Author Topic: Critical Lunar Industrial Infrastructure  (Read 25476 times)

Offline wingod

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Critical Lunar Industrial Infrastructure
« on: 03/11/2008 05:25 PM »
I have been thinking a lot about what it would take as a minimal set of hardware to enable the industrial development of lunar resources.  Here are a few thoughts.  What  are yours?

1. Power

Without energy nothing else is possible, therefore it is the number 1 priority.  However, sending up powerlanders from the Earth at $400M a pop is not cost effective in the long term.  What would be needed to jump start in-situ solar production?

We do start out with 1.21 megawatts of electrical power (delivered as 480 volt three phase power) and then whatever solar thermal we can generate.  That is the baseline.

2. Machinery

What is the minimal complement of machine tools necessary to bootstrap lunar industry?  This would go from very minimal (metal forming, heating, melting, pouring) in order to build structures from flat plates to more complex machinery that could build something like rover frames, pressure fed engines (including injectors).  Would that be enough?  What else would be needed.

3. Metallurgy

Companion to machinery is metallurgy.  What metals can we produce in quantity and what alloys are possible on the Moon with ISRU resources or with minimal additives from the Earth?  We know that we can get Magnesium, Iron, Silicon, and Aluminum directly from any regolith.  We can also get Nickel and cobalt in large quantities from Ni-Fe fines in the regolith.  Titanium from the Mare region is another really interesting possibility but implies a lot more infrastructure than what is needed at the poles alone.

Bottom line is that we need metallurgy experts to chime in here.

This is a start as this is the fundamentals.

4. buildings.  We are going to have to build buildings to house this machinery and to do work in a short sleeve environment.  That has many implications as well.  It is my estimate that we need a minimum of 20,000 ft/sq to begin manufacturing with an industrial sized airlock.

What else and how does it move forward?

Ideas?



Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #1 on: 03/11/2008 06:31 PM »
Why do you start with solar power? That might be your first show stopper.
"Paper planes do fly much better than paper spacecrafts."

Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #2 on: 03/11/2008 06:40 PM »
The machines should be designed to be general purpose.  Transport costs are enormous, so one 1.5mT machine able to make several things is better than two 1 mT machines.

One to think about is are desktop fabricators similar to this one.
http://technology.newscientist.com/article/dn10922

Even if it cannot make parts out of iron, it can make the mould into which the iron is cast.

Offline alexterrell

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RE: Critical Lunar Industrial Infrastructure
« Reply #3 on: 03/11/2008 07:58 PM »

Good questions.
1. Power: I just started a thread under general on using the POWOW concept for the moon. The way I see it is that 10 tons at L1 can deliver 200KWe 24/7 (or is that 600/12?) to the lunar base. So for the launch effort of a single lunar mission, you could probably deliver 1MWe. Solar collectors on "hangers" and buildings could deliver a few hundred KW at the right time of day.

2. First and foremost:
- Diggers. These will be needed to bury/half bury habitats and mine areas. NASA should start a competition now to design a digger that can work 24/7 under remote control on the lunar surface. Electric joints? Li-ion or fuel cells? Recharging processes? Packaging?
- General Purpose Robots. These would be remote controlled and able to undertake simple operations on the lunar surface. They should be as dextrous as an astronaut wearing gloves.

3. Then, brick/glass sintering, ice processing (assuming a polar base), and volatiles storage. Then iron extraction. Then finally aluminium.  

4. First buildings need to be:
- Tents to house reusable landers and protect them from extreme heat and micro-meteorites.
- A buried hab module
- Workshops. I was thinking something that could be landed on one mission, with two inflatable airlocks that form pressurisable work areas. This would provide a shirt sleeve repair environment.

 

Given how tricky it is to send humans, all of the above should be shipped out before humans arrive.

How does it progress?

1. Establish base and start water mining

2. Start ore processing and using resusable landers fueled on the lunar surface.

3. Expand the base and build an electromagnetic catapult

4. Exponentially expand the base. Exported lunar material is used to expand the L1 solar base which expands the power available to the base which expands the base operations and range of exports.

5. Build secondary bases and colonisation.

 


 

 


Offline n0madik1

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Re: Critical Lunar Industrial Infrastructure
« Reply #4 on: 03/11/2008 09:01 PM »
I think the transportation infrastructure needs to be addressed from the very beginning as well.

Since the success seems to hinge on the availability of lunar ice-water, the Malapert Mt. area seems to be the best area to begin this.  It seems a 'boot-strap' approach is the most viable one here, and this is the place to hedge one's bets.  Lots of available sunlight, and some craters in permanent shadow that are worth exploring.

The problem here is location (both an asset and liability) in light of transportation requirements.  Circumpolar orbits are a bit more difficult than equatorial ones.  I think a rotovator in this context is the best way to go (though still unproven).


Offline Big Al

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Re: Critical Lunar Industrial Infrastructure
« Reply #5 on: 03/11/2008 10:08 PM »
In starting out on this project, I would think NASA would want to send a series of robotic “factories” to the moon to test out different processes for lunar mining. I haven’t seen anything in the way of such a probe mentions, but I would think it would be high on their propriety list. It is an important pathfinder technology for a solid manned lunar program.

Under the present lunar exploration program, what are the stated objectives as far as manned lunar exploration? It has occured to me that there needs to be a lot of robotic help in any manned exploration effort, but I haven’t seen a document that outlines the over all plan for our present lunar exploration effort.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #6 on: 03/11/2008 10:14 PM »
Quote
sandrot - 11/3/2008  2:31 PM

Why do you start with solar power? That might be your first show stopper.

Solar power on the Moon (assuming a lunar polar location where there is 100% sunlight) is actually a no brainer.



Offline wingod

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RE: Critical Lunar Industrial Infrastructure
« Reply #7 on: 03/11/2008 10:27 PM »
Quote
alexterrell - 11/3/2008  3:58 PM

Good questions.
1. Power: I just started a thread under general on using the POWOW concept for the moon. The way I see it is that 10 tons at L1 can deliver 200KWe 24/7 (or is that 600/12?) to the lunar base. So for the launch effort of a single lunar mission, you could probably deliver 1MWe. Solar collectors on "hangers" and buildings could deliver a few hundred KW at the right time of day.

2. First and foremost:
- Diggers. These will be needed to bury/half bury habitats and mine areas. NASA should start a competition now to design a digger that can work 24/7 under remote control on the lunar surface. Electric joints? Li-ion or fuel cells? Recharging processes? Packaging?
- General Purpose Robots. These would be remote controlled and able to undertake simple operations on the lunar surface. They should be as dextrous as an astronaut wearing gloves.

3. Then, brick/glass sintering, ice processing (assuming a polar base), and volatiles storage. Then iron extraction. Then finally aluminium.  

4. First buildings need to be:
- Tents to house reusable landers and protect them from extreme heat and micro-meteorites.
- A buried hab module
- Workshops. I was thinking something that could be landed on one mission, with two inflatable

Good questions.
1. Power: I just started a thread under general on using the POWOW concept for the moon. The way I see it is that 10 tons at L1 can deliver 200KWe 24/7 (or is that 600/12?) to the lunar base. So for the launch effort of a single manned mission, you could probably deliver 1GW. Solar collectors on "hangers" and buildings could deliver a few hundred KW at the right time of day.

2. First and foremost:
- Diggers. These will be needed to bury habitats and mine areas. NASA should start a competition now to design a digger that can work 24/7 under remote control on the lunar surface. Electric joints? Li-ion or fuel cells? Recharging processes? Packaging?
- General Purpose Robots. These would be remote controlled and able to undertake simple operations on the lunar surface. They should be as dextrous as an astronaut wearing gloves.

3. Then, brick/glass sintering (how about using lego style connection techniques), ice processing (assuming a polar base), and volatiles storage. Then iron extraction. Then finally aluminium.  

4. First buildings need to be:
- Tents to house reusable landers and protect them from extreme heat and micro-meteorites.
- A buried hab module, or a half buried module with lunar soil between the inner and outer shell.
- Workshops. I was thinking something that could be landed in one mission, with large inflatable airlocks that form pressurisable work areas. This would provide a shirt sleeve repair environment.

 

Given how tricky it is to send humans, all of the above should be shipped out before humans arrive.

How does it progress?

1. Establish base and start water mining

2. Start ore processing and using resusable landers fueled on the lunar surface.

3. Expand the base and build an electromagnetic catapult

4. Exponentially expand the base. Exported lunar material is used to expand the L1 solar base which expands the power available to the base which expands the base operations and range of exports.

5. Build secondary bases and colonisation.

 


 

 


Unless Spudis is right and there is a LOT of water, I do not think that we want to count on it.  Also, mining water at 35 degrees kelvin in the dark is a lot harder than anyone is currently thinking.  I am willing to forego it entirely, at least in the beginning.

Also, I do agree that robotics and regolith moving machinery is key in the early days as well.

The thermal environment at the lunar poles is benign enough to not worry too much about it.  

I do agree with a hab module, partially or fully buried.  However, I don't want to send up a lot of stuff that can be fabricated on the Moon, such as workshops.  The ISRU system must be able to create metals and with the metals we can make structures.  Micrometeorites are not a big deal for less than one year stays.

You are NOT going to deliver anywhere near a GW on a single launch or even a megawatt.

Solar collectors on buildings that are not sun pointing are useless in the polar regions due to the angles involved.  I do agree with brick sintering as well as a means to sinter a road as developed by Dr. Larry Taylor and his cohorts.

The next building has to be able to have an atmosphere to grow food as well.

Just some thoughts, good thinking everyone so far.





Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #8 on: 03/11/2008 10:27 PM »
Quote
Big Al - 11/3/2008  6:08 PM

In starting out on this project, I would think NASA would want to send a series of robotic “factories” to the moon to test out different processes for lunar mining. I haven’t seen anything in the way of such a probe mentions, but I would think it would be high on their propriety list. It is an important pathfinder technology for a solid manned lunar program.

Under the present lunar exploration program, what are the stated objectives as far as manned lunar exploration? It has occured to me that there needs to be a lot of robotic help in any manned exploration effort, but I haven’t seen a document that outlines the over all plan for our present lunar exploration effort.

LPRP program could do this.



Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #9 on: 03/12/2008 03:05 AM »
Oxygen will be valuable for both breathing and as a propellant when people arrive so the metal extraction facilities should also try to extract oxygen.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #10 on: 03/12/2008 03:31 AM »
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A_M_Swallow - 11/3/2008  11:05 PM

Oxygen will be valuable for both breathing and as a propellant when people arrive so the metal extraction facilities should also try to extract oxygen.

Since all metals on the Moon are in solution with oxygen, this is assumed.



Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #11 on: 03/12/2008 03:37 AM »
Quote
wingod - 11/3/2008  7:14 PM

Quote
sandrot - 11/3/2008  2:31 PM

Why do you start with solar power? That might be your first show stopper.

Solar power on the Moon (assuming a lunar polar location where there is 100% sunlight) is actually a no brainer.



Polar terrain is more rugged, not so easy to go around. Do you assume you land and use minerals in the terrain just around you?

