Author Topic: Rocket propellant from seawater and sunlight  (Read 6679 times)

Offline Ludus

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Rocket propellant from seawater and sunlight
« on: 03/31/2013 05:22 PM »
http://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/#more-6020

I'm curious how practical it would be for Canaveral or other major space launch sites to produce rocket propellant on site in a zero net carbon method.

I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.

The notion is that seawater can be used as a source of hydrogen and carbon for Fisher-Tropsch http://en.wikipedia.org/wiki/FischerĖTropsch_process.

Seawater has 200x the density of carbon dioxide as the atmosphere and interacts with it so carbon extracted from seawater is equivalent to taking it out of the air and hydrocarbon fuels made in this way are zero net carbon producing.

In the ordinary version of this for say Naval jet fuel, the oxygen produced would just be vented. In the space launch version obviously the oxygen also has a use.

The process ought to be able to produce a synthetic RP-1 equivalent. This is a question for anybody with a real understanding of rocket fuels and engines. What issues would there be? As I understand it, the spec for RP-1 calls for a very low sulfur variant which would be an excellent fit for a synthetic that could easily be zero sulfur. Are there other problems?

IIRC the process should have no trouble producing pure methane or pure hydrogen from and earlier process stage than kerosene.

As far as the electricity to run it, it seems like there would be a couple good fits. First it matches well practically and politically with PV solar on site. Canaveral is sunny, on the sea and has a lot of open space for safety and security that might be used for pv arrays. Beyond that, this use would be a good match for long term deals with power utilities to level demand. Propellant synthesis could soak up excess electric production in low demand periods matching both intermittant sources like renewables and greater base load like nuclear. The synthesis could change it's power draw to productively use power the grid doesn't need.

If the system had more capacity than was needed for rockets, it could switch to jet fuel grade production.

I think there is real interest in the military in developing this kind of tech given the enormous costs they have of providing lots of fuel in exotic locations.

Since rocket fuel is already premium priced it would be a closer match to the higher costs of a new synthesis technology.

Critiques?

Offline Jim

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Re: Rocket propellant from seawater and sunlight
« Reply #1 on: 03/31/2013 05:27 PM »
Canaveral is sunny, on the sea and has a lot of open space for safety and security that might be used for pv arrays.

No, not really.  It is a wildlife refuge which is not compatible with array farms.

Offline Jim

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Re: Rocket propellant from seawater and sunlight
« Reply #2 on: 03/31/2013 05:31 PM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

Offline RocketmanUS

Re: Rocket propellant from seawater and sunlight
« Reply #3 on: 03/31/2013 05:58 PM »
Power source can be miles away. So could use solar cells and/or wind.
Takes energy to make these power sources, that most likely will produce CO2 and other by products.
Note, we need CO2 for the life cycle here on Earth.

Propellants from sea water would be LH2 and LOX. Possible CH4 if there is an economical source of CO2.

Must cost less than to bring the propellants in from another source.
There will need to be a high enough demand to justify putting in such a system.

If extra CH4 were to be made as it is the main part of natural gas it could be sold to the local market for natural gas use.
« Last Edit: 03/31/2013 06:46 PM by RocketmanUS »
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Offline Hyperion5

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Re: Rocket propellant from seawater and sunlight
« Reply #4 on: 03/31/2013 06:00 PM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

He's just following the general rule of NSF, which basically is that the longer a conversation goes on at this site, the chance of Spacex appearing in that conversation approaches 100%. 

Offline blazotron

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Re: Rocket propellant from seawater and sunlight
« Reply #5 on: 03/31/2013 06:18 PM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

For what it's worth, I've heard SpaceX is the largest consumer of RP-1. 

As far as whether Fischer-Tropsch fuel can be used to replace RP-1, the RP-1 spec (and even more so the RP-2 spec, which is a tighter spec that sits inside the RP-1 spec) is designed to optimize energy density, boiling point curves, and amounts of certain chemical components (such as sulfur, aromatics, and olefins) which have significant effects on combustion characteristics.  Both were designed around fuels made from particular feedstocks primarily derived from refined petroleum. 

