Moonwards - 2017-04-29

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12:00 AM

>If this is done in vacuum, the temperature where that starts would be lower
no, it's not. 1 bar does not make such great difference for melting and crystallizing solid materials. Hae calculated influence for aluminum melting point(rough estimation) results are so insignificant that even not worth of mentioning

>the Moon doesn't have enough silica for it to aggregate as a pure mineral (quartz) at the end of a magma crystallization process.
needs clarification here what do you mean.
also funny video about sand https://www.youtube.com/watch?v=pxmHHoTPSKI

https://isru.nasa.gov/OxygenfromRegolith.html
40% od SiO2 more than enough of anything

12:16 AM

@MolbOrg perhaps it is different with molecules. i have a handbook about vacuum furnaces that lists the melting point of a number of metal oxides as being quite a bit lower. let me look for the link.

solaratm.com/tech-downloads/critical-melting-points-booklet

hm, probably i misinterpreted a chart about vapor pressures of various metal oxides at different pressures

i made a chart a year or so ago that was based on a chart in that booklet, and i think i mislabeled it

user image

@MolbOrg the silica bonds with other metal oxides in the melt, and only if there is silica left over once everything else is bonded does it crystallize as quartz.

yeah, i can edit that to make it clearer. and i'll take out the stuff about different melt temperatures.

12:36 AM

@kimholder actually the chart is excellent and exactly what you need to purify glass with simple means, but I didn't end to read the post(fighting with style atm, can't read wall of text on dark background, at least on the laptop)

oh, it's hard to read? not enough contrast?

hmm.... as i get older i notice i have more difficulty reading with the colors reversed too... i've always really liked the look of light text on a darker background, but i think i could reverse that in a way that still keeps the feel...

i'll play with it over the weekend

12:54 AM

yeah, i'm trying a set of light colors. i can change it over in a bit - i just need a little time to change all the text color, there are a bunch of them.

@kimholder it may be personal, at first glance is fine looking no problem there. Just my personal thing probably

well, i'm going to play with it a little. i set all my programs to dark backgrounds, and many of them come that way now. however, you are not the only person to have mentioned it.

the website is now set up in a format that makes it easy to play with colors, i can change things across the site by changing a short list of color classes

at any rate... now i'm reading about vapor pressures

I prefer light colors for all my backgrounds so it need accommodation, I know people who use darker - matter of habit
btw https://upload.wikimedia.org/wikipedia/commons/e/e8/JSC-1A_lunar_simulant_60X.agr.jpg seems they have silica crystals or something similar, needs better information what regolith is on particles level. hmm if I recall correctly have seen something like that when searched about aluminum, have seen that on nasa site in projects about IRSU moon aluminium mining

1:12 AM

i have taken my data from the Lunar SourceBook. It focuses almost exclusively on plagioclase, pyroxene, and olivine

because there is pretty much nothing else.

i just did a search in it for quartz and found a good quote

> Silica minerals include several structurally
different minerals, all of which have the simple
formula SiO 2 . These minerals are generally rare on
the Moon. This rarity is one of the major mineralogic
differences between the Moon and the Earth, where
silica minerals are abundant in such common rocks
as granite, sandstone, and chert. The relative absence
of silica minerals on the Moon is a result of several
factors. For one thing, the Moon has apparently not
evolved chemically beyond the formation of a low-

@kimholder more or less it is what the video about sand was about. But it does not mean there is not enough material aka SiO2 to form anything while it is melted.

no, definitely not. the difficulty is getting it pure.

as about refining goes, I think you overcomplicating stuff

in what way? the method i ended up with seems pretty simple to me.

first of all there is a lot of dust on the surface, 6 meters deep, and 4 billion tons is not that much.
particles are not a homogenous mix of everything, but particles which more or less consist of different materials. That includes metal oxides, metal particles, SiO2 particles, with inclusions without inclusion fuzed etc etc

and thus the first stage is not melting, but separation of those particles,

the same way as we do that on earth with ores and such.

