views, or mirror set-ups, but just generate energy on the surface to power lights, and screens (for a view) below. Basically build your space-ship underground, or bury it with all the Life Support you were depending on the whole way there. You'd already have the Solar Arrays, outer envelope, internal volume, and machinery to recycle chemicals (Air, water, fluids, carbon, nitrogen...) so re-purpose them.

Dig a hole, sift out all the valuable stuff you came for, and rake the excess over it. Then, you can dig down/out to expand with all the benefits of Radiation Shielding pretty much for free. This eliminates the need to actually make huge arrays of mirrors, or quarz crystals several feet thick, just use what you brought with you. This mindset is essential for space survival.