In order to  be a drop in replacement for RP-1, the new fuel would not only need to meet the spec, but in practice closely match the typical RP-1 composition to match RP-1 performance for use on engines qualified for RP-1.  In rocket engines, replicating the exact fuel performance is a much bigger deal than other applications of non-fossil-fuels, such as biodiesel and FT fuel used in cars.  Rocket engines are typically operated in a regime where significant changes in heat production rate, evaporation rate, density, surface tension, viscosity, hydrogen content, or constituent fractions affect mixing and combustion in injectors.  Similarly, significant changes in heat capacity, density,  coking rate, and boiling point curves can effect heat rejection into regenerative cooling circuits.  Energy density also affects the performance of a rocket as a whole as a change in the density would cause the vehicle to store more or less total energy. 

Matching all these characteristics would be relatively difficult to do with synthetic fuels and would require extensive processing of the fuels.  This makes it unlikely that a drop in replacement for existing fuels is feasible. 

This is not to say that a good rocket fuel cannot be made by Fischer-Tropsch, bio-derived, or other alternative processes.  And in fact there are several efforts underway to do this.  See for instance this article which describes some testing that has been done as well as some of the challenges I alluded to above.
http://www.flightglobal.com/news/articles/biodiesel-powers-atlas-rocket-engine-321321/
However, at that point you would be better off developing a new specification, and any program that wanted to use the new fuel would qualify their vehicles specifically to operate on it (possibly alongside RP-1). 

Offline Patchouli

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Re: Rocket propellant from seawater and sunlight
« Reply #6 on: 03/31/2013 06:50 PM »


For what it's worth, I've heard SpaceX is the largest consumer of RP-1. 

As far as whether Fischer-Tropsch fuel can be used to replace RP-1, the RP-1 spec (and even more so the RP-2 spec, which is a tighter spec that sits inside the RP-1 spec) is designed to optimize energy density, boiling point curves, and amounts of certain chemical components (such as sulfur, aromatics, and olefins) which have significant effects on combustion characteristics.  Both were designed around fuels made from particular feedstocks primarily derived from refined petroleum. 

In order to  be a drop in replacement for RP-1, the new fuel would not only need to meet the spec, but in practice closely match the typical RP-1 composition to match RP-1 performance for use on engines qualified for RP-1.  In rocket engines, replicating the exact fuel performance is a much bigger deal than other applications of non-fossil-fuels, such as biodiesel and FT fuel used in cars.  Rocket engines are typically operated in a regime where significant changes in heat production rate, evaporation rate, density, surface tension, viscosity, hydrogen content, or constituent fractions affect mixing and combustion in injectors.  Similarly, significant changes in heat capacity, density,  coking rate, and boiling point curves can effect heat rejection into regenerative cooling circuits.  Energy density also affects the performance of a rocket as a whole as a change in the density would cause the vehicle to store more or less total energy. 

Matching all these characteristics would be relatively difficult to do with synthetic fuels and would require extensive processing of the fuels.  This makes it unlikely that a drop in replacement for existing fuels is feasible. 

This is not to say that a good rocket fuel cannot be made by Fischer-Tropsch, bio-derived, or other alternative processes.  And in fact there are several efforts underway to do this.  See for instance this article which describes some testing that has been done as well as some of the challenges I alluded to above.
http://www.flightglobal.com/news/articles/biodiesel-powers-atlas-rocket-engine-321321/
However, at that point you would be better off developing a new specification, and any program that wanted to use the new fuel would qualify their vehicles specifically to operate on it (possibly alongside RP-1). 