1:26 AM

that actually isn't the case on the moon. because all the particles were created by impact processes, they are all made of a mix of things. no particles are one thing.

the only exception is metallic iron, and to what degree that is really true is debateable

@kimholder ok I have to find the link, and no the statement is not true, for different reasons

things are separated on earth thanks to weathering. there is no weathering on the moon.

not only because of weathering and meteorites impacts can be considered as the weather.
a single impact melts the thing, and it then freezes again, and it has time to for crystals and such, next impact breaks the thing, and again and again, the different strength of impacts, so much of them that the surface is covered with 6-meter deep dust from those impacts

so on particle level there is separation of materials by different properties lize metling tempertures, strengh, etc

*like

i'm searching in that same book for any references to that. every image i've ever seen of a particle of lunar material has shown it is a mix of different minerals

but what you are saying is making me think, maybe i have heard some reference to that before.

not the link I recall, but just for the moment page 14 https://www.nasa.gov/pdf/203084main_ISRU%20TEC%2011-07%20V3.pdf
Yes it is a mix of different material, but the size of particles and that they exesting what makes the difference, the particles may form agglutinate of the same chemical compositions.

*still searching

@kimholder not the link I wished but exactly what I'm talking about nasa.gov/centers/johnson/pdf/282811main_ISRUDeansConf1006.pdf 3th page

1:50 AM

yeah, but those rock chips and beads are all made of different stuff. it doesn't say there was the particles are made of.

the other presentation shows a process that increases iron content, and that i can believe because it is magnetic.

what i really love about those papers are the images of the reactors. i'm going to have to go looking for the papers about those reactors.

doesn't say what the particles are made of, i meant...

i have to make dinner, MolbOrg, but i will consider further what you are saying

pay attention to <50 um particles aka dust, they are vapors, vapors different materials condensate at different temperatures and thus time after impact and thus different distances from the impactor. basically, that is the separation in rectifying column as is.

i'm going to read the whole Lunar Regolith chapter end to end, something i've never done. i usually look just for the parts i need at the moment.

but as you have heat you can just evaporate the stuff and condense it and collect it. SiO2 2200+ , and with reflectors, you can have about 5000-6000K max it is more that enough to evaporate and rectify the stuff you need and because of vacuum nothing stops you from doing that just in regolith bed

2:06 AM

collecting such hot vapors sounds challenging. how do you rectify such hot vapors?

not more challenging than rectifying two liquids with different evaporating temperatures
As usual, have a colder place, any surface below 2200K will be cold enough for those vapors to condensate.

the main problem is to have huge amount of cheap energy

i'm having a hard time imagining the process. having a surface that is so hot only the vapors with the hottest melting point will collect there is pretty high temperature material.

the energy doesn't really bother me, as you say, there is plenty of sun.

2:35 AM

no no no, the surface has to be below 2500K, it can be 100K, it can be 1000K does not matter it has to be below.
The process let say you pour the magma with small flow trough focal point of a lens, it heats there some stuff evaporates (with lesser boiling point - metals mostly), it flies down in a magma pond, pond constantly looses heat(walls, IR), and constantly is headed by incoming flow, and it contains stuff with higher boiling point, you pour the stuff through another focal point etc. one by one you boil off the different stuff with higher and higher melting point.

it do not have to be magma ponds and those magma flows, there are different ways to do the evaporation and separation of vapors

Another point and I go sleep
You do not have to have clear glass for the purposes you suggest it(if I understood correctly)
A nvidia debunking video about moon photo https://www.youtube.com/watch?v=syVP6zDZN7I it is interesting in the sense of getting practical feeling how bright is the sun without atmosphere
You will be ok with 50% or less transparency fo the glass, and to make it diffuse you will be ok with the crystals and inclusions and other opaque looking stuff.

2 hours later…

4:22 AM

@MolbOrg let me think about it a bit. for now i have to turn in. i'll look at this tomorrow.

11 hours later…

3:13 PM

@MolbOrg As far as that goes, yes, where glass is on ceilings, it doesn't need to be clear. But in a lot of places it would still be better if it was clear. In others it would be better to use cloudy and tinted glass because if it all got through it would be too strong. The atrium designs already reduces light by using beams between the glazed areas, so it would be nice if the glazing was transparent enough to view the sky.

there are also areas where the purpose of the windows is to give people a sense of the outdoors, in those places the glass needs good transparency.

@MolbOrg The thing is, unless the heat applied to the lava is only enough to evaporate certain things, that are easy enough to separate afterwards, everything will mix again when it solidifies on the walls. I guess that is what you are trying to say here, apply heat several times, more each time so that different things evaporate. That sounds feasible, it would be a question of designing the system to see if any problems come up. It does sound like it could work though.

