DeGrasse Tyson's Mars challenge to Elon Musk

Dook · 2017-04-14 08:57:50

kbd512 wrote:

Apis Cor has a very compact (4m x 1.6m x 1.5m) 3D printer that weighs 1,815kg. It printed a small house in 24 hours. To obtain the temperatures required for concrete to set in the Russian winter, a tent was built around the house during construction. That same technique could be used on Mars. The printer uses a variety of available construction materials as feedstock to supply material to the print head. A pulverized Martian Sulfacrete (sulfur concrete made using Martian sulfur and regolith, stronger than Earth concrete and uses sulfur and heat instead of water to solidify the aggregate mix) could obviously be fed into the print head.
The finished prototype house cost ~$10K USD to construct and a cost breakdown is provided in the link below. Obviously wiring, piping, and an air lock must be added for use on Mars, but surely another robot could print regolith piping with a plastic liner to supply water or steam. The maximum size of the printed structure is 3.1m in height and 5m in diameter, for a maximum area of 132m^2. That could be increased with a larger printer arm.
The first on-site house has been printed in Russia
There is no possibility that any structure we could affordably transport from Earth to Mars would ever provide as much radiation protection or protection from meteoroids. The walls could literally be a meter thick using the 3D printer and easily hold 14.7psi. More importantly, if water and breathing gases are locally sourced, then the only things we need to send to Mars are finished goods for power production, tanks for water / LOX / LN2 storage, computers, and aerospace vehicles.
The total tonnage required to create and support colonies becomes much more reasonable when the building materials come from Mars. Mr. Musk's Mars colonization plan then falls within the realm of economic feasibility. Landers can be simple Cygnus-derived tuna cans since habitation requirements have been taken care of before prospective Martians ever set foot on the planet. If textiles were fabricated from Martian grown cotton and hemp, then the colonists would have locally sourced sheets, towels, and clothing. The machinery to process cotton or hemp and to fabricate textiles weighs a lot less than the rocket fuel required to send clothing, sheets, and towels to Mars for any significant number of people. If locally grown fruits and vegetables are added to the economics equation, then shipping people and electronics seems imminently reasonable.
The point is, we're not stuck with 20th century construction and growing methods. If we limited ourselves to 20th century construction and growing methods, then a Mars colony is probably infeasible as a function of construction costs alone.

You need water to make concrete, a lot of it. The article did not say how much water was used by the 3D printer to build the house, probably because water is readily available on the Earth.

Water can only exist on Mars between the temperatures 33-36 degrees F. How are you going to keep your Martian water in that temperature range so the 3D printer can spray it?

Dook · 2017-04-14 09:13:08

Robots could scoop up and deliver the iron ore? Robots powered by batteries? The batteries would last about an hour before the robot would need to be recharged. Also, the robots would only be able to move small amounts.

Why separate out the silicon? If your idea is to get a lot of oxygen from heating iron oxide you would need to use regolith that was almost all iron oxide. I don't think you're going to get enough oxygen from this process.

A community of 1,000 would only be using 2000 tonnes of iron ore per year? There won't be 1,000 people on Mars for 500 years or more. 2000 tonnes is 4 million lbs. I know that number means nothing to you but it's not reasonable on Mars.

You skipped clean over the fact that when there is a dust storm your mirrors won't work and they can't make oxygen. The dust storms can last a full year.

Solar mirrors can be 3D printed? Using what material? Material sent from Earth?

elderflower · 2017-04-14 09:21:10

for the low demands in early years we would only need a few Ni/Fe meteorites like the Cape York one that was stolen from the Inuit. Then we would have plenty of material to make mirrors, small tools and small structural elements. It might well be possible to print these using carbonyl technology.