In theory a fully synthetic or bio derived rocket propellant can be superior to that derived from petroleum.
You have more control over what's in it.
A good example is the Russian synthetic kerosene fuel Sintin.
Though I think the Russians used natural gas as the starting point a  Fischer-Tropsch process would just be adding one more step.
« Last Edit: 03/31/2013 06:52 PM by Patchouli »

Offline Lars_J

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Re: Rocket propellant from seawater and sunlight
« Reply #7 on: 03/31/2013 07:55 PM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

For what it's worth, I've heard SpaceX is the largest consumer of RP-1. 

What, how could they be? ULA should use more, even if one only counts their east coast pad. That might change in the future, but ULA should use more for the immediate future.

Offline joek

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Re: Rocket propellant from seawater and sunlight
« Reply #8 on: 03/31/2013 08:04 PM »
For what it's worth, I've heard SpaceX is the largest consumer of RP-1. 
What, how could they be? ULA should use more, even if one only counts their east coast pad. That might change in the future, but ULA should use more for the immediate future.

SpaceX appears to do quite a bit of testing.  How much is that likely to contribute to consumption?

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #9 on: 03/31/2013 09:18 PM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

Because Musk has an major public association with "green" projects. The fact that the amounts used are relatively low is what makes a project to supply them more practical.

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #10 on: 03/31/2013 09:25 PM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

DOD's interest is not for rocket propellant, it's for jetfuel and diesel at the end of costly logistical chains...and probably would be better served by small modular reactors than solar, but the chemical plant end using the electricity is about the same.

Offline gospacex

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Re: Rocket propellant from seawater and sunlight
« Reply #11 on: 03/31/2013 09:28 PM »
http://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/#more-6020

I'm curious how practical it would be for Canaveral or other major space launch sites to produce rocket propellant on site in a zero net carbon method.

I think spaceports should launch rockets.
Fuel production should be left for petrochemical industry.

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #12 on: 04/01/2013 12:08 AM »
I should explain a bit more why I think this might be useful. When engineering oriented folk look at rocket fuel they realize it's such a tiny fraction of hydrocarbon fuel use that it's effectively meaningless as a issue with carbon and climate (aside from whether they are concerned about that at all). When most people look at rocket launches they see extravangant fuel use and consequences. Rocket fuel also popularly seems powerful and explosive when in fact the major difference from other grades of fuel is that it's better as an engine coolant and more stable.

Zero net carbon rocket propellant would have significant popular image benefits for space launches and aerospace in general. It would actually be a pilot for broader use of the technology.

Rockets that burn zero net carbon fuel...would also have a PR benefit for the image of such fuel as "potent" whether that's technically meaningful or not.

SpaceX is mentioned specifically because given the association through Musk with Tesla and Solar City, this sort of benefit may appeal to them more.

As to sources of electricity, I think the image of launch pads surrounded in the immediate area with solar arrays makes sense as an image. It's not important what fraction of power they supply. The more important source of supply would be deals for demand leveling with the local grid.

The popular image of rocket launches is of powerful machines that are extravagant wasters of energy and sources of pollution. This seeks to address that image issue and pilot technologies of broader interest at relatively low cost.

Offline QuantumG

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Re: Rocket propellant from seawater and sunlight
« Reply #13 on: 04/01/2013 12:14 AM »
How would it be net zero carbon rocket propellant?

Quote from: Ludus
Seawater has 200x the density of carbon dioxide as the atmosphere and interacts with it so carbon extracted from seawater is equivalent to taking it out of the air and hydrocarbon fuels made in this way are zero net carbon producing.

Maybe I'm just missing your point here, but extracting carbon from the ocean only to put it back in the atmosphere is something I'd expect the warmers wouldn't warm to.
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Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #14 on: 04/01/2013 12:33 AM »
How would it be net zero carbon rocket propellant?

Quote from: Ludus
Seawater has 200x the density of carbon dioxide as the atmosphere and interacts with it so carbon extracted from seawater is equivalent to taking it out of the air and hydrocarbon fuels made in this way are zero net carbon producing.