This isn't so different from what the dust roaster does, actually. The only thing is that once the lava stream has been vaporized, the different components are separated by passing them through an electric field that causes different elements to deflect by different amounts. Collectors are placed in front of the different streams.

However, the dust roaster is designed to produce only pure elements, not metal oxides.

Unless what you propose could be done using only sunlight, i am not sure it would be an efficient way to do this. The dust roasters need a lot of power, but because they produce a range of really useful products, that seems acceptable. And actually, the slag would be calcia and magnesia, which are two of the metal oxides it would be convenient to have.

What i propose - assuming it actually works - produces silica, and possibly variants of it could be used to obtain other metal oxides like titania. It probably isn't going to give you good purity, but it could be good enough to do the job.

4:15 PM

@MolbOrg Okay, this blog post has now been edited both on the website and on blogger to remove the inaccuracies and clarify that point about quartz.

3 hours later…

7:30 PM

> I guess that is what you are trying to say here, apply heat several times, more each time so that different things evaporate.

yes. Do you familiar with the theory of frac
tionating column https://en.wikipedia.org/wiki/Fractionating_column or how moonshine is made from that mix of (do not know how it calls) it is a basic process of separation stuff with different boiling points.

There is the same. and you can do that even in the traditional way because you have a free vacuum and the stuff begins to evaporate at temperatures lower than melting points of stuff we may use (Al2O3 as an exam…

if you put one of these marks >, they figure the whole thing is a quote

how to make actual quote

the formatting you have up there is for a quote

to put it separately, i'd probably just put the part that is a quote in actual quotation marks

or put it on it's own line, then start another for my reply

as soon as you put >, the whole thing is going to be formatted as a quote

ok i will experiment with that later

I was expecting usual SE formatin will work but it does not

no, several things don't work here, such as MathJax

7:35 PM

ok, not important

(it would actually be really nice if MathJax worked in chat...)

what you propose is interesting. but i have no idea how we could estimate yields.

one thing to note - there is already a plan for a large reservoir of lava that is used to power turbines all through the night

and the vapors from that reservoir are already planned to be collected

but that reservoir stays in one spot, and i'm not sure how hot we can make it.

the paper it is based on estimated that a system like that in continuous use could withstand a working temperature of 1800 C

moonwards.com/machines2.html#TESS

>What i propose - assuming it actually works - produces silica, and possibly variants of it could be used to obtain other metal oxides like titania. It probably isn't going to give you good purity, but it could be good enough to do the job.

(you need a space between > and the rest)

8:08 PM

about that I didn't say it will not work, it will work, I just said there are simplier ways to do the same (that I meant by writing "you over complicate the problem in the case") reducing oxides with hydrogen -> water -> electrolysis <- electric generators, turbines, etc etc => when you have all that there are more efficient ways to purify the stuff - like direct electrolysis. it have also interesting properties - by setting the voltage you may selectively reduce(deoxidize) stuff (not so simple, but )

yes, i have had that impression too, that solutions that would be much better aren't looked at because it all has to arrive on one ship, in one piece, and work without being repaired.

but i have always prioritized methods that work with heat, because heat strikes me as the cheapest and most plentiful thing of all.

and although i have planned for a transport infrastructure that can deliver lots of cargo, things that depend on catalysts and reagents that need to be continuously resupplied are not my favorite things.

@kimholder nice model, need to think about, hm

if the catalyst can be recovered quite well, then probably systems that use chlorine and fluorine would indeed be better.

or carbothermal reactions - i want to go find the papers on that from the presentations you listed yesterday

in general, my belief is that if a process doesn't take advantage of the vacuum, or the low gravity, or the plentiful sun, or the plentiful cold (you need radiators, but the cold of space is always right there, and the bedrock is -20 C, everywhere, always) - if a process doesn't use at least one of those, there is probably a better way.

@kimholder agree, as with next 4 messages

here I disagree a little bit. Technology has to be chosen with certain criteria, and a lot of processes can benefit from a vacuum, low gravity, temperature differences, but at the end deciding criteria has to be what is better. If some process does not benefit from vacuum but is better that one which does the same in vacuum, why not, it is not such a big deal to make a box for the process (in some cases it might be unacceptable, it adds complexity etc)

I prefer the simplest solutions which should work and which is ok to be a part of the system. Because if there exists a simple solution and…

how big is magma pond?

ah, ok see 40 by 40

8:32 PM

as big as possible, Hohmannfan demonstrated that the efficiency of the method improves with scale. I have no idea what it is reasonable to say that the complete phase 1 colony at lalande can make, 40 x 40 was an estimate, a very loose one.

