Author Topic: Power options for a Mars settlement  (Read 44358 times)

Offline guckyfan

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Re: Power options for a Mars settlement
« Reply #180 on: 05/18/2017 02:08 PM »
Or an blower driven by electric motor. If the atmosphere is thick enough for wind to blow dust, it's thick enough for a blower to blow dust.

I am a little bit worried it may just blow the dust to the next panel.

Offline Kaputnik

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Re: Power options for a Mars settlement
« Reply #181 on: 05/18/2017 02:33 PM »
Or an blower driven by electric motor. If the atmosphere is thick enough for wind to blow dust, it's thick enough for a blower to blow dust.

I am a little bit worried it may just blow the dust to the next panel.

If it's a tracking array, then you need to have space between each row of panel- the greater the gap, the wider range of angles they can work on.
But maybe Robotbeat's idea of hoping the dust will just fall off by itself will be sufficient.

And, hey, sending people out there with an EMU and a broom could be a useful minor punishment for petty crimes... I mean this place is going to need a law and order system after all :D
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Offline john smith 19

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Re: Power options for a Mars settlement
« Reply #182 on: 05/18/2017 06:29 PM »
Mars colony needs to make metals anyway, it's impractical to completely get rid of them.
Reduce, not eliminate.  :(

If you look at solar farms you see most of them use steel supports for their PV arrays or mirrors. I think settlers will have to look much more carefully at the use of metals for structural support applications.

I think Martian bricks (or Marscrete) will be adequate for a surprising number of tasks. I'd like to see the cells made on Mars as well but we'll see.

"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline AC in NC

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Re: Power options for a Mars settlement
« Reply #183 on: 05/18/2017 07:22 PM »
I'm compelled to believe that beyond bootstrapping the colonization effort and prior to full ISRU independence from Earth, that one of the most critical factors is easy setup and low-maintenance.  If that is as critical as it feels to me then I don't see how big solar farms play a big role except as residual assets post-bootstrap or other incidental applications.

Does this sound logical or am I missing something?

I know nuclear isn't trivial but I've seen lots and lots of design-work already invested in modular nuclear.  The Tom Meuller interview and Elon's success leads me to think their approach and mindset could solve almost any problem that physics doesn't preclude.

Naively perhaps, with all this investment I'm surprised that there isn't further progress toward working examples.  Is it beyond reason to develop in the appropriate timeframes a self-contained modular nuclear package that could plug into the martian grid to obviate the requirement of large solar farms post-bootstrap?  Am I really stretching to believe the same could serve as a pluggable "energy pack" for large logistics equipment like material handling, regolith-moving, and tunnel-boring?
« Last Edit: 05/18/2017 08:21 PM by AC in NC »

Offline Robotbeat

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Re: Power options for a Mars settlement
« Reply #184 on: 05/18/2017 10:21 PM »
Mars colony needs to make metals anyway, it's impractical to completely get rid of them.
Reduce, not eliminate.  :(

If you look at solar farms you see most of them use steel supports for their PV arrays or mirrors. I think settlers will have to look much more carefully at the use of metals for structural support applications.

I think Martian bricks (or Marscrete) will be adequate for a surprising number of tasks. I'd like to see the cells made on Mars as well but we'll see.
Meteoric iron is plentiful on Mars. Already refined and just sitting there on the surface waiting for settlers to pick it up and cast it.
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Offline montyrmanley

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Re: Power options for a Mars settlement
« Reply #185 on: 05/18/2017 10:35 PM »
Mars colony needs to make metals anyway, it's impractical to completely get rid of them.
Reduce, not eliminate.  :(

If you look at solar farms you see most of them use steel supports for their PV arrays or mirrors. I think settlers will have to look much more carefully at the use of metals for structural support applications.

I think Martian bricks (or Marscrete) will be adequate for a surprising number of tasks. I'd like to see the cells made on Mars as well but we'll see.
Meteoric iron is plentiful on Mars. Already refined and just sitting there on the surface waiting for settlers to pick it up and cast it.