Polar location assumes vertically mounted solar panels. And you need to perch them on the rim of a  properly exposed crater (peak of eternal light).
"Paper planes do fly much better than paper spacecrafts."

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #12 on: 03/12/2008 03:47 AM »
To complete my previous post...

I don't see rovers going around scouting for minerals on solar power at the poles.

It is much better to get power from a nuclear reactor of some kind (see also related threads in Advanced Concepts). At least we can go further away from the poles. And, if you're not at the poles for the water, what's the point of being there? Sun tan? :cool:
"Paper planes do fly much better than paper spacecrafts."

Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #13 on: 03/12/2008 04:49 AM »
Quote
wingod - 12/3/2008  5:31 AM

Quote
A_M_Swallow - 11/3/2008  11:05 PM

Oxygen will be valuable for both breathing and as a propellant when people arrive so the metal extraction facilities should also try to extract oxygen.

Since all metals on the Moon are in solution with oxygen, this is assumed.

Many methods of extracting metals work by oxidising the impurities.  Unless oxygen extraction is explicitly specified as a requirement it could easily be optimised out.

The blast in a blast furnace is an example of oxygen contamination.
http://www.bbc.co.uk/schools/gcsebitesize/chemistry/usefulproductsrocks/iron_blastfurnacerev3.shtml

The moon is very short of carbon so plastic objects could be replaced by locally made ones made out of silicon including fibre glass.

Offline alexterrell

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RE: Critical Lunar Industrial Infrastructure
« Reply #14 on: 03/12/2008 08:05 AM »
Quote
wingod - 11/3/2008  6:27 PM

Unless Spudis is right and there is a LOT of water, I do not think that we want to count on it.  Also, mining water at 35 degrees kelvin in the dark is a lot harder than anyone is currently thinking.  I am willing to forego it entirely, at least in the beginning.

Also, I do agree that robotics and regolith moving machinery is key in the early days as well.

The thermal environment at the lunar poles is benign enough to not worry too much about it.  

I do agree with a hab module, partially or fully buried.  However, I don't want to send up a lot of stuff that can be fabricated on the Moon, such as workshops.  The ISRU system must be able to create metals and with the metals we can make structures.  Micrometeorites are not a big deal for less than one year stays.

You are NOT going to deliver anywhere near a GW on a single launch or even a megawatt.

Solar collectors on buildings that are not sun pointing are useless in the polar regions due to the angles involved.  I do agree with brick sintering as well as a means to sinter a road as developed by Dr. Larry Taylor and his cohorts.

The next building has to be able to have an atmosphere to grow food as well.

Just some thoughts, good thinking everyone so far.



Clearly, identifying how much water there is should be the focus of exploration from ASAP till 2015. As for mining it: Light is not an issue if electricity is available. The diggers need to be designed to work at 30K. The tents are designed to house reusable landers whilst not being used. Tent's don't weigh much but help with thermal equilibrium. They can also pop out of a bag.

As for the workshop, you have a chicken and egg dilemma. I don't think you can build in-situ a workshop without good working machinery. You can't have that without a workshop. Hence a small workshop, with inflatable working areas to start.

There's no single ISRU system. You start with mining, and end up with metal fabrication. Building the steps on the way will take a long time.

Solar cells can be positioned in space at 10 tons / MW. The only problem is unpacking them. I'd look at inflatable tubes for deployment - the bouncy castle approach.

Solar collectors on buildings are worthwhile if you cover them with thin film solar material. Even if their utilisation is 20% it makes sense. At the poles, it's the walls, not the roofs you cover.

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #15 on: 03/12/2008 08:41 AM »

Offline Kaputnik

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Re: Critical Lunar Industrial Infrastructure
« Reply #16 on: 03/12/2008 10:23 AM »
I'm just trying to picture life at the lunar poles. The sun will always be very low, about 90-degrees. That means that any building, hab, rover, etc, will cast a shadow that goes on forever, presumably. I'd love to hear the arguments that will happen when someone parks their rover in the wrong place!
The other thing that comes to mind is that the sun will always be in your eyes. I live quite far north (but nowhere near 90-degrees!) and at this time of year the sun is right in my eyes on the way home from work. It's bloomin' annoying!
But I'm sure NASA have thought of all of this.
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Offline sandrot

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RE: Critical Lunar Industrial Infrastructure
« Reply #17 on: 03/12/2008 12:46 PM »
Quote
alexterrell - 12/3/2008  5:05 AM

[...]

Solar cells can be positioned in space at 10 tons / MW. The only problem is unpacking them. I'd look at inflatable tubes for deployment - the bouncy castle approach.

[...]


For the ISS we are at 15 tons / 65kW. Please recheck your numbers.
"Paper planes do fly much better than paper spacecrafts."

Offline alexterrell

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RE: Critical Lunar Industrial Infrastructure
« Reply #18 on: 03/12/2008 02:41 PM »
Quote
sandrot - 12/3/2008  8:46 AM

Quote
alexterrell - 12/3/2008  5:05 AM

[...]

Solar cells can be positioned in space at 10 tons / MW. The only problem is unpacking them. I'd look at inflatable tubes for deployment - the bouncy castle approach.

[...]


For the ISS we are at 15 tons / 65kW. Please recheck your numbers.

ISS (4.3 W/kg) is very low indeed. The figure I'm looking for is 10t/MW = 100 W/kg.

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/9136/28987/01305402.pdf = 250W / kg.

This 2002 article from ESa expects 400W / kg. http://www.esa.int/esaCP/ESA2CKS162D_FeatureWeek_2.html

The POWOW concept http://www.aec-able.com/corpinfo/Resources/IAF%202000POWOW.pdf is now a few years old and gives 449KW from a 2488kg panel, or about 200W/kg

http://www.entechsolar.com/STAIF04.pdf gives a state of play. Figure 11 shows we're already above 100W/kg.

These papers were all done before nano solar.

And somewhere, but I can't find the link, there's an ESA photograph of a ~20m wide solar sheet, which looks as thin as foil.

Not sure about the weight of the lasers and ion engine. And as I said, the challenge is unpacking it.



Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #19 on: 03/12/2008 03:29 PM »
No, the challenge is to make it stand. You're talking about a football field worth of solar panels vertically installed on the rim of a crater, with a SARJ equivalent to follow the 28 days lunar revolution.

You also need to see how thin film behave in space. The ESA article expresses interest in thin film but announces projects to test other kinds of solar cells.

Solar is not viable for rovers operating at the poles as humorously expressed by Kaputnik.

"Paper planes do fly much better than paper spacecrafts."

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #20 on: 03/12/2008 03:35 PM »
If you want to use regolith for ISRU (I really liked the discovery that regolith may be vitrified applying a moderate dose of microwaves), you need to see how much regolith you have at the poles. There is infact a milder contribution to regolith formation due to thermal excursion.
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Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #21 on: 03/12/2008 03:39 PM »
Quote
sandrot - 11/3/2008  11:37 PM

Quote
wingod - 11/3/2008  7:14 PM

Quote
sandrot - 11/3/2008  2:31 PM

Why do you start with solar power? That might be your first show stopper.

Solar power on the Moon (assuming a lunar polar location where there is 100% sunlight) is actually a no brainer.



Polar terrain is more rugged, not so easy to go around. Do you assume you land and use minerals in the terrain just around you?

Polar location assumes vertically mounted solar panels. And you need to perch them on the rim of a  properly exposed crater (peak of eternal light).

The south pole is much more rugged than the north and that is why I favor that location.  There are four sites there that are not in a bad area for travel down to the Mare Frigioris.  I have mapped out a couple of routes already.

Yep on the solar arrays and there are four locations where this is the case and in the north they are on easier terrain than in the south.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #22 on: 03/12/2008 03:42 PM »
Quote
sandrot - 11/3/2008  11:47 PM

To complete my previous post...

I don't see rovers going around scouting for minerals on solar power at the poles.

It is much better to get power from a nuclear reactor of some kind (see also related threads in Advanced Concepts). At least we can go further away from the poles. And, if you're not at the poles for the water, what's the point of being there? Sun tan? :cool:

Don't have to.  With adequate power, the highlands basalts make good feedstocks, which has always been assumed.

Power is the reason to be there, power without having to spend billions of dollars on developing nuclear power.  That has always been a show stopper before.  There are several areas that are in eternal sunlight and with emplacing a megwatt or two of power and with solar thermal, you have the basis for lunar industrialization.

Offline wingod

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RE: Critical Lunar Industrial Infrastructure
« Reply #23 on: 03/12/2008 03:48 PM »
Quote
alexterrell - 12/3/2008  4:05 AM

Quote
wingod - 11/3/2008  6:27 PM

Unless Spudis is right and there is a LOT of water, I do not think that we want to count on it.  Also, mining water at 35 degrees kelvin in the dark is a lot harder than anyone is currently thinking.  I am willing to forego it entirely, at least in the beginning.

Also, I do agree that robotics and regolith moving machinery is key in the early days as well.

The thermal environment at the lunar poles is benign enough to not worry too much about it.  

I do agree with a hab module, partially or fully buried.  However, I don't want to send up a lot of stuff that can be fabricated on the Moon, such as workshops.  The ISRU system must be able to create metals and with the metals we can make structures.  Micrometeorites are not a big deal for less than one year stays.

You are NOT going to deliver anywhere near a GW on a single launch or even a megawatt.

Solar collectors on buildings that are not sun pointing are useless in the polar regions due to the angles involved.  I do agree with brick sintering as well as a means to sinter a road as developed by Dr. Larry Taylor and his cohorts.

The next building has to be able to have an atmosphere to grow food as well.

Just some thoughts, good thinking everyone so far.



Clearly, identifying how much water there is should be the focus of exploration from ASAP till 2015. As for mining it: Light is not an issue if electricity is available. The diggers need to be designed to work at 30K. The tents are designed to house reusable landers whilst not being used. Tent's don't weigh much but help with thermal equilibrium. They can also pop out of a bag.

As for the workshop, you have a chicken and egg dilemma. I don't think you can build in-situ a workshop without good working machinery. You can't have that without a workshop. Hence a small workshop, with inflatable working areas to start.

There's no single ISRU system. You start with mining, and end up with metal fabrication. Building the steps on the way will take a long time.

Solar cells can be positioned in space at 10 tons / MW. The only problem is unpacking them. I'd look at inflatable tubes for deployment - the bouncy castle approach.

Solar collectors on buildings are worthwhile if you cover them with thin film solar material. Even if their utilisation is 20% it makes sense. At the poles, it's the walls, not the roofs you cover.

Flat plate iron requires only a sintered regolith mold and a lifting device.  A lot of building can be built that way.

Solar collectors on buildings makes some sense but not as much as you think.  The problem is that you don't want the buildings in the permanent sunlit area as that is the most valuable property for power production.  You could do it in such a way as to have them mounted on the top of the structures but they still have to point at the sun.  At a loss factor of (cos 85) the output for flat plat solar is essentially zero.