Oldfart1939 · 2017-04-14 09:49:45

Louis-

In addition to heating your Iron Oxide to 500 degrees, how are you going to reduce it to elemental Iron? You need a source of a reducing agent, such as carbon Monoxide (see Blast Furnace equations in Wikipedia for explanation). The Iron also needs to be considerably hotter for these reactions to become viable. The Moxie unit simply won't produce enough CO to really matter. The concept of using Iron in the Zero oxidation state to produce energy would be minimally useful, even if the Iron were all available. Yeah, I realize this is a "Green" energy production concept, but get over it. It. Won't. Work. Ever. Period.

The Blast Furnace reactions are commonly taught in Freshman Chemistry, but the basic one is:

Fe3O4 + 4 CO ------------> 3 Fe + 4 CO2

The modern blast furnaces use also a charge of limestone and a flux (Ca2O3) and the result is a cleaner Iron product along with "slag."

In the initial stages of colonization, the small nuclear reactor such as the SAFE-100 is about all we can COUNT ON. I'd expect that a small operational research station and colony of 100 could become functional over 10 years of infrastructure building. We'll definitely need power in the Megawatt range in order for things to begin happening.

Dook-

You need to read kbd512's comments more carefully; he's proposing a Sulfacrete concrete--molten Sulfur plus regolith. NO WATER INVOLVED. Please read before commenting.

Last edited by Oldfart1939 (2017-04-14 10:30:48)

GW Johnson · 2017-04-14 10:26:41

The more fact-challenged the participants get, the more acrimonious this thread gets.

One example among several: "setting off AN with a spark". Doesn't happen. AN is sensitive only to (1) shock (as in a blasting cap and booster charge, and only in 6 inch diameters or larger), and (2) heating in a fire, but only (!!!) under confinement.

Metallic iron can be an inefficient fuel if you have an oxidizer to react it with. It must be very finely ground to do this. The application here at home is fireworks, most notably the sparklers that children wave around. The "blueberry" iron nodules on Mars are not metallic, they are oxide. The energy to reduce them to metallic state plus the energy to grind such hard things to powder exceeds the energy yield for re-oxidation. If you don't grind it to powder, the oxidation rate ("rusting") is too slow to be useful.

Unless you want to do your gardening in your greenhouse in a super-clumsy spacesuit, you had better have a human-supporting atmosphere in your greenhouse. In practical terms for long-term exposure (not a short EVA), that's about 10 or so psia with no more than 30% oxygen (3 psi) to preclude untenable fire dangers. The 7 or so psia dilution gases can be nitrogen, argon, or a mixture. There needs to be trace CO2 in it for the plants: 200 to 500 ppm works fine. CO2 starts getting poisonous to humans at around 2%, uniformly lethal around 4% (based on a century of suffocation deaths of stranded submarine crews).

The plants also need oxygen, and they need humidity. About 3-5% of the total pressure should be water vapor for best results, unless you are growing cactus. Some free surface area on a pool of water in the greenhouse will do that quite naturally.

That means your greenhouse is a pressure vessel structure, not some flimsy plastic film nonsense. You must deal with that unpleasant little fact of life. Bounce sunlight into it with mirrors through triple-pane windows. Use enough mirrors outside for a concentration factor of 2-ish, and you have Earthly levels of sunlight for growing Earthly plants. What could be simpler? Use local rocks and a concrete-equivalent to do reinforced masonry construction. Bring the rebar from Earth.

You get your water from buried ice, which definitely restricts where you land. You're betting lives on this, so you have to be sure it is really there, before you send people dependent upon it. That's just basic human ethics, which must trump technical convenience, everywhere and always. The local ice may be too briny to use outright, but the salts are the built-in electrolyte for electrolysis. That's where you get your oxygen. You'll need a desalination plant to generate fresh water for drinking and growing.

The dirt is known to be "poisoned" with salts like perchlorates in many locations, but you can wash it well enough if you already have some fresh water available. Better bring several tons of fresh water from home to get started bootstrapping into operation.

You're gonna need a LOT of electricity to do all this. It'll take both nuke and solar to get started. But the "heavy lifting" (like electrolysis) is going to have to be nuke. There's just no way around that.

