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#26 2019-11-04 14:51:11

louis
Member
From: UK
Registered: 2008-03-24
Posts: 6,927

Re: Practical Water Extraction Methods for Starship Missions

There is certainly "till" in glaciers but when you get beyond the ice-regolith boundary, I think the ice on Mars is pretty pure (researchers deduce this from radar reflections). I don't think ground ice is a good indication for purity of ice in glaciers or crater ice lakes. Basal ice is nearly always very dirty, from what I've read but above that layer ice can be very pure.

I am not saying "no EVAs" and you make a good point about getting away from the sense of confinement. I think for me that would be catered for by exploration missions which would involve EVAs and "something to look at".

I think the main work activities will be: 1. Propellant plant production and fuelling of return Starship - monitoring and maintenance. 2. Water ice mining. 3. Exploration missions. 4. Energy system monitoring and maintenance. 5. Small experimental farm facility. 6. Coms. 7. Hab cleaning and maintenance. 8. 3D printing/industrial processing. 9. Return launch preparedness. 10. Kitchen duties. 11. Archiving of finds. In addition, pioneers will need to carry out a scheduled hygiene and exercise regime which might take up a couple of hours per day.

GW Johnson wrote:

Re Louis Post 19:

I rather doubt that there will be pure water ice available just under the surface.  That was what they expected to find with the polar lander,  and the ground truth was vastly different.  You will find rocks,  boulders,  sand,  and gravel,  all thoroughly mixed with the ice.  There will be layers with more ice content,  and there will be other layers with less ice content. 

Each layer will be very,  very inhomogenous,  because of the history of meteor impacts.  This stuff will more-than-likely look like permafrost soil full of rocks,  with an ice content under 50% by volume. 

That's pretty much what real ice-containing glacial deposits and permafrost-type ground look like on Earth.  Mars should be similar,  except for more rocky debris strewn about by the meteor impacts. 

You ain't gonna successfully mine that (or drill it) with some damned robot.  This is the "more-art-than-science" thing that cannot effectively be automated at this time in history.  At this time,  robots still cannot cope with art or even highly-variable science.

Besides,  your preference for no EVA work is going to drive a crew crazy from confinement.  They were cooped up in a tin can for months getting there (big payloads do not go with fast trips,  so says physics!),  and you want to coop them up inside tin can habitats once there?  Not only no,  but hell,  no!  They have to go outside to feel unconfined,  even if the spacesuit is a clumsy one.  Necessary for mental health. 

Besides,  what do you expect them to do,  sit on their butts watching some computer screen all day?  EVERY day?  If you're going to go to all the fuss and bother to send people to Mars,  then let them go outside and EXPLORE the place!.  You cannot do that sitting in a building or a pressurized vehicle.  You have to go and dig and put your (gloved) hands in the dirt,  and poke your (helmeted) nose into nooks and crannies to see what is there. 

If you cannot tell,  I quite agree with Kbd512 about this!

GW


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#27 2019-11-04 17:38:29

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

I was reminded that ice would after the surface freeze would lack the steering effects that would make it contaminated and would result as it cools more pure over time as it descends with continued temperatures remaining cold. But once you get towards the bottom that will not hold true as the contamination levels will increase.

https://en.wikipedia.org/wiki/Ice

The oxygenation or in this case CO2 would slowly stop making the ice less strong over time as the gas will seperate out of the liquid water to form bubbles.

From https://www.sciencedirect.com/science/a … 2X11000395 I see from the information that the colder it is the harder the ice will be.


https://books.google.com/books?id=R_Q6j … th&f=false

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#28 2019-11-04 20:17:23

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

Here is the drill for the life search on mars
1-marsrovertes.jpg

https://www.technology.org/2019/09/20/n … n-its-own/

But if you are thinking of using this for water you would be dead wrong as its not heavy enough and the drill diameter is tiny for what we are looking to do.