Solar cells are only one part of a power distribution system.  A 250 kW inverter weighs 2 tons and if you go all DC you have a lot of problems with power losses.  An AC system makes a lot more sense.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #24 on: 03/12/2008 03:49 PM »
Quote
Kaputnik - 12/3/2008  6:23 AM

I'm just trying to picture life at the lunar poles. The sun will always be very low, about 90-degrees. That means that any building, hab, rover, etc, will cast a shadow that goes on forever, presumably. I'd love to hear the arguments that will happen when someone parks their rover in the wrong place!
The other thing that comes to mind is that the sun will always be in your eyes. I live quite far north (but nowhere near 90-degrees!) and at this time of year the sun is right in my eyes on the way home from work. It's bloomin' annoying!
But I'm sure NASA have thought of all of this.

The thermal environment at the poles is a LOT better than at the equator but the shadows will be interesting!



Offline wingod

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RE: Critical Lunar Industrial Infrastructure
« Reply #25 on: 03/12/2008 03:51 PM »
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alexterrell - 12/3/2008  10:41 AM

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sandrot - 12/3/2008  8:46 AM

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alexterrell - 12/3/2008  5:05 AM

[...]

Solar cells can be positioned in space at 10 tons / MW. The only problem is unpacking them. I'd look at inflatable tubes for deployment - the bouncy castle approach.

[...]


For the ISS we are at 15 tons / 65kW. Please recheck your numbers.

ISS (4.3 W/kg) is very low indeed. The figure I'm looking for is 10t/MW = 100 W/kg.

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/9136/28987/01305402.pdf = 250W / kg.

This 2002 article from ESa expects 400W / kg. http://www.esa.int/esaCP/ESA2CKS162D_FeatureWeek_2.html

The POWOW concept http://www.aec-able.com/corpinfo/Resources/IAF%202000POWOW.pdf is now a few years old and gives 449KW from a 2488kg panel, or about 200W/kg

http://www.entechsolar.com/STAIF04.pdf gives a state of play. Figure 11 shows we're already above 100W/kg.

These papers were all done before nano solar.

And somewhere, but I can't find the link, there's an ESA photograph of a ~20m wide solar sheet, which looks as thin as foil.

Not sure about the weight of the lasers and ion engine. And as I said, the challenge is unpacking it.



You are forgetting the rest of the things that make a power system work.  The inverters alone are very heavy and require radiators themselves.

As for the solar power, maybe the Entech system makes sense, maybe not.  I tend to favor flat panel systems due to their ease of construction and longevity.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #26 on: 03/12/2008 03:53 PM »
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sandrot - 12/3/2008  11:29 AM

No, the challenge is to make it stand. You're talking about a football field worth of solar panels vertically installed on the rim of a crater, with a SARJ equivalent to follow the 28 days lunar revolution.

You also need to see how thin film behave in space. The ESA article expresses interest in thin film but announces projects to test other kinds of solar cells.

Solar is not viable for rovers operating at the poles as humorously expressed by Kaputnik.


Agreed.  I would think that regenerative fuel cells would be the ticket for rovers and other machinery.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #27 on: 03/12/2008 03:56 PM »
Again

Thanks for a lot of good replies, I just am trying to iterate here and give some of the thoughts that we have put into the effort.



Offline mwfair

Re: Critical Lunar Industrial Infrastructure
« Reply #28 on: 03/12/2008 04:10 PM »
The comment about flat plate seems valuable, relative to the notion of making iron beams etc to build structures.  Simple design is best, and igloos seem like the simplest of all buildings.  For this reason, flat plates, and bricks seem like the best starting point.  
Seems to me that the main resources to be used on the lunar poles, in order of both availability and utility, are time, mass, and sunlight.  Assuming the initial buildup process is autonomous or RC, we can take months just to build one building.  Time makes polar solar easier, since the 35% efficiency problem relative to  the motion of the sun doesn't matter, just take a 20 day siesta!  But the mass available on the moon is the sweetest thing, given enough time.  Who cares about structural efficiency, just make bricks or plate and pile them up.  If it takes months, so what?  Forget large batteries, these store energy in chemical form, but this requires mass.  Ignore the chemistry and build flywheels with bricks.  Seems to me a 3m diameter merry go round can store 1MWhr, enough at least to stay alive during said siesta!
Mike Fair

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Re: Critical Lunar Industrial Infrastructure
« Reply #29 on: 03/12/2008 04:25 PM »
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wingod - 12/3/2008  12:39 PM

[...]

Yep on the solar arrays and there are four locations where this is the case and in the north they are on easier terrain than in the south.


My point is: with solar we return to the moon just to be stuck in 4 places (I'm sure there are many more much interesting), and we have anyway to develop other technologies to move stuff around (rovers).

There can be more efficient approaches.

Regarding mobility, let's keep an eye on MSL.

Also, it is interesting to follow the DARPA sponsored Darpa Grand Challenge
  http://en.wikipedia.org/wiki/DARPA_Grand_Challenge

When I read one of the MER's has moved 40mm in one sol, I'm less than enthusiastic, thinking of what still needs to be done for the ISRU scout rovers.
"Paper planes do fly much better than paper spacecrafts."

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #30 on: 03/12/2008 04:28 PM »
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mwfair - 12/3/2008  1:10 PM

[...]

Seems to me a 3m diameter merry go round can store 1MWhr, enough at least to stay alive during said siesta!

Not to turn you off, but building a balanced flywheel out of locally produced bricks seems a challenge to me.
"Paper planes do fly much better than paper spacecrafts."

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #31 on: 03/12/2008 04:41 PM »
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mwfair - 12/3/2008  1:10 PM

The comment about flat plate seems valuable, relative to the notion of making iron beams etc to build structures.  Simple design is best, and igloos seem like the simplest of all buildings.  For this reason, flat plates, and bricks seem like the best starting point.  

[..]


I agree wrt the bricks, if we can make them microwaving regolith, which by all accounts seems to be a process not so power hungry.

Flat plate may be tricky to achieve, you need to have machinery as wide as the plate you want to build. And maybe iron is not the 1st choice (because of its melting point for once).

For structural elements I would look more into aluminum, as it is more pliable. Aluminum could be produced and stored in rolls. From the rolls you can automatically assemble trusses, as proven during an early STS mission.
"Paper planes do fly much better than paper spacecrafts."

Offline mwfair

Re: Critical Lunar Industrial Infrastructure
« Reply #32 on: 03/12/2008 04:43 PM »
Assume a cylindrical building, 20k ft^2 = 160 ft diameter.  Lets say 10 ft tall  = 5000 ft^2 walls.  35% efficient wrt sun-in-view gives 1500 sq ft solar panel, which produces 6kW at 4W/ft^2.  Wow, not much.  But time is on our side, we just need enough to run a conveyor belt, an arm, and a laser sinter device.
Mike Fair

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #33 on: 03/12/2008 05:51 PM »
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mwfair - 12/3/2008  12:10 PM

The comment about flat plate seems valuable, relative to the notion of making iron beams etc to build structures.  Simple design is best, and igloos seem like the simplest of all buildings.  For this reason, flat plates, and bricks seem like the best starting point.  
Seems to me that the main resources to be used on the lunar poles, in order of both availability and utility, are time, mass, and sunlight.  Assuming the initial buildup process is autonomous or RC, we can take months just to build one building.  Time makes polar solar easier, since the 35% efficiency problem relative to  the motion of the sun doesn't matter, just take a 20 day siesta!  But the mass available on the moon is the sweetest thing, given enough time.  Who cares about structural efficiency, just make bricks or plate and pile them up.  If it takes months, so what?  Forget large batteries, these store energy in chemical form, but this requires mass.  Ignore the chemistry and build flywheels with bricks.  Seems to me a 3m diameter merry go round can store 1MWhr, enough at least to stay alive during said siesta!

I really like the idea about the flywheel.  However, I don't understand the 20 day siesta as the permanent lighted areas mean zero downtime.  With humans on the Earth to operate equipment during the human on the Moon off hours the overall efficiency of the industrial system is dramatically increased, something impossible for Mars.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #34 on: 03/12/2008 05:57 PM »
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sandrot - 12/3/2008  12:25 PM

Quote
wingod - 12/3/2008  12:39 PM

[...]

Yep on the solar arrays and there are four locations where this is the case and in the north they are on easier terrain than in the south.


My point is: with solar we return to the moon just to be stuck in 4 places (I'm sure there are many more much interesting), and we have anyway to develop other technologies to move stuff around (rovers).

There can be more efficient approaches.

Regarding mobility, let's keep an eye on MSL.

Also, it is interesting to follow the DARPA sponsored Darpa Grand Challenge
  http://en.wikipedia.org/wiki/DARPA_Grand_Challenge

When I read one of the MER's has moved 40mm in one sol, I'm less than enthusiastic, thinking of what still needs to be done for the ISRU scout rovers.

Please take this in the spirit in which it is offered but I don't give a flying flip about more interesting places, the point is economic development, which completely changes how lunar operations play out.  With that power becomes the principle consideration and then a location that allows for mobility within that constraint, which to me, means the lunar north pole.

Rovers are trivial in the sense that we know how to do them and much better ones than something like MSL.  I really like the old LOTRAN from Eagle Engineering.  I am actually working with NASA Langely with their crane effort that is being built now for testing this year on moving regolith around.

The Russian rovers moved tens of kilometers per sol when they were on the Moon.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #35 on: 03/12/2008 06:00 PM »
Quote
sandrot - 12/3/2008  12:41 PM

Quote
mwfair - 12/3/2008  1:10 PM

The comment about flat plate seems valuable, relative to the notion of making iron beams etc to build structures.  Simple design is best, and igloos seem like the simplest of all buildings.  For this reason, flat plates, and bricks seem like the best starting point.  

[..]


I agree wrt the bricks, if we can make them microwaving regolith, which by all accounts seems to be a process not so power hungry.

Flat plate may be tricky to achieve, you need to have machinery as wide as the plate you want to build. And maybe iron is not the 1st choice (because of its melting point for once).

For structural elements I would look more into aluminum, as it is more pliable. Aluminum could be produced and stored in rolls. From the rolls you can automatically assemble trusses, as proven during an early STS mission.

While I like Aluminum the problem is that it takes several hundred degrees higher temperature to get it out of solution with oxygen than Iron.  Also up to 1% of any regolith sample has Ni-Fe from asteroid impacts and that makes a really simple feedstock for the flat plate.  You don't need machinery, just a sintered mold to pour the liquid iron into.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #36 on: 03/12/2008 06:02 PM »
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mwfair - 12/3/2008  12:43 PM

Assume a cylindrical building, 20k ft^2 = 160 ft diameter.  Lets say 10 ft tall  = 5000 ft^2 walls.  35% efficient wrt sun-in-view gives 1500 sq ft solar panel, which produces 6kW at 4W/ft^2.  Wow, not much.  But time is on our side, we just need enough to run a conveyor belt, an arm, and a laser sinter device.

That same square footage, turned toward the sun will product well over 100 kW.  That is the difference.



Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #37 on: 03/12/2008 06:22 PM »
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wingod - 12/3/2008  3:00 PM

[...]