@MolbOrg Yeah, at least that size. We did some thermal calculations. But there are big benefits with a larger one.

As far as I can see, that is the only way to store enough energy if it is not generated continuously.

The lunar night is long.

Hi, by the way.

you might like to use the tool Hohmannfan made for those calculations

github.com/briligg/moonwards/blob/master/tools/…

Not at all. It is a shitty cli program written in an evening. The thermal model works, but it is not very sophisticated.

that's still helpful

and it's in the repo there, so it can be built on

Getting good simulations means working with a good thermal framework. We need that, or someone who has the numbers.

8:37 PM

ah, that we have

ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920005262.pdf

also the top 2 stars in the sidebar are to screenshots of especially helpful bits of that paper

Yes, heating is probably cheapest and simplest way to store the energy overnight. Not sure through that molten glass/lava is the easiest technology wise, mostly because it freezes after some point(which is still hot and useful) Basically heating regolith on conveyor and stockpiling it would work the same way,

@Hohmannfan hi

Yes, but the phase change of the melting is in itself a good energy reservoir.

@Hohmannfan oh wait - you know that. i thought i was talking to MolbOrg. You think we need something better, huh?

@Hohmannfan I have shittier programs and I'm satisfy, they do what I can't so more power for shitty programs which make our live easier

@kimholder Not really, the papers show enough to prove the approach is usable. What is missing is a good design. That part we have to guess for now.

@MolbOrg Yes, they do work. Useful, but not THe-ONe-MAsterpiece.

8:46 PM

i had already been toying with the idea of clearing a space around most of the tank so that it can be tapped for other purposes. what MolbOrg says makes me really want to come up with a good way to do that.

Use your Blender powers

I am home for the weekend. Learning my little brother to be a proper super villain.

@Hohmannfan i am in fact doing that right now

true, and how much it is in the case? and yes probably melting freezing isn't that big of a problem if it is a permanent storage. The heat exchanger will be more of a problem, in the case of burying pipes in the regolith and making a bigger stockpile pipes can be made from the same material(ceramic pipes) and jut move the dust around to the place to cover them layer by layer.
It is scalable and you basically can make it as big as it is needed with lesser effort and lesser demands for the precision, materials etc. Freezing stuff in the container means contraction and expanding, stresses on t…

or better iron,aluminium pipes, easier to seal them, bend, keep them warm enough if it is needed.

9:03 PM

user image

alright, that tank is 60 x 60 meters, and has a good 20 meters to the north and the south to put in other infrastructure beside it.

obviously many other things need to be updated in consideration of that

at least it turns out that the area was already 60 m wide, i just hadn't measured it and forgot i'd made it that large :P

but what did we say we should count as a buffer zone? 5 m of regolith on all sides?

so that would make the zone that is actually tapped for heat 50 m across by - lets call it 50 m deep so there is a little room at the top for whatever reason

and then there is the big brother of this arrangement, on the hill, that i only started working on and then set aside.

so, i'd say, the whole top of this thing should be re-thought - how best to capture and sequester vapors

and maybe there should be a place where the contents can flow from the side and be sent into a processor

* I wonder how much models are better than pictures, used them just a bit and now I'm totally spoiled ))

i need to split that whole thing into parts that can be worked on separately, and then are put together to make the whole

there are many, many different levels of sophistication in blender

by the way - that luxury of being able to refer to a model is what i hope will cause moonwards to take off once it is large enough.

this installation is 4.5 degrees S, and because the inclination of the sun changes so little over the course of the year, the angle of the sun stays between 3 and 6 degrees of vertical on the north - south axis, all year.

an installation like this at the poles could, of course, get sun for months on end if it was in the right spot, and though you could use just photovoltaics for power, if you do it this way, you have a constant processing stream for whatever product you can extract using that heat.

@MolbOrg i'd favor iron, for the pipes going to the turbines. there is lots of it and it isn't hard to get at, and it can stand hotter temperatures.

but that means the loop closest to the core can't be where it will get hotter than maybe, what, 1400 C, when the tank is at its hottest.

