Converting Slabs of ice into seas. Brine Resouces.

Calliban · 2020-07-03 17:12:36

I am not sure I understand what you are describing. I believe the ice pond idea is a good one, but it will need some sort of glass or polymer covering structure to prevent dust from contaminating the ice and destroying the transparency. A non-pressurised greenhouse would also help control evaporation losses. If the greenhouse is carefully counter weighted such that internal pressure were ~1KPa, the water could remain liquid.

Ideally, we would want to thermally stratify the pond so it is warmer at the bottom. Thin polyethylene sheets would be a cheap way of doing this. These would be anchored to the bottom. They would suppress convection between the upper and lower water layers and a boundary layer would form of each side of the sheet, providing insulation. The bottom layer could be much warmer than the top. Silica aerogel would be even better, but it is expensive. If the layer of water under the sheet is oxygenated, it will be darker due to the presence of algae. It will therefore absorb sunlight. We could have multiple layers of polyethylene, forming a sandwich insulation. Oxygen bubbles under the sheet would further improve insulation.

Void · 2020-07-03 17:27:04

Many plastics will break down under the Martian UV.

As for the ponds, at the very cold Martian temperatures even in the polar summer, sublimation of surface ice may be something that can be handled.

Starting with the ponds. If you have a (+) charge in the pond water under the ice, then if you could charge cold steam with an opposite charge (-), you may be able to electrostatically deposit fresh ice at a rate satisfactory. The ice is an electrical insulator. If you kept the surface of the ice at a charge opposite from that of the water, then you have a capacitor. I think the British even call it a condenser sometimes. The opposite charge polarity could also be tried.

I am looking for a way to have a transparent/translucent window without using plastic films or glass to protect it. I think the best chances are in polar areas where it is rather cold in the summer.

And all during the growing season in the summer, I would intend to have a vapor well to supplement the ice as necessary. A vapor well would be a borehole drilled by a laser. It would be kept at a sufficiently low partial vacuum inside so that water vapor would not condense. For the ice temperatures probably, that might require a pressure in the borehole of less than 1 mbar. Of course there would be a lid on the thing, the laser depending from it below the lid. Korelev crater ice and polar ice cap ice goes rather deep. Might be some trouble with dust layers, but maybe not a major impediment. And as a bonus, you could drop sensors down the bore holes and get data at times on the ice layers.

The vapors extracted would be somewhat pressurized, given the suitable electric charge, and electrostatically painted to the surface ice outer layer as required.

------

For the igloo dome, a metal frame of as fine a mesh as is needed, and then paint ice onto it, replenish as necessary. Again a differential electrical charge between the inner and outer surface, so as to use electrostatic force to try to raise the "Air Pressure" of an electrostatic film on the surfaces of the ice, so as to reduce the tendency to sublimate.

And then inside of that a inflated and otherwise thermally protected tent for growing crops.

Again, a borehole to continuously replenish any ice losses during the summer.

If the ice by itself is not good enough to block and absorb U.V., then add some Titanium Dioxide powder to the ice.

-----

In the case of the pond, the ice layer is a thermal insulator, so the surface may not get all that warm. If the electrostatic force field works, then that will discourage sublimation. But I will confess U.V. absorbed in the ice may tend to warm it up. Perhaps that will be a problem, but as I have said, the ice sheet can be "Watered" by electrostatically painting a highly humidified cold air on it.

For the ice dome, yes sunlight will try to sublimate ice off from it, but similar treatments of electrostatic humidity may counteract that.

And if the air between the ice dome and the plastic bubble in side is ~10 mbar, then you are beginning to have a thermos bottle where convection will not do as much as it might on Earth, as the air density is ~100 time less, and the lower gravity of Mars will slow down convection. Heat radiating from the plastic bubble? We we have window coverings that can reduce that. We use it to conserve energy.

And if you really want to put up with my BS, I did say a metal mesh. That could be cooling pipes. But I will admit, I was trying to avoid complexity. But it might be worth it.

It needs to be remembered that both polar ice caps and probably Korev are more or less the lands of the midnight sun, which would be good if you could create an environment where crops would grow. You would shut the thing down during the winter of course.

And we have one other possible useful factor of the ice sheets. They are reflective. With clever methods it may be possible to "Amp" up the amount of light that is received by the devices. But that is complexity also.

Farming in Alaska is rather favored in selected places because of the long duration of the days.

Maybe these if tested will be graded as "Fail", but I am not sure of it. And also room should be left for further discovery and innovation that might bring these systems in to "Passing".

Done.

Last edited by Void (2020-07-03 18:06:59)

Void · 2020-07-03 18:23:56

I will back away from my notions a bit, and say that I think Korolev crater will be much easier than the polar ice caps.

It seems to have a permanent weather conditions that locks mosture.

I think I understand Dr. Zubrin's moat lake around the ice slab. No special tricks needed, just add liquid water from the ice, using liquid water. As the ice surface may evaporate over time just add more melted water. I believe he said nuclear power.

My stuff is more on the edge. It may or may not work and it may or may not be worth it.

I will say this, if some of my stuff is a fail, even so, with the moat lake, it will be possible to have methods to directly use sunlight for plant growth.

Also, remember that the ice slab gardens are not essential. But the solar panels with power transmission to receivers, perhaps by microwaves should be worthwhile.

Done.

Last edited by Void (2020-07-03 18:24:14)

Void · 2020-07-04 09:30:29

Perhaps sunscreen. Specially made, maybe spray on, oily, hopefully forming a skin over the cold ice, blocking some U.V., and making a vapor barrier. Probably would need changing out periodically. Just scrape it off, and spray on new. I presume some Titanium Dioxide in it.

Worth a look perhaps, if it does not cost too much.

Done.

Void · 2020-07-04 10:19:10

Don't mind me, I am just mumbling to myself.

Yes some kind of oil with fine particles of Titanium Dioxide in it, something which would be rather stable in a vacuum, so as to discolor slowly.

