Industrial development on Mars

louis · 2017-04-29 17:33:46

The original industrial revolution on Earth was driven particularly by an agricultural revolution (increased production of food), increased population, improvements in mining, steam power and factory production of textiles. The motor for all this was capital accumulation.

We need to recall as well that when the industrial revolution happened on Earth there were already around 1000 million people living on that planet. On Mars the industrial revolution will happen with only a few hundred humans present.

Industrialisation on Mars is clearly going to be a much more rational, planned procedure, not driven by markets, population pressure or capital accumulation.

However, I thought it might be worth going through some of the headings on the Wikipedia Industrial Revolution page to get a feel for how industry might develop on Mars...

Textile Manufacture

This was clearly a key factor in the original Industrial Revolution. I think it will play very little part in developing industry on Mars. Textiles are a low mass product but require fairly complex machines to produce to reasonable quality. They will follow on the Mars industrialisation project rather than lead it.

Metallurgy

This will clearly be vital to the early stages of Mars industrialisation. The early colonists will bring metal powders from Earth which they use with 3D machines. One of the early tasks will be locating rich iron ore fields which can be used in steel production. Locating calcium resources on Mars to facilitate steel production may prove difficult in which case some supplies, certainly at the outset, may need to be brought in from Earth.

The Mars colonists need to have machines available that can process and purify ores and also - v. important - turn them into powders that can be used with 3D printing machines.

Steam power

The great thing about the Mars Industrial Revolution is that - unlike the Earthbound industrial revolution - we will arrive with a huge energy surplus above and beyond our own muscle power and that can easily be grown.

We can bring PV panels or nuclear power facilities that will generate many multiples of our own animal energy, far more per capita than was the case in the early industrial revolution on Earth.

Steam power may seem very 19th century but on Mars it may come into its own again since Mars colonists will be able to make solar reflectors and steam engines at an early stage. With that set up, they can generate electricity. Perfecto!

Machine tools

The early colonists will have many "machine tools" (imported from Earth) available to produce metal and other parts. CNC machines (computer controlled lathes etc) and 3D printer machines will give just a few colonists a huge ability to manufacture machines...even machines that make machine tools!

Chemicals

This is absolutely vital to Mars industrial revolution. Many of the chemicals that are vital to industry on Earth are not easily obtainable on Mars. We need to be able to produce them in quantity by various processes e.g. electrolysis. Searching for the right minerals on Mars will be an absolutely vital first step in developing industry on Mars. We will need to import machines that can analyse materials, process chemicals and purify materials to produce the elements and chemicals we need. I think electrolysis facilities should be within the scope of the early colonists.

Cement

Mars cement may be a bit of a challenge given the paucity of calcium but it looks like we can do it.

Gas lighting

Gas lighting won't be important on Mars but gas - methane - might be the perfect form of flexible energy storage. Lgihting will be electrical - much safer.

Glass making

Mars has virtually all the resources for glass making and the process can be automated. Glass is a v. useful material all round. Easier to produce than plastic. I can envisage we will use glass a lot for storage of foods, chemicals and so on in the early stages. Paper machine

Paper machine

I can't see any uses for paper on Mars. So I don't think paper will be part of Mars industrial development.

Agriculture

Agriculture will not be a big initial driver of industrial development on Mars. However it will be a big energy user once feeding the Mars colonists with Mars food becomes a priority. We each need half a tonne of food a year (but that's including water content). You could probably feed someone on 300 kgs of dehydrated food. So even for a colony of 1000 that's only 300 tonnes per annum or about 5 Falcon Heavy rides to LEO.

I think agriculture will very much follow industry on Mars. If we can produce energy on Mars from ISRU then agriculture on Mars will follow.

Mining

This should probably be top of the list for industrial development on Mars! From the outset we will be scouting for resources and as soon as we find them - water ice, iron ore, aluminium, calcium, etc - we will mine them.

Transportation

I don't think transportation will be a problem on Mars as it was on rain sodden Earth!

We clear boulders and rocks to make smooth road trails along which rovers can pass with relative ease. We don't need canals, railways or metalled roads.

Well there you go - a brief survey contrasting the original industrial revolution on Earth with the one we need on Mars. I hope to produce a detailed industrial plan for Mars shortly.