9:33 PM

Locally produced iron is going to be really bad. But I hope it is usable for pipes.

we might be able to afford to make them thicker to make up for weakness, and still have that be cheaper than importing pipes.

A cavity through regolith that does not collapse by itself. That is the only quality requirement.

what about the way the melt pool expands and contracts?

difficult to deal with.

i suppose we could keep all the pipes outside that zone, always, and the diffusion of heat would still make them hot enough to serve the turbines

but i don't know if their temperature could be kept steady

9:37 PM

IDK I would use them everywhere because it is easier to form and shape them, seal/connect them. They do not need to be strong or super duper, making a 50x50 m heat exchange grid, with 10-20 cm distances between them, 100 layers of that and not expecting them to crack is just priceless.

to crack under regolith pressure, from temperature changes etc

That raises the question about what the working fluid is though. It has to be something we can afford to waste quite a bit of.

nitrogen is often used for brayton turbines of this type

usually for iron are bad S, P what else - if those are present on moon in quantities to make the iron bad is just good ))

P would be a blessing.

sulfur we don't have to worry about, there is almost none. phosphorus, maybe 0.5 % in the basalt right around the colony

9:42 PM

Take (element.amount in life)/(element.amount total) for all elements. Sort the list. P is the bottle neck for our expansion.

@kimholder Sadly, nitrogen is close to impossible to produce on the Moon.

iron will be not the steel - because of the absence of carbon - other metals do not make it super worse so I guess iron should be pretty fine

fine quality - but it is a question to investigate, in general

@Hohmannfan yes, but it is pretty easy to import. and there might be some in the polar ices.

The total lack of carbon makes some quite interesting forms of iron metal.

@kimholder 1. Why? 2. How?

import tanks of liquid nitrogen? we need it for all of the air, anyhow. polar ices, couldn't tell you.

at least in the turbines, it is a closed cycle. it just keeps going around the loop.

we just have to try to prevent leaks

Did we end up with a 1atm atmosphere?

9:47 PM

i think that is the best idea, long term

at first, we could go as low as 0.7 atm

it makes it hard to fly, but i guess i can live with that :)

I disagree with it being the long term goal. But I am going to bed soon, so I can not argue now.

we could maybe meet in the middle. in the long term, i don't think the challenges of containing a bit more pressure would be a big deal.

Oxygen. not a super choice for heated stuff, but with the absence of water and water vapors which kinda are catalysts of rust forming, and probably with an aluminum coating or aluminum tubes oxygens can be used to the certain temperature.
And there is no problem to extract oxygen from oxides.

@kimholder But what is the benefit?

@MolbOrg oxygen burns really well. it makes me nervous.

9:50 PM

@kimholder Burning needs something to burn as well.

We can not have that anyway, so oxygen is no problem

@kimholder nuclear plants explode - I'm stoic about that ))

@Hohmannfan frankly, a more ideal living environment. flying to me is a big deal. the city is being designed to incorporate it a lot.

The most flammable thing in the base should be the bodies of the cosmonauts. No other things should be permitted to have that property.

actually molten aluminum can be a heat carrier in some places, one of the problems is the possibility to plug the whole thing

@MolbOrg Molten aluminium has some nasty crystal forming properties. That makes me worry for the pipes.

9:54 PM

@Hohmannfan it just has to be used in places where replacement can be made easy, and where temperature is high enough to prevent all that forming

So, in the hot part of the nuclear end of the thermal system then.

I'm more worried that it may dissolve metal and thus destroy the pipe over time. So it can't be used in places with no easy access

Some metals are indeed easily dissolved in aluminium. I have forgotten what metals.

brayton closed-cycle turbines are usually designed to run on non-reactive gasses

but it can be used inside ceramic pipes - but still needs some durability tests/estimations

9:57 PM

I remember my father telling me not to try using regular steel screws in aluminium plates.

there is data for ones using nitrogen, and in the interest of realism, detail, and also because it isn't like the pipes constantly need to be refilled, i don't know why we would use something else

@kimholder helium and hydrogen fro them - they definitely has to be protected from the oxygen

@Hohmannfan electrochemical potential, makes the aluminium corrode faster(if I recall correctly)

There are at least two heat exchangers in between the turbines and the rest. We can have multiple systems.

ah. that occurred to me after i typed that in.

@MolbOrg Aluminium boat and bad on board electrical system →RIP your boat :)

10:01 PM

@Hohmannfan exactly

(you don't want to fall in the water where Hoh lives. Very cold.)