You cannot tie rebar or build concrete-equivalent casting forms in the clumsy spacesuits we use. You cannot drive a backhoe wearing bullshit like that, either. Better get on with perfecting MCP suits to use on Mars.

Sorry to bust so many balloons.

GW

Last edited by GW Johnson (2017-04-14 10:45:18)

Dook · 2017-04-14 10:32:50

Oldfart1939 wrote:

Louis-
In addition to heating your Iron Oxide to 500 degrees, how are you going to reduce it to elemental Iron? You need a source of a reducing agent, such as carbon Monoxide (see Blast Furnace equations in Wikipedia for explanation). The Iron also needs to be considerably hotter for these reactions to become viable. The Moxie unit simply won't produce enough CO to really matter. The concept of using Iron in the Zero oxidation state to produce energy would be minimally useful, even if the Iron were all available. Yeah, I realize this is a "Green" energy production concept, but get over it. It. Won't. Work. Ever. Period.
The Blast Furnace reactions are commonly taught in Freshman Chemistry, but the basic one is:
Fe3O4 + 4 CO ------------> 3 Fe + 4 CO2
The modern blast furnaces use also a charge of limestone and a flux (Ca2O3) and the result is a cleaner Iron product along with "slag."
In the initial stages of colonization, the small nuclear reactor such as the SAFE-100 is about all we can COUNT ON. I'd expect that a small operational research station and colony of 100 could become functional over 10 years of infrastructure building. We'll definitely need power in the Megawatt range in order for things to begin happening.
Dook-
You need to read kbd512's comments more carefully; he's proposing a Sulfacrete concrete--molten Sulfur plus regolith. NO WATER INVOLVED. Please read before commenting.

How hot does the sulfur have to be to melt in Mars low pressure?

Where did you get the sulfur from to spray your house?

How are you going to oxygenate this new residence?

How are you going to heat the new residence?

What are you going to make the roof out of?

Is this home going to have electricity?

Where does the pressure door come from? Did you take it from the Mars lander that you landed in?

Everyone who lands on Mars will land in a tuna can that has everything necessary. Why would a settler leave a tuna can lander with everything to live in a cement home?

Why would a settlement waste time, electricity, and equipment, on building separate homes when it's more efficient to heat, power, monitor CO2 levels, and oxygenate, one habitat?

You all think that this is expansion and progress, it's not. Taking a 3D printer means taking less food.

No Mars settlement is going to do anything to expand. All new settlements are going to come from the Earth.

Oldfart1939 · 2017-04-14 10:38:09

GW-

Thanks for your commonsense input. Most participants do NOT understand Thermodynamics of the "System" determine it's viability. But--it would also help if participants READ the entire comments before spouting off.

I'm not certain all the buried ice will be saline, but we won't know that until we get there, will we. Desalinization is easy: vacuum distillation. No need to bring water along other than for immediate needs. Of course--another energy requirement. NUKES!

GW Johnson · 2017-04-14 10:48:47

Vacuum flash works great, but you do need a copious source of waste heat. Nukes do make a lot of that. It's needed to keep greenhouses and living quarters warm, too. Better bring some pipe and fittings and pipe insulation. And, you won't be able to do pipefitting wearing those clumsy spacesuits, either. Can you even imagine trying to put a gasket in a flange joint wearing gloves like that? Or using a standard roll of tape on your pipe insulation?

BTW, I posted a design concept for both the greenhouse and living quarters buildings over at "exrocketman" some time ago. All that was really needed was a concrete equivalent, for which the sulfur/regolith idea may well work, if a bit stinky. The article is "Aboveground Mars Houses", dated 1-26-13. The site is http://exrocketman.blogspot.com. Search kewords you can click on as filters are "Mars" or "space program".