Silicone Oil?

https://en.wikipedia.org/wiki/Silicone_oil
Quote:

A silicone oil is any liquid polymerized siloxane with organic side chains. The most important member is polydimethylsiloxane. These polymers are of commercial interest because of their relatively high thermal stability and their lubricating properties.[1]

I like the words thermally stable. But the stuff is likely sort of expensive, but maybe worth it, if it suits the needs.
I am guessing it may form a solid film at polar temperatures.

Some are very good at high vacuum, I know from work experience, or I think I know

So, who knows? Maybe it work.

For a pond greenhouse or the ice dome greenhouse, we don't particularly want to have the ice absorb either infrared or U.V. Just want it transparent/translucent to visible light that plants use.

So, I give it a five star maybe for potential. Some form of it, perhaps specially invented.

Silicone oil sunblock for Mars ice.

Done.

Last edited by Void (2020-07-04 10:25:51)

Calliban · 2020-07-04 18:00:09

You would need some kind of covering to prevent ice from subliming in most locations on Mars. I would propose a transparent polymer cover, which is coated with a mixture of organic and inorganic blockers. This could be periodically replaced as the UV degraded it. Rather like polytunnels of Earth. They don't last forever and it doesn't matter so long as they are cheap.

Then again, as you suggest, if sublimation is a slow process and you have an abundant source of water, you could simply top up the ponds as the ice layer evaporates. The inorganic blockers would remain in the upper layer of the ice sheet and the sheet will regrow from beneath due to heat transfer out of the top layer of water under the ice. One would expect the ice sheet to grow and shrink depending upon the amount of solar radiation reaching the pond each day. During the Martian winter, the ice would grow very thick. In the summer, it would be thinner.

I think your idea of ice covered ponds for aquaculture is a good one. Provided that sufficient volumes of ice can be found, it is arguably more efficient to produce food and organic materials on Mars in aquaculture systems, rather than in pressurized greenhouses. If you place a layer of aero gel under the ice sheet, then the water beneath the aerogel could in principle be significantly warmer than the ice above it. The floating ice sheet would provide the pressure needed to prevent the water from boiling. At a water temperature of 20C, the vapour pressure of water is 2.33KPa, equivalent to the weight of an ice slab some 70cm thick on Mars. It would still have 90% optical transmittance. The only problem I can see is contamination of the ice sheet with Martian dust blown in the wind. This would rapidly ruin its optical properties. Which is why I suggested a non-pressurised greenhouse over the top of the pond. Maybe a polymer cover, which could be hosed down periodically.

The bottom of a deep ice covered pond, may be a good place to build human habitats on Mars. If a layer of aero gel is placed under the ice sheet, the water can be maintained at room temperature. The colonists could enter the water equipped with an oxygen mask and weighted boots, but would not need counter pressure suits. A colony built at the bottom of the pond would need to counter the effects of buoyancy and would need to be water tight. But the structures would not need to be pressure vessels, because the weight of the water would counterbalance internal pressure. The best option would be concrete structures, since the forces acting on the structures are compressive.

Last edited by Calliban (2020-07-04 18:19:21)

SpaceNut · 2020-07-04 20:59:18

Once you have a steady state water lake under ice or sea we will need to aerate the water for fish life to exist, plant will still need some but not as much oxygen so a co2 bubbler would be ok to aerate with. Forcing air into the water will mean a thicker heavier ice layer will be needed.

Void · 2020-07-06 10:09:33

I appreciate the inputs from both of you Spacenut and Calaban.

I took the weekend off to think about things further.

This topic has been useful for those inputs, and also has challenged me as well, to assess which parts proposed seem more plausible, and which are perhaps needing more innovation, to be even possible.

One thing I think is going to be excellent, is that we have many crater rings on worlds like Mars, and it does seem to me that power distribution by microwave, could really be useful.

Korolav seems like the best place to start developing such a method, and many other proposed methods.

However, I think that it is more likely that if SpaceX does it their way, we will first have at least a town, in their preferred location on Mars. And that is OK.

Calaban, I am looking into Silicone products now. Have a hunch that although they may be expensive, there could be a potential for their usage in some needs on Mars. I think they may have analogs to Carbon based products that we call plastics. I think they may even be able to be desired transparent materials/ Translucent materials.

Here are some hints in that direction:
https://www.wisegeek.com/what-is-silicone-resin.htm
Quote:

Silicone resin exhibits very good resistance to ultra-violet light degradation

https://www.bing.com/videos/search?q=tr … ORM=VDQVAP

I guess if we have a choice for naked ice, or ice with cloths on, I guess the calculations must be based in practicality and potential economic gains.

I think that Silicone products should be strongly investigated for Mars. If useful, very fine Titanium Dioxide particles could be included into it, which may make it more useful, and perhaps increase it's working life.

While window glass, and plastics that include Carbon and Fluorine are also important to look into, we now have another path to seek into as well.

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If you are the kind of people who feel that the words naked or exposed ice, entitle you to first outlaw it and then sell it on the black market, please go away. I guess we could use the words native, or natural ice.

Here is the primary game. Find out what they want/need. Take it away from them. Sell it back to them.

I really am unfortunate/fortunate, as I do see some of the silly and also tragic characteristics of humans with a low awareness of what they are about. Oh well, they does what they doze.

So, I guess, a safe verbal zone is to say we might irrigate a body of water on Mars (I said body ) Some of you peoples are so weird. I pity people who willfully choose not to have eyes to see, or those who are just blind to what words do.

So, a ring moat lake in Korolav crater could be ice water, and exposed ice. You might just not care, as you continually renew what evaporates from the ice. Maybe this is a do, that is worth the trouble.

OK, batteries getting low, getting a bit harder to care.

If you have such a body of water, that can be effectively made to persist to exist for your purposes at a acceptable cost in efforts. It is a layer that indeed could allow some means of agriculture. Not that other things may not. Other proposals should be evaluated for use. Glass greenhouses, Fluorine containing plastics and maybe now silicone involving products.