Last edited by louis (2017-04-30 08:15:50)

RobS · 2017-04-29 18:59:31

I think you need to consider the role of metal carbonyls: https://en.wikipedia.org/wiki/Metal_carbonyl . Zubrin's Case for Mars suggests that nickel-iron meteorite can be blasted with hot carbon monoxide, producing metal carbonyl gas. When you cool the carbonyls they liquify at different temperatures, so a fractionation tower will separate then. You can pour the liquids into molds and drive off the CO and reuse it. You can use it to produce metal powders for three d printers, too. I suspect we won't smelt steel on Mars, but seed iron carbonyl with a certain amount of carbon.

SpaceNut · 2017-04-29 19:39:08

The industrial revolution was pave due to the creation of power sources that could make the types of industry that needed it to modernize the machines to grow. It allowed for night to become day so that the factory could be open 24/7.

This charge started with water, and wind but was followed up with coal, oil and gas with the early 1900 having some solar hot water which gave under the cheap cost of oil.

Mars barely has solar for its energy source and while dust storm can last for months the amount of wind in nearly nill...

So energy is the short straw which mars is missing even when we supply the rest of what we need to produce what we need.

But the first hurdle which mars has long on mars is an atmospher which we can not live in and must use even more power and other structures to make a liveable condition for man to be with in.

SpaceNut · 2017-04-29 20:21:21

For mars I would look at early batteries being made from insitu resources such as Iron Edison a NIFe design. There is yahoo group that has alternative energy topics related to this battery storage methods.

Oldfart1939 · 2017-04-30 13:29:30

I'd suspect the first real industry will be combined with mining--mining out below surface regolith-ice mixtures and processing for massive amounts of water. I've previously suggested a strip mining approach followed by transportation to a processing facility of icy regolith--remaining in the frozen state for transport. This is doubly important, since very little chemical industry can operate without water. Agriculture will undoubtedly be the initial customer for this recovered resource.

Water will provide the feedstock for large scale electrolysis plants for the production of Oxygen, Hydrogen, and subsequently, Methane.

Last edited by Oldfart1939 (2017-04-30 13:31:13)

louis · 2017-04-30 14:16:36

I think you are right. A stockpile of water will indeed be vital and will be our first priority. Of course for Mission One the water might been extracted from the atmosphere in the first place. But yes, we will need tonnes of water as industry develops. Waste water BTW can probably be frozen and then moved by Robot rover to a designated waste area e.g. a crater.

Personally I think we'll be focussed on industrial processes before agriculture becomes a major enterprise (and water can in any case largely be recycled within an agricultural facility).

Oldfart1939 wrote:

I'd suspect the first real industry will be combined with mining--mining out below surface regolith-ice mixtures and processing for massive amounts of water. I've previously suggested a strip mining approach followed by transportation to a processing facility of icy regolith--remaining in the frozen state for transport. This is doubly important, since very little chemical industry can operate without water. Agriculture will undoubtedly be the initial customer for this recovered resource.
Water will provide the feedstock for large scale electrolysis plants for the production of Oxygen, Hydrogen, and subsequently, Methane.

louis · 2017-05-01 09:47:32

Yes - can't claim to understand all the many processes involved - but they sound very useful.

There may be more than one way to skin a cat in terms of producing steel. I've heard some people claiming here than the rolling process imparts certain necessary qualities to steel, but on the other hand top grade steel has been created in small forges.

We need to find a technique, preferably mostly automated, that will suit a small colony on Mars. Ideally, the whole process might be automated: robot rovers dig up and collect iron ore, which is delivered to the industrial hab. Iron oxide is separated out and then seeded with carbon extracted from the CO2 atmosphere. Presumably we need some calcium for the process as well?

RobS wrote:

I think you need to consider the role of metal carbonyls: https://en.wikipedia.org/wiki/Metal_carbonyl . Zubrin's Case for Mars suggests that nickel-iron meteorite can be blasted with hot carbon monoxide, producing metal carbonyl gas. When you cool the carbonyls they liquify at different temperatures, so a fractionation tower will separate then. You can pour the liquids into molds and drive off the CO and reuse it. You can use it to produce metal powders for three d printers, too. I suspect we won't smelt steel on Mars, but seed iron carbonyl with a certain amount of carbon.