I looked it up. The current sea temperature here is 6 degrees.

for the record, the regolith around the colony may have about 0.5 % P2O5. which still actually doesn't look right, because is part of the regolith, so why would it have 5 oxygen atoms. but that's what the chart says.

@Hohmannfan [shudder]

@kimholder Phosphate reserves are measured in that way, even if that is not the actual mineral. Common on Earth too.

they break it down and measure what comes off, i guess, right? that makes sense...

10:08 PM

most likely oposite, it forms phosphoric acid and it is easier to detect the acid

and you can make testing in a solution etc

Measuring elemental phosphorous is more difficult and makes less sense.

ah

okay, so for starters, i need to add heat exchangers between the tank and the turbines.

would that be one combined unit using 2 fluids?

@Hohmannfan Mg probably, aluminum-magnesium-silicon alloys are pretty common stuff

@MolbOrg More ore less the composition of regolith.

heh, i thought the same thing. minus the pun.

at least, for the highlands. but it also has calcium.

and a whole bunch of oxygen.

10:14 PM

@kimholder Search for "heat exchanger diagram" to get plenty of inspiration.

hmmm...

pretty interesting about aluminum alloys totalmateria.com/Article55.htm I have though that they are a bit simpler stuff ))

> Mercury has been used at the level of 0.05% in sacrificial anodes used to protect steel structures. Other than for this use, mercury in aluminum or in contact with it as a metal or a salt will cause rapid corrosion of most aluminum alloys

They are not kidding.

(space after >)

But that hides the intentional markup :P

> does it
>> nest
> > or like this
inside a > sentence? (unlikely)
>>> special with three of them?
:> combination?

feature mapped.

10:21 PM

!>lalala

…

unicode tricks. i forget how that one works.

that one is truly potentially useful.

and makes you look cool in nerdy chat rooms.

Yay!

40x40 meter tank seems to be too small to me - if there is let's say 5MW consumption overnight

it's actually 50 x 50 at the moment

and remember its big brother will be added on the hill

10:25 PM

@MolbOrg You are correct. The 40x40 is based on a lower power consumption.

how much?

A low .5-3 MW. The numbers are sensitive so the precision is low.

the output i listed for what there is at the moment is 10 MW - so i should drop that figure down then.

@kimholder Now you have numbers :P

I see why you decided for the tank - with molten stuff it probably a good pick.
I see the problem differently - how easy it is to build it, how scalable is the solution, how much processes are involved in the thing.
Is there some reasons besides it can store a lot of energy because the stuff is molten and at super high temperature

10:32 PM

Well, a thermal system is needed anyway for using reactors. This is basically extending the buffer into a full energy storage system.

other reasons to use a tank, you mean?

yes, reasons to use a tank with molten stuff.

a tank can be isolated from the surroundings. that makes it easier to precisely control it.

the pipes from the mirrors to the tank get longer and longer, the more units you add. unless you make the mirrors wider and raise the trough.

@kimholder more in sense of heat storage, because the layer of regolith can be used as heat storage and it will be isolated by itself and the crust - just lay pipes and cover it with stuff from the side

there are still considerable heat losses over the entire night

and it makes it more difficult to do the other things we are talking about

the early days of the settlement are powered by nuclear reactors, so by the time this is done, the machines to do it exist.

excavation isn't that hard, the system for that is pretty robust

10:38 PM

true, but is just matter of how much energy it costs us produce aluminium foil for reflectors and the construction and the capabilities to produce them

import the foil. it's pretty light.

after all, we have to use that huge cargo capacity i'm making for something

for that matter, one thing that still has to be modeled is the production of mirrors in quantity

that would be vacuum deposition of aluminum on a substrate, probably of a basalt glass material

that would take a lot more manufacturing, but it would take very little aluminum

also - the dust roasters produce aluminum

no need to import, even no need in having the foil - the coating on the proper surface is enough.
But it is actually my point the collector might be very cheap construction

so heat loss has to be acceptable level and does not have to be perfect

what about collection of vapors?

appealing part is ease of establishing of the field, it can be done remotely (which I'm personally interested in)

a tank can be emptied and filled as desired. the contents can be adjusted to yield desired mixes.