While I like Aluminum the problem is that it takes several hundred degrees higher temperature to get it out of solution with oxygen than Iron.  Also up to 1% of any regolith sample has Ni-Fe from asteroid impacts and that makes a really simple feedstock for the flat plate.  You don't need machinery, just a sintered mold to pour the liquid iron into.

Here peaks of eternal light come handy... solar furnace?
"Paper planes do fly much better than paper spacecrafts."

Offline mwfair

Re: Critical Lunar Industrial Infrastructure
« Reply #38 on: 03/12/2008 06:28 PM »
Regarding rotating the solar panel to face the sun, I'd like to see an estimate of the mass ratio between turning mechanisms and the panel itself.  I bet it is at least 1:1.  If the superstructure available is ISRU, like the side of a brick wall, then the panel mass goes down.  But the mass of the motors, gears, bearings, and especially the cantilevered structure climbs fast, maybe with the square of the area.  So would you rather make one panel that rotates, or two that are fixed.  I'll take the two fixed.  
Lunar sol is almost 30 days.  Circumference of a circle is pi*d, but only the diameter sees the sun at any moment, so the geometrical efficiency of a circular building is 1/pi, a square building gets 25% sometimes, 35% max.  The siesta comment didn't really make sense, just an illustration that its okay if solar efficiency is low if time and mass are on your side.  If you have a small payload from earth, I suggest 1 fixed solar panel with a siesta, rather than either bringing a rotational base or second (or 3rd) panel.
I always prefer intrinsic numbers rather than extrinsic, its easier to show the whole system is viable.  If you insist on a certain total power number, the mass budget quickly climbs out of reason.  Better first to show a complete system, then scale it up.  Even still, I realize there is a minimum feasible power and mass requirement, no matter how long the timescale or how high-tech the ISRU.
Mike Fair

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #39 on: 03/12/2008 06:57 PM »
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wingod - 12/3/2008  2:57 PM

[...]

The Russian rovers moved tens of kilometers per sol when they were on the Moon.

Here what comes into play is the ability to move autonomously.

I see ISRU working better if we can deploy a "robotic community" where some stationary heavy machinery is fed/unloaded by rovers.

Although we can imagine robots accomplishing very complex tasks (imagine what they could do if they were just as intelligent as an ant or a termite), I believe they would work very well in manufacturing and storing elements for future human use.
"Paper planes do fly much better than paper spacecrafts."

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #40 on: 03/12/2008 07:21 PM »
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sandrot - 12/3/2008  11:29 AM

No, the challenge is to make it stand. You're talking about a football field worth of solar panels vertically installed on the rim of a crater, with a SARJ equivalent to follow the 28 days lunar revolution.

You also need to see how thin film behave in space. The ESA article expresses interest in thin film but announces projects to test other kinds of solar cells.

Solar is not viable for rovers operating at the poles as humorously expressed by Kaputnik.

I said earlier the 1MW solar array is based at L1, in zero g. (Though the 1MWe laser might weigh   more).

This is the question I asked under the General Discussions. Taking the POWOW concept, is it worth putting the solar arrays at L1 and beaming the power down to the moon. System efficiency is about 25%, but L1 is, in effect, 1/4 the price of the lunar surface, and in almost permanently in sunlight.

On the moon, you need a solar "curtain" about 20m by 20m. (assuming 1nm wavelength). This though is usable up about 5MWe on the lunar surface. And it always points towards fixed L1.

(A wider aperture laser could be used to focus the beam down further for vehicle powering).

I fully agree about the problem of large scale vertical axis towers on the surface. They're probably good for about 30m high and 10m wide, so 30KW. You might want a few for backup.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #41 on: 03/12/2008 07:39 PM »
The space based solar array has been rehashed several times in the Advanced Concepts.  Eg:

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=9660&posts=62&start=1

Your L1 is about 60000 km from the Lunar surface! When you beam the power down you have beam dispersion, and the effect is that it is much more practical economical and efficient to have surface based solar arrays (even considering non optimal solar exposure).

"Paper planes do fly much better than paper spacecrafts."

Offline n0madik1

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Re: Critical Lunar Industrial Infrastructure
« Reply #42 on: 03/12/2008 07:56 PM »
Wouldn't making structures out of basalt bricks be a lot easier to do than making said structures out of iron or aluminum?  The combination of basalt's melting point and the simplicity of forming (no need for milling, etc.) means that you'd need a much smaller initial industrial base, at least in terms of providing safe and strong structures.

I'm also curious with the electrical issues here about how the current will be moved about.  Is the assumption here that electrical wire will be made from calcium metal?  It seems to be a fairly abundant resource (relatively speaking of course.)

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #43 on: 03/12/2008 08:01 PM »
Even better than bricks somebody proposed bags full of regolith.
"Paper planes do fly much better than paper spacecrafts."

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #44 on: 03/12/2008 08:08 PM »
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n0madik1 - 12/3/2008  4:56 PM

I'm also curious with the electrical issues here about how the current will be moved about.  Is the assumption here that electrical wire will be made from calcium metal?  It seems to be a fairly abundant resource (relatively speaking of course.)

Aluminum is a very good conductor.

What can be used as insulator for in situ produced cables?

A glass fiber jacket?

How easy is it is to produce lunar glass?

Glass fiber, BTW has several other uses.
"Paper planes do fly much better than paper spacecrafts."

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #45 on: 03/12/2008 08:15 PM »
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sandrot - 12/3/2008  3:39 PM

The space based solar array has been rehashed several times in the Advanced Concepts.  Eg:

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=9660&posts=62&start=1

Your L1 is about 60000 km from the Lunar surface! When you beam the power down you have beam dispersion, and the effect is that it is much more practical economical and efficient to have surface based solar arrays (even considering non optimal solar exposure).

The link doesn't cover this topic, and Google doesn't help. Do you have any more links because this is an interesting possibility?

http://www.aec-able.com/corpinfo/Resources/IAF%202000POWOW.pdf estimates a 6.8m diameter receiver for 17,000km (Mars Aerosynchronous), so for 60,000km a 25m x 25m suspended curtain would provide 250KW up to 5MW.

Yes you lose 75%, but as said, getting stuff to L1 is 1/4 the cost and effort of getting it to the lunar surface.

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #46 on: 03/12/2008 08:24 PM »
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mwfair - 12/3/2008  2:28 PM

Regarding rotating the solar panel to face the sun, I'd like to see an estimate of the mass ratio between turning mechanisms and the panel itself.  I bet it is at least 1:1.  If the superstructure available is ISRU, like the side of a brick wall, then the panel mass goes down.  But the mass of the motors, gears, bearings, and especially the cantilevered structure climbs fast, maybe with the square of the area.  So would you rather make one panel that rotates, or two that are fixed.  I'll take the two fixed.  
Lunar sol is almost 30 days.  Circumference of a circle is pi*d, but only the diameter sees the sun at any moment, so the geometrical efficiency of a circular building is 1/pi, a square building gets 25% sometimes, 35% max.  The siesta comment didn't really make sense, just an illustration that its okay if solar efficiency is low if time and mass are on your side.  If you have a small payload from earth, I suggest 1 fixed solar panel with a siesta, rather than either bringing a rotational base or second (or 3rd) panel.
I always prefer intrinsic numbers rather than extrinsic, its easier to show the whole system is viable.  If you insist on a certain total power number, the mass budget quickly climbs out of reason.  Better first to show a complete system, then scale it up.  Even still, I realize there is a minimum feasible power and mass requirement, no matter how long the timescale or how high-tech the ISRU.

I think this sort of thing is best done on a small scale, say 30m high tower, with a radius of 10m, gives 600m2 and about 120KW. The solar cloth only needs to be about 1/4mm thick with a density of about 2, so it weighs only 300kg.

A 30m high mast to support 50kg effective weight, and two 10m cantilevers might be doable for a similar weight - but that's a guess. Then you either need to go a few metres into the lunar surface or have a big base plate.

Storing and erecting the mast will be a real pain. Especially if you want to send these ahead of the people. And then you'd want a few of these around the crater rim. And even then, you get a few days per month in the winter when you get no sunlight.

As for the fixed ones, well, thin film solar material is effectively free.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #47 on: 03/12/2008 08:28 PM »
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alexterrell - 12/3/2008  5:15 PM

The link doesn't cover this topic, and Google doesn't help. Do you have any more links because this is an interesting possibility? In the thread IIRC several documents are referenced.

[...]

In the "space solar power" thread IIRC several documents are referenced.

Bottom line is: power density achievable by a rectenna farm is similar to power density achievable by a ground based solar array. There's no point in converting solar to electricity to microwaves to electricity, when it is much simpler just to convert solar to electricity.

So, if you are concerned about weight of solar panels on the lunar surface, you need to be aware that you will have the same weight in rectifying antennas if you go with a space based solar array (plus obviously the cost and the weight of your SBSA).
"Paper planes do fly much better than paper spacecrafts."

Offline meiza

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Re: Critical Lunar Industrial Infrastructure
« Reply #48 on: 03/12/2008 08:33 PM »
glass is easy but the glue isn't since those are organic materials that need carbon. Arcing happens easier in a vacuum than in air for example. And with the dust getting everywhere, it's a problem. But a glass cloth could be very useful for very many things still. I wonder if you could use it as an insulator and for regolith bags.

Offline Bill White

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Re: Critical Lunar Industrial Infrastructure
« Reply #49 on: 03/12/2008 08:38 PM »
Quote
wingod - 12/3/2008  1:57 PM

Quote
sandrot - 12/3/2008  12:25 PM

Quote
wingod - 12/3/2008  12:39 PM

[...]

Yep on the solar arrays and there are four locations where this is the case and in the north they are on easier terrain than in the south.


My point is: with solar we return to the moon just to be stuck in 4 places (I'm sure there are many more much interesting), and we have anyway to develop other technologies to move stuff around (rovers).

There can be more efficient approaches.

Regarding mobility, let's keep an eye on MSL.

Also, it is interesting to follow the DARPA sponsored Darpa Grand Challenge
  http://en.wikipedia.org/wiki/DARPA_Grand_Challenge

When I read one of the MER's has moved 40mm in one sol, I'm less than enthusiastic, thinking of what still needs to be done for the ISRU scout rovers.

Please take this in the spirit in which it is offered but I don't give a flying flip about more interesting places, the point is economic development, which completely changes how lunar operations play out.  With that power becomes the principle consideration and then a location that allows for mobility within that constraint, which to me, means the lunar north pole.

Dennis, does hope remain for large intact fragments of Ni-Fe asteroids? Or are you now persuaded that any incoming PGM bearing asteroids have all been shattered to tiny bits?

If there are reasonably intact Ni-Fe fragments with higher than normal PGM concentrations couldn't they be ANYWHERE on the Moon or is there reason to believe those would be concentrated at the poles?

Satellites with very good cameras could map the likely locations easily enough, but won't we need global lunar access to actually grab some samples and test for PGM concentrations?