GW

Last edited by GW Johnson (2017-04-14 10:56:47)

Dook · 2017-04-14 10:53:04

GW Johnson wrote:

The more fact-challenged the participants get, the more acrimonious this thread gets.
One example among several: "setting off AN with a spark". Doesn't happen. AN is sensitive only to (1) shock (as in a blasting cap and booster charge, and only in 6 inch diameters or larger), and (2) heating in a fire, but only (!!!) under confinement.
Metallic iron can be an inefficient fuel if you have an oxidizer to react it with. It must be very finely ground to do this. The application here at home is fireworks, most notably the sparklers that children wave around. The "blueberry" iron nodules on Mars are not metallic, they are oxide. The energy to reduce them to metallic state plus the energy to grind such hard things to powder exceeds the energy yield for re-oxidation. If you don't grind it to powder, the oxidation rate ("rusting") is too slow to be useful.
Unless you want to do your gardening in your greenhouse in a super-clumsy spacesuit, you had better have a human-supporting atmosphere in your greenhouse. In practical terms for long-term exposure (not a short EVA), that's about 10 or so psia with no more than 30% oxygen (3 psi) to preclude untenable fire dangers. The 7 or so psia dilution gases can be nitrogen, argon, or a mixture. There needs to be trace CO2 in it for the plants: 200 to 500 ppm works fine. CO2 starts getting poisonous to humans at around 2%, uniformly lethal around 4% (based on a century of suffocation deaths of stranded submarine crews).
The plants also need oxygen, and they need humidity. About 3-5% of the total pressure should be water vapor for best results, unless you are growing cactus. Some free surface area on a pool of water in the greenhouse will do that quite naturally.
That means your greenhouse is a pressure vessel structure, not some flimsy plastic film nonsense. You must deal with that unpleasant little fact of life. Bounce sunlight into it with mirrors through triple-pane windows. Use enough mirrors outside for a concentration factor of 2-ish, and you have Earthly levels of sunlight for growing Earthly plants. What could be simpler? Use local rocks and a concrete-equivalent to do reinforced masonry construction. Bring the rebar from Earth.
You get your water from buried ice, which definitely restricts where you land. You're betting lives on this, so you have to be sure it is really there, before you send people dependent upon it. That's just basic human ethics, which must trump technical convenience, everywhere and always. The local ice may be too briny to use outright, but the salts are the built-in electrolyte for electrolysis. That's where you get your oxygen. You'll need a desalination plant to generate fresh water for drinking and growing.
The dirt is known to be "poisoned" with salts like perchlorates in many locations, but you can wash it well enough if you already have some fresh water available. Better bring several tons of fresh water from home to get started bootstrapping into operation.
You're gonna need a LOT of electricity to do all this. It'll take both nuke and solar to get started. But the "heavy lifting" (like electrolysis) is going to have to be nuke. There's just no way around that.
You cannot tie rebar or build concrete-equivalent casting forms in the clumsy spacesuits we use. You cannot drive a backhoe wearing bullshit like that, either. Better get on with perfecting MCP suits to use on Mars.
Sorry to bust so many balloons.
GW

You need to shock AN to set it off? So launch vibrations, Mars aero-capture, parachute opening, rocket firing, and the abrupt jolt of landing are not shocks? And we should risk the entire mission and crew just to have some fertilizer? Isn't diluted human urine fertilizer? If settlers took some chickens along, don't they provide fertilizer? And, can't plants grow without fertilizer?

What about gardening in a 5 psi greenhouse with an oxygen mask?

The greenhouse is a pressure vessel, not some flimsy plastic film? We absolutely agree. We're the only ones who think that way though.

Use triple pane windows? We're on the same page. How cold do you think the greenhouse would get at night? We have to keep the plants from going dormant, I think apple trees go dormant after 3 days of 50 degree F.