Antius · 2017-05-01 16:45:33

CO2 would work better as a power cycle working fluid than steam on Mars, as there is an endless supply of it from the atmosphere. It is denser and therefore allows more compact power machinery. The near vacuum conditions mean that any horizontal surface would function as an efficient solar collector during day and a radiator at night. Dynamic cycles would be at least as efficient as PV and much easier to build.

Food may be difficult, as there is insufficient solar constant at Mars to keep a greenhouse above freezing without some form of additional heating. This suggests that some combination of natural and synthetic lighting may work best, or maybe mixing agricultural areas with high heat generation industrial areas to keep the greenhouses above freezing.

I tend to agree that transport is easier on Mars, as the place is a single giant continent. There is no place that cannot be reached by road and ultimately all commodities can be transported by road, rail or pipeline.

Many tools and machinery will be powered by compressed air or CO2, as this power source can easily be stored and gas tools are lighter and much easier to make than electric tools.

Without an active hydrosphere, rammed soil, compressed soil blocks, adobe and simple clay based mortars can perform many of the tasks fulfilled by concrete on Earth.

Last edited by Antius (2017-05-01 17:04:09)

Dook · 2017-05-01 16:53:28

Antius wrote:

CO2 would work better as a power cycle working fluid than steam on Mars, as there is an endless supply of it from the atmosphere. It is denser and therefore allows more compact power machinery. The near vacuum conditions mean that any horizontal surface would function as an efficient solar collector during day and a radiator at night. Dynamic cycles would be at least as efficient as PV and much easier to build.
Food may be difficult, as there is insufficient solar constant at Mars to keep a greenhouse above freezing without some form of additional heating. This suggests that some combination of natural and synthetic lighting may work best, or maybe mixing agricultural areas with high heat generation industrial areas to keep the greenhouses above freezing.
I tend to agree that transport is easier on Mars, as the place is a single giant continent. There is no place that cannot be reached by road and ultimately many commodities can be transported by road, rail or pipeline.
Many tools and machinery will be powered by compressed air or CO2, as this power source can easily be stored and gas tools are lighter and much easier to make than electric tools.

Look at the Viking 1 pictures of Mars. It's an impassable rock field as far as you can see.

There are also areas that are entirely sand dunes. Drive in there and your wheels will sink down into the sand and you won't be coming out.

There also may be areas of salt water that are liquid for long periods in the day time, that would be impassable.

louis · 2017-05-01 17:38:51

I'm not sure I follow your first para completely...do you mean CO2 on Mars could be used like water on Earth...building up pressure to drive turbines? If so, can you give more detail on how that would work?

I quite like the idea of mixing agriculture and industry on Mars, since we need oxygen for combustion processes. However dust storms are a reality on Mars, and they can be quite dramatic...It's surely better to "make hay while the sun shines" - collect your solar energy while it's there especially as creating 2D "ambient light" farming requires you put a huge amount of energy into construction.

Not sure why you think rail is part of a Mars transport solution. Why do people build rail on Earth...? It's basically a cost equation.

For some products (heavy and bulky over a very long distance) rail is cheaper than road. But that's partly because (a) rail construction on Earth, deploying huge amounts of labour and heavy machinery is relatively cheap (whereas on Mars it will be relatively expensive given the labour shortage and the expense of constructing heavy machinery on Mars) (b) gravity is more of a constraint on Earth than Mars and (c) the weather/climate on Earth means road construction is very expensive.

On Mars, the reverse applies: (a) on Mars labour will be very scarce and constructing heavy machinery will be extremely difficult (= expensive for rail) (b) gravity is less of a constraint on Mars and (c) the weather/climate on Mars means road building involves no more than getting the boulders, rocks and stones out of the way.

I would add a fourth consideration - for many decades the population on Mars will be tiny in comparison with Earth's population so we don't need to move millions of tonnes of stuff...we will be more in the hundreds of tonnes.