= = =

On the topic of Ni-Fe, I recall reading about a NASA-SIBR study done in Kalamazoo Michigan (Western Michigan University) which seemed to conclude that carbonyl digestion (Mond Process) extracted metallic nickel rather easily from asteroidal fragments and since nickel vapor deposition is a well understood process that works at benign temperatures and pressures, intricate parts could be cast from pure nickel with only a modest consumption of energy.

Find a nickel rich fragment or a PGM rich somewhere on the Moon and it seems to me that is where the factories need to go. Wherever it may be. Or am I missing something?

EML architectures should be seen as ratchet opportunities

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #50 on: 03/12/2008 09:02 PM »
Quote
sandrot - 12/3/2008  4:28 PM

Quote
alexterrell - 12/3/2008  5:15 PM

The link doesn't cover this topic, and Google doesn't help. Do you have any more links because this is an interesting possibility? In the thread IIRC several documents are referenced.

[...]

In the "space solar power" thread IIRC several documents are referenced.

Bottom line is: power density achievable by a rectenna farm is similar to power density achievable by a ground based solar array. There's no point in converting solar to electricity to microwaves to electricity, when it is much simpler just to convert solar to electricity.

So, if you are concerned about weight of solar panels on the lunar surface, you need to be aware that you will have the same weight in rectifying antennas if you go with a space based solar array (plus obviously the cost and the weight of your SBSA).

No - Microwaves don't come into this - at least not till you have several GW to transmit, and preferably then to an equatorial site.

For the moon lasers are best. Yes you have 75% loss, but that's made up for by lower transport costs to L1

Actually - I have seen a similar proposal to use laser light from Earth. You'd need a 5m aperture at >4,000m altitude, and you'd need three sites around the world. This could be a good back-up solution - Space Solar Power in reverse!

Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #51 on: 03/12/2008 09:33 PM »
Using lateral thinking there may be replacements for glues.

"A mechanical surface adhesive using micromachined silicon structures"
http://www.iop.org/EJ/abstract/0960-1317/1/1/006

Molten glass will stick to glass and possibly a few other substances - that is all you need for an adhesive.
(See step six of the bead making process)
http://home1.fvcc.edu/~msettle/final/makingbeads/glassbeads.html

Carbon and silicon are both members of the same group in the periodic table.  There may be a weird Si compound that can act as a glue.

Candy bars can be coated with molten chocolate.  A similar technique may permit metal wires to be coated with molten glass/glass fibre, producing an insulated wire.

Plenty ideas here that a chemist may be able to turn one into something useful.

Offline Patchouli

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Re: Critical Lunar Industrial Infrastructure
« Reply #52 on: 03/12/2008 09:51 PM »
There are some solutions to the lack of organics on the moon.
The first use a solar or nuclear electric tug using ion or VASIMR engines for bulk cargo transport ie anything that doesn't have people on it this will cut the costs and increase the payload by 4 to 5x.
Such a tug can get to the moon twice as fast as the ESA smart one as we have better engines and solar cells that are over twice as efficient in testing as those used on smart one.
Anything that doesn't have people or perishable items on it can take it's time getting to the moon.

Second make anything expendable that gets left on the lunar surface the descent stage tanks on landers expendable cargo containers etc out of plastic and composites when and where possible and have these reused and reprocessed on the moon for their carbon,nitrogen and water content.

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #53 on: 03/12/2008 09:54 PM »
Quote
A_M_Swallow - 12/3/2008  5:33 PM

Using lateral thinking there may be replacements for glues.


Lego?

Or use aluminium rods to tie bricks together.

Not ideal in tension but good enough for compression structures.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #54 on: 03/12/2008 10:13 PM »
Quote
sandrot - 12/3/2008  2:22 PM

Quote
wingod - 12/3/2008  3:00 PM

[...]

While I like Aluminum the problem is that it takes several hundred degrees higher temperature to get it out of solution with oxygen than Iron.  Also up to 1% of any regolith sample has Ni-Fe from asteroid impacts and that makes a really simple feedstock for the flat plate.  You don't need machinery, just a sintered mold to pour the liquid iron into.

Here peaks of eternal light come handy... solar furnace?

Yep



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #55 on: 03/12/2008 10:15 PM »
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mwfair - 12/3/2008  2:28 PM

Regarding rotating the solar panel to face the sun, I'd like to see an estimate of the mass ratio between turning mechanisms and the panel itself.  I bet it is at least 1:1.  If the superstructure available is ISRU, like the side of a brick wall, then the panel mass goes down.  But the mass of the motors, gears, bearings, and especially the cantilevered structure climbs fast, maybe with the square of the area.  So would you rather make one panel that rotates, or two that are fixed.  I'll take the two fixed.  
Lunar sol is almost 30 days.  Circumference of a circle is pi*d, but only the diameter sees the sun at any moment, so the geometrical efficiency of a circular building is 1/pi, a square building gets 25% sometimes, 35% max.  The siesta comment didn't really make sense, just an illustration that its okay if solar efficiency is low if time and mass are on your side.  If you have a small payload from earth, I suggest 1 fixed solar panel with a siesta, rather than either bringing a rotational base or second (or 3rd) panel.
I always prefer intrinsic numbers rather than extrinsic, its easier to show the whole system is viable.  If you insist on a certain total power number, the mass budget quickly climbs out of reason.  Better first to show a complete system, then scale it up.  Even still, I realize there is a minimum feasible power and mass requirement, no matter how long the timescale or how high-tech the ISRU.

The angle to the sun is so low that there is basically zero output at the polar regions.  Cos-85 is a very small number.


Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #56 on: 03/12/2008 10:18 PM »
Quote
mwfair - 12/3/2008  2:28 PM

Regarding rotating the solar panel to face the sun, I'd like to see an estimate of the mass ratio between turning mechanisms and the panel itself.  I bet it is at least 1:1.  If the superstructure available is ISRU, like the side of a brick wall, then the panel mass goes down.  But the mass of the motors, gears, bearings, and especially the cantilevered structure climbs fast, maybe with the square of the area.  So would you rather make one panel that rotates, or two that are fixed.  I'll take the two fixed.  
Lunar sol is almost 30 days.  Circumference of a circle is pi*d, but only the diameter sees the sun at any moment, so the geometrical efficiency of a circular building is 1/pi, a square building gets 25% sometimes, 35% max.  The siesta comment didn't really make sense, just an illustration that its okay if solar efficiency is low if time and mass are on your side.  If you have a small payload from earth, I suggest 1 fixed solar panel with a siesta, rather than either bringing a rotational base or second (or 3rd) panel.
I always prefer intrinsic numbers rather than extrinsic, its easier to show the whole system is viable.  If you insist on a certain total power number, the mass budget quickly climbs out of reason.  Better first to show a complete system, then scale it up.  Even still, I realize there is a minimum feasible power and mass requirement, no matter how long the timescale or how high-tech the ISRU.

I did show a complete system.  A delta IV heavy with 2500 kg of downmass payload can put about 110 kW worth of solar on the ground, along with the DC/AC inverter.  The solar mass comes from a 120 watt/kg array and the inverter is pretty much off the shelf from Xantrex (not really but it is a good starting point)  (I may have shown the powerlander in another thread).





Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #57 on: 03/12/2008 10:20 PM »
Quote
alexterrell - 12/3/2008  3:21 PM

Quote
sandrot - 12/3/2008  11:29 AM

No, the challenge is to make it stand. You're talking about a football field worth of solar panels vertically installed on the rim of a crater, with a SARJ equivalent to follow the 28 days lunar revolution.

You also need to see how thin film behave in space. The ESA article expresses interest in thin film but announces projects to test other kinds of solar cells.

Solar is not viable for rovers operating at the poles as humorously expressed by Kaputnik.

I said earlier the 1MW solar array is based at L1, in zero g. (Though the 1MWe laser might weigh   more).



This is the question I asked under the General Discussions. Taking the POWOW concept, is it worth putting the solar arrays at L1 and beaming the power down to the moon. System efficiency is about 25%, but L1 is, in effect, 1/4 the price of the lunar surface, and in almost permanently in sunlight.

On the moon, you need a solar "curtain" about 20m by 20m. (assuming 1nm wavelength). This though is usable up about 5MWe on the lunar surface. And it always points towards fixed L1.

(A wider aperture laser could be used to focus the beam down further for vehicle powering).

I fully agree about the problem of large scale vertical axis towers on the surface. They're probably good for about 30m high and 10m wide, so 30KW. You might want a few for backup.

I don't buy power beaming at this time.  Too much effort during the bootstrap phase, maybe later it would be a player.

A landed solar array is a very straightforward affair.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #58 on: 03/12/2008 10:22 PM »
Quote
n0madik1 - 12/3/2008  3:56 PM

Wouldn't making structures out of basalt bricks be a lot easier to do than making said structures out of iron or aluminum?  The combination of basalt's melting point and the simplicity of forming (no need for milling, etc.) means that you'd need a much smaller initial industrial base, at least in terms of providing safe and strong structures.

I'm also curious with the electrical issues here about how the current will be moved about.  Is the assumption here that electrical wire will be made from calcium metal?  It seems to be a fairly abundant resource (relatively speaking of course.)

There is definitely merit to what you say.  The Germans have been making cast basalt for water pipes for years.  I would definitely put that into the long term trade space.



Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #59 on: 03/12/2008 10:24 PM »
Quote
sandrot - 12/3/2008  4:08 PM

Quote
n0madik1 - 12/3/2008  4:56 PM

I'm also curious with the electrical issues here about how the current will be moved about.  Is the assumption here that electrical wire will be made from calcium metal?  It seems to be a fairly abundant resource (relatively speaking of course.)

Aluminum is a very good conductor.

What can be used as insulator for in situ produced cables?

A glass fiber jacket?

How easy is it is to produce lunar glass?

Glass fiber, BTW has several other uses.

You are right about Aluminum.  Maybe with a cast basalt jacket.  As stated before, the GErmans have been making cast basalt water pipes for several years now.



Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #60 on: 03/12/2008 10:58 PM »
Quote
I don't buy power beaming at this time.  Too much effort during the bootstrap phase, maybe later it would be a player.

A landed solar array is a very straightforward affair.

I do like your Powerlander concept. Do you have any measurements and calculations as well as the pictures?

However, I would like to see an analysis of power beaming as an option. I have seen suggestions of power beaming from Earth to moon, but not L1 to Moon.

A delta IV heavy could place 1MW (estimate - might work better with electric propulsion from just above the Van Allen belts to L1) of solar at L1 which translates to 250KW at the base.

Its also scalable to GW capacities. You'd run out of prime space on the crater rims at the poles given the desire to avoid shadowing.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #61 on: 03/12/2008 11:00 PM »
Quote
Bill White - 12/3/2008  4:38 PM

Quote
wingod - 12/3/2008  1:57 PM

Quote
sandrot - 12/3/2008  12:25 PM

Quote
wingod - 12/3/2008  12:39 PM

[...]

Yep on the solar arrays and there are four locations where this is the case and in the north they are on easier terrain than in the south.


My point is: with solar we return to the moon just to be stuck in 4 places (I'm sure there are many more much interesting), and we have anyway to develop other technologies to move stuff around (rovers).

There can be more efficient approaches.

