Lunar Environmental Challenges

[darthgently]

Dustbuster

 

Edited April 24 by darthgently

[Nuke]

regolith removal will be essential for most moon bases. i imagine giant leaf blowers being used. but since there is no air, you will need a rocket or some other compressed gas source. then you will have issue with low gravity, so you will need to steak everything down during operation. the reverse vacuum cleaner approach, where you use a gas stream to blow dust into machinery that can remove it mechanically. of course its going to eat that machinery alive.

best approach ive seen is a rover with a giant magnifying glass that will slowly glassily the surface into bricks, which you can later use in construction or as rad shielding. you could do the same with lasers i guess, much faster, if you have the power.

or just get a bunch of guys in space suits with shovels to scoop it into your lunar regolith 3d printer. i imagine a system of interlocking bricks with perforations that allow cables to be passed through. you can then form brick rings, and tighten the cables. these could be interlocked in sections and capped off with other printed elements. cinch all the cables to be as air tight as possible, then coat the interior with resin, and perhaps glass fiber made form regolith (think cotton candy machine from hell). you could then pile on regolith bricks until the internal pressure is equivalent to the pressure of compression from the external material. the result is a pressure holding volueme for lunar habs. though it might be easier to just bring a hab sized printer.

Edited April 25 by Nuke

[SunlitZelkova]

3 hours ago, Nuke said:

regolith removal will be essential for most moon bases. i imagine giant leaf blowers being used. but since there is no air, you will need a rocket or some other compressed gas source. then you will have issue with low gravity, so you will need to steak everything down during operation. the reverse vacuum cleaner approach, where you use a gas stream to blow dust into machinery that can remove it mechanically. of course its going to eat that machinery alive.

best approach ive seen is a rover with a giant magnifying glass that will slowly glassily the surface into bricks, which you can later use in construction or as rad shielding. you could do the same with lasers i guess, much faster, if you have the power.

or just get a bunch of guys in space suits with shovels to scoop it into your lunar regolith 3d printer. i imagine a system of interlocking bricks with perforations that allow cables to be passed through. you can then form brick rings, and tighten the cables. these could be interlocked in sections and capped off with other printed elements. cinch all the cables to be as air tight as possible, then coat the interior with resin, and perhaps glass fiber made form regolith (think cotton candy machine from hell). you could then pile on regolith bricks until the internal pressure is equivalent to the pressure of compression from the external material. the result is a pressure holding volueme for lunar habs. though it might be easier to just bring a hab sized printer.

The things I’ve heard about from either sci-fi sources or actual research papers are-

1. Making concrete out of regolith and paving the area around the base.

2. Using a sort of lawnmower type rover to suck up the regolith underneath and throw it on to base. This doesn’t actually apply to removal, I just heard you mention vacuum and thought there might be a way to repurpose it. The regolith would help protect the base from micrometeoroid strikes and radiation.

[Nuke]

problem with lunacrete is where do you get the water? will concrete even cure if its in a vacuum?

[AckSed]

8 minutes ago, Nuke said:

Problem with lunacrete is where do you get the water? Will concrete even cure if its in a vacuum?

I can't speak to the first, but yes, concrete will cure in a vacuum: https://space.nss.org/wp-content/uploads/Lunar-Bases-conference-2-518-Lunar-Concrete-For-Construction.pdf

In fact, the concrete ended up being stronger, and did not lose as much water as thought. The real challenge is that concrete's compressive strength is not as much of an advantage in lower gravity. If making a pressure vessel out of it, the tensile strength is needed more - and that has historically been lower. Reinforcing it with glass fibres spun out of melted regolith may be needed.

Last year, concrete was flown on the outside of the ISS, and made inside: https://www.concrete.org/publications/getarticle.aspx?m=icap&pubID=51738695

Extracting sulphur from troilite (an iron sulphur ore found on the Moon), melting it and mixing in ground-up regolith simulant has been tested, as the same technique's used to make acid-resistant sulphur concrete on Earth. The strength was lower but still fine. However, there are concerns that the sulphur would sublimate away in vacuum, and you do have to pre-heat the mould or you will have voids in the centre. Its advantage is that it's easily recyclable: heat it up and recast it. I've seen one video of railway sleepers made of the stuff being recycled this way.

Amusingly, astronaut pee has been considered, as urea acts like a plasticiser in "geopolymer" concrete (regolith plus sodium silicate and sodium hydroxide), allowing the use of less water: https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Astronaut_urine_for_building_a_Moon_base

Using it as mortar for sintered regolith blocks is also an option.

[darthgently]

2 hours ago, AckSed said:

I can't speak to the first, but yes, concrete will cure in a vacuum: https://space.nss.org/wp-content/uploads/Lunar-Bases-conference-2-518-Lunar-Concrete-For-Construction.pdf

In fact, the concrete ended up being stronger, and did not lose as much water as thought. The real challenge is that concrete's compressive strength is not as much of an advantage in lower gravity. If making a pressure vessel out of it, the tensile strength is needed more - and that has historically been lower. Reinforcing it with glass fibres spun out of melted regolith may be needed.

Last year, concrete was flown on the outside of the ISS, and made inside: https://www.concrete.org/publications/getarticle.aspx?m=icap&pubID=51738695

Extracting sulphur from troilite (an iron sulphur ore found on the Moon), melting it and mixing in ground-up regolith simulant has been tested, as the same technique's used to make acid-resistant sulphur concrete on Earth. The strength was lower but still fine. However, there are concerns that the sulphur would sublimate away in vacuum, and you do have to pre-heat the mould or you will have voids in the centre. Its advantage is that it's easily recyclable: heat it up and recast it. I've seen one video of railway sleepers made of the stuff being recycled this way.

Amusingly, astronaut pee has been considered, as urea acts like a plasticiser in "geopolymer" concrete (regolith plus sodium silicate and sodium hydroxide), allowing the use of less water: https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Astronaut_urine_for_building_a_Moon_base

Using it as mortar for sintered regolith blocks is also an option.

I wonder if the more jagged non-weathered quality of lunar rock and dust will make better aggragate and stronger concrete in that respect. Maybe offsetting the lowered strengths of other aspects described.  Do lunar dirt simulants have this same jaggedness? Idk

[farmerben]

The key thing will be to positively charge the area around the base so that dust does not fall there at night.  

[kerbiloid]

On 4/25/2024 at 11:37 PM, Nuke said:

problem with lunacrete is where do you get the water? will concrete even cure if its in a vacuum?

They should use a vacuum cleaner. It's a lot of vacuum around.

On 4/26/2024 at 12:24 AM, AckSed said:

astronaut pee has been considered, as urea acts like a plasticiser in "geopolymer" concrete

Used astronaut diapers. This should also save the mass of the lunar ship by absence of toilet.

***

Btw, has anyone suggested a broom?

Of course, we know that there are no dust clouds in vacuum.

A long broom with an alpenstock at the opposite end.

An a PP-duster for fine cleaning.

17 hours ago, farmerben said:

The key thing will be to positively charge the area around the base so that dust does not fall there at night.  

By nuking it first, they can have a flat lake of glass.

***

Upd.

Latex suits!

Expendable layer of liquid latex spray.

Spray it on the suit before EVA to look stylish on the Moon, scratch it off after getting inside.
All dust will be in a trashcan.

Edited April 27 by kerbiloid

[kerbiloid]

_(multipost)

Edited April 27 by kerbiloid