Antius wrote:

CO2 would work better as a power cycle working fluid than steam on Mars, as there is an endless supply of it from the atmosphere. It is denser and therefore allows more compact power machinery. The near vacuum conditions mean that any horizontal surface would function as an efficient solar collector during day and a radiator at night. Dynamic cycles would be at least as efficient as PV and much easier to build.
Food may be difficult, as there is insufficient solar constant at Mars to keep a greenhouse above freezing without some form of additional heating. This suggests that some combination of natural and synthetic lighting may work best, or maybe mixing agricultural areas with high heat generation industrial areas to keep the greenhouses above freezing.
I tend to agree that transport is easier on Mars, as the place is a single giant continent. There is no place that cannot be reached by road and ultimately all commodities can be transported by road, rail or pipeline.
Many tools and machinery will be powered by compressed air or CO2, as this power source can easily be stored and gas tools are lighter and much easier to make than electric tools.

Antius · 2017-05-02 07:53:31

In answer to your first question: yes. CO2 has a higher molecular mass than water, making it a more power dense working fluid and its properties make it more efficient as well. The downside is S-CO2 power cycles work at high pressures, but not really much higher than modern steam cycles.

This is probably the best reference to S-CO2 power cycle generic info: http://energy.sandia.gov/energy/renewab … tical-co2/

Wiki provides a brief discussion too: https://en.wikipedia.org/wiki/Supercrit … king_fluid

Will discuss the rest later.

louis · 2017-05-02 10:38:14

Thanks - v. helpful.

Antius wrote:

In answer to your first question: yes. CO2 has a higher molecular mass than water, making it a more power dense working fluid and its properties make it more efficient as well. The downside is S-CO2 power cycles work at high pressures, but not really much higher than modern steam cycles.
This is probably the best reference to S-CO2 power cycle generic info: http://energy.sandia.gov/energy/renewab … tical-co2/
Wiki provides a brief discussion too: https://en.wikipedia.org/wiki/Supercrit … king_fluid
Will discuss the rest later.

kbd512 · 2017-05-02 11:30:58

I agree with Antius' idea about using CO2 as a working fluid for tools and, presumably, fission reactors or solar concentrators for electrical power generation. To use CO2 as a working fluid in high temperature processes common in utility electrical power generation, high grade stainless steels are required to reduce corrosion to acceptable levels. This is not a severe problem on Earth where transportation of heavy steel alloys is not a substantial impediment to their implementation.

Although prices have come down over the years, the latest and greatest PV panels are still incredibly expensive and shipping them to Mars is even more expensive. For utility grade power, molten salt solar concentrators or fission reactors will be the least expensive and most performant technologies available. I think molten salts will be the best energy storage mechanism for primary loops and CO2 will be the best energy transfer mechanism for secondary loops that drive gas turbines to produce electrical power. Salts are plentiful and readily available on Mars and the processes required to extract water could also produce the salts required for thermal energy storage.

PV panels and batteries or small fission reactors can produce the electrical power required to obtain the salts and CO2 required for deployment of utility grade power. Even if it takes two years to collect the materials, the cost savings associated with local production will more than cover the cost of shipping the solar concentrators or fission reactors to Mars. The benefits derived from local production are more profound than simple dollars and cents indicates. If working fluids are lost, for whatever reason, then there's more where that came from and it's sitting outside the habitat module, rather than aboard a Mars-bound freighter that can only deliver cargo every two years.

Antius · 2017-05-02 13:58:29

The corrosion rate of steel in hot CO2 is governed by the Arhenius equation - I.e. it increases exponentially with temperature. The UKs first generation gas cooled reactors operated at 400C and used carbon steel pressure vessels. They operated for over 50 years without excessive corrosion problems. The next generation operated at 650C and had to make use of stainless steel liners. Some of these units required boiler replacements after 20 years of operation, which cost a fortune.

The lesson is carbon steel components can be used in hot CO2 if temperatures are kept at or beneath 400C. This limits efficiency to less than 40%, but would allow the use of carbonyl cast components. One useful feature of the Martian environment is its temperature extremes. Mars night time temperatures are easily sufficient to condense down to a liquid. This means recompression energy expenditure can be extremely low, boosting cycle efficiency to high values even at modest temperatures.

At Martian night time temperatures of -80C, CO2 can be stored as liquid at pressure of 5.1 bars. Solar heat can be stored in the latent heat of fusion of water. Liquid CO2 can be converted to high pressure gas by boiling it at zero Celsius. Carnot efficiency between these temperatures is 29%. Practical efficiency is about 19%.