OK a liquid water column. At this time I see some options.
1) Sunlight, either as is or with concentrating mirrors, (Either above, or in the water).
2) Artificial lighting.
3) Chemosynthesis.
4) Electrosynthesis. This would I am afraid only involve slime things, micobes.

And I am getting restless, want a walk.

I will see what other Wise Dumb I can inflict on you later.

Done.

Last edited by Void (2020-07-06 10:55:37)

SpaceNut · 2020-07-06 19:00:08

Korolev impact crater, two-kilometre-deep crater is permanently covered by an ice field that has a maximum thickness of 1800 metres. This deposit forms an extensive reservoir of non-polar ice on Mars, the volume of which is estimated to be approximately 2200 cubic kilometres.

https://www.dlr.de/content/en/articles/ … -mars.html

•This simulated flight takes the viewer over the 82-kilometre-wide Korolev Crater on Mars, which is permanently filled with water ice.

Void · 2020-07-07 06:52:48

I like that Spacenut.

From Spacenuts post #10:
https://www.centauri-dreams.org/2020/05 … -for-mars/

Manufacturing ice caves/domes is discussed.

I am going to suggest and early adoption by SpaceX. They are not expected to choose Korolev crater for their first adventure, but they do intend to locate where there is a lot of ice.

I see a length of 160 feet / 50 meters for Starship, from this article:
https://www.bing.com/search?q=Length+of … 9c4e834c13

Ice Slab:
https://www.aol.com/article/2015/09/14/ … /21235627/
So we have an ice slab of great size, and some depth:
Quotes:

Scientists have long known that there are large quantities of ice underneath the surface of Mars, but recent research reveals that the subterranean ice field may cover as much area as California and Texas combined.

Data from the combined experiments revealed that the buried layers are ice, and lots of it, measuring 130 feet thick in places.

And it is I believe at the edge of Arcadia Planitia:
https://www.inverse.com/article/59036-s … nd-on-mars

So, at first they are going to mine the ice it is supposed. I am after something(s) in connection with that.

First off, I would look at lasers as a mining tool. You clear off the dirt, and make a hole to land a Starship into. ~130' deep (Speculative), leaves 30 feet of that Starship sticking up out of the hole.

The bottom of the Starship is sitting on regolith. You fill the hole around the Starship with ice. Melt, refreeze? Some problems there perhaps. This does need more work.

The easy part of laser mining, would be to simply vaporize the ice with the laser, and have some kind of a method to vacuum it up. I will leave that open for ideas how. I originally though a sheet of plastic and a suction. But we could just have a vacuum cleaner hose. Compress the vapors into liquid water in a tank.

Back to the Starship, I believe that fully used for pressurized volume, it might be 2400 Cubic Meters.

Having the Starship mostly surrounded by ice, will complicate things if you want to heat the interior. So, work needed there.

But you have some fair radiation protection. I don't believe that the sun will ever be directly overhead, so that it protective. There would be options for additional radiation protections for the overhead, if needed anyway. Perhaps a pond of liquid water with duckweed in it might be a method for that.

If you have a hatch built towards the base of the Starship, then you can open it, and begin horizontal laser water mining, and propellants manufacturing. So, instead of strip mining, doing horizontal shaft mining, it is possible that the created tunnels, could be pressurized, and utilized for various things. The floor would be Regolith. And pressurizing ice volumes is covered a bit in this article.
https://www.centauri-dreams.org/2020/05 … -for-mars/

------

A bit related might be to dig a silo in the Korolev ice mass, line it with bricks, and have a lid device that could be deployed over it to "Shut the Garage door. For maintenance, maybe even for unloading.

Done.

Not Done

Um....Instead of filling around the Starship with ice, fill with soil that will freeze. Put a layer of dirt down, let it cool down at night, the spray it with steam to freeze. It would be a cold steam. Repeat....Repeat until filled up.

That way, it should not buckle the ship inwards. Sort of an additive manufacturing Pykrete. https://en.wikipedia.org/wiki/Pykrete

I can think of various methods to insure that the pressure seal is maintained even if the Pykrete melts lower down. But probably a good idea to thermally insulate the walls of the ship. May be possible to attach a sequence of toroidal/disk flanges as you fill the hole with Pykrete. Like anything I would think that over time best practices would be discovered.

Also, something that I would almost say is cute about this system, is you can have many Starships in holes connected by ice tunnels. A city of sorts.

Done.

Last edited by Void (2020-07-07 07:59:35)

Calliban · 2020-07-07 09:34:06

Void, just finished reading the Centauri Dreams article written by Zubrin. Some excellent ideas, I think. The only problem I can see is that ice is only stable on Mars at very low temperatures and at low insolation levels. This makes it difficult to see how we could use ice slabs or domes as roofs for agricultural areas. The best options for agriculture are relatively close to the equator. One option might be to cover the ice sheet in glass or plastic, preventing sublimation. But this is relatively expensive. Zubrin talks about using electric power to provide artificial lighting in an aquatic ecosystem. Previously he dismissed artificial lighting for agriculture as being hopelessly uneconomic.

What are your thoughts?

Void · 2020-07-07 09:52:15

It is very good of you to give the attention you do.

I believe from the start that I can contest the assertion that the equator is the best place for agriculture.
If you think about it, how well does agriculture work in the Mantanuska and Tanana valleys work in Alaska?
https://en.wikipedia.org/wiki/Agriculture_in_Alaska
https://en.wikipedia.org/wiki/Tanana_Valley
Land of the midnight sun. The very long summer days suit some crops well.

If Alaska were as it is now, but on Mars, the growing season would not be ~90 days, but ~180 days. This is why I suggest seasonal migrations for most Martians. Live a life of Summer, and a bit of Spring and Fall, at both poles.