Then again if you think this is going to mars anytime soon you would be wrong again
mars_exploring_vehicle_by_novaillusion-d94pt1a.jpg

Of course what Nasa would build would be closer to this
isru_marsice_close_copy.jpg

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#29 2019-11-04 20:28:58

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

Now to be honest if the ice is sheets under the dirt of mars even at a depth of a foot or two once cleared I am thinking that you would do more like new englanders have done for centuries with blocks of ice being cut from the lake ice with cutting saws. The saw would need mass to allow for the blade to cut into the ice straight or at angles to make chunks that could be pulled from where it rests and then dumped into a collection truck to be hauled to the processing plant.

Sure this is a bit old tech but it works
ice-block-cutting-machine-underwood-archives.jpg

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#30 2019-11-05 04:06:26

louis
Member
From: UK
Registered: 2008-03-24
Posts: 6,927

Re: Practical Water Extraction Methods for Starship Missions

Great images. Personally I am favouring a rover-mounted hydraulic hammer coming down at 45 degrees or thereabouts on ice exposed on an incline, the regolith having first been removed by a small bull dozer. The bull dozer rover could have both blade and hydraulic hammer - maybe one on "front" and one on "rear".


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#31 2019-11-05 08:02:01

elderflower
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Registered: 2016-06-19
Posts: 1,262

Re: Practical Water Extraction Methods for Starship Missions

The mass (therefore weight) of a drilling rig could be enhanced by fitting hoppers to it and filling them with loose rocks/regolith/sand. They can be emptied before relocating the rig and refilled at the new site.

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#32 2019-11-05 08:28:24

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

Which is also true for the other earth moving designs that we would send to mars. The electric drive systems will need a very powerfull energy source to be able to get the work we need done with them.

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#33 2021-06-27 19:31:16

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Practical Water Extraction Methods for Starship Missions

https://www.source.co/commercial/?utm_s … _974067958

Does SOURCE purify and filter the water it produces?
SOURCE Water starts pure and is made better through mineralization, unlike most water which starts dirty and has to be cleaned. To protect SOURCE Water quality, the Hydropanels filter the air before it passes through the system, and water is kept clean with ozonation.

For SpaceNut ....

I have no idea what this is, but the AI at Yahoo apparently thought I would be interested.

(th)

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#34 2021-06-27 20:04:25

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

It read the cookies of the websites that you have read items from in the cache of your browser that you are using.

This particular unit style has been talked about in the mars cart topic from what I remember.

Here is the main subject of Solar + air = water
In places that have a lot of solar energy you can and would make use of it for sure.

It uses chemical reactions and cooling to pull the water out of what circulates within the chambers.

https://akvosphere.com/air-to-water-technology/

https://us.watergen.com/

https://www.smithsonianmag.com/innovati … 180969398/

The key to the water harvester is a new class of materials called metal-organic frameworks (MOFs). These MOFs are solid but porous materials with enormous surface areas—an MOF the size of sugar cube can have the internal surface area as big as many football fields.

http://globalscience.berkeley.edu/sites … esting.pdf

https://www.universityofcalifornia.edu/ … r-thin-air

A post from another topic

SpaceNut wrote:

An application for water would come from a dome over a soil sample to heat from solar concentration under the robotic unit. The heat would cause the ground to warm and the moisture would be released for capture at the top of the dome to enter the unit along with the co2 in the dome. The unit would then move and do this once more as it processes the captured materials to make into fuel. At the bottom of the dome would be a software surface to make a semi seal for a return air blower to send back what is not processed from the previous intake.
Now to go research the MOF materials as to if these can be made on mars or brought.

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#35 2021-06-27 20:54:39

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

found 2 more posts

SpaceNut wrote:

Changing how and from what we collect co2 from is as important as the energy to which we need to make the conversion happen.
Capturing CO2 from trucks and reducing their emissions by 90 percent

Europe, transport is responsible for nearly 30% of the total CO2 emissions, of which 72% comes from road transportation*.
Researchers at EPFL have now come up with a novel solution: capturing CO2 directly in the trucks' exhaust system and liquefying it in a box on the vehicle's roof. The liquid CO2 is then delivered to a service station, where it is turned into conventional fuel using renewable energy.

