[discussDev]

Misleading title, funny enough the road outside my house is nothing more then compacted gravel that the intentionally leave the dust in... its called B2 modified I think. so as long as your moon buggies have reasonably wide tire to weight all you need to do is grind it to the right size and compact it. ... but the article itself is about much more then that and it will be interesting if 57M can actually build a solid structure from those materials. As others have said no water or anything so if it can be done without a big supply chain then I bet the "tech" will be to compress what's there into bricks of some sort. So they just reproduce the materials here and see how much they need to be compressed to make something usable.

[Etheryte]

Since my childhood home is next to a gravel road, I somewhat doubt that compacted gravel would be feasible. Gravel roads of all kinds spin up a lot of dust when you drive on them, and on the Moon it would take even longer to settle than on Earth. A constant cloud of floating particles can not be good for your gear if you want to travel through it with any reasonable frequency.

[avmich]

> A constant cloud of floating particles can not be good for your gear if you want to travel through it with any reasonable frequency.

I bet on the Moon that dust behaves very different. No atmosphere, so no usual clouds. Static electricity, so some possible weird behavior. No erosion and soil, so dust is sharp and hard.

It would be interesting to see how road construction looks like on the Moon.

[throwawaymaths]

Moon dust is totally weird stuff. Because there's no erosion, it's super shardey and pokey. This also means that points of contact between individual dust particles are minimal, so it's highly insulating and also has very poor thermal conductivity across the bulk.

I wonder if it would be worth it to set up a mid/high frequency vibration device up to the moon and just run it for a few months? Years? To cause vibrational contact erosion in the immediate environs of wherever you intend to land to soften up the shards... Would that even work?

[dr_dshiv]

“I wonder if it would be worth it to set up a mid/high frequency vibration device up to the moon and just run it for a few months? Years? To cause vibrational contact erosion in the immediate environs of wherever you intend to land to soften up the shards...“

Love this. Very creative.

[frosted-flakes]

I recall that one of the moon rovers had a broken fender, and the dust it was kicking up was causing all sorts of problems. So the next day they fashioned a homemade fender out of duct tape and some laminated maps. On the moon.

https://science.nasa.gov/science-news/science-at-nasa/2008/2...

> One dousing with dust was enough to make a deep impression on Schmitt. Back on Earth he opined that "the dust issue is one that just has to be addressed. It's going to be the major environmental issue for future missions to the Moon."

[Etheryte]

That was a great read, plus a good highlight for just how much of a problem dust is for Moon (and Mars and beyond) missions. Thanks for linking it!

[frosted-flakes]

I'm pretty sure I first heard about it in Gene Cernan's book The Last Man on the Moon. It's a very good read, and not too long (5hr audiobook), so if you want more of those stories that book is filled with them. He also narrated the audiobook himself, and did a pretty good job.

https://www.audible.com/pd/B002VACH5S

[adrian_b]

To make a solid from moon dust just by pressure would need a too high pressure.

Nevertheless, it should be possible to sinter the dust into ceramic blocks, by moderate pressure and temperature, together with some kind of binder.

As a sintering aid that works as a binder, there are various oxides that could be extracted from moon rocks, e.g. yttria, though some of the more abundant oxides, e.g. of magnesium or calcium, might also work.

So I think that the most difficult part of making solids from moon dust or broken moon rocks is the extraction from the rocks of the oxides that can be used as binders for sintering.

Sintering has the great advantage that it needs only energy and materials that are abundant on the Moon. Cements and adhesives, which are cheaper on Earth, need materials that are very scarce or absent on the Moon.

[ggillas]

There have been attempts at solar sintering, which may be viable in arrays or a central paver base: https://www.dezeen.com/2011/06/28/the-solar-sinter-by-markus...

[adrian_b]

That would not work like that on Moon, because the technique described works for sand, which is highly enriched in silicon dioxide.

Such deposits of rocks with very high content of silicon dioxide, like sands, are formed on Earth by the action of water, which dissolves the more alkaline oxides from the rocks, leaving sand made mostly of quartz. There are no such sands on the Moon.

However, I have not mentioned above that besides sintering, there is an alternative way of making solids from lunar dust and rocks, which is to melt them completely and cast them into solid blocks.

However, this would be more difficult than sintering, because it must be done inside a sealed space, filled with some gas (materials do not melt in vacuum, they sublimate), and it would require a greater energy.

When introducing in the sealed space and extracting from it the raw materials and the end products, there would be some losses of the pressuring gas. Nevertheless, when melting rocks made of oxides, unlike when melting metals, the gas could be oxygen extracted from the lunar rocks, so its losses would not be important.

However, the use of oxygen as the working gas would make difficult to find a material from which to make the walls and the casting die, because such a material would have to resist both oxygen and melted oxides at high temperatures, which few materials are able to do, except some platinum-group metals, but even those do not last forever and need periodic replacements.