Now about ice protections. I start with bare ice and do whatever is then necessary to make it stick around for a while. It may not be that different from irrigating crops in the desert. OK, you have the Rio Grand, and you are irrigating crops. You use a lot of water. It evaporates, as expected. But as long as you have replacement water you are OK. So, that is where I start with Korolev crater's presumed Moat-Lake.

If it is more expensive to replace the water, then I guess you think about how you may use some techniques to reduce the water losses.

That article is not only about artificial lighting:
Quote:

Assuming that the ice cover is reduced to less than 30 meters, there will be enough natural light during daytime to support phytoplankton growth, as has been observed in the Earth’s Arctic ocean [5]. The lake’s primary biological productivity could be greatly augmented, however, by the addition of artificial light.

And I support the use of artificial lighting, as if the system were nuclear, you could grow crops year around, dust storms or not.

As for the ice, if it is >30 meters thick, even so, the amount of heat conducted from the liquid water to the ice surface would be minimal, not a concern I will venture.

As for the sunlight. Well it is a concern. Particularly the U.V., which may absorb into the ice. The Infrared should bounce off, and the visible may penetrate to some degree.

For most places on Mars, I do expect that assistance by some means is going to be required to reduce ice loss. But Korolev may be an exception, and I am looking for an exception.

And please keep in mind, that for my assertions, we may not only be thinking about the now, but perhaps how things might work if the atmospheric pressure is doubled, which seems possible in the future.

To start with some questions, are how warm will the surface ice of a lake in Korolev crater become in the summertime? There will be very little heat from the water going to the surface ice. So, it is mostly a matter of how much will the sunlight warm up the ice. Also of concern may be the velocity of the winds, that may sweep over the ice and absorb moisture from it.

I will admit, that I may have a bad case, but I think I want to discover truth about it.

Korolev seems special:
https://en.wikipedia.org/wiki/Korolev_(Martian_crater)
Quote:

Ice formation
The ice is permanently stable because the crater acts as a natural cold trap. The thin Martian air above the crater ice is colder than air surrounding the crater; the colder local atmosphere is also heavier so it sinks to form a protective layer, insulating the ice, shielding it from melting and evaporation.[2][3] Recent research indicates that the ice deposit formed in place within the crater and was not previously part of a once-larger polar ice sheet.[4] The ice in the crater is part of the vast water resources at Mars poles.[3]

So, we are already talking about ice that is stable in the sunshine. It is more or less reflective of at least the visible wavelengths. I am not privy to what the U.V. wavelengths do to it.

So, what happens if you convert reflective ice to transparent/translucent light? Well we have three main categories. Infrared should bounce off in both cases. U.V.? Honestly not certain. I think that the U.V. penetrates the ice in both cases. But this needs discovery. What about the Visible? Well, it penetrates the ice to a degree, even some of it may penetrate into a layer of liquid water at the bottom of the ice.

So, what is the vapor pressure of the surface of the ice going to be? There are two ways to remove ice. Exceed the triple point of water, or dry winds blowing over an ice surface that is warmer than those dry winds.

Last edited by Void (2020-07-07 10:22:12)

Calliban · 2020-07-07 10:20:13

Yes. I suppose the long summer days in the northern hemisphere would be an asset for the production of food. And we don't have to grow food all year round, as we do have the ability to store it.

This link throws into question whether sublimation of ice would be such a problem after all.
https://www.lyotechnology.com/vapor-pressure-of-ice.cfm

At 0C, the vapour pressure of ice is just a tad over 600 Pascal. It would appear that the Martian atmosphere has enough pressure to prevent rapid sublimation of ice so long as the radiation temperature at the ice surface, does not approach melting point.

A thin layer of titanium oxide doped polymer would prevent evaporation. If it does degrade in Martian sunlight, it wouldn't actually matter that much so long as it is cheap to replace. One cubic metre of polyethylene, extruded into sheets 0.1mm thick, would cover 10,000m2 of ice. Or we could top up the ice as you suggest as it sublimes. It suggests to me that we could grow cereal crops in trenches under ice slabs in the northern regions of Mars. Reduced insolation would be partially mitigated by more CO2 rich atmosphere.

Last edited by Calliban (2020-07-07 10:21:32)

Void · 2020-07-07 10:35:28

I appreciate your abilities to dig, and to balance your vision.

Although it may be expensive, rather than polymer, I would try to look at a vacuum oil related product, with some finely ground titanium dust included. But that needs testing. If it absorbs too much U.V., then perhaps vapors will penetrate into the oils. Actually I am hoping for a solid phase of the oil at a low temperature. Or rather, a substance related to vacuum oils. I believe I mentioned that in a previous post. Polymers may easily yellow. But still, scrape it off and replace, is also a option to consider.

You mentioned dust in a previous post. It may be that that will be a problem as well. So, scrape, clean and reuse the sealant???

I am not going to assert certainty. I only suggest that we try to get by with the least bother, and then bother only as much as is required by reality, "Ground Truth", as someone on this site may say.

Silicon based suntan lotion for the ice then if required, provided that the skin of it does not reach the triple point of water.

Else, do what you must. If you pay for a formal glass method, you may then be able to reduce the ice thickness and make the waters more productive. It really comes down to feasibility and cost. Also we may question if there may be a more productive way to expend our efforts to achieve more. I am quite open to such arguments.

There is the option to add ice on as it might sublime, but easier may be to just keep adding liquid water below the ice, and expect that both the cold conditions of the environment, and the evaporative cooling will drive cold down into the ice and replenish it's thickness.

Lots of "Cool" questions.

If we do not upset the natural conditions of Korolev crater where it is a moisture trap, what evaporates off of the Moat-Lake, may condense out as ice on that large ice slab. So, possibly a renewable resource indefinitely.

Very good, something else to consider:
Quote:

It suggests to me that we could grow cereal crops in trenches under ice slabs in the northern regions of Mars. Reduced insolation would be partially mitigated by more CO2 rich atmosphere.

Good!

Done.

I think I will be unavailable for a while now.