First, the vehicle's flue gases in the exhaust pipe are cooled down and the water is separated from the gases. CO2 is isolated from the other gases (nitrogen and oxygen) with a temperature swing adsorption system, using metal-organic frameworks (MOFs) adsorbent, which are specially designed to absorb CO2.

The whole process takes place within a capsule measuring 2 m x 0.9 m x 1.2 m, placed above the driver's cabin. "The weight of the capsule and the tank is only 7% of the vehicle's payload," adds Marechal. "The process itself uses little energy, because all of its stages have been optimized."

The researchers' calculations show that a truck using 1 kg of conventional fuel could produce 3kg of liquid CO2, and that the conversion does not involve any energy penalty.

Only 10% of the CO2 emissions cannot be recycled, and the researchers propose to offset that using biomass.

http://www.epfl.ch/index.en.html

https://www.frontiersin.org/articles/10 … 00143/full

SpaceNut wrote:

Thanks for the link.
The dewater system for desert water creation has been around for a while now and gives the life blood for those that can not get water from wells.
A dehumidifier and boxed air conditioning that is use to condense the moisture out of the air.
The use of solar is a plus in those areas for power creation for those that can afford the panels.
Temporary batteries and an AC convertor is used to provide the power to the units that are beeing used.

The article talks about porous crystalline material, known as a metal-organic framework (MOF), that acts like a sponge or catalyst for the reaction to occur at temperature.

solar panel to power a fan and heater, which speed the cycles, the device produces up to 1.3 liters of water per kilogram of MOF per day from desert air. Yaghi expects further improvements to boost that number to 8 to 10 liters per day. Last year, he formed a company called Water Harvesting that this fall plans to release a microwave-size device able to provide up to 8 liters per day. The company promises a scaled-up version next year that will produce 22,500 liters per day, enough to supply a small village.

Its catalyst is multi function as it has the zirconia to split the co2 into co and o2 as heat is applied. Still in experimental state and not a commercial off the shelf.

The solar panel looks like a 4 ft x 6 ft size in the 300 -400 w size. connected to a invertor for the batteries at 24 v a piece for a 48 v source for the ac convertor.


I do so much research its a wonder I can remember anything....

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#36 2021-06-28 17:21:44

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Practical Water Extraction Methods for Starship Missions

For SpaceNut ... another item for your collection ...

https://www.yahoo.com/lifestyle/researc … p_deeplink

Courtesy of Cockrell School of Engineering, The University of Texas at Austin

Essentially, the shape allows for direct access to sunlight on the petals. The tube takes in water and "feeds" it to the top of the flower. When the water hits the petals, it soon turns into steam and filters out any salt or bacteria. "We designed the purification-collection unisystem to include a connection point for a low-pressure pump to help condense the water more effectively," Weigu Li, a Ph.D. candidate in Fan's lab and lead author on the paper, said. "Once it is condensed, the glass jar is designed to be compact, sturdy and secure for storing clean water."

"Our rational design and low-cost fabrication of 3D origami photothermal materials represents a first-of-its-kind portable low-pressure solar-steaming-collection system," Li said. "This could inspire new paradigms of solar-steaming technologies in clean water production for individuals and homes."

Nature makes fresh water for an entire planet using nothing but Solar Power.

Here is an adaptation of solar power used to distill water molecule by molecule.

(th)

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#37 2021-06-28 19:02:07

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,790
Website

Re: Practical Water Extraction Methods for Starship Missions

Did we want to discuss this? One issue is how much pressure can ice take. There are glaciers lining the sides of canyons at mid-latitudes, documented by Mars Reconnaissance Orbiter. The frozen pack ice of Elysium Planetia. Yes, last time I talked to someone from NASA about it they continue to claim it's lava. The European Space Agency is adamant it's ice. One method is to use steam to melt ice. Do so deep within the ice to create a cavern. This will produce a puddle or pond at the bottom. Use a hose to suck up the water. The issue is the difference between freezing and boiling at Mars pressure is very slight. Curiosity rover recorded 8.25 millibar pressure before climbing Mount Sharp. Pressure varies with weather, and with day/night temperature. To do this practically requires containing water in the cave. A sealed cave can slightly increase pressure vs Mars surface. How much pressure can ice withstand? And this isn't a carefully formed block of ice, it's natural, with all the cracks and fissures of a natural formation.