Maybe I'm just missing your point here, but extracting carbon from the ocean only to put it back in the atmosphere is something I'd expect the warmers wouldn't warm to.


Zero net carbon fuels use carbon extracted from the atmosphere/ocean system and put it back when they are burned. The net effect is to neither add or subtract carbon, hence zero. Global civilization could burn an unlimited amount of hydrocarbon fuels of this sort forever without adding any more carbon to the atmosphere. Fossil sourced hydrocarbon fuels add carbon that was previously buried and out of the atmosphere/ocean.

Hydrocarbon fuels are MUCH easier to handle than hydrogen...and if the carbon component is just recycled through the atmosphere they are completely "sustainable". They cease to a source of energy and are just a storage medium like hydrogen was intended to be in visions of a "hydrogen economy". Hydrogen just turns out to be too hard to handle...plus would need a whole new infrastructure.

Offline QuantumG

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Re: Rocket propellant from seawater and sunlight
« Reply #15 on: 04/01/2013 12:38 AM »
the atmosphere/ocean.

I don't know where you're getting this idea that the atmosphere and the ocean are interchangeable, but they're not. Extracting carbon from the ocean to dump into the atmosphere is going to get you just as much flack from the people you're trying to appease as fracking for natural gas would.
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Offline Patchouli

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Re: Rocket propellant from seawater and sunlight
« Reply #16 on: 04/01/2013 12:52 AM »
the atmosphere/ocean.

I don't know where you're getting this idea that the atmosphere and the ocean are interchangeable, but they're not. Extracting carbon from the ocean to dump into the atmosphere is going to get you just as much flack from the people you're trying to appease as fracking for natural gas would.


The atmosphere and ocean constantly exchange gasses so taking CO2 out of the ocean would have zero net CO2 emissions.
In fact taking CO2 out of the ocean could offset ocean acidification which would be beneficial.
« Last Edit: 04/01/2013 12:52 AM by Patchouli »

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #17 on: 04/01/2013 01:21 AM »
the atmosphere/ocean.

I don't know where you're getting this idea that the atmosphere and the ocean are interchangeable, but they're not. Extracting carbon from the ocean to dump into the atmosphere is going to get you just as much flack from the people you're trying to appease as fracking for natural gas would.


Patchouli's right. The ocean/atmosphere are part of a single system as far as CO2 and extracting it from the ocean would be no different than extracting from the atmosphere...just easier cuz it's more concentrated.

Nobody concerned with CO2 and climate change would question that. Not saying they wouldn't wuestion other thngs about it, but not that.

Offline QuantumG

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Re: Rocket propellant from seawater and sunlight
« Reply #18 on: 04/01/2013 03:52 AM »
Nobody concerned with CO2 and climate change would question that.

Yes they would.

You're making a logical argument for something you already said was irrational.

Any human activity that increases CO2 levels in the atmosphere is suspect to some people. Messing with the oceans just gives them bonus points.
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Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #19 on: 04/01/2013 04:20 AM »
Nobody concerned with CO2 and climate change would question that.

Yes they would.

You're making a logical argument for something you already said was irrational.

Any human activity that increases CO2 levels in the atmosphere is suspect to some people. Messing with the oceans just gives them bonus points.

Not quite sure what you mean. This does not increase CO2 levels in the atmosphere. I don't think it's irrational, just that the main reason it might be interesting is not it's direct impact (since space launches are a tiny fraction of fossil hydrocarbon use) but it's impact on public image and it's utility as a pilot project for broader uses of the same technology.

I think this approach in general has huge promise and it's use for rocket propellant might be an interesting choice for some of the same reasons that Tesla is better off competing with the BMW 7 series than making econoboxes. Rocket fuel is the upscale high image end of the fuel biz. To me people who criticize Tesla for not making cars for the masses don't get the point.