Iron oxide. Mars is full up of it. It's the "red planet" for a reason. Problem is, it takes energy to separate all that iron oxide into usable oxygen and iron, and if that separation can't be done in an effcient and cost-effective way, it may not matter. It's kind of like desalinating ocean water on earth to make it drinkable: it's only done more or less as a last resort when no other sources of potable water are available because of the inefficient and energy-intensive desalination process.

We really need to invest a lot of money into shrinking and "containerizing" fission reactors. And not just for Mars, but for earthbound uses as well.

Offline Robotbeat

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Re: Power options for a Mars settlement
« Reply #186 on: 05/18/2017 11:27 PM »
I'm pretty sure I said meteoric iron, not iron oxide (when is even more plentiful). Did I mistype??

Let me go back and check to make sure I said meteoric iron...

...Meteoric iron...
Yup! Looks like meteoric iron is what I said, not iron oxide.
« Last Edit: 05/18/2017 11:28 PM by Robotbeat »
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Offline Stan-1967

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Re: Power options for a Mars settlement
« Reply #187 on: 05/18/2017 11:47 PM »

Meteoric iron is plentiful on Mars. Already refined and just sitting there on the surface waiting for settlers to pick it up and cast it.

Meteoric iron could be very useful for simple structural needs.  I think it might be preferable to bring along a furnace to melt meteoric Ni:Fe , & make metal powders out of it vs. casting.  Metal powders could be used laser sintering in 3-D additive processes, which would enable greater complexity & more flexibility in what could be made.

I also have an interest in trying to figure out how to use martian resources like perchlorates, sulfates, & nitrates to  be used in electrochemical process for refining metal oxides or digesting & purifying metals through electrowining or precipitation. 

Both pathways are power intensive.   Making metal powders is probably the best initial path.   


Offline BobHk

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Re: Power options for a Mars settlement
« Reply #188 on: 05/19/2017 01:25 AM »
There is a solution to most dust build up on the surface of solar panels:

http://www.tandfonline.com/doi/abs/10.1080/02726350601146341

Mashing the martian soil into lego bricks to build habitats with is already theoretically possible:

https://www.theverge.com/2017/4/27/15436154/mars-soil-simulant-study-building-human-missions

Quote
After working with the material for a while, the engineers found that just adding the right amount of pressure was enough to form the soil into tiny, stiff blocks stronger than steel-reinforced concrete.

SO you bring a machine with you that mashes soils into building blocks and set up the solar panels with native materials holding them up off the ground, integrate them into shelters as roof tiles also as the panels anti dust tech could be used to keep them from getting buried.

No iron smelting/melting needed.

If we import polymers they can be used to 3dprint essential tools and support struts that cant be made with compacted dusts.

http://www.inquisitr.com/4147743/do-it-yourself-mars-colony-3d-printer-would-use-mars-dust-to-make-tools-building-materials/

Native metals would be best used with sinter printing, allowing the 3d printing of tools that uses a minimal amount of the native meteoric iron material and gives maximal strength for the design. 

I'm a fan of amerecium rtgs.  SpaceX could start landing them as red dragon like power pods as soon as retropropulsive landings are safe enough to trust a rtg on a drone landing mission near a prospective colony site. 

Once colonists land they could hook up to the rtg landers power and set up the colony.  How long can transmission lines be?  It doesnt have to be close and could probably be buried if you didnt want to maintenance the thing after its hooked up to colony power lines.  More than one rtg could be landed and daisy chained together as needed.

Offline meekGee

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Re: Power options for a Mars settlement
« Reply #189 on: 05/19/2017 02:19 AM »
So, what you bring to Mars is the facility to fabricate solar cells/panels. 
Then set up shop and sell them to Kaputnik
Solar cells can be made so thin that a single ITS could land Gigawatts of cells. And, if you're concentrating the sunlight using Mars-made concentrators, hundreds of Gigawatts or even a Terawatt worth of cells per ITS payload.