Last edited by Void (2020-07-07 10:51:50)

Calliban · 2020-07-07 12:14:45

One thing that Zubrin's idea does depend upon is a large nuclear heat source. There is no way of melting a polar lake using solar power. So it come down to how best to produce a nuclear reactor that generates large amounts of nuclear heat.

Void · 2020-07-07 12:35:08

Lollygagging today, so I continue.

It is good for you to offer contrast to what I assert (Emphasis on A**).

One of the toys I like to play with is reuse of energy.

I am all for Nuclear, I don't think it will be done nearly as stupid as the methods we have used, where you get ecological disasters. Molten salt reactors, or the other things I have seen offered here.

First, I am going to make a case for forgetting about clear ice. Maybe it is more trouble than we would want. How about a covering of vacuum bottle snow. That is snow on Mars heaped up on lake ice, should be a good thermal insulator, because the air density is so relatively low, and also, the gravity being less, convection is relatively inhibited. And we know that reflective frost condensates in Korolev seem to be stable.

I do not necessarily dismiss solar though.

For instance I recall a discussion with GW Johnson, about boiling water with a solar concentrating mirror, perhaps activating a turbine, and quenching the steam in a body of water. A secondary neat trick then would be to extract the heat to boil something like an Ammonia solution, or who knows, CO2, in the Martian night, radiating the heat into the sky. Winters also. So, big enough lake, and you don't care about dust storms. You have electric. But nuclear can make similar claims, provided you have the nuclear fuels.

Another way to play the game would be to have your factories underground under the lake. Your waste heat from industrial processes then going into the lake. You may then dump the excess heat to generate electric power.

Another trick is chemosynthesis. While I think it would be great to have underwater artificially lit gardens, no reason if you have the power that you would not dump chemicals into the water. Not as scary as it sounds. Oxygen, Methane, Hydrogen. Microbes to feed on them, and by their metabolism to generate heat, which you may dump to generate electricity to the universe. Something like a moist hay pile heating up by fermentation, even to light itself on fire.

One interesting thing could be to indeed melt an ice cavern down to regolith. Make regolith berms around the edges. Make a dome of metal. Then you have the surface of the dome to walk on where it will need to be cold. Under the dome, you may have open water or ice, maybe both. In iceland, the air may be cold, but you might have a geothermally heated swimming pool. I am not so sure about geothermal, but I do think heated pools. If ice, then you may build flimsy plant grow houses. I had at onetime thought something like tar paper, but with basalt fibers.

And the entire flat of the Korolev ice mass is a reflector. Why not put solar panels on the south facing slope of the crater rim? it would get direct sunlight, and some reflected sunlight.

And sun following solar panels on the ice body. Or maybe an entire field of heliostat mirrors that can be pointed at south facing portions of the interior of the rim. Then your solar panels get lots of photons. Some, I believe can take very high temperatures.

We have looked at this before.
https://phys.org/news/2016-08-high-temp … solar.html
Quote:

In experiments, the new absorbers were shown to operate at a temperature of 800 degrees Celsius and to absorb light of wavelengths ranging from 300 to 1750 nanometers, that is, from ultraviolet (UV) to near-infrared wavelengths.

Possibly some heat could be extracted for other purposes, if that was not counter productive.
But the power from this if it would light up gardens ether aquatic, or underground, could be useful. If it is underground gardens, then you can cool it off with running water, and then heat your lake that way as well, again capturing waste heat to use to generate electricity in sunless times.

So, there are lots of games that could be played, in my opinion.

Only thing about exposed equipment on the surface, is that CO2 condensate may damage it in the winter. So, that would require some engineering.

But I kind of tip towards the nuclear, as I said, if you can get the makings for it.

Done.

Last edited by Void (2020-07-07 13:01:09)

Calliban · 2020-07-07 13:04:26

One idea that may be relatively cheap. Dig a circular pit, a few metres wide and maybe 5m deep. Cast a circular, disc shaped ice block, some 5m wide and 1.5m thick at the edges and 2m thick in the middle. Reinforce the ice block with transparent polymer fibres and coat the top with titanium oxide particles. These won't need to be in grease if they are embedded within the ice. The lens shaped block in slightly convex and polished, to minimise the potential for dust contamination.

Place the lens over the pit and pressurise with a suitable gas mix to 180mbar. You are going to grow plants at the bottom of the pit. That needs to stay warm - at least 5C at night and probably 10C during day. The top of the pit needs to stay cold to avoid the ice from melting or creeping, say -10C. So we need to maintain a 15 - 20C temperature difference. An easy way of doing that would be to put a layer of transparent polyethylene about half way up the pit. This would divide the pit into a warm lower layer and a cold upper layer, by suppressing convection between the two.

I probably need to do some heat transfer modelling at this point.

Last edited by Calliban (2020-07-07 13:12:08)

SpaceNut · 2020-07-07 13:08:11

continuing from voids posted link in #35

On Earth, 10 meters of water creates one atmosphere of pressure. Because Martian gravity is only 38 percent as great as that of Earth, 26 meters of water would be required to create the same pressure. But so much pressure is not necessary.
With as little as 10 meters of water above, we would still have 0.38 bar of outside pressure, or 5.6 psi, allowing a 3 psi oxygen/2.6 psi nitrogen atmosphere comparable to that used on the Skylab space station.

So a thin cover over the water and a supporting floor 10 meters down with the water in between provides the radiation protection, and makes for a natural lighted garden underneath the clear floor of glass. It would be supported on an Iron framed unit to establish the floor and ceiling for the living space.

So basically a fish tank with a clear plastic cover.
https://www.monsterfishkeepers.com/foru … ium.50760/
https://www.monsterfishkeepers.com/foru … 898/page-9

https://technicalglass.com/pressure_calculations/

That allows for a growing and living chamber under the water shield as created by the ice in the crater using a partial pressure living area.