You get your water from Mars? I disagree. You land in a tuna can that recycles all the water used in it so you don't really need much. You build a greenhouse and use some brought water for the plants. The water evaporates from the regolith around the trees during the warm days and humidifies the greenhouse during the warm day. The water condenses on the inside walls at night and runs down the inside walls of your greenhouse into trays along the bottom. The trays could have plastic irrigation tubes that run to every tree. So, there is no water loss in your greenhouse except when you open the pressure door there would be a small amount of evaporated water lost to the outside. Double pressure doors would help.

And, if you built a buried habitat and then built a greenhouse over your buried habitat, you don't have to open the pressure door nearly as much.

elderflower · 2017-04-14 10:57:21

Ice can be quite pure. Old Arctic sea ice will yield drinkable water. It has to be old to give time for the brine to separate from it. Mars ice may be salty but crushing and washing will clean it. Refreeze and recycle the wash water and discard the now concentrated brine with any dirt that may have settled out. Not a difficult process. Maybe the brine might yield something useful such as hypochlorite. Passing your ice through two stage of this process would result in something that would be usable for many purposes. but still might need RO or ion exchange for drinking.
I understand that there isn't so much HDO that it would present a problem for people, animals or plants.

GW Johnson · 2017-04-14 11:08:01

Dook, there's "shock" and then there's "shock". Mechanical shock is fairly ineffective, excepting a hammer blow against an anvil. A proper detonation shock (blast) wave is what works reliably. Deflagration won't work, there is no shock wave, despite what you think you see in such explosions.

They used 9-inch boreholes at the Mesabi iron ore mines, into which they poured a 80-pound sack of fertilizer-grade AN, followed by a gallon of diesel fuel, repeating until the full charge was down-hole. To that you add an electric blasting cap poked into a quarter stick of dynamite, dropped onto the charge by its wires. Do this in multiple drill holes across the face of iron ore to be blasted. Then cap it off with some drilling mud for confinement. Stand way, way back, and set it off. The usual cobble size is about a cubit in diameter.

As for water, if you don't look for buried ice to tap, you will always be short. There's lots of water there, but it's not in every place. It needs cleaning, and probably desalination. If you simply electrolyze it, you have a lot more oxygen faster than any of these Martian atmosphere processing toys could ever do. And you have hydrogen to work with. Such as for making methane, or any other chemistry you might want to attempt. Or even for rocket fuel. Including nuclear thermal rocket propellant.

As for 5 psi CO2 in a greenhouse, with humans wearing masks, yeah, that might work. Except that plants need oxygen as well as CO2. If you have to put oxygen in the mix (and you do), you might as well do a human-breathable atmosphere. After all, that's what those plants evolved in here. Just supply what we all evolved in, and forget about it. It's when you deviate from that baseline that you get into trouble.

GW

Last edited by GW Johnson (2017-04-14 11:13:19)

Oldfart1939 · 2017-04-14 11:08:52

Elderflower: What you describe is called recrystallization. Melt; refreeze partially, decant off the unfrozen water. Repeat several times. Result is a pure solid. I suspect a system could be built similar to a zone-refiner use to ultra-purify organic chemicals could be built. On the other hand, vacuum distillation is much more efficient.

Oldfart1939 · 2017-04-14 11:29:29

Dook-

You need to check under the heading "Life Support Systems," and on the second page of sub-topics, you'll see "Chickens." Also "swine." You'll also see a lot more of various contributions regarding greenhouses.

My position on greenhouses is only an initial "quickie" greenhouse will be an inflatable. I've argued for a rigid structure, as have many others here on this forum. My idea was making Lexan (polycarbonate window panels and an ABS or Linear Polyethylene framework) and a very substantial structure capable of withstanding micrometeorite impacts.

By the way, up until the Oklahoma City bombing, almost every rancher was somewhat of an expert blaster using ANFO (ammonium nitrate-fuel oil) explosives to remove tree stumps, remove beaver dams from irrigation ditches, etc. GW addressed the hazards (almost non-existent) of handling the stuff. Shock, is understood to mean "shock wave" as propagated by an initiator explosive. Shooting a barrel filled with the stuff, using rifled slugs or high velocity rifle bullets won't detonate it. I know this. Don't ask how!