Here's a table showing boiling temperature of clean water at various pressures. Yes, salt will both reduce melting temperature and increase boiling temperature. But how much salt is in your ice deposit? If there is significant salt, it will have to be desalinated before you can drink it.
89286.jpg

Note: 8.25 millibar = 0.825 kPa.
This table shows 0.841 kPa, boiling @ 4.4°C (40°F). For 0.772 kPa, boiling 3.3°C (38°F). Remember, water freezes at 0°C regardless of pressure, so that doesn't give you much to work with. The hotter the steam you use to melt the glacier or frozen lake, the faster the ice will melt. But if you boil the ice to steam, and that steam escapes to Mars atmosphere, you lost your water. It may be more practical to use radiant heat: electric heating elements like the red-hot wires of a toaster.

Can you pressurize the cave to 0.8374 psi (5.774 kPa) above Mars ambient? If Mars ambient is 0.772 kPa (7.72 millibar) then absolute pressure in the cave will be 6.546 kPa, so boiling will be 37.8°C (100°F). I think it would be practical to keep melt water below that. You could then suck up the hot water with a pump.

Question: would water vapour leaking through cracks in ice, freeze as it touches the ice? Causing any cracks to self-seal? Again the trick is to keep pressure well below the limit of your natural ice deposit.

Drill deep into a glacier or frozen lake, place a suction hose down the hole, seal with something (rubber gasket?), then put a heater at the bottom of the well. It will self-pressurize with steam. As pressurize rises, some steam will condense, dropping pressure. As long as heat is applied, pressure will continue to rise. Use the suction hose to release pressure, but maintain pressure at the desired level. Might need something to move the end of the hose as the hole grows to become a cave.

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#38 2021-06-28 22:54:15

Void
Member
Registered: 2011-12-29
Posts: 3,931

Re: Practical Water Extraction Methods for Starship Missions

Robert,

That is a harsh place I guess I would intend to ask where in the time line you are thinking?

First missions, or 1 million people on Mars?

To solve for each and for the transition may require different answers.

Done.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#39 2021-06-29 06:26:04

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,790
Website

Re: Practical Water Extraction Methods for Starship Missions

Void,
I'm thinking first permanent base with 12 people. And thereafter with 1 million people.

Years ago I listed qualifications for location of a human settlement. A lot based on JPL qualifications. Low altitude so there is more atmosphere for radiation shielding. Relatively flat and smooth for safe landing. Close to the equator so it's relatively warm, and so the site has consistent sunlight. High latitude will have long winters with short sunlight hours, which hinders solar panels for power as well as greenhouses. There must be a major water deposit nearby. Resources for construction. And it must be interesting so scientists have something to study. This list of requirements appears contradictory, because ice deposits tend to be at high latitudes, not near the equator. But individuals on this forum convinced me of the frozen pack ice. It's 5° north latitude, so close to the equator. Bottom of the dried-up ocean basin, so low altitude. Relatively flat and smooth. Cerberus Fossae is an area within Elysium Planetia where the frozen pack ice is; it does have broken terrain. But it's safe enough to land. Most importantly ESA has analyzed it, found there's more ice than all the water of the Great Lakes combined. That's definitely enough to support a city of 1 million people.

I attended the Lunar and Planetary Space Sciences Conference in 2005. I spoke to a couple NASA people about the frozen pack ice. They were sure it's just lava, not ice. However, the European Space Agency has analyzed the frozen pack ice using their Mars Express orbiter. ESA had many scientists with Ph.D.s in geology study it. They said there's no way that's lava. That is definitely ice, and yes the ice is still there. Several craters have punched holes in the ice, which shows them how deep the ice is. It's 45 metres deep. (147 feet, 7 inches and a bit. Round to 2 significant digits.) That's the same depth as Lake Erie. Not as deep as Lake Superior, but the same as Erie. It's 800 km x 900 km (497 miles x 559 miles).