Let’s do the math. Melting ice at 0 C requires 334 kJ/kg. We will need to supply this plus another 200 kJ/kg, assuming that the ice’s initial temperature is -100 C, for 534 kJ/kg in all. Ice has a density of 0.92 kg/liter, so melting 1 cubic kilometer of ice would require 4.9 x 1017 J, or 15.6 GW-years of energy. A 1 GWe nuclear power plant on Earth requires about 3 GWt of thermal power generation

So even if we are not using all of the energy to dump into the water as heat to keep it from totally melting and staying liquid we still would have energy for other uses inside the garden human living area.

Void · 2020-07-08 08:37:30

Yes, I think you are on to something. I think for this, then you use brute force only as much as you have to. Beyond that you adopt harmonization with what Mars will permit relatively willingly.

I have a desire to talk about your concept a bit. Probably take more than one post. And you may have to advise me if I have not sufficiently understood your concept. I think we are getting close to understanding what Mars will allow. As for the "Force" devices, such as ~Plastic Lid, and aquarium floor, which is the ceiling for your premium pressurized environment, we do have some notions. I think Robert has some good ideas for this historically. I will say something about glass, when wet it tends to be weakened. When in vacuum it tends to be stronger.

But necessity being the mother of invention, now that we have notions of what is desired to accomplish, we can expect inventive people to come up with notions of good materials for the various purposes. The Mars rules being different that the Earth rules, now there is a necessity for adaptation to the nature of Mars.

------

For now, it is relatively safe to suppose that what is needed can be available.

So, I want to run with it, and think about what will try to be in the water or ice of your tank, and how we might manipulate that. For the moment I have critters, and Henry's Laws about gasses dissolved in the liquid or ice. Also, the temperature cycles of Mars, and ice. Also how to handle U.V. according to various desires.

For your tanks, supposing one situation, (There are a large number of possibilities), simply pure water presumed. If you don't want critters, you may degas the water with a vacuum pump. And with this process you may extract some of the heat that might accumulate during the day. You may also do partially forced distillation. Some of the process would be from heat of the days solar flux, and some from the energy you use to brute force the distillation process. You may also try to eliminate nutrients with this process to further inhibit critters in the water.

But you may choose to harmonize with critters in the water. Regulate the nutrients, and have a robot to clean them off of the surfaces you want to be clear. And I this it may be possible to get the critters to work for us.

Typically in the Martian early morning, (More or less), the atmosphere is at it's highest relative humidity. And it should be slightly more dense as well, then during the day. So, with an electrical source, you may pump a quantity into the tank. But Henry's laws have to be abided by. You could pump it to the top of the tank, and then your plastic cover has to be stronger, to hold the additional pressure created.

Or if you have stratified water, you might dissolve the gasses (Including moisture), into a lower layer. This would be approximately like putting sparkling water into the bottom, with higher layers, imposing the force to stop it from fizzing to bubbles. Since you are using critters, and the gas will contain various dissolved gasses, you want the critters to treat the solution.

The first thing is to get rid of the Carbon Monoxide. As it happens there is about twice the amount of Oxygen in the air, so even at night, you may have some critters that will deal with the chemical food Carbon Monoxide by consuming it. During the day, we might presume that photosynthesis will be active, and consume the Carbon Dioxide. So, then what remains after that will mostly be Nitrogen, and Argon, and Oxygen, a mix you could extract at some point in this batch process. Henry's laws say that some of this will naturally move up the water column and form bubbles. So you simply degas what accumulates on the top, and at the same time may distill water. Of course some of the critter materials would need to be extracted by a robot, and maybe used to enrich soils, or grow mushrooms. You would then put more nutrients back in. Pre-treated human waste materials in some part.

Expecting some losses over time from your premium pressurized space, here then we may have a way to with some simplicity, have make up gas which has been ridded of the poison gas Carbon Monoxide. (Chemosynthesis actually).

Obviously you cannot do this during a Global Dust Storm, the night, or deep winters.

But this could actually be a system that accumulates water from the air, normally it probably does not matter. But I am going to presume some kind of industrial activity such as mining, in a particularly arid location on Mars. This could be helpful for that.

There are many other schemes.

I will rest for a bit.

Done.

Last edited by Void (2020-07-08 09:03:06)

Calliban · 2020-07-08 10:33:51

Void, if you compress Martian atmosphere under Mars night time temperatures (-100C) the CO2 will be liquefied at a pressure of about 100mbar. An axial compressor is probably your best bet at the low pressures involved. Very little compression energy is needed to do this, but you do need to provide a heat exchanging surface that the CO2 will concede onto. You can then pump it out of the chamber as a liquid and you are left with whatever remains - mostly nitrogen and argon, with about 2% CO and O2 from memory. Heat the resultant mixture and pass it over a nickel catalyst bed and the CO will react exothermically with the oxygen. It may liberate enough heat to make the reaction self sustaining.

The big question hanging over the ice covered pond or greenhouse idea, is how much photosynthetical available radiation we have left after passing sunlight through several metres of ice and water. If it turns out to be a lot (I.e at least half) then we are in business. If the water and ice absorbs a lot more than half, then it all begins to look a lot less attractive. We need to know the answer to that question me thinks. Keep in mind that Mars recieves has only 43% of the Earth's sunlight flux to begin with. We are most interested in those specific wavelengths that plants make use of, blue and red visible light.

Last edited by Calliban (2020-07-08 10:36:25)

Void · 2020-07-08 10:37:19

Spacenut, we should be able to incorporate a 4 door barometric airlock into your device.

Inside of the courtyard a chamber with one door to enter the first segment of airlock, another door to proceed into the water column. Pumping methods to fill and empty the chamber with water.

Then the bulk of the differential pressure handled by climbing a ladder perhaps, up to the surface of the water, where there would be another 2 door chamber. This one would be used to handle the remaining pressure differential. The surface of the water needs to be kept from boiling, so the pressure used is dependent of the surface temperature of your water.

For fresh water, this could be freezing, so, the triple point of water. But you could have higher pressures and so higher temperatures, or with brine, lower pressures and temperature. Brine will tend to be brutal on the structures though. But.....