Regarding mobility, let's keep an eye on MSL.

Also, it is interesting to follow the DARPA sponsored Darpa Grand Challenge
  http://en.wikipedia.org/wiki/DARPA_Grand_Challenge

When I read one of the MER's has moved 40mm in one sol, I'm less than enthusiastic, thinking of what still needs to be done for the ISRU scout rovers.

Please take this in the spirit in which it is offered but I don't give a flying flip about more interesting places, the point is economic development, which completely changes how lunar operations play out.  With that power becomes the principle consideration and then a location that allows for mobility within that constraint, which to me, means the lunar north pole.

Dennis, does hope remain for large intact fragments of Ni-Fe asteroids? Or are you now persuaded that any incoming PGM bearing asteroids have all been shattered to tiny bits?

If there are reasonably intact Ni-Fe fragments with higher than normal PGM concentrations couldn't they be ANYWHERE on the Moon or is there reason to believe those would be concentrated at the poles?

Satellites with very good cameras could map the likely locations easily enough, but won't we need global lunar access to actually grab some samples and test for PGM concentrations?

= = =

On the topic of Ni-Fe, I recall reading about a NASA-SIBR study done in Kalamazoo Michigan (Western Michigan University) which seemed to conclude that carbonyl digestion (Mond Process) extracted metallic nickel rather easily from asteroidal fragments and since nickel vapor deposition is a well understood process that works at benign temperatures and pressures, intricate parts could be cast from pure nickel with only a modest consumption of energy.

Find a nickel rich fragment or a PGM rich somewhere on the Moon and it seems to me that is where the factories need to go. Wherever it may be. Or am I missing something?


Bill

If you go back and read the Apollo science reports you will see that any regolith sample has between 0.1%-1% Ni-Fe as metallic fines.  That constitutes the lower boundary for the resource.  I think that there is a hell of a good chance that large fragements of Ni-Fe will be found somewhere within a 100 km radius of a lunar outpost.  However, a lot can be done with just the metallic fines, which are actually better for the carbonyl process.

The carbonyl process is way good for this type of material in exactly the manner that you describe.


Online Lampyridae

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Re: Critical Lunar Industrial Infrastructure
« Reply #62 on: 03/12/2008 11:16 PM »
Regarding solar trackers, an 18% gain can be made for single-axis tracking and 30% for two-axis tracking. Some small losses arise because of mutual shading. They are routinely used in remote applications such as pumping stations and are being scaled up for larger systems. Given that the arrays will need to be mounted on masts and that there will be no need for much power storage - batteries fuel cells, etc., I don't think the overall mass penalty will be much at all. In fact, mass required per average kilowatt should be lower than equatorial sites.
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Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #63 on: 03/13/2008 01:30 AM »
Quote
alexterrell - 12/3/2008  6:58 PM

Quote
I don't buy power beaming at this time.  Too much effort during the bootstrap phase, maybe later it would be a player.

A landed solar array is a very straightforward affair.

I do like your Powerlander concept. Do you have any measurements and calculations as well as the pictures?

However, I would like to see an analysis of power beaming as an option. I have seen suggestions of power beaming from Earth to moon, but not L1 to Moon.

A delta IV heavy could place 1MW (estimate - might work better with electric propulsion from just above the Van Allen belts to L1) of solar at L1 which translates to 250KW at the base.

Its also scalable to GW capacities. You'd run out of prime space on the crater rims at the poles given the desire to avoid shadowing.

A Delta IV is not going to put a megawatt to L1.  The payload to that altitude is about 6000kg which might get you the solar cells but is not going to get you the power conversion even to power the laser.

You are not going to get 250 kW on the surface either.  This is one of the problems with lasers.  The best efficiency that I know of today is about 12%.  Do you have better?  Also, you have to have solar cells with far better bandgap control than anything I have ever heard of.  Conversion efficiencies at a single wavelength is only about 2%.  A 50% solar cell converts energy across a spectrum and at individual frequencies the conversion is pretty bad.

Also, you have to then convert that DC to AC.  Now you can do that today at 96% efficiency but you still  have to land that power supply as well as the hardware that you need.

About the best end to end laser efficiency that I know of is about 5%, including all losses.  At 60,000 km it is a pain in the rear  as well to keep on station.


Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #64 on: 03/13/2008 01:37 AM »
Quote
Lampyridae - 12/3/2008  7:16 PM

Regarding solar trackers, an 18% gain can be made for single-axis tracking and 30% for two-axis tracking. Some small losses arise because of mutual shading. They are routinely used in remote applications such as pumping stations and are being scaled up for larger systems. Given that the arrays will need to be mounted on masts and that there will be no need for much power storage - batteries fuel cells, etc., I don't think the overall mass penalty will be much at all. In fact, mass required per average kilowatt should be lower than equatorial sites.

This is not the Earth.  All you need at the polar location is a single axis, 360 degree tracker.

For a 100 kw inverter, it weighs 1 ton.  At 110 watts/kg you get 110 kilowatts worth of power for another ton.  That leaves 500 kg for wiring, rotary joint, and everything else.  Those are very good first cut numbers.



Offline meiza

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Re: Critical Lunar Industrial Infrastructure
« Reply #65 on: 03/13/2008 10:16 AM »
The problem with glass is that it's very brittle unless very thin strands are used - making glass fiber strands or cloth. But that is a porous material. You need glue / matrix for that for load sharing and to make it solid (but flexible). But those glues are organic materials (organic means carbon is involved). You can't use glass for the "glue" because then it would just be a solid block of glass and that would defeat the whole purpose of the glass fiber, the avoidance of fragility.
Now, the cloth and fibers can still be used for many things even if there is no glue/matrix/plastic. Just not for all the things real glass fiber composite would be useful for alone, like building pressure vessels or non-conducting structures. It could be that the cloth would structures would have to be lined with aluminium sheets or foil for example for pressure vessels (assuming the al is much more expensive to make). And for electrical insulation solid glass could be used instead. There are very many things where you do need insulators. Also joining is hard when there is no glue.

Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #66 on: 03/13/2008 01:20 PM »
Soldering and welding are forms of 'glueing' suitable for metals.

Human bones are made out of calcium.  Bones grow and breaks are repaired so there is a way of attaching calcium to calcium and other materials.

Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #67 on: 03/13/2008 01:33 PM »
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meiza - 13/3/2008  6:16 AM

The problem with glass is that it's very brittle unless very thin strands are used - making glass fiber strands or cloth. But that is a porous material. You need glue / matrix for that for load sharing and to make it solid (but flexible). But those glues are organic materials (organic means carbon is involved). You can't use glass for the "glue" because then it would just be a solid block of glass and that would defeat the whole purpose of the glass fiber, the avoidance of fragility.
Now, the cloth and fibers can still be used for many things even if there is no glue/matrix/plastic. Just not for all the things real glass fiber composite would be useful for alone, like building pressure vessels or non-conducting structures. It could be that the cloth would structures would have to be lined with aluminium sheets or foil for example for pressure vessels (assuming the al is much more expensive to make). And for electrical insulation solid glass could be used instead. There are very many things where you do need insulators. Also joining is hard when there is no glue.

Good thoughts.  This will certainly be an issue for a lunar industrial infrastructure.



Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #68 on: 03/13/2008 01:37 PM »
Quote
meiza - 13/3/2008  12:16 PM

The problem with glass is that it's very brittle unless very thin strands are used - making glass fiber strands or cloth. But that is a porous material. You need glue / matrix for that for load sharing and to make it solid (but flexible). But those glues are organic materials (organic means carbon is involved). You can't use glass for the "glue" because then it would just be a solid block of glass and that would defeat the whole purpose of the glass fiber, the avoidance of fragility.

There are objects where being porous is not a problem.  See the chairs below.  On Earth they are made with carbon but with ingenuity glass fibre could be used.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #69 on: 03/13/2008 01:53 PM »
A_M_Swallow: to have a composite you need to have two materials. If you use only one (glass) you have no benefit. What would you use as glue?

I was thinking about the putty used to repair shuttle tiles. It hardens when heated. Does a similar material exist that would work with fiberglass?
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Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #70 on: 03/13/2008 02:06 PM »
Quote
sandrot - 13/3/2008  3:53 PM

A_M_Swallow: to have a composite you need to have two materials. If you use only one (glass) you have no benefit. What would you use as glue?

Molten glass can be used as a glue.  It will stick to both glass and hot metal.  See
http://www.newton.dep.anl.gov/askasci/eng99/eng99295.htm

There are probably better glues but molten glass is a start.

One advantage of not using carbon and hydrogen, things are less likely to burn.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #71 on: 03/13/2008 02:12 PM »
Glass on glass is not viable for composites.

Ok, it might be viable for glass on metal.

I am not getting what would be burning in the void of space.
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Offline meiza

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Re: Critical Lunar Industrial Infrastructure
« Reply #72 on: 03/13/2008 02:18 PM »
Quote
A_M_Swallow - 13/3/2008  3:20 PM

Soldering and welding are forms of 'glueing' suitable for metals.

Human bones are made out of calcium.  Bones grow and breaks are repaired so there is a way of attaching calcium to calcium and other materials.

Yeah, but you can't glue glass fiber with glass... or you can, but the joint will not be as flexible as the glass fiber sheets.
Of course, one alternative is to make a shape out of smallish glass fiber sheets and then just melt the whole thing back to glass, if you don't need flexibility. If you do this in a vacuum, there isn't even the bubble problem. :) And the advantage vs construction directly from glass is that the shapes would be much easier to make.
Glass fiber dust is abrasive and gets everywhere though, it's nasty to work with. I think it's messy to cut for example.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #73 on: 03/13/2008 02:22 PM »
... and we're sure that thermal stress of glass on metal would be limited, right?

We need otherwise to figure out a way to do pyrex in situ.
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Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #74 on: 03/13/2008 03:07 PM »
Quote
sandrot - 13/3/2008  3:53 PM

A_M_Swallow: to have a composite you need to have two materials. If you use only one (glass) you have no benefit. What would you use as glue?

I notice that magnesium reacts with aluminium, (magnesium) and silicon so strips of pure magnesium may act as a glue when heated.  Calcium has similar properties.  They would have to be kept free from oxygen, carbon dioxide, nitrogen, water and rocket exhaust - not too hard in the Moon's vacuum.

http://en.wikipedia.org/wiki/Category:Magnesium_compounds

Offline khallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #75 on: 03/13/2008 03:26 PM »
Quote
sandrot - 13/3/2008  8:12 AM

Glass on glass is not viable for composites.

Ok, it might be viable for glass on metal.

I am not getting what would be burning in the void of space.

There are two burnable environments to worry about. The reducing atmosphere that people breathe and LOX tanks.
Karl Hallowell

Offline mwfair

Re: Critical Lunar Industrial Infrastructure
« Reply #76 on: 03/13/2008 03:26 PM »
Quote
meiza - 13/3/2008  10:18 AM
Glass fiber dust is abrasive and gets everywhere though, it's nasty to work with. I think it's messy to cut for example.
Not the only dust and abrasion problem to be faced on the moon.  The regolith dust cannot be ignored, especially in rotary joints, connectors, assembly processes, radiators, and probably in chemical processes.
Mike Fair

Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #77 on: 03/13/2008 03:43 PM »
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sandrot - 13/3/2008  4:12 PM

I am not getting what would be burning in the void of space.