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#40 2021-06-29 06:44:54

Void
Member
Registered: 2011-12-29
Posts: 3,931

Re: Practical Water Extraction Methods for Starship Missions

Robert,

Thank you for responding.  I share confusion.  I am approaching a lack of trust.

I have significant means to keep my situation in order.  But the next few days, really map out as screwed up.  So, I have to dance in ways I do not normally choose to behave.  It is unwise for me to devote energy to this project at this time as things are complicated, and I could respond with emotions and messed up thinking.

I really appreciate that you were willing to respond to my question.  I think that with the lack of information that is needed, and my situation for the next few days, I should withdraw.

But good luck with your quest.

Done.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#41 2021-06-29 20:46:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

Yet Nasa continues to send mission looking for life signs rather than getting to the water locked up in ice.
That is something that we do need to do and its got a back burner all of the time instead.

This would be a perfect fit for a helicopter mission where the rover is at the top while the cameras onboard map a path for close up testing of what might be found at such an ice cliff glacier….

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#42 2021-07-17 06:47:03

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,680

Re: Practical Water Extraction Methods for Starship Missions

For SpaceNut ...

Your mention of having fresh water available that is laden with minerals has stayed with me.

Recently someone posted a report of work done at MIT to develop a solar water still.  The poster might well have been you << grin >>.

It seems to me you subsequently expressed a mild interest in actually trying to build a solar still for this kind of water preparation.

Very recently, OF1939 reported use of a technique to remove water from food in commercial facilities.  His post included the word "film" and I'm looking forward to following that hint later this weekend.

The reason I'm posting ** now ** is to inquire if you might be interested in seeing if you can collect a gallon of distilled water from a solar device at your location.  The gallon would be accumulated on a sunny day above freezing, using water from your local supply as input.

The wrinkle I'd like to toss into the mix today is to use the cool water from the source at your location to cool the condensation surface, instead of depending upon air to extract heat from the water molecules floating in the air above a heated bath.

The base of the machine might have a black floor, to absorb as many photons as possible.

I'm thinking of including a condensation surface other than the glass pane that admits sunlight (or in addition to) ...

The volume has to be enclosed so the condensation mechanism can do it's work, and that means the glass pane is going to collect condensation.

The water collecting on the glass will impede flow of sunlight into the volume, so a way of encouraging water to flow into the collecting trough might seem advisable, but (most likely) that would be a mechanical device similar to a squeegee (tm).

(th)

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#43 2021-07-17 09:48:21

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,403

Re: Practical Water Extraction Methods for Starship Missions

Still not finding time for research into heat to evaporation rate as well as the cooling required to cause droplets to slide down into catch trough at end of slope.
Depth of water is a factor to heat laden amount to produce a rate of water to be evaporated.

Not to disturb the follow on post

mother earth news
http://ogden.whatcounts.com/dm?id=95210 … 8FE30910B5
The Complete Crock Water System

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#44 2021-07-17 12:55:45

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,680

Re: Practical Water Extraction Methods for Starship Missions

For SpaceNut re #43

Thanks for continuing to think about this mini-project ...

A gallon of distilled water per day seems reasonable to me, without having much in the way of numbers to go on at this point.

The output of the system would be distilled water by one path, and moderately enriched "natural" water via the drain valve.  I presume scale would accumulate on the walls of the heating vessel, the way it does on my double boiler heating pans.  The water delivered from the city mains ** definitely ** is rich with suspended material, which we humans (and pets for that matter) seem to be able to take in without ill effect.

The output of the distillation system would (if I understand the requirements correctly) need addition of a small amount of nourishing minerals for human consumption.  My understanding is that ** really pure ** distilled water actually leaches minerals ** out ** of the body, so it should be avoided.

Still, it would be helpful to have clean water to work with, instead of the output from the underground fissures in your area.

Update at 15:50 local time ... Use of mirrors to reflect sunlight into the distillation chamber would increase effectiveness.  Potentially the cost could be modest, if old mirrors can be found at estate sales or similar sources. 