You could have -13 degC water at the top if it is brine, and 20 degC at the bottom. Perhaps..... In that case if your passage though the water did not mix the water much, you might only have one door and no airlock, if you did not mind loosing a little moisture. For water rich areas this might be judged to be OK.

Else, if you do not want water vapor losses, you may have a two door chamber, and suck the moisture out of the chamber before you opened the outer door.

Although the above section of airlock could be relatively flimsy, I am tempted to want it to be able to hold an emergency pressure, in case the person outside needs emergency pressurization. On the other hand though, in a 1 door situation where a cold brine surface area was in use, that person might be able to rapidly pass through the door and dive to the bottom of the pool to pressurize. Funny deal. Quick passage through freezing brine, and then room temperatures. Balloon suit would need ballast though.

Looking at Calabans table previously available, I think we might get away with a surface water temperature of -2 degC.

Done.

Last edited by Void (2020-07-08 10:53:12)

tahanson43206 · 2020-07-08 10:46:03

For Void re topic .... If I've been following along correctly, I ** think ** you've arrived at a vision of an underwater shelter for humans, with the distinctive characteristic that the pressure of the water outside the habitat balances the air pressure inside, at a level which is comfortable for people.

In the most recent posts, there was discussion of using air locks. However, air locks would not be necessary if the habitat is designed as I've understood it. Simply set the habitat with an open face facing down, and allow swimmers to come and go at will.

This arrangement has been used on Earth, although the pressures are greater due to the greater gravity.

Management of air pressure would be somewhat more important in this scenario than might be the case topside, but management of air pressure is going to be important everywhere on Mars.

(th)

Void · 2020-07-08 10:50:30

Missed your post until now Calaban. Yes all of that matters. But it is a good problem to have if you have options. You also may look at Antarctica, and wonder what can be considered useful. See "Antarctic Dry Valley Lakes". Even through a thick layer of ice, photosynthesis occurs. It is rather clear ice. There may be so much Oxygen in the water, that it may fizz when you drill a hole.

My explanation for that is that when the brief summer water flows go into these lakes, in some cases, they compress CO2 into the water and then the phytoplankton generates Oxygen from sunshine.

Where I have been working with Spacenuts recent post, we may not be using ice at all. That of course then requires that we do something about U.V. But I am not too worried about that just now. Sunscreen perhaps.

I will attempt to get you an example of a lake. There are many kinds in Antarctica.

Here is one, so, that may illuminate our understanding of the situation
https://en.wikipedia.org/wiki/Lake_Vanda
Quote:

Lake Vanda is a lake in Wright Valley, Victoria Land, Ross Dependency, Antarctica. The lake is 5 km long and has a maximum depth of 69 m.[2] On its shore, New Zealand maintained Vanda Station from 1968 to 1995. Lake Vanda is a hypersaline lake with a salinity more than ten times that of seawater,[3] more than the salinity of the Dead Sea, and perhaps even more than of Lake Assal (Djibouti), which is the world's most saline lake outside of Antarctica. (Previous sentence, however, is not true according to List of bodies of water by salinity). Lake Vanda is also meromictic, which means that the deeper waters of the lake don't mix with the shallower waters.[4] There are three distinct layers of water ranging in temperature from 23 °C (73 °F) on the bottom to the middle layer of 7 °C (45 °F) and the upper layer ranges from 4–6 °C (39–43 °F).[5] It is only one of the many saline lakes in the ice-free valleys of the Transantarctic Mountains. The longest river of Antarctica, Onyx River, flows West, inland, into Lake Vanda. There is a meteorological station at the mouth of the river.

Ice-covered Lake Vanda with Onyx River in the right foreground
The lake is covered by a transparent ice sheet 3.5–4 metres (11–13 ft) year-round, though melting in late December forms a moat out to approximately 50 metres (160 ft) from the shore. The surface of the ice is not covered with snow and is "deeply rutted with cracks and melt lines".[5] During the colder months the moat refreezes.
While no species of fish live in Lake Vanda or the Onyx River, microscopic life such as cyanobacteria algal blooms have been recorded. Due to the concerns over impact to the natural environment that may occur during research, scientific diving operations are limited to work in the upper layer (above 30 metres (98 ft)) and remotely operated underwater vehicle use is not allowed.[5]

So, Dr. Zubrin, I believe cites a situation where a layer of ice might allow phytoplankton to grow in the waters below. I think that he may have said 30 Meters maximum allowed for that. You can look back and see what you find.

For our purposes, with nuclear power and solar power, we might thin the ice in summer, and let it thicken in winter, for thermal insulation purposes. We will also be concerned about ice stability, we have discussed that a lot. In many places, we may want to use techniques to our advantage, to reduce evaporation from the ice. But those tricks will all cost from our potential economic gains, but may also increase economic gains.

Here is a potential one. Water or oil pillows. Oil seems like a chance, although under U.V. it may yellow, but then this is our version of Whale blubber.

A pillow made of a transparent film. Fill it with oil to simulate whale blubber. Put it on the ice. Abut it to many others. I would be shy about thickness. I don't think I want them floating on liquid water. Rather to keep the seams between pillows from breathing out moisture, best if the oil actually gets rather cold at night. So, that is a game to play. But it also adds to the expense account.

I have something else I like. Batch farming underwater, using heliostats underwater. So imagine a robot in the water, where it has a greenhouse which may be filled with water or air. Under it a concentrating mirror. The whole device has a range of motion where it can follow the sun. Although this could be good for aquatic crops, I am particularly fond of an air filled greenhouse option.

First, since these things are robots, they are free to dwell in the cold upper layers to collect sunlight, and to also travel down to the bottom of the lake for servicing. Servicing could involve repairs in the event of equipment breakdown. It could involve cleaning the concentrating mirror, and the transparent greenhouse envelope. It could involve planting a crop or harvesting it.