Last edited by Antius (2017-05-02 14:22:43)

Antius · 2017-05-02 16:24:49

louis wrote:

Not sure why you think rail is part of a Mars transport solution. Why do people build rail on Earth...? It's basically a cost equation.
For some products (heavy and bulky over a very long distance) rail is cheaper than road. But that's partly because (a) rail construction on Earth, deploying huge amounts of labour and heavy machinery is relatively cheap (whereas on Mars it will be relatively expensive given the labour shortage and the expense of constructing heavy machinery on Mars) (b) gravity is more of a constraint on Earth than Mars and (c) the weather/climate on Earth means road construction is very expensive.
On Mars, the reverse applies: (a) on Mars labour will be very scarce and constructing heavy machinery will be extremely difficult (= expensive for rail) (b) gravity is less of a constraint on Mars and (c) the weather/climate on Mars means road building involves no more than getting the boulders, rocks and stones out of the way.
I would add a fourth consideration - for many decades the population on Mars will be tiny in comparison with Earth's population so we don't need to move millions of tonnes of stuff...we will be more in the hundreds of tonnes

Your logic is sound. Rail is cheap for bulk transport on Earth partly due to energy efficiency - lower friction and lower air resistance per tonne-mile; and partly due to labour efficiency - a lot of freight hauled per man-hour. There is no air resistance on Mars and only two-fifths the gravity. What's more, road vehicles can haul a lot of tonnes per man-hour and could even be automated as you suggested.

Automated vehicles might use direct solar power without need for batteries. That would save a lot of weight, but would reduce the number of hours available for driving. If the vehicle was simple in design, it could be constructed from local iron and polymers with only the PV panels imported.

Last edited by Antius (2017-05-02 16:28:27)

Antius · 2017-05-02 16:45:59

kbd512 wrote:

I agree with Antius' idea about using CO2 as a working fluid for tools and, presumably, fission reactors or solar concentrators for electrical power generation. To use CO2 as a working fluid in high temperature processes common in utility electrical power generation, high grade stainless steels are required to reduce corrosion to acceptable levels. This is not a severe problem on Earth where transportation of heavy steel alloys is not a substantial impediment to their implementation.
Although prices have come down over the years, the latest and greatest PV panels are still incredibly expensive and shipping them to Mars is even more expensive. For utility grade power, molten salt solar concentrators or fission reactors will be the least expensive and most performant technologies available. I think molten salts will be the best energy storage mechanism for primary loops and CO2 will be the best energy transfer mechanism for secondary loops that drive gas turbines to produce electrical power. Salts are plentiful and readily available on Mars and the processes required to extract water could also produce the salts required for thermal energy storage.
PV panels and batteries or small fission reactors can produce the electrical power required to obtain the salts and CO2 required for deployment of utility grade power. Even if it takes two years to collect the materials, the cost savings associated with local production will more than cover the cost of shipping the solar concentrators or fission reactors to Mars. The benefits derived from local production are more profound than simple dollars and cents indicates. If working fluids are lost, for whatever reason, then there's more where that came from and it's sitting outside the habitat module, rather than aboard a Mars-bound freighter that can only deliver cargo every two years.

How about a boiling CO2 reactor? Looking at the phase diagram for CO2, at a pressure of about 30 bar, it boils at about zero centigrade. This is above average Martian temperatures everywhere on the planet. A reactor heating CO2 from liquid at 0C to dry gas at 400C could work on a direct cycle and would be extremely compact.

https://upload.wikimedia.org/wikipedia/ … iagram.svg

As the moderating power of CO2 is much lower than water, the core would function in the fast spectrum which should allow high power density. The only parts of power plant that would need to be imported are the fuel, the centrifugal injection pumps and possibly fuel handling equipment.

At such relatively low pressures, most pressure containing components could be low-carbon steel. The pressure vessel itself could be pre-stressed concrete, using steel pre-stressing tendons.

Last edited by Antius (2017-05-02 16:50:47)

kbd512 · 2017-05-02 18:16:55

Antius,

I'd really like the process heat that a molten salt reactor can produce, but that does require the difficult to come by stainless steels. In any event, how compact would a 1000MWt BCR (Boiling CO2 Reactor) be?