(th)

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#45 2021-07-17 13:57:50

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,239

Re: Practical Water Extraction Methods for Starship Missions

Thomas--

Look at several of the chemical processing equipment websites. Pfaudler, and DeDietrich come to mind.

It's called a "wiped film evaporator." Basically a cylinder with a vertical driveshaft and a system of sprayers. The driveshaft powers wipers to spread the incoming liquid evenly on the heated walls as would windshield wipers. Large surface area plus heat, and easy evaporation under vacuum. The effluent vapors can be recondensed as highly purified water, and the residual solids flow down the walls into a receiver at the base of the system. Highly efficient and would turn a brine onto drinking water quickly and on a flow type basis, not a batch basis.

https://www.pfaudler.com/systems-proces … ators#gref

We don't need to keep reinventing the wheel when there's some expertise handy.

This is used in virtually every food processing plant that makes tomato products. Tomato juice in = tomato puree out.

Last edited by Oldfart1939 (2021-07-17 14:07:51)

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#46 2021-07-17 14:32:45

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Practical Water Extraction Methods for Starship Missions

For OF1939 re #45

Thank you for this helpful update!

The website at pfaudler ** really ** helps to show what is working for their customers!

The applications that are paying their bills appear (to my eye anyway) to be food products that need to be de-humidified without damage, and from what I can gather, the use of high vacuum helps greatly to reduce temperatures needed for distillation.

High vacuum is readily available in space and it is ** much ** less expensive at Mars.

However, the applications for Space and Mars are a bit different than seem to be popular on Earth.

I'm hoping you will be intrigued by the challenges SpaceNut has offered (on one hand) and the needs of space travelling crews and Mars or Lunar residents on the other.

SpaceNut is (or appears to be) interested in recovering fresh water from the highly mineral laden ground water at his location on Earth.

Space travelers, on the other hand, will be producing quantities of moist material that needs to be recycled on a daily basis.

Would a system such as shown at pfaudler work for the mineral laden water situation?

Likewise, would such a system be able to extract water from the moist material generated by humans in their daily activities?

Presumably the water output from such a system (treating waste) would need to go through secondary refinement before it is put back into the common fresh water supply.

(th)

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#47 2021-07-17 15:33:27

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,239

Re: Practical Water Extraction Methods for Starship Missions

Thomas-

The high vacuum of space available at Mars wouldn't work. The water vapors need to be in a closed system for re condensation to a liquid. We aren't drying the minerals, but want to recover the purified water.

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#48 2021-07-17 15:42:05

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,239

Re: Practical Water Extraction Methods for Starship Missions

Sublimation is a relatively slow process. My thoughts about "mining water" would be strictly digging/blasting out chunks of regolith/ice mixture and hauling it to a heated but pressurized environment where it could be melted before purification as a thin mud or brine. This would be done on a multi-ton basis, daily.  Then the wiped film evaporator would be used to make "gray water," or water for agricultural use and sanitation (flushing toilets).  Potable water would be obtained by reverse osmosis from this "gray water." Other "polishing" operations would remove odors by activated carbon filtration.

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#49 2021-07-17 16:43:45

tahanson43206
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Registered: 2018-04-27
Posts: 7,680

Re: Practical Water Extraction Methods for Starship Missions

For OF1939 re Post #47

It is easy to make mistakes in wording, and I may have do so in my post about applying the pfaudler process at Mars.

Here are some snippets kindly provided by Google, to help to clarify what I was trying to say:



Mars atmospheric pressures (~ 4 - 6 torr) are obtained by using critical orifices and mass flow controllers between the source and sink of the CO 2. A flow schematic can be found in the Schematic section. The table below briefly shows the approximate range of conditions the Mars chamber can achieve.
Mars Atmospheric Simulation Chamber | Aeronautics and ...
www.aa.washington.edu/research/ISRU/facilities

Convert Atmospheres to Torrs - CalculateMe.com
https://www.calculateme.com/pressure/at … s/to-torrs
143 rows · An atmosphere of pressure, or atm, is the pressure exerted by the Earth's atmosphere at sea level. Since this number varies, a standard atmosphere is defined as 101,325 pascals. A torr is a unit of pressure defined as 1/760 th of a standard atmosphere. It is based on the pressure of a column of mercury that is one millimeter high.