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #20 on: 04/01/2013 04:28 AM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

For what it's worth, I've heard SpaceX is the largest consumer of RP-1. 

As far as whether Fischer-Tropsch fuel can be used to replace RP-1, the RP-1 spec (and even more so the RP-2 spec, which is a tighter spec that sits inside the RP-1 spec) is designed to optimize energy density, boiling point curves, and amounts of certain chemical components (such as sulfur, aromatics, and olefins) which have significant effects on combustion characteristics.  Both were designed around fuels made from particular feedstocks primarily derived from refined petroleum. 

In order to  be a drop in replacement for RP-1, the new fuel would not only need to meet the spec, but in practice closely match the typical RP-1 composition to match RP-1 performance for use on engines qualified for RP-1.  In rocket engines, replicating the exact fuel performance is a much bigger deal than other applications of non-fossil-fuels, such as biodiesel and FT fuel used in cars.  Rocket engines are typically operated in a regime where significant changes in heat production rate, evaporation rate, density, surface tension, viscosity, hydrogen content, or constituent fractions affect mixing and combustion in injectors.  Similarly, significant changes in heat capacity, density,  coking rate, and boiling point curves can effect heat rejection into regenerative cooling circuits.  Energy density also affects the performance of a rocket as a whole as a change in the density would cause the vehicle to store more or less total energy. 

Matching all these characteristics would be relatively difficult to do with synthetic fuels and would require extensive processing of the fuels.  This makes it unlikely that a drop in replacement for existing fuels is feasible. 

This is not to say that a good rocket fuel cannot be made by Fischer-Tropsch, bio-derived, or other alternative processes.  And in fact there are several efforts underway to do this.  See for instance this article which describes some testing that has been done as well as some of the challenges I alluded to above.
http://www.flightglobal.com/news/articles/biodiesel-powers-atlas-rocket-engine-321321/
However, at that point you would be better off developing a new specification, and any program that wanted to use the new fuel would qualify their vehicles specifically to operate on it (possibly alongside RP-1). 


That makes a lot of sense that it's much harder to make drop in equivalents because the standard is designed around refined petroleum stocks and the engines are precisely engineered for the standard.

Probably much easier for methane or hydrogen. I looked at the document for the RP-1 and RP-2 standard and besides the even lower sulfur content (which is easy) had no sense of whether the other fractions were important.

Online KelvinZero

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Re: Rocket propellant from seawater and sunlight
« Reply #21 on: 04/01/2013 07:56 AM »
http://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/#more-6020

I'm curious how practical it would be for Canaveral or other major space launch sites to produce rocket propellant on site in a zero net carbon method.

I think spaceports should launch rockets.
Fuel production should be left for petrochemical industry.

I would generally agree. It could make a nice side project though, perhaps purely development. After all they need to develop a reliable lightweight plant for methane ISRU at some point for mars don't they? No petrochemical industries there! Perhaps there is something small and marketable that could be done now without going overboard, just to learn the ropes and perhaps get some more exposure.

Offline JohnFornaro

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Re: Rocket propellant from seawater and sunlight
« Reply #22 on: 04/01/2013 01:40 PM »
However, at that point you would be better off developing a new specification, and any program that wanted to use the new fuel would qualify their vehicles specifically to operate on it (possibly alongside RP-1).

During WWII and for a decade or so afterwards, some Farmall tractors were dual fuel; kerosene and gasoline.  Kero being lower on the hydrocarbon food chain, and thus somewhat less rationed than gasoline.  These are pretty different hydrocarbons, but the engine using them is also less demanding than a rocket engine.

You've listed some of the parameters above, which would have to be considered. 

Would building a "dual fuel" rocket engine be economically and technically feasible?
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: Rocket propellant from seawater and sunlight
« Reply #23 on: 04/01/2013 01:43 PM »
SpaceX is mentioned specifically because given the association through Musk with Tesla and Solar City, this sort of benefit may appeal to them more.