What would be required to store the spent fuel elements from a BCR?

I'm not so sure about using a concrete pressure vessel. The thermal gradient between the walls of the vessel and the atmosphere is huge. This seems like a cracking problem waiting to happen, but can you provide more information on the composition of the concrete to be used? Would it be buried?

I was kinda set on a molten salt core to maximize fuel burn up, but I'm flexible if the mass, cost, and simplicity of the overall design are conducive to minimization of support requirements.

I'm trying to understand your overall concept here. Are we doing this merely to reduce steel usage or quality required or are there other benefits from a lower thermal output design, like overall or operations simplicity, for example?

SpaceNut · 2017-05-02 19:16:25

A 400 'C delta is going to be an input 12,660 watts of energy.

https://en.wikipedia.org/wiki/Heat_capa … t_capacity

https://en.wikipedia.org/wiki/Carbon_di … data_page)

Sort of like a hot water boiler in that once you put the energy into the Co2 liquid that it is used to move a turbine to which as it exits into an exspansion tank which would drop the pressure and then use a pump to repressurize it back into a liquid as it cools. In some ways this is simular to A/C freon loop and radiator...

Entropy and the Three Laws of Thermodynamics

Something simular to a steam generator as well
Heating loop
File:Steam_Generator.png

Pump and turbine

Cooling radiator collector

So the question can CO2 replace water in such a power generation system... google.... that would be a Yes...

https://www.scientificamerican.com/arti … ate-power/

http://www.innovation-america.org/exit- … o2-turbine

Antius · 2017-05-03 09:00:52

kbd512 wrote:

Antius,
I'd really like the process heat that a molten salt reactor can produce, but that does require the difficult to come by stainless steels. In any event, how compact would a 1000MWt BCR (Boiling CO2 Reactor) be?
What would be required to store the spent fuel elements from a BCR?
I'm not so sure about using a concrete pressure vessel. The thermal gradient between the walls of the vessel and the atmosphere is huge. This seems like a cracking problem waiting to happen, but can you provide more information on the composition of the concrete to be used? Would it be buried?
I was kinda set on a molten salt core to maximize fuel burn up, but I'm flexible if the mass, cost, and simplicity of the overall design are conducive to minimization of support requirements.
I'm trying to understand your overall concept here. Are we doing this merely to reduce steel usage or quality required or are there other benefits from a lower thermal output design, like overall or operations simplicity, for example?

The molten salt reactor has some strong advantages: very high core power density; no need for high pressurisation; a naturally integral fuel cycle; negative void temperature coefficient; no need for manufactured fuel, just pure fluoride salts; and of course, the fuel can reach high temperatures without ‘damage’ as it doesn’t have any geometry that can be lost with temperature – only phase change. Heat exchangers and secondary working fluids would appear to be a necessity, but these too can be relatively compact.

The major downside of the MSR is materials ageing concerns. You have a highly corrosive salt mixture containing literally thousands of actinide and fission product chemical compounds. It is very difficult to design a containment vessel and heat exchangers that will last decades. One way around the problem would be to design the primary circuit as a module that can simply be replaced every decade or two. Stainless steels probably won’t be up to the task for MSR primary circuit, the halide cracking issues are too onerous. Nickel alloys have been examined.

My thoughts in terms of the low temperature CO2 reactor are that provided the fuel and core barrel are shipped from Earth, the remainder of plant could be 3D printed on Mars from carbon steels. Low-pressure turbines might be produced in this way, along with primary circuit pipework. Obviously, this sort of project is unlikely to be attempted until base population has reached a relatively high level and energy demand is high enough to justify the effort.

Concrete pressure vessels have been used on UK reactors since about 1970. They include steel liners and internal cooling channels to prevent thermal degradation. They are a cheaper and easier option for relatively low pressures (<100bar) but it may be difficult to find a concrete strong enough to resist cracking beyond that. I am not sure about the state of the art. One of the advantages of a PCRV is its inherent safety against catastrophic failure.