If you mean hydrogen, this is usable on Mars but I am not certain how much there is on the moon.  If there is insufficient ice at the lunar poles then hydrogen would have to be imported from Earth (or Mars).  At $760,000 a gallon very little water will be used as a glue.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #78 on: 03/13/2008 03:53 PM »
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khallow - 13/3/2008  12:26 PM

There are two burnable environments to worry about. The reducing atmosphere that people breathe and LOX tanks.

Both are not the void of space.

Some problems have been solved with composites if the X-33 hydrogen tank was to be a honeycomb composite (in close vicinity of oxygen tanks!).
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Offline khallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #79 on: 03/13/2008 05:27 PM »
Quote
sandrot - 13/3/2008  9:53 AM

Quote
khallow - 13/3/2008  12:26 PM

There are two burnable environments to worry about. The reducing atmosphere that people breathe and LOX tanks.

Both are not the void of space.

Exactly my point. There will be other environments where burning is an issue.
Karl Hallowell

Offline n0madik1

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Re: Critical Lunar Industrial Infrastructure
« Reply #80 on: 03/13/2008 06:13 PM »
Regarding burnable environments:

In order to achieve this bootstrapping, a certain amount of industrial/chemical supplies are going to have to be delivered.  

Wouldn't it make sense to try to eliminate the 'pure' oxygen environment right from the beginning?  In other words, if there's a need for ammonia for leaching, etc., why not bring in supplies of ammonium-nitrate and give up the nitrogen to supplement the breathable atmosphere?  An approach like this would make the endeavor that much safer.

Offline alexterrell

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Re: Critical Lunar Industrial Infrastructure
« Reply #81 on: 03/13/2008 10:42 PM »
Quote
wingod - 12/3/2008  9:30 PM
A Delta IV is not going to put a megawatt to L1.  The payload to that altitude is about 6000kg which might get you the solar cells but is not going to get you the power conversion even to power the laser.

You are not going to get 250 kW on the surface either.  This is one of the problems with lasers.  The best efficiency that I know of today is about 12%.  Do you have better?  Also, you have to have solar cells with far better bandgap control than anything I have ever heard of.  Conversion efficiencies at a single wavelength is only about 2%.  A 50% solar cell converts energy across a spectrum and at individual frequencies the conversion is pretty bad.

Also, you have to then convert that DC to AC.  Now you can do that today at 96% efficiency but you still  have to land that power supply as well as the hardware that you need.

About the best end to end laser efficiency that I know of is about 5%, including all losses.  At 60,000 km it is a pain in the rear  as well to keep on station.

HLV Capability: Given a large solar array, it's probably sensible to deploy the payload  just above the inner Van Allen belt and user SEP to go to L1. Arianne5 can do 10 tons to GEO. I can't find much on laser weight.

Laser efficiency: http://wistechnology.com/articles/942/?id=942 claims 65% though mosts posts claim 30%. The POWOW study from 2000 claims Lawrence Livermore achieved 43% in 1995.

Cell efficiency: For monochromatic laser light conversation, efficiencies is much higher than for sunlight, where most bandwidth is lost. Laser conversion efficiencies are typically 50%. All in it appears 25% is achievable.

DC - AC conversion: You have this problem anyway.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #82 on: 03/13/2008 10:55 PM »
alexterrel, please quit. This is not the thread for space based solar power. The POWOW study is flawed. And the logic behind laser energy transmission is flawed too. Continuous transfer of power in excess of 300 KW is unfeasible with today and tomorrow's systems. You misunderstand peak power with rated continuous power. If you transfer 300 kw at 50% efficiency you've got to dissipate 300 kw and you need the infrastructure for that with additional weight, complexity. Let's chase another rabbit, please.
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Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #83 on: 03/13/2008 11:05 PM »
I repost what I posted elsewhere for POWOW --->

An excerpt from the POWOW paper:

Quote
Extensive research is being conducted into various laser options in this wavelength range.2 Figure 10 shows the 192 bar laser diode array that yielded 23 kW of peak power at 0.900 µm wavelength with an efficiency of 43% reported by the Lawrence Livermore National Laboratory3. However, cooling requirements for this array are substantial and are not covered in this paper.

So, it is feasable just, find us a way to cool the laser diodes that has 0 mass and requires 0 energy to operate.
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Offline tnphysics

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Re: Critical Lunar Industrial Infrastructure
« Reply #84 on: 03/13/2008 11:49 PM »
Radiation to space, possibly assisted by conduction.

Other than that, there is none.

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Re: Critical Lunar Industrial Infrastructure
« Reply #85 on: 03/14/2008 12:16 AM »
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tnphysics - 13/3/2008  8:49 PM

Radiation to space, possibly assisted by conduction.

Other than that, there is none.

This may be interesting, when you think heat radiation, think ISS radiators:

  http://science.nasa.gov/headlines/y2001/ast21mar_1.htm

Maybe somewhere in the ISS Q/A they say how much heat is radiated from ISS.
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Offline wingod

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Re: Critical Lunar Industrial Infrastructure
« Reply #86 on: 03/14/2008 03:22 AM »
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alexterrell - 13/3/2008  6:42 PM

Quote
wingod - 12/3/2008  9:30 PM
A Delta IV is not going to put a megawatt to L1.  The payload to that altitude is about 6000kg which might get you the solar cells but is not going to get you the power conversion even to power the laser.

You are not going to get 250 kW on the surface either.  This is one of the problems with lasers.  The best efficiency that I know of today is about 12%.  Do you have better?  Also, you have to have solar cells with far better bandgap control than anything I have ever heard of.  Conversion efficiencies at a single wavelength is only about 2%.  A 50% solar cell converts energy across a spectrum and at individual frequencies the conversion is pretty bad.

Also, you have to then convert that DC to AC.  Now you can do that today at 96% efficiency but you still  have to land that power supply as well as the hardware that you need.

About the best end to end laser efficiency that I know of is about 5%, including all losses.  At 60,000 km it is a pain in the rear  as well to keep on station.

HLV Capability: Given a large solar array, it's probably sensible to deploy the payload  just above the inner Van Allen belt and user SEP to go to L1. Arianne5 can do 10 tons to GEO. I can't find much on laser weight.

Laser efficiency: http://wistechnology.com/articles/942/?id=942 claims 65% though mosts posts claim 30%. The POWOW study from 2000 claims Lawrence Livermore achieved 43% in 1995.

Cell efficiency: For monochromatic laser light conversation, efficiencies is much higher than for sunlight, where most bandwidth is lost. Laser conversion efficiencies are typically 50%. All in it appears 25% is achievable.

DC - AC conversion: You have this problem anyway.

You have to prove this to me by test reports.  I have never seen a solar cell that converts at  efficiencies that high at a single wavelength.  I may be wrong but you have to show it.  As for the laser, the latest efficiencies that I have seen in actual operation in a realistic environment are not that high but I am willing to be persuaded.



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Re: Critical Lunar Industrial Infrastructure
« Reply #87 on: 03/14/2008 03:29 AM »
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alexterrell - 13/3/2008  6:42 PM

Quote
wingod - 12/3/2008  9:30 PM
A Delta IV is not going to put a megawatt to L1.  The payload to that altitude is about 6000kg which might get you the solar cells but is not going to get you the power conversion even to power the laser.

You are not going to get 250 kW on the surface either.  This is one of the problems with lasers.  The best efficiency that I know of today is about 12%.  Do you have better?  Also, you have to have solar cells with far better bandgap control than anything I have ever heard of.  Conversion efficiencies at a single wavelength is only about 2%.  A 50% solar cell converts energy across a spectrum and at individual frequencies the conversion is pretty bad.

Also, you have to then convert that DC to AC.  Now you can do that today at 96% efficiency but you still  have to land that power supply as well as the hardware that you need.

About the best end to end laser efficiency that I know of is about 5%, including all losses.  At 60,000 km it is a pain in the rear  as well to keep on station.

HLV Capability: Given a large solar array, it's probably sensible to deploy the payload  just above the inner Van Allen belt and user SEP to go to L1. Arianne5 can do 10 tons to GEO. I can't find much on laser weight.

Laser efficiency: http://wistechnology.com/articles/942/?id=942 claims 65% though mosts posts claim 30%. The POWOW study from 2000 claims Lawrence Livermore achieved 43% in 1995.

Cell efficiency: For monochromatic laser light conversation, efficiencies is much higher than for sunlight, where most bandwidth is lost. Laser conversion efficiencies are typically 50%. All in it appears 25% is achievable.

DC - AC conversion: You have this problem anyway.

Ariane V can do ten tons to GTO, not GEO.  The lasers in the study that you site are low power lasers not megawatt class systems.  Ganging them?  Don't know.

I actually design SEP systems and understand them but you are not going to get a megawatt of SEP on an Ariane V, Atlas V, or Delta IV heavy.  You can get 250 kilowatts, which is what we did in our study at NASA Langely.  That carried fuel as well to get it to the higher orbit along with the SEP thrusters.  Part of the problem is not weight, it is packing the darn thing to where you can actually deploy it.  There is a volume problem.  These large structures just don't deploy themselves with the greatest of ease.  There is a way around this but you are just asking for a lot of things to happen that are all really hard to do autonomously.  

The laser efficiency gain is good but we still have not seen end to end efficiencies anywhere near has high as what you are talking about here in the SPS group.



Offline mwfair

Re: Critical Lunar Industrial Infrastructure
« Reply #88 on: 03/14/2008 03:42 PM »
Quote
sandrot - 13/3/2008  6:55 PM
alexterrel, please quit. This is not the thread for space based solar power. Let's chase another rabbit, please.
With all due respect, I agree.  I admire the SSP model, benefits, and technically challenging details.  But this is very much the wrong thread.  No matter how much of a benefit this power approach may bring, especially in terms of launch costs, it leaves a huge amount of the topic at hand untouched.
I think we should go the simple route, and add power/energy capability to the lunar site as needed, and of a more generic variety.  That is, as we discuss the size and variety of mining, material processing, and manufacturing operations at the lunar site, we can discuss the complexities of more and more power.
Mike Fair

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Re: Critical Lunar Industrial Infrastructure
« Reply #89 on: 03/14/2008 04:19 PM »
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khallow - 13/3/2008  5:26 PM

There are two burnable environments to worry about. The reducing atmosphere that people breathe and LOX tanks.

There is a third burnable environment - magnesium will burn in Mar's atmosphere.  So magnesium (and possibly calcium) processing will need protecting against CO2.

A thin layer of MgO can be used to protect solid magnesium objects from oxygen but it is best if magnesium is not used in oxygen, nitrogen and CO2 environments.  There is not much oxygen in the lunar surface vacuum.