Oldfart1939 · 2017-04-14 11:36:02

By the way, I just looked this up. Cubit = the distance from the extended middle finger tip to the elbow; roughly 20 inches.

Dook · 2017-04-14 11:42:44

GW Johnson wrote:

GW

The shock from launch and landing won't be enough to set off AN? Okay, fine, it just seems completely non-essential thing to take. Plants grow fine without fertilizer and we will get fertilizer from urine and chickens anyway. Which is better, taking fertilizer that over time helps you grow a little more food or substituting the fertilizer for more food in the first place?

If we don't use Mars ice to get water we will always be short? Where's the water loss? The tuna can will have water recycling, the greenhouse water will be confined, where's the loss?

Also, when you build a greenhouse over Martian regolith and heat it some water will evaporate from the regolith, not a lot but some.

And, we can use zeolite panels that we leave outside on Mars for months at a time then bring inside our greenhouse, use mirrors to heat the zeolite to outgas water vapor. I know it's not a lot but our water loss should be minimal anyway.

The plants in the greenhouse will make oxygen, so, over time they will create a breathable atmosphere on their own. I think it depends on how much oxygen your Moxie is making. If you have plenty then it's fine to use some oxygen in your greenhouse.

I still don't get the idea of a settlement sending things back to the Earth. Why waste time, energy, and use water for that unless you have so much that you just can't store any more?

kbd512 · 2017-04-14 11:50:38

Dook wrote:

You need water to make concrete, a lot of it. The article did not say how much water was used by the 3D printer to build the house, probably because water is readily available on the Earth.

Mars has sulfur readily available on the surface of the planet as a result of past volcanic activity. Sulfur can also be used to make concrete. The process doesn't use a single drop of water. The sulfur is mixed with the aggregate, in the same way that water would be mixed with concrete here on Earth, and then heat is applied. The resultant concrete has 2.5 times the compressive yield strength, as compared to Earth concrete made with water.

Materials Scientists Make Martian Concrete

Dook wrote:

Water can only exist on Mars between the temperatures 33-36 degrees F. How are you going to keep your Martian water in that temperature range so the 3D printer can spray it?

Sulfacrete doesn't use any water at all to harden, so the ambient temperature of Mars does not affect the ability of Sulfacrete to harden.

Dook · 2017-04-14 11:52:25

Oldfart1939 wrote:

Dook-
You need to check under the heading "Life Support Systems," and on the second page of sub-topics, you'll see "Chickens." Also "swine." You'll also see a lot more of various contributions regarding greenhouses.
My position on greenhouses is only an initial "quickie" greenhouse will be an inflatable. I've argued for a rigid structure, as have many others here on this forum. My idea was making Lexan (polycarbonate window panels and an ABS or Linear Polyethylene framework) and a very substantial structure capable of withstanding micrometeorite impacts.
By the way, up until the Oklahoma City bombing, almost every rancher was somewhat of an expert blaster using ANFO (ammonium nitrate-fuel oil) explosives to remove tree stumps, remove beaver dams from irrigation ditches, etc. GW addressed the hazards (almost non-existent) of handling the stuff. Shock, is understood to mean "shock wave" as propagated by an initiator explosive. Shooting a barrel filled with the stuff, using rifled slugs or high velocity rifle bullets won't detonate it. I know this. Don't ask how!

I think the first exploration teams to go to Mars will use inflatable greenhouses. I wouldn't plan for a settlement to use them.

Why try to make lexan on Mars when we can ship all the components for a greenhouse on one launch and we'll know that it will fit together and work?

Each settlement will take 6 launches, a tuna can, rover hanger with 2 ATV's, Moxie #1, Moxie #2, nuclear power plant, greenhouse. And you might send a seventh launch full of just food/water.