So there's no real reason you would need an actual solar cell manufacturing plant on Mars except complete independence.

Tom Mueller directly contradicted this, by saying that Nuclear delivers more Watts per kg.

This is presumably after studying the matter.

The GWatts per ITS can only be achieved by taking the mass of in-space zero-g thin film systems such as the ATK product.  Those don't work in atmosphere, and don't have longevity on Mars.

Solar is an ok interim solution, if flown from Earth.

Mars-originated solar has a chance, but it has to be on vast scales, or else the energy put into solar panel production exceeds the energy it generates over its lifetime.  (and even if was "only" 50% of that energy, it'd still be problematic since you need to invest that energy upfront)

If those problems can be solved, then yes - you could use Mars-native solar.   But that's a very big if.
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Offline Robotbeat

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Re: Power options for a Mars settlement
« Reply #190 on: 05/19/2017 02:32 AM »
So, what you bring to Mars is the facility to fabricate solar cells/panels. 
Then set up shop and sell them to Kaputnik
Solar cells can be made so thin that a single ITS could land Gigawatts of cells. And, if you're concentrating the sunlight using Mars-made concentrators, hundreds of Gigawatts or even a Terawatt worth of cells per ITS payload.

So there's no real reason you would need an actual solar cell manufacturing plant on Mars except complete independence.

Tom Mueller directly contradicted this, by saying that Nuclear delivers more Watts per kg.

This is presumably after studying the matter.
I've also studied the matter and I disagree. He's perhaps the world's best liquid rocket engine engineer, but he's not the world-premier expert in everything. Also, please quote where he actually said what you're claiming to be a direct contradiction.

Quote
The GWatts per ITS can only be achieved by taking the mass of in-space zero-g thin film systems such as the ATK product.  Those don't work in atmosphere, and don't have longevity on Mars.
Sure they do. And anyway, making supporting material is way simpler than the cells themselves.
« Last Edit: 05/19/2017 02:35 AM by Robotbeat »
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Offline Semmel

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Re: Power options for a Mars settlement
« Reply #191 on: 05/19/2017 06:10 AM »
I dont think that dust on solar panels is a big issue. It can easily be mitigated, for example put the solar panels at least at a slight angle (you want to do that anyway to optimize the angle to the sun) and mount a small piezo element at the backside of the panel. When dust accumulates on the solar panels, vibrate the piezo element with a suitable frequency. Effectively the solar panel acts like a speaker membrane and the dust walks right off. No complicated cleaning machinery, just a few grams of piezo element and wires per solar panel.

Offline john smith 19

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Re: Power options for a Mars settlement
« Reply #192 on: 05/19/2017 09:55 AM »
We really need to invest a lot of money into shrinking and "containerizing" fission reactors. And not just for Mars, but for earthbound uses as well.
An idea that's been around for several decades.

Technically the PWR's were the closest to getting to serial production but they have issues. The main problems with all the proposed designs are they come from people looking to leverage their existing experience, none of which is ideal. Multiply that by a regulatory regime that takes no account of the size of the reactor and you need deep pockets to start with.

In terms of safety, ease of of construction cost and freedom from proliferation issues anywhere within the current experience base the ideal would be an unenriched (natural Uranium) thermal reactor using a 10%BiPb alloy, graphite moderator and natural circulation or heat pipes operating at around 540c.

Such a system eliminates the need for enriched Uranium and high pressure vessels (beyond  the dead weight of the lead, 10s, not 100s of atm) and operates at temperatures that allow conventional steam turbine (available down to the 100s of Kws) easily. russian experience suggest using Martensitic (AISI 400 series) rather than Austenitic (300 series) as they are more resistant to neutron damage and easier to weld. BTW I don't think anyone's tried FSW on such steels, but that would probably substantially reduce weld issues.