The image of the early Ford plants always appealed to me.  Wood, ore, coal, leather, and so forth went in one end of the plant, and cars came out of the other end. 

This association would take the idea of vertical integration one step further; where they also made their own rocket fuel.
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Offline JohnFornaro

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Re: Rocket propellant from seawater and sunlight
« Reply #24 on: 04/01/2013 01:56 PM »
Nobody concerned with CO2 and climate change would question that.

Yes they would.

You're making a logical argument for something you already said was irrational.

Any human activity that increases CO2 levels in the atmosphere is suspect to some people. Messing with the oceans just gives them bonus points.

Not quite sure what you mean. This does not increase CO2 levels in the atmosphere. I don't think it's irrational, just that the main reason it might be interesting is not it's direct impact (since space launches are a tiny fraction of fossil hydrocarbon use) but it's impact on public image and it's utility as a pilot project for broader uses of the same technology.

I think this approach in general has huge promise and it's use for rocket propellant might be an interesting choice for some of the same reasons that Tesla is better off competing with the BMW 7 series than making econoboxes. Rocket fuel is the upscale high image end of the fuel biz. To me people who criticize Tesla for not making cars for the masses don't get the point.

Bottom line:  Easier said than done.

As Ludus points out, recycling carbon between atmosphere and ocean is done all the time naturally.  It is somewhat rational to make the "public image" argument, since people don't see the clouds of exhaust gas coming out of automobiles, except when the guy in front of them has bad rings.  Truth be told, cars pump out exhaust at least as spectacularly as rockets, given their scale, but people literally don't see that.

I could envision a PR campaign around the effort that Ludus sketches out.  Even that would be an uphill fight.  Already, Ludus is encountering opposition from someone who should know something about carbon cycles.

BTW, some people do get that wealthy people are being asked to finance a possible transition to having many more battery operated cars on the road.  Those prices are already falling somewhat.
Sometimes I just flat out don't get it.

Offline Solman

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Re: Rocket propellant from seawater and sunlight
« Reply #25 on: 04/01/2013 04:45 PM »
Canaveral is sunny, on the sea and has a lot of open space for safety and security that might be used for pv arrays.

No, not really.  It is a wildlife refuge which is not compatible with array farms.

Citation?
Is this based on a study, regulations, or is this just your assertion?
Rooftops, power line right of ways and even perhaps elevated panels over roadways are possible I think, even if regs or research stops placement of panel in refuge areas.

Offline Andy USA

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Re: Rocket propellant from seawater and sunlight
« Reply #26 on: 04/01/2013 11:56 PM »
This is NOT a thread for Climate Change. We deal with space flight hardware here.

Offline indaco1

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Re: Rocket propellant from seawater and sunlight
« Reply #27 on: 04/02/2013 12:40 AM »
Would building a "dual fuel" rocket engine be economically and technically feasible?

I think a tri-propellant engine is very attractive.

But it's not for the environment, it's to increase dramatically launch performance (an engine that uses a dense fuel enabling a better T/W during boost phase and an high isp fuel during sustain phase allows to save total engine mass compared to have both specialized engines and optimize tank volume and cryogenic fuel usage). Eg: http://en.wikipedia.org/wiki/RD-701

On the other hand I think syntetic fuels will be very useful for the environment, but it's not for space launch only.
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Offline RocketmanUS

Re: Rocket propellant from seawater and sunlight
« Reply #28 on: 04/02/2013 01:59 AM »
How would they extract the CO2 from ?
1 ) the air
2 ) sea water

From there we already know how to make the CH4 ( methane ) for rocket fuel.
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Offline arachnitect

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Re: Rocket propellant from seawater and sunlight
« Reply #29 on: 04/02/2013 02:00 AM »
http://www.caafi.org/about/faq.html
Quote
Do alternative fuels affect aircraft performance? Effects can be positive or negative. For example, lower density fuels can improve fuel burn but adversely affect payload range. The current fuel alternatives can absorb more heat than existing fuels an important factor for newer aircraft with more electronic equipment. CAAFI is exploring all performance impacts.