High temperature process heat would be very useful, as it would allow direct thermochemical H2 and CO production without the need for electrolysis. That would be a big advantage for Martian steel and propellant production but it is very difficult to find materials that would stand up to the required temperatures. Stainless steels aren’t much good at temperatures greater than 800C. UK AGRs have an output temperature of 650C and couldn't go much higher due to cladding creep and heat exchanger oxidation issues.

Last edited by Antius (2017-05-03 09:42:11)

SpaceNut · 2017-05-03 20:17:43

Thanks for the molten salt discusion will research to see what a scaled down unit for home use might look like but for mars were is the heat source if we are not using Solar concentration or nuclear reactors to create it?

louis · 2017-05-04 09:11:05

Presumably a choice of PV panels during sollight or chemical batteries (previously replenished by PV) or methane combustion (methane and oxygen previously produced with PV power). I presume pressure can be maintained for several hours after initial heating with the right insulation. I like the idea of a concrete pressure vessel. I think if the concrete is thick enough, the issue of cracks becomes redundant...I'm thinking of those wartime bunkers that could withstand hugely powerful explosions.

SpaceNut wrote:

Thanks for the molten salt discussion will research to see what a scaled down unit for home use might look like but for mars were is the heat source if we are not using Solar concentration or nuclear reactors to create it?

kbd512 · 2017-05-04 09:59:56

SpaceNut,

The heat source is a fission reactor. Small solar concentrators can also work, but utility grade power production using that method would require substantial investment in local resource production that can only happen if there is sufficient power for processing ores into metals to begin with and PV panels and batteries won't provide enough power unless most of the mass delivered is PV panels and batteries.

We're not going to burn CH4 on Mars using precious local water supplies, just so we can avoid using nuclear power. Louis seems to think Mars is more like Earth than it actually is or hasn't thought through the implications of what he proposed. We're not going to truck thousands of tons of batteries, PV arrays, and cryogen plants from Earth just to make this PV power nonsense work. PV panels and batteries are workable for small exploration missions, but it just won't provide utility grade power unless we're willing to spend billions on batteries and PV panels and additional billions shipping it all to Mars. For simple economic reasons, nuclear power is what NASA is currently working on for their rather modest Mars exploration base.

We're also not going to make any nuclear reactor pressure vessels on Mars until a reactor brought from Earth is online. That kind of stuff is about five decades into the future, minimum.

Antius · 2017-05-04 10:38:54

kbd512 wrote:

SpaceNut,
The heat source is a fission reactor. Small solar concentrators can also work, but utility grade power production using that method would require substantial investment in local resource production that can only happen if there is sufficient power for processing ores into metals to begin with and PV panels and batteries won't provide enough power unless most of the mass delivered is PV panels and batteries.
We're not going to burn CH4 on Mars using precious local water supplies, just so we can avoid using nuclear power. Louis seems to think Mars is more like Earth than it actually is or hasn't thought through the implications of what he proposed. We're not going to truck thousands of tons of batteries, PV arrays, and cryogen plants from Earth just to make this PV power nonsense work. PV panels and batteries are workable for small exploration missions, but it just won't provide utility grade power unless we're willing to spend billions on batteries and PV panels and additional billions shipping it all to Mars. For simple economic reasons, nuclear power is what NASA is currently working on for their rather modest Mars exploration base.
We're also not going to make any nuclear reactor pressure vessels on Mars until a reactor brought from Earth is online. That kind of stuff is about five decades into the future, minimum.

Agreed. I thought initially that some form of solar dynamic power system using liquid CO2 could be built using native resources with a modest manufacturing base. But the amount of energy needed is just too large. The sort of ‘colony’ that Musk has in mind would need 80MWhe/man-year just for food production. Making propellants and expanding living space and manufacturing infrastructure at a reasonable rate are all energy hungry tasks. They will require a lot of steel that needs to be produced by reducing iron ore. On Mars, that will eat a lot of electric power, because it will require electrolysis of water or splitting CO2 into CO and O2. To make steel cost effectively on Mars, you need cheap electricity and there is no escape from that.

We would need a lot more refined energy per capita to survive on Mars than we do on Earth because everything has to be manufactured in one way or another, whereas the Earth provides a lot of things for free. To make matters worse, the solar constant is lower on Mars.