The 10%Bi results in temperatures low enough to freeze out Polonium without the coolant freezing, the biggest hazards of this type of system.

The (relatively) easy availability of enriched Uranium has been the quick fix for reactor designers but it's also the key issue around proliferation. People don't want to be dependent on others for supplies of enriched uranium but existing nuclear countries are nervous about supplying enrichment technology to new countries, fearing its use in nuclear weapons. Only a natural Uranium design completely eliminates that risk and gives control of supply to the client country without fear of proliferation.   

Needless to say no one has spent any significant time working on such a concept.  :(
« Last Edit: 05/19/2017 10:08 AM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline john smith 19

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Re: Power options for a Mars settlement
« Reply #193 on: 05/19/2017 09:55 AM »


Meteoric iron could be very useful for simple structural needs.  I think it might be preferable to bring along a furnace to melt meteoric Ni:Fe , & make metal powders out of it vs. casting.  Metal powders could be used laser sintering in 3-D additive processes, which would enable greater complexity & more flexibility in what could be made.

I also have an interest in trying to figure out how to use martian resources like perchlorates, sulfates, & nitrates to  be used in electrochemical process for refining metal oxides or digesting & purifying metals through electrowining or precipitation. 

Both pathways are power intensive.   Making metal powders is probably the best initial path.
Yes that's the problem. Powders as an intermediate for different mfg routes sounds a good idea.

It's only when you try to replace coal, oil or natural gas you realize just how much energy Earth civilization uses.  Not in terms of operating but in mfg new stuff.

On Earth a 1GW power plant is a fairly typical sized unit. Using the worst case Martian energy budget (60Wk/person/day) that's 16 000 people, or say half that with the rest driving mfg systems. But given Mar's extra distance from the Sun (140 Vs 93 million miles)and thin film PV's (10-20% efficiency) that's maybe 85W/m^2 IE 1GW is close to 12 sq Km of PV cells. Or 5x that to allow for dust storms cutting off direct sunlight by 80% (or 100% at night).

Not impossible but it does give an idea of the scale of work you've got to do on Mars to give you the kind of power levels people take for granted from the grid on Earth.

Obviously I don't think that will be available immediately but that's the kind of scale that a solar only solution needs.

"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline guckyfan

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Re: Power options for a Mars settlement
« Reply #194 on: 05/19/2017 10:18 AM »
During the worst of bad sandstorms they can switch off energy intensive manufacturing. It is not like strong sandstorms are as frequent as cloud cover in most regions of the earth.

Offline AncientU

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Re: Power options for a Mars settlement
« Reply #195 on: 05/19/2017 01:14 PM »
They'll also need copious battery banks for overnight/emergency use (e.g., severing cables from power generating facility(ies)) that can also accommodate dust storms to a great degree.
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Offline john smith 19

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Re: Power options for a Mars settlement
« Reply #196 on: 05/19/2017 04:54 PM »
They'll also need copious battery banks for overnight/emergency use (e.g., severing cables from power generating facility(ies)) that can also accommodate dust storms to a great degree.

Good insulation can help you retain heat and efficient lighting can be a minimal power drain but once you get into just cooking stuff your power needs go up.

It also turns out that growing plants in artificial light is very power hungry. You'd really want to grow them under sunlight, but of course if you have a month long sandstorm that will affect your PV array as well.

I'm not sure if it can generate enough energy but I think biogas will definitely be used.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline AC in NC

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Re: Power options for a Mars settlement
« Reply #197 on: 05/19/2017 09:16 PM »
An idea that's been around for several decades.

Technically the PWR's were the closest to getting to serial production but they have issues. The main problems with all the proposed designs are they come from people looking to leverage their existing experience, none of which is ideal. Multiply that by a regulatory regime that takes no account of the size of the reactor and you need deep pockets to start with.

Needless to say no one has spent any significant time working on such a concept.  :(

I can think of someone that likes ambitious projects and could perhaps help with the regulatory stuff.  I also know someone else that likes to think big and could provide some invaluable guidance.  I can also think of a system that could economically dispose of the biggest problem if it can reliably abort during ascent and maintain payload integrity.