Test firing a kerolox engine with synthetic RP-1 might be a worthwhile experiment to try, maybe as a project to keep some of the junior engineers busy and give them some project management experience.

Offline arachnitect

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Re: Rocket propellant from seawater and sunlight
« Reply #30 on: 04/02/2013 02:45 AM »
How would they extract the CO2 from ?
1 ) the air

All kinds of ways.

Amine (or other chemical) contactor or water-gas shift reactor are possibilities.

Quote
How would they extract the CO2 from ?
2 ) sea water

electrolysis + membrane contactor
http://pubs.rsc.org/en/content/articlelanding/2012/ee/c2ee03393c

I don't see a problem producing synfuels. The problems are more about finding a reason to do it and making sure the synthetic fuel is compatible with your rocket.

Honestly the problem is motivation; there's no reason we couldn't use "net zero" LH2 in rockets (didn't we already have a thread on this stuff?).

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #31 on: 10/03/2017 04:58 PM »
I thought it might be easier to revive this 4.5 year old thread than starting over. The context has evolved somewhat. It would now be about just synthesis of methane and would apply to SpaceX, Blue Origin and ULA using Vulcan.

The SpaceX BFR\BFS system requires this system to synthesize Methane on Mars and in the last IAU speech Elon mentioned the potential to make BFR sustainable by this path.

Methane from natural gas is very cheap and Iím not suggesting that the industry try to switch over to zero net carbon methane at current costs, but that it could take a leadership position by backing the technology development and buying the output at higher prices.

This technology is critical to SpaceXís system and a development cycle on earth advances that.

An example system might be an offshore wind farm built in cooperation with a Power company where the grid takes power when it needs it but off peak excess goes to a power to gas plant.

LOX production from entirely zero carbon power sources like wind maybe affordable at current cost levels and would be a big step in itself.

https://en.m.wikipedia.org/wiki/Power_to_gas
« Last Edit: 10/03/2017 05:13 PM by Ludus »

Offline stefan r

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Re: Rocket propellant from seawater and sunlight
« Reply #32 on: 10/03/2017 06:49 PM »
...
The SpaceX BFR\BFS system requires this system to synthesize Methane on Mars and in the last IAU speech Elon mentioned the potential to make BFR sustainable by this path.

...

An example system might be an offshore wind farm built in cooperation with a Power company where the grid takes power when it needs it but off peak excess goes to a power to gas plant.

LOX production from entirely zero carbon power sources like wind maybe affordable at current cost levels and would be a big step in itself.

https://en.m.wikipedia.org/wiki/Power_to_gas

Cape canaveral is downstream from Orlando, Disney world and a bunch of cattle farms.  Modern cities and cows generate sewage.  You can inject small amounts of a steam/oxygen mix into a large vat of sewage/sludge and thermophilic anoxic bacteria will produce methane.  If you run out of sewage (unlikely) you could add yard waste and other agricultural waste.  This requires trivial amounts of energy which  could be generated with some of the methane produced.  The high temperature generated will kill everything except the thermophilic bacteria which makes it sterile with respect to pathogens. 

Florida has issues with water pollution.  http://www.cnn.com/2016/07/01/us/florida-algae-pollution/index.html  Would be best to concentrate the sewage, generate methane, and avoid the algae bloom.  But if you wanted to you could collect algae (or duckweed) from open waters and then feed them to the bacteria for methanogenesis.  Tourists, turtles and porpoises do not like sludge on Florida beaches. 

Building bioreactors and associated piping costs infrastructure.  There is no need to drain energy from other areas.  If the carbon and hydrogen in our rocket fuel are coming from bodies of water it is best to get it before it dilutes the ocean.  Pipping ocean water inland and then adding energy to process it would be very wasteful. 