AN is safer than I think? Okay, but how is it necessary? You can grow plants without it. How is fertilizer more important than using that same weight/space to just take more food?

Dook · 2017-04-14 12:07:51

kbd512 wrote:

Dook wrote:
You need water to make concrete, a lot of it. The article did not say how much water was used by the 3D printer to build the house, probably because water is readily available on the Earth.
Mars has sulfur readily available on the surface of the planet as a result of past volcanic activity. Sulfur can also be used to make concrete. The process doesn't use a single drop of water. The sulfur is mixed with the aggregate, in the same way that water would be mixed with concrete here on Earth, and then heat is applied. The resultant concrete has 2.5 times the compressive yield strength, as compared to Earth concrete made with water.
Materials Scientists Make Martian Concrete
Dook wrote:
Water can only exist on Mars between the temperatures 33-36 degrees F. How are you going to keep your Martian water in that temperature range so the 3D printer can spray it?
Sulfacrete doesn't use any water at all to harden, so the ambient temperature of Mars does not affect the ability of Sulfacrete to harden.

Sulfur is readily available on Mars? I'm sure it is, spread out and mixed with silicon and other elements. You want to drive around Mars, scoop regolith into a cart, pull it back to the base, separate the impurities somehow just to get minimal amounts of sulfur, go back and do it over and over again?

Mars temperatures don't affect the sulfacrete? Sulfur melts at 239 degrees F on the Earth. With Mars low atmospheric pressure, at what temperature will sulfur melt? If the melting temperature is too low, will the sulfacrete still harden on Mars?

Why build a secondary structure and then heat, oxygenate, and provide electricity to two structures when you already have one that works? Why spend time to do that? Why use the rover for that? Why use rocket space for the sprayer and centrifuges when the tuna can provides habitat?

In 500 years, when settlers on Mars start having babies, we'll need home building equipment on Mars.

Oldfart1939 · 2017-04-14 12:16:06

Dook-

Melting points are not ambient pressure sensitive; boiling point of liquids are. You flunk Chemistry 101.

You also need to investigate the years of thoughtful commentary posted elsewhere on this website; many of your preconceptions will then be modified.

Dook · 2017-04-14 13:06:58

Oldfart1939 wrote:

Dook-
Melting points are not ambient pressure sensitive; boiling point of liquids are. You flunk Chemistry 101.
You also need to investigate the years of thoughtful commentary posted elsewhere on this website; many of your preconceptions will then be modified.

Okay, yeah, I'm not a chemist, but you're inefficient and wasteful.

Where's your sewage treatment plant and 1,000 gallon a day water treatment plant going to go?

I should peruse the years of thoughtful commentary on this website? The only new thing here is Elon Musk. The debates we're having now are exactly the same ones we had years ago, and, back then, we had real rocket scientists on here.

Also, my registered date says 2004 and yours says 2016, rookie.

louis · 2017-04-14 13:18:40

Oldfart,

I think threads may be getting mixed up here...

Here I was referring to oxygen production. I was wondering (with respect to oxygen production) whether it's not simpler to just heat up iron oxide, so as to produce oxygen...not very complicated for a small colony to work on.

Iron as a fuel is a lot more speculative. It would really only work, as far as I can see, if it could be shown to be a superior method of energy storage over methane, chemical batteries and so on.

But we do also need iron for iron/steel powder in use with 3D printer machines. For a colony of 1000 we probably wouldn't need huge amounts, but it might make sense to produce it as a by product of oxygen production.

I don't know how you go about purifying the product, but presumably that's an issue however you produce iron on Mars.

Oldfart1939 wrote:

Louis-
In addition to heating your Iron Oxide to 500 degrees, how are you going to reduce it to elemental Iron?