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Re: Critical Lunar Industrial Infrastructure
« Reply #90 on: 03/14/2008 04:26 PM »
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A_M_Swallow - 14/3/2008  1:19 PM

There is a third burnable environment - magnesium will burn in Mar's atmosphere.  So magnesium (and possibly calcium) processing will need protecting against CO2.

[...]

What would you use magnesium for?

What is the relative abundance of magnesium in, say, regolith?
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Re: Critical Lunar Industrial Infrastructure
« Reply #91 on: 03/14/2008 05:30 PM »
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sandrot - 13/3/2008  6:55 PM

alexterrel, please quit. This is not the thread for space based solar power. The POWOW study is flawed. And the logic behind laser energy transmission is flawed too. Continuous transfer of power in excess of 300 KW is unfeasible with today and tomorrow's systems. You misunderstand peak power with rated continuous power. If you transfer 300 kw at 50% efficiency you've got to dissipate 300 kw and you need the infrastructure for that with additional weight, complexity. Let's chase another rabbit, please.

Sandrot, This thread is about Critical Lunar Industrial Infrastructure and solar power is clearly relevant to this.

I see three alternatives to powering a base: Surface solar, Space solar, Nuclear. The optimum combination of these may change according to where the base is located (e.g. polar sites may favour surface solar as you can get ~80-90% utilisation). We know Surface Solar is feasible, nuclear is being investigated. (I've also seen Earth based lasers suggested).

I'm happy to quit on the space option now because the objections have been laid out:
- Laser conversion on the lunar surface: No an issue
- Creation of high power continuous laser with efficiency close to 50%: May be a show stopper, though perhaps not in a few years.
- Removal of waste heat from said laser: Probably a show stopper if large radiators are not affordable. (Nuclear power station on the lunar surface will have to remove even more heat, though that could be useful in industrial processes).
- Direction and pointing of laser: Could be a problem, would require further study
- Unfurling large solar panels in space: Solvable issue.

Before NASA spends several billion dollars of your money on providing electricity to a base, it should explore the alternatives. An investigation would probably conclude that Surface Solar is the best bet for the first base, but we don't know that till its done.

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Re: Critical Lunar Industrial Infrastructure
« Reply #92 on: 03/14/2008 05:52 PM »
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alexterrell - 14/3/2008  7:30 PM

Sandrot, This thread is about Critical Lunar Industrial Infrastructure and solar power is clearly relevant to this.

@Alexterrel, POWOW has its own thread.  Only a cross reference is needed in this thread.

Offline A_M_Swallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #93 on: 03/14/2008 06:11 PM »
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sandrot - 14/3/2008  6:26 PM

Quote
A_M_Swallow - 14/3/2008  1:19 PM

There is a third burnable environment - magnesium will burn in Mar's atmosphere.  So magnesium (and possibly calcium) processing will need protecting against CO2.

[...]

What would you use magnesium for?

What is the relative abundance of magnesium in, say, regolith?

Magnesium forms 4.8% of regolith making it the sixth most common element.  Oxygen is the most common at 40% of lunar regolith.
http://www.moonminer.com/Lunar_regolith.html

Magnesium is a metal so it can be used for anything a metal is used for, particularly structural items.  It is very reactive so lots of compounds can be made, some of which are useful.  Plants use magnesium as an ingredient of chlorophyll, making Mg necessary for life.  Many alloys of iron and aluminium use magnesium, possibly permitting replacements for steel to be developed.  Steel contains carbon which is very rare (and expensive) on the moon.
http://en.wikipedia.org/wiki/Magnesium

One interesting use for magnesium is as a recyclable fuel.  Magnesium can be burnt to produce heat, keeping buildings warm during the long lunar night.  A sterling engine can be used to convert heat into electricity powering household equipment, industrial processes and rovers.  Unlike hydrogen magnesium does not have to be kept cold.  The MgO ash produced can be treated as a high quality ore and processed to extract the magnesium and oxygen using solar power.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #94 on: 03/14/2008 06:23 PM »
How many Stirling engines have run in space?

It looks like WRT the latest missions there's been resistance to use them.
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Re: Critical Lunar Industrial Infrastructure
« Reply #95 on: 03/14/2008 06:32 PM »
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sandrot - 14/3/2008  8:23 PM

It looks like WRT the latest missions there's been resistance to use them.

Is that resistance to sterling engines or resistance to nuclear?

This project used a large sterling engine in a car
http://www.grc.nasa.gov/WWW/tmsb/stirling/doc/ase.html
using ordinary fuel.

Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #96 on: 03/14/2008 06:54 PM »
Resistance to Stirling.

Due to the rate our spinning hardware in space fails, I don't think there's too much space (pun intended) for Stirlings unless some serious tests are done in space.
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Re: Critical Lunar Industrial Infrastructure
« Reply #97 on: 09/23/2008 09:16 AM »
glass is easy but the glue isn't since those are organic materials that need carbon. Arcing happens easier in a vacuum than in air for example. And with the dust getting everywhere, it's a problem. But a glass cloth could be very useful for very many things still. I wonder if you could use it as an insulator and for regolith bags.

For joining metals together I found thermite welding.  Thermite can also be used for cutting and drilling.
http://en.wikipedia.org/wiki/Thermite

Thermite is make by mixing powdered aluminium and powdered iron oxide.  Light and stand back.  All these are easily available on the Moon.

A magnesium fuse or possibly sparks from a flint is needed as a means of ignition.

A do it your self YouTube on making thermite.



If aluminium is this reactive will it burn in Mars's CO2 atmosphere?   If so we may need to ensure that engine parts are properly coated.

Since thermite brings its own oxygen, does it work in a vacuum?

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Re: Critical Lunar Industrial Infrastructure
« Reply #98 on: 09/23/2008 09:41 AM »
Many items can be fastened together using nuts and bolts and appropriate sized washers.

Tie-fasteners can hold cloth and metal together.  These ones are made from plastic but iron or aluminium could be used.
http://www.business.com/directory/industrial_goods_and_services/industrial_supplies/fasteners/cable_ties



Offline khallow

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Re: Critical Lunar Industrial Infrastructure
« Reply #99 on: 09/23/2008 01:28 PM »
You also have eyelets and gromlets. Or some sort of snap and lock thing. Plenty of ways to put things together out there.

I think thermite would work in vacuum. Might not generate as much heat though.
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Offline sandrot

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Re: Critical Lunar Industrial Infrastructure
« Reply #100 on: 09/23/2008 01:32 PM »
NASA goes nuclear on the moon?

http://blogs.discovermagazine.com/80beats/2008/09/14/nasa-considers-nuclear-energy-to-power-a-lunar-outpost/

(I hate posting blogs links, but the article clearly references multiple sources)

It looks like deploying radiators for dissipating excess heat is going to be a challenge.
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Offline adeclama

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Re: Critical Lunar Industrial Infrastructure
« Reply #101 on: 09/29/2008 04:00 PM »



Dennis, does hope remain for large intact fragments of Ni-Fe asteroids? Or are you now persuaded that any incoming PGM bearing asteroids have all been shattered to tiny bits?

If there are reasonably intact Ni-Fe fragments with higher than normal PGM concentrations couldn't they be ANYWHERE on the Moon or is there reason to believe those would be concentrated at the poles?

Satellites with very good cameras could map the likely locations easily enough, but won't we need global lunar access to actually grab some samples and test for PGM concentrations?

= = =

On the topic of Ni-Fe, I recall reading about a NASA-SIBR study done in Kalamazoo Michigan (Western Michigan University) which seemed to conclude that carbonyl digestion (Mond Process) extracted metallic nickel rather easily from asteroidal fragments and since nickel vapor deposition is a well understood process that works at benign temperatures and pressures, intricate parts could be cast from pure nickel with only a modest consumption of energy.

Find a nickel rich fragment or a PGM rich somewhere on the Moon and it seems to me that is where the factories need to go. Wherever it may be. Or am I missing something?



The Mond Process is a good one but I tihnk it is better suited to processing asteroids themseilves instead of fragments on the moon.  Where would we get get the carbon and hydrogen required for the process.  Otherwise Mond processing can be adapted to many other metals, including iron and using lcvd pretty complex shapes can be made.
« Last Edit: 09/29/2008 04:02 PM by adeclama »

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Re: Critical Lunar Industrial Infrastructure
« Reply #102 on: 09/29/2008 04:13 PM »
You also have eyelets and gromlets. Or some sort of snap and lock thing. Plenty of ways to put things together out there.

I think thermite would work in vacuum. Might not generate as much heat though.

Thermite will burn in vacuum because its ingredients bring their own oxygen to the reaction.  However, getting thermite to ignite will take some tinkering because it takes a considerable amount of heat to ignite it.  The best way i've seen is to use a burning magnesium strip.  Maybe an electrical starter of some kind.

Another option is taking advantage of what would otherwise be considered a nuisance - vacuum welding.

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Re: Critical Lunar Industrial Infrastructure
« Reply #103 on: 09/29/2008 04:48 PM »
Putting a high current through a thin wire makes the wire very hot - this may work as a lighter.

Alternatively striking mixtures of magnesium + LOX and titanium + LOX causes then to catch fire.  The hit it with a hammer solution could work; a tiny hammer may be best.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930008606_1993008606.pdf

From 'Liquid Oxygen/Metal Gelled Monopropellants; Final Report November 1991; NASA CR187193' by John H Wickman.

"... Shock sensitivity tests by NASA white Sands eliminated titanium from the test matrix due to its extreme sensitivity to any impact.   A weight from a height of 6 inches consistently caused a reaction 100% of the time."

On safety grounds mixing the titanium with the gelled oxygen probably needs delaying until shortly before ignition.

Offline DMeader

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Re: Critical Lunar Industrial Infrastructure
« Reply #104 on: 09/29/2008 07:08 PM »
Putting a high current through a thin wire makes the wire very hot - this may work as a lighter.

Sounds like what you have there is an exploding bridgewire detonator. Trying to set off a nuclear weapon??   ;)

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Re: Critical Lunar Industrial Infrastructure
« Reply #105 on: 09/29/2008 07:31 PM »
Putting a high current through a thin wire makes the wire very hot - this may work as a lighter.

Sounds like what you have there is an exploding bridgewire detonator. Trying to set off a nuclear weapon??   ;)

This is space/Moon, so you are working in a vacuum.

Offline adeclama

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Re: Critical Lunar Industrial Infrastructure
« Reply #106 on: 09/30/2008 07:13 PM »
Putting a high current through a thin wire makes the wire very hot - this may work as a lighter.

Sounds like what you have there is an exploding bridgewire detonator. Trying to set off a nuclear weapon??   ;)

Sounds more like an incadescent light bulb to me  :)

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Re: Critical Lunar Industrial Infrastructure
« Reply #107 on: 10/01/2008 04:42 AM »
Putting a high current through a thin wire makes the wire very hot - this may work as a lighter.

Sounds like what you have there is an exploding bridgewire detonator. Trying to set off a nuclear weapon??   ;)

Sounds more like an incadescent light bulb to me  :)
Incandescent lights are a well proven technology.

The struck titanium would be the ignition system rather than the rocket fuel or welding material.  So only a tiny amount of titanium would be needed, possibly the head of the hammer.

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