To realise the sort of vision that Musk has in mind, one very quickly has to face up to the task of building nuclear reactors using native materials. As soon as a Mars base transitions from a base of 100's to a colony of thousands, we face that necessity. If we can pull that off at a reasonable cost, then real colonisation is plausible. If not, then it never will be.

Last edited by Antius (2017-05-04 10:44:17)

louis · 2017-05-04 12:10:13

Ah well, if you are talking a Musk-style approach, then you do have to think big. But solar sizes up just as well as nuclear power - better I would say because with a Musk-sized settlement you are soon getting into health and safety issues. Based on the MIT study (which delivered a constant 100KwE from 25k sq. metres of ultralightweight PV), you'd need 20million sq metres or an area of about 4.5kms x 4.5 kms. Not at all a problem I would say - and if we are talking about a sizeable community, a lot of that PV power will of course be on the roof.

The MIT study had quite low efficiency PV but if we are talking about Musk's ITS system delivering a staggering 450 tonnes per journey to the Mars surface the PV could be state of the art, so much more like 30% rather than 10% (so maybe more like 6 million sq. metres at 3,000 tonnes)...why on Earth wouldn't you choose PV , and methane production if you had a Musk system at your fingertips. So much more flexible. Methane (with oxygen) can be used for any number of rovers or for heating isolated units. PV can be set up to power sub-bases. Of course, the thing about a Musk mission as well is that we could within a few years import all the equipment we need to make Mars ISRU PV panels, so we can make the PV system on Mars rather than import it from Earth.

Antius wrote:

kbd512 wrote:
SpaceNut,
The heat source is a fission reactor. Small solar concentrators can also work, but utility grade power production using that method would require substantial investment in local resource production that can only happen if there is sufficient power for processing ores into metals to begin with and PV panels and batteries won't provide enough power unless most of the mass delivered is PV panels and batteries.
We're not going to burn CH4 on Mars using precious local water supplies, just so we can avoid using nuclear power. Louis seems to think Mars is more like Earth than it actually is or hasn't thought through the implications of what he proposed. We're not going to truck thousands of tons of batteries, PV arrays, and cryogen plants from Earth just to make this PV power nonsense work. PV panels and batteries are workable for small exploration missions, but it just won't provide utility grade power unless we're willing to spend billions on batteries and PV panels and additional billions shipping it all to Mars. For simple economic reasons, nuclear power is what NASA is currently working on for their rather modest Mars exploration base.
We're also not going to make any nuclear reactor pressure vessels on Mars until a reactor brought from Earth is online. That kind of stuff is about five decades into the future, minimum.
Agreed. I thought initially that some form of solar dynamic power system using liquid CO2 could be built using native resources with a modest manufacturing base. But the amount of energy needed is just too large. The sort of ‘colony’ that Musk has in mind would need 80MWhe/man-year just for food production. Making propellants and expanding living space and manufacturing infrastructure at a reasonable rate are all energy hungry tasks. They will require a lot of steel that needs to be produced by reducing iron ore. On Mars, that will eat a lot of electric power, because it will require electrolysis of water or splitting CO2 into CO and O2. To make steel cost effectively on Mars, you need cheap electricity and there is no escape from that.
We would need a lot more refined energy per capita to survive on Mars than we do on Earth because everything has to be manufactured in one way or another, whereas the Earth provides a lot of things for free. To make matters worse, the solar constant is lower on Mars.
To realise the sort of vision that Musk has in mind, one very quickly has to face up to the task of building nuclear reactors using native materials. As soon as a Mars base transitions from a base of 100's to a colony of thousands, we face that necessity. If we can pull that off at a reasonable cost, then real colonisation is plausible. If not, then it never will be.

kbd512 · 2017-05-04 16:08:09

Louis,

A 100kW fission reactor produces power 24/7/365, no matter what the local weather conditions are, time of day, or where it's located. No assembly is required. On Mars, you can bury reactors in the ground and put a fence around the reactor to mark the exclusion zone. There's no actual engineering issue with doing any of that and no EPA to stop you from doing it. The reactor vessel itself is smaller than a 55 gallon drum and about two times as long. It'd weigh about 760kg on Mars or 2,000kg on Earth. If you put the reactor on wheels with 4 1kW hub motors, then two people can easily move the reactor into position, dig a hole with hand tools, and bury it.

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