It seems to me like that time is right now for this Manhattan Project.
« Last Edit: 05/19/2017 09:17 PM by AC in NC »

Offline meekGee

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Re: Power options for a Mars settlement
« Reply #198 on: 05/20/2017 01:45 AM »
So, what you bring to Mars is the facility to fabricate solar cells/panels. 
Then set up shop and sell them to Kaputnik
Solar cells can be made so thin that a single ITS could land Gigawatts of cells. And, if you're concentrating the sunlight using Mars-made concentrators, hundreds of Gigawatts or even a Terawatt worth of cells per ITS payload.

So there's no real reason you would need an actual solar cell manufacturing plant on Mars except complete independence.

Tom Mueller directly contradicted this, by saying that Nuclear delivers more Watts per kg.

This is presumably after studying the matter.
I've also studied the matter and I disagree. He's perhaps the world's best liquid rocket engine engineer, but he's not the world-premier expert in everything. Also, please quote where he actually said what you're claiming to be a direct contradiction.

Quote
The GWatts per ITS can only be achieved by taking the mass of in-space zero-g thin film systems such as the ATK product.  Those don't work in atmosphere, and don't have longevity on Mars.
Sure they do. And anyway, making supporting material is way simpler than the cells themselves.

What he said is that they studied the matter, and Nuclear provides better power/mass than solar does.

He was not expressing the result of a study he did.  He explained what conclusion SpaceX arrived at, and I assume they also gave it some thought.

The reasons why de-facto solar is so different then spec-sheet solar have been explained upthread so many times...  I also spend some time "giving it thought", and am a solar advocate - when it makes sense.  Which is plenty of times.

But there are a number of reasons why it's a problematic solution for Mars.

Now, your point upthread was that "You can bring Solar from Earth, and that the ONLY reason to manufacture Solar on Mars is energy independence (for Mars).".   

But if you want energy independence, you need to fabricate the whole thing on Mars, and there's an energy balance problem there, since the scale is small.

I think Solar has a lot to offer for the early stage where you still can't set up nuclear.  Or for temporary remote installations.  And definitely for in-space applications.

You can't just waive off Mueller's conclusion so easily without actually showing a viable path forward with solar, one that addresses longevity, environmental issues starting with wind and dust, one that brings into account structure and not just the thin film, etc.

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Offline Robotbeat

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Re: Power options for a Mars settlement
« Reply #199 on: 05/20/2017 01:58 AM »
Fission has longevity issues. I mean, almost all the problems solar has, fission also has (sometimes worse, sometimes not as bad). Even dust! Dust settling on radiators reduces their effectiveness. Fission requires refueling, and Mars is fissionable-poor.

I have, in fact, developed a very good lightweight solar solution which addresses wind and dust while also being extremely efficient structurally. I plan on proposing it sometime.

And it's not like conventional fission is super amazingly good. Kilopower is like 5-10W/kg, which is barely better than RTGs and not really any better than even conventional solar and batteries. And Kilopower is actually better than the previous nuclear reactor concept that was used. It's only designed for like a 12 year lifespan. In fact, I'd say relatively conventional solar outperforms near-term nuclear overall.

But I think something like Kilopower as an addition to solar makes a lot of sense to help smooth over interruptions of power from dust storms. It seems like it has reasonable development cost, and as long as NASA's contributing the reactor, the fuel is actually free (it comes from dismantled nuclear weapons stockpile and is actually free for space reactors).

I'd like to see the assumptions behind Mueller's numbers. Also, I want a DIRECT quote, not a paraphrase. It's also possible that Musk disagrees with Mueller. I CAN just handwave away your paraphrase of his opinion, and again, this is his opinion, a man who is a propulsion (not energy systems) expert.
« Last Edit: 05/20/2017 02:01 AM by Robotbeat »
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