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #33 on: 10/03/2017 10:46 PM »
...
The SpaceX BFR\BFS system requires this system to synthesize Methane on Mars and in the last IAU speech Elon mentioned the potential to make BFR sustainable by this path.

...

An example system might be an offshore wind farm built in cooperation with a Power company where the grid takes power when it needs it but off peak excess goes to a power to gas plant.

LOX production from entirely zero carbon power sources like wind maybe affordable at current cost levels and would be a big step in itself.

https://en.m.wikipedia.org/wiki/Power_to_gas

Cape canaveral is downstream from Orlando, Disney world and a bunch of cattle farms.  Modern cities and cows generate sewage.  You can inject small amounts of a steam/oxygen mix into a large vat of sewage/sludge and thermophilic anoxic bacteria will produce methane.  If you run out of sewage (unlikely) you could add yard waste and other agricultural waste.  This requires trivial amounts of energy which  could be generated with some of the methane produced.  The high temperature generated will kill everything except the thermophilic bacteria which makes it sterile with respect to pathogens. 

Florida has issues with water pollution.  http://www.cnn.com/2016/07/01/us/florida-algae-pollution/index.html  Would be best to concentrate the sewage, generate methane, and avoid the algae bloom.  But if you wanted to you could collect algae (or duckweed) from open waters and then feed them to the bacteria for methanogenesis.  Tourists, turtles and porpoises do not like sludge on Florida beaches. 

Building bioreactors and associated piping costs infrastructure.  There is no need to drain energy from other areas.  If the carbon and hydrogen in our rocket fuel are coming from bodies of water it is best to get it before it dilutes the ocean.  Pipping ocean water inland and then adding energy to process it would be very wasteful.

Thatís an interesting alternative. Bio Methane is produced from Carbon in the carbon cycle now rather than from fossil fuels so itís zero net.

The synthetic process wouldnít involve piping ocean water inland but it would be more energy intensive. The reason for developing it is that biomethane isnít scalable for Mars rocket fuel (though Ag on Mars might produce some this way also). On earth power to gas is potentially a method of using excess power from sources like wind in off peak periods.

Offline IRobot

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Re: Rocket propellant from seawater and sunlight
« Reply #34 on: 10/03/2017 10:52 PM »

And why is Spacex singled out?

He's just following the general rule of NSF, which basically is that the longer a conversation goes on at this site, the chance of Spacex appearing in that conversation approaches 100%.
Reductio ad SpaceXum, Argumentum ad SpaceXum.

Somehow it reminds me of:
https://en.wikipedia.org/wiki/Reductio_ad_Hitlerum

Something like: "SpaceX makes cool rockets, so all rockets discussions must be about SpaceX".

Or, a derivation of Godwin's law:
 "As an online rocket discussion grows longer, the probability of a comparison involving SpaceX approaches 1"
https://en.wikipedia.org/wiki/Godwin%27s_law
« Last Edit: 10/03/2017 10:54 PM by IRobot »

Offline Ludus

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Re: Rocket propellant from seawater and sunlight
« Reply #35 on: 10/04/2017 01:47 AM »
To be fair SpaceX is now pretty much the focus, much more than 4 years ago for quite a few reasons. Elon Musk has a major interest in climate change and sustainability. SpaceX is pivoting to just build a methane fueled rocket that requires methane synthesis ISRU on Mars. Musk has publically mentioned than BFR can follow this route eventually. No other aerospace company is as connected to the topic.

Online KelvinZero

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Re: Rocket propellant from seawater and sunlight
« Reply #36 on: 10/04/2017 02:48 AM »
The recent spacex presentation also showed a launch pad at sea, and mentioned the intention to generate methane from renewable energy sources.

I think it would be interesting to figure out what sort of surface area you would need around a BFR launcher to launch at least daily. At sea you have access to sun, wind and wave.

.. I suspect a lot of surface area :)

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