Diving bells at the bottom of the lake/sea, would allow humans to directly interface with a robot checking in for servicing. The environment should be thermally and else acceptable. Although Lake Vanda may have warm anoxic waters at it's bottom, our lake/sea may be Oxygenated at the bottom by our manipulations.

This trick might be done on the surface of Mars as well, but with considerably more trouble. I prefer the lake version.

Potatoes and Mushrooms. While the device may breath the gasses in the water, and also expel gases into the water, a crude balance of Oxygen and CO2 could possibly be maintained within a sealed transparent enclosure with these two life forms. The Mushrooms consume Oxygen provided by the Potatoes, and the Potatoes consume CO2 and produce Oxygen. Of course the Mushrooms are feeding on supplied organic matter, the Potatoes consume sunlight and nutrients, that may in part come from the organic matter the Mushrooms consume.

Scale??? Whatever is realistic, economical, and suits your needs.

Done.

Last edited by Void (2020-07-08 11:20:15)

Calliban · 2020-07-08 12:19:59

Attempting to quantify the problem. Apparently, for photosynthesis, the most important factor is the total number of photons arriving with wavelengths between 400-700um. Hence daily light integral.
https://en.m.wikipedia.org/wiki/Daily_light_integral

'Outdoors, DLI values vary depending on latitude, time of year, and cloud cover. Occasionally, values over 70 mol·m−2·d−1 can be reached at bright summer days at some locations. Monthly-averaged DLI values range between 20-40 in the tropics, 15-60 at 30° latitude and 1-40 at 60° latitude.[6] For plants growing in the shade of taller plants, such as on the forest floor, DLI may be less than 1 mol·m−2·d−1, even in summer.

In greenhouses, 30-70% of the outside light will be absorbed or reflected by the glass and other greenhouse structures. DLI levels in greenhouses therefore rarely exceed 30 mol·m−2·d−1. In growth chambers, values between 10 and 30 mol·m−2·d−1 are most common.'

Void · 2020-07-08 12:23:44

So, then continuing with underwater farming with robots, some improvements are possible, to reduce the complexity of the heliostat greenhouse robot. Helpers for it.

It is probably not worthwhile to have a complex robot that can by itself navigate the water column vertical and horizontal, and to also hold position by squirting water. So, we can have anchors in the ice for it to hang onto, and pivot on as needed, to follow the sun. We may also have a heavy tractor robot at the bottom of the lake/sea, with a fishing line with a bobber. The robots coordinating with each other, when it is time to deploy to the anchor, or be retrieved from the anchor, the fishing line would be used. The greenhouse robot would be slightly buoyant so, the tractor robot has to pull it down, and then it brings it to a diving bell reception area for service.

For this kind of farming of vascular plants, I think that the oil pillows will serve well. In some locations where the climate allows, we might consider snow over ice, for phytoplankton growth. If the snow can survive for reasonable periods of time, robots would simply resurface the ice periodically. The snow should be a better insulator that ice by itself, and if it is not too thick may still allow light though and allow for a thinner layer of ice.

This may work in Korolev. Maybe the extreme poles.

For the ice slab that SpaceX may work with, I think you forget about the phytoplankton, except as consequence of light being in the water, because we might be doing farming of vascular plant crops. And in that case I would certainly look at oil pillows. I would like to discuss that more.

I am visualizing them as like a tile floor, on top of the ice. The seams or cracks between, may need additional treatments, and I think those a possible. Perhaps pouring liquid wax into them?

But without such means, it might be worth thinking about what would happen with the setup.

I think that in some locations, depending on season and climate, ice may possibly accumulate in them. If the cold of night can be retained by the oil tile/pillows, and the ice below it through the day, then it may be possible in some locations depending on the seasonal and daily moisture conditions.

In my little world, I imagine starships embedded in ice in that ice slab, and ice tunnels connecting them at the regolith line. The question then is how do we transition to our water farms? I think I will leave that open for now, and discuss using Starships for skyscrapers, that only poke up out of the ice slab about 30 feet.

It seems a shame to dispose of a heat shield, and flaps this way, and I would really like to retrieve the engines.

So, I will propose a system that might allow that. OK, the flaps and engines should not be so hard. The heat shield, may not be worth worrying about, but I will give that a try later.

For the easier items, you land the ship on a mount on the surface of the ice slab, not immediately into the hole. You retrieve the parts you want to reuse. Perhaps the flaps assemblies, and raptor engines.

Then you put a ring of canted engines onto the upper part of the ship. Of course they have to be plumbed. The ship lifts off, and lands in the hole. You retrieve your canted engines ring, to use again.

For a retrievable heat shield, you would have a formed plate that would attach to the ship canister. You could retrieve that for re-use, but I kind of think it is not worth it. Better, if the ships are being mass produced on Earth specifically for this purpose, perhaps just use an ablative heat shield, and call it a day.

To reuse the engines, and flaps. Becomes tricky. You either haul them all the way back to the Earth's surface by some means, or you attach them in orbit, which is going to be an expense. And you could not get these things to Martian orbit with a Hohmann method without flaps and raptors.

So, Ballistic Capture again. I am particularly fond of this sort of thing: (Solar wind sailing with a Ballistic Capture)
https://ui.adsabs.harvard.edu/abs/2005A … S/abstract
https://www.centauri-dreams.org/2017/12 … nd-beyond/
I see no reason why we would not put solar panels to work in transit. Then they could be brought to the surface of Mars in Starships.
No reason not to bring along Starship "Blanks", too, to embed in an ice slab. That is if it proves practical to attach flaps and engines on them in orbit. I suppose if that were done, you would also bring the landing propellant up to them from Mars.

I think that's a lot.

Done.

Not Done:

For the oil tile/pillows, I think it may be possible to redo the ice under them in place, to make it clearer. You would just want to leave the seams between the tiles alone. Clearer ice might result from degassed distilled water. Less clouding from air bubbles.

Now I am done.

Last edited by Void (2020-07-08 12:59:59)

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