I deduce that Earth's standard atmosphere is equal to 760 torr.

A company wanting to achieve .0004 torr in a vacuum chamber would have to invest energy sufficient to reduce pressure to 4 to 6 torr, before then proceeding to achieve .0004 torr on Earth.

In contrast, a company wanting to achieve .0004 torr at Mars would start at 4-6 torre, and achieve .0004 torr through investment of energy, presumably equal to that required from the same point on Earth. 

From these figures, I would deduce that the investment of energy needed to achieve .0004 torr on Mars would be less than that needed to achieve the same pressure on Earth.

(th)

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#50 2021-07-17 17:47:35

Void
Member
Registered: 2011-12-29
Posts: 3,931

Re: Practical Water Extraction Methods for Starship Missions

OK, I will try something perhaps new here.

I do not like the idea of people landing on Mars and having to trust that they can
drill and blast and load and purify water.  For one thing it is more mechanical work
than I would like to see, and you then have people on life support on the planet.

For one thing, you have to remove the overburden during this method.  Not a trivial
task.

And we do not have all that firm an assurance that the methods we plan might work.

Meteors punch craters in ice quite regularly.

So, how about bombing Mars, and trying to use robots to harvest the ice?  At least
as proof of concept??

At least if you produced an icy crater, you could have a robot sample the ice.  You
could also process at least some samples to see what the results would be.  That might
be the least best result.  The best-best result would be if Elons driving car technology
might allow water to be processed without humans.

Electrical energy will be the show stopper there.  However, Robert Zubrin has suggested
in Mars Direct, that a "Put-Put" car could take a reactor to a distance and maybe put
it behind a hill.  I am guessing that "Cars" could bulldoze a berm between the active
reactor and a landed Starship.

Of course what I am wanting is production of propellants prior to human arrival.

So, here is a variation on the concept SpaceX appears to me to have expressed.

Bomb maybe three places.  Land the Starship(s) at some productive location.  That is
it may be possible to bomb to produce a Crator(s), and get data back from existing
orbital probes.  Then land the Starships if possible close enough to a apparent ice
crator.  Then with very good automation, and the co-operation of someone with nuclear
reactors (NASA?), deploy a reactor(s), and produce a protective berm between the
reactors and the Starship(s).  At that point then you may attempt to sample the ice.
This would also be for scientific data.  If possible then try to harvest the ice with
advanced automation.  If it fails, you still have power to a Starship, and you may
produce all of the Oxygen needed for both life support for later arriving humans.
You may also produce all of the needed return propellants.  I presume that food can
be delivered long before the humans arrive.  If you have food and Oxygen, and if the
exposed ice can be harvested and cleaned to potable water, then even if it becomes
not possible to generate enough Methane for the return trip, it is possible that the
stranded humans can wait out what ever situation had prevented their return trip.

After all in that situation they would have electric power from the Reactor(s). 
They would have food.  They would ample Oxygen to breath, as I anticipate that all
Oxygen would have been generated from atmospheric CO2, prior even to the humans
departing Earth.  And they would potentially have shelters either in the Starships,
or in delivered goods.

And you would notice that if all the Oxygen at least was produced prior to human
launch, then the only chemical that would need processing would be water and Carbon.

And the Carbon is a problem,  I suggest that the tank that was for Methane be filled
with CO when the Oxygen was being extracted.  Then that would be drawn off, to make
Methane after the humans arrived.

An alternative to that would be if the robotic devices could actually harvest the
exposed water ice, and in that case it might be possible to manufature Methane,
without storing large amounts of CO.

Of course in our dreams we might suppose that solar pannels might be deployed instead
of nuclear reactors.

Bombs.  Efficient perhapss.  And some of the kenetic energy from the fall may assist
in creating the ice crators.

Done.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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