10:46 PM

@kimholder it does not disturb the whole idea, and actually can be part of it, you scrap the vapors from heat exchangers which pump heat in the heat storage, and if the storage is at lower (not molten temperatures) the heat will be good enough

but if you don't have a closed system, you are going to lose some of those vapors

well, actually i suppose not.... the edges of the molten field will turn to rock and basically stay that way

i still like a tank overall. there are a lot of large rocks in the regolith around the site

they would totally mess up your heat flow

for 50% efficiency of energy storage 300K temperature difference is enough, and if it will be 50% I count it as a good deal, for simple, scalable and easy to make construction.

remember that thing about the regolith only being 6 m deep?

@kimholder if you talk about refining the regolith, there is no need to care about that, it is for free around, and it is hard to loose those compositions (except of gases)

the composition of the regolith constantly changes, and there are a lot of rocks in it around lalande - way more than average, thanks to the crater.

the mirrors are very easy to make and tack on more, but what about the pipes that carry molten salts to the lava pit?

those require specialized materials, that part might be expensive

10:54 PM

yes, I remember about 6m, scrape nearby field of the same size and make it 12.
But yes, working on larger surface and move a lot of regolith _vs_ drill bedrock and be more concentrated in efforts
I have to calculate heat losses for the field

there is increased difficulty in making the tank, but once you've made it, the efficiency gain is permanent

my points are anyway it needs to move regolith, a lot of it for metals, for gases

to be fair, the regolith is a lot more than 6 m deep, it's just that under the first meters, there are more and more large chunks.

and where the lalande colony site is, the regolith is probably twice that deep if not more, because it is right on the edge of a crater. but there are also a lot more rocks for the same reason.

@kimholder Here is how you can use the spoiler formatting. Use this script to set it up, and after that you can just run:
spoiler "text here"
to get it on your clipboard. Ctrl-v to paste into chat.
Setup command follows:

the tank could be fed, along with a bunch of other reactors and the dust roasters, just with the material that is excavated for the galleries over the first years of the colony

10:59 PM

yes, that true. it is probably because of difference in goals - my is fast grow, less humans faster resources to orbit stage, humans in space habitats.
But in general energy balance has to be positive, and both systems can exists for different reasons

sudo apt install xclip && cd ~ && echo " " > .spacestorage.hoh;for i in {0..800};do sed -i -e 's/$/\xE2\x80\x8B/' .spacestorage.hoh;done && echo 'echo "$1" > .tmpspace.hoh && cat .spacestorage.hoh .tmpspace.hoh | xclip -selection c' > .spoilerscript.hoh && chmod +x .spoilerscript.hoh && alias spoiler='./.spoilerscript.hoh' && echo 'alias spoiler='"'"'./.spoilerscript.hoh'"'" >> .bashrc

gee, what an awful lot of hohs there are in there...

Just to not accidentally mess up any other files and make it easier to find later

do i need to think about that odd box section in the middle?

box?

11:02 PM

do you see the box around the text that starts with /\?

Screenshot?

seems charset is missing so he gets replacement instead of symbols - I see no boxes

i now have so many screenshots on my desktop that every time i take a new one i have to hunt for it...

user image

Looks like a $ inside does that.

Let me see if I can format as code

save screenshots to picture folder, have thousand there, pick the last by mod date each time

11:06 PM

I setup my screenshot to prompt for filename. That makes things more organized.

yeah, a lot of the time i like to have things on my desktop so that i remember them

but that system is breaking down...

@kimholder Is the box gone?

my names it like screenshot and data-time and does not ask me for anything ))

Ah! yes, it is :)

actually, i'm also always prompted to give it a name and almost never do

…

Yup, it works.

11:10 PM

is that xclip the stacking clipboard thing you mentioned?

No, it is just a way to send things to your clipboard.

It may not be installed by default by all distros, so I added that install part just to be safe.

yes, it did indeed install it. and then i decided to do an autoremove, and it is still working on that :P

A bunch of old kernels, eh?

yep

…

it works!

Just remember to paste it in its own chat message and not at the end of a longer one.

In the book <x>...
SPOILER!

…

11:16 PM

ah yes - important to get that 'Spoiler!' part in the right spot.

well, i'm going to make dinner. over the next couple of days i'll make changes to that solar thermal model to reflect what we've discussed

good night.

i am going to make it not too neat, just fast so i can adjust it based on feedback

good night Hoh

talk to you soon, MolbOrg

kk

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Apr '1729

Moonwards

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