Oldfart1939 · 2017-04-14 13:51:18

Louis-

Thanks for asking in a civilized manner; sorry, simply heating up Iron Oxide will NOT liberate Oxygen. That would be a disproportionation reaction that's thermodynamically impossible. It's not as simple as liberating water from a hydrated salt. The Oxygen is covalently bound to the Iron. That is a simple chemical fact.

Energy storage in the form of Methane IS possible, but again, energetically wasteful. I'm afraid you're going to HAVE TO LIVE WITH NUKES! If, say, we have manufactured a huge surplus of LOX from either a Moxie unit or through electrolysis of In Situ water production--then fine. Otherwise, the 2 energy choices are Nuclear and Solar. Nuclear works 25/7 (haha! modified for a Sol), whereas Solar only during daylight hours. All of these alternative energy production schemes are highly infrastructure intensive, including all the solar reflectors. A nuclear reactor arrives from Earth. Turn it on and go.

elderflower · 2017-04-14 13:54:01

Iron can be purified by decomposing Iron Carbonyl. This method is not used for iron on earth but it is used for Nickel. It is called the Mond process after it's discoverer. It is a lot easier to do with Nickel than with Iron, but it can be done. There will be plenty of CO available as a byproduct of MOXIE.

louis · 2017-04-14 14:06:19

Whoops, obviously misread something earlier and went down the wrong track, thinking oxygen went free from the iron oxide. Apologise to you and everyone else for my confusion over that!

How long does your nuclear reactor take to turn on? And what happens if it malfunctions? I think you have to have back up. And if you want to go exploring you have to have PV panels as well.

Oldfart1939 wrote:

Louis-
Thanks for asking in a civilized manner; sorry, simply heating up Iron Oxide will NOT liberate Oxygen. That would be a disproportionation reaction that's thermodynamically impossible. It's not as simple as liberating water from a hydrated salt. The Oxygen is covalently bound to the Iron. That is a simple chemical fact.
Energy storage in the form of Methane IS possible, but again, energetically wasteful. I'm afraid you're going to HAVE TO LIVE WITH NUKES! If, say, we have manufactured a huge surplus of LOX from either a Moxie unit or through electrolysis of In Situ water production--then fine. Otherwise, the 2 energy choices are Nuclear and Solar. Nuclear works 25/7 (haha! modified for a Sol), whereas Solar only during daylight hours. All of these alternative energy production schemes are highly infrastructure intensive, including all the solar reflectors. A nuclear reactor arrives from Earth. Turn it on and go.

Oldfart1939 · 2017-04-14 14:26:13

Louis- The SAFE-100 is simply a turn-key operation, once all the electrical system is in place and the reactor in it's sheltered location. Chance of malfunction? Very, very low. But--that's why we bring along at least 5 of them over time. Four of them running, but only one at maximum electrical output. One as a reserve spare.

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#76 2017-04-14 08:57:50

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#77 2017-04-14 09:13:08

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#78 2017-04-14 09:21:10

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#79 2017-04-14 09:49:45

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#80 2017-04-14 10:26:41

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#81 2017-04-14 10:32:50

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#82 2017-04-14 10:38:09

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#83 2017-04-14 10:48:47

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#84 2017-04-14 10:53:04

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#85 2017-04-14 10:57:21

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#86 2017-04-14 11:08:01

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#87 2017-04-14 11:08:52

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#88 2017-04-14 11:29:29

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#89 2017-04-14 11:36:02

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#90 2017-04-14 11:42:44

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#91 2017-04-14 11:50:38

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#92 2017-04-14 11:52:25

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#93 2017-04-14 12:07:51

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#94 2017-04-14 12:16:06

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#95 2017-04-14 13:06:58

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#96 2017-04-14 13:18:40

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#97 2017-04-14 13:51:18

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#98 2017-04-14 13:54:01

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#99 2017-04-14 14:06:19

Re: DeGrasse Tyson's Mars challenge to Elon Musk

#100 2017-04-14 14:26:13

Re: DeGrasse Tyson's Mars challenge to Elon Musk

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