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ISRU-technology for propellant

Posted by: Ekkehard Augustin - Thu Sep 14, 2006 10:31 am
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ISRU-technology for propellant 
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Post ISRU-technology for propellant   Posted on: Thu Sep 14, 2006 10:31 am
Under www.wissenschaft.de an article is reporting today that italian scientists are researching a way to change CO2 back into carbonhydrogens. Then gasoline and Diesel could be made of them. The scientists think that this could contribute to the reduction of climate warming.

First the scientists used solar power to split water into oxygen, hydrogen ions and electrons - according to the article. Next they made the ions react with the CO2. The forming of carbonhydrogens here is enabled by a new catalysator.

At present hte method is in its infancy of development and the amount of carbonhydrogens is small yet but the scientists are convinced that the peformance can be increased by optimizations.

Explicitly the method could be used to produce propellant required for flying back from Mars out of the martian atmosphere.

But it will last at least ten years until a solar reactor for the production of carbonhydrogens is available.

The article refers to Gabriele Centi, University Messina, and his team and to New Scientist , 16th of September, page 30.

By the way - it might be interesting for Venus also to et back probes for example or for sample return missions.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


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Post    Posted on: Fri Oct 06, 2006 10:32 pm
Solar production of hydrocarbons. I never would have expected that.


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Post    Posted on: Mon Feb 05, 2007 3:27 pm
In between I a few times was thinking about lunar ressource for propellant other than LOX/LH2 also. The reasons are landers under development.

In principle H2O2 and Ethanol should be possible - but the lunar crust contains 0.002% carbon only.

So what to do - import carbon elsewhere or modify landers to LOX/LH2 if the should use lunar ISRU-propellant?



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Post    Posted on: Mon Feb 19, 2007 6:22 pm
Rube Goldberg at work again! CO2 doesn't convert into hydrocarbons. There's no hydrogen in CO2. Considering how thin the martian atmosphere is, and how little solar power there is available, why not just use the frozen water to make H2 and O2?


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Post    Posted on: Mon Feb 19, 2007 7:39 pm
Hello, Vendigo,

the point is that it is still supposed that there might be accessable and sufficient deposits of hydrogen on the Moon. Oxygen is part of the lunar Regolith - so the only element left is carbon.

I wasn't talking about CO2 in my previous post - what made you talk about CO2 and Mars?



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Post    Posted on: Tue Feb 20, 2007 12:30 pm
Not in the previous post, but in the first one you did.

What becomes of the second, post, I really wonder what's the point in putting extra effort to create less efficient fuel.


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Post    Posted on: Tue Feb 20, 2007 2:11 pm
Hello, Vendigo,

the point regarding the less efficient fuel is that the landers under development by Armadillo Aerospace or Micro Space are based on that less efficient fuel.

Those two landers are developed for use on the Moon. So given these two landers consuming ethanol or methanol (in combination with LOX or H2O2, Hydrazine) ISRU-production of ethanol or methanol is the point.

On Mars there is not only CO2 but water also - CO2 and H2O are avaliable. This is what the intalian scientists are basing their thoughts on - and they have in mind application on Earth in the first place which means that the technology will be tested, worked out and matured if it will be applied on Mars later.



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Post    Posted on: Tue Feb 20, 2007 5:33 pm
Ever heard of Ocham's razor?


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Post fuels   Posted on: Tue Feb 20, 2007 9:56 pm
I don't think changing fuels is all that big of a deal -- we are on our third propellant now, and considering oters.

For lunar use, I think high pressure electrolyss of water directly into propellant tanks is potentially interesting.

John Carmack


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Post    Posted on: Tue Feb 20, 2007 10:14 pm
I must point out that the landers under development by Armadillo Aerospace or Micro Space are not being developed for use on the Moon. In particular, John Carmack has explicitly said his vehicles are not prototype lunar landers.


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Post Moon Lander   Posted on: Tue Feb 20, 2007 11:13 pm
The Micro-Space effort actually is intended to be a prototype Lunar Lander. Since it uses storable (not cryogenic) propellants, boiloff during many days of delay in space on the way to the Moon is not an issue. We assume that we will be using 90% H2O2 for the actual lunar system, although 70% is adequate. The fuel component will probably be Methyl Alcohol with Hydrazine added. Refractory “Radiation Cooledâ€


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Post propellants   Posted on: Wed Feb 21, 2007 6:07 pm
rspeck: that is a perfectly reasonable technical direction, but I don't think it does anyone any good to characterize a monoprop vehicle mockup as a prototype lunar lander.

When are you actually going to try and fly the vehicle, anyway? I did find it disingenuous that you characterized your obsticles at the LLC as regulatory in nature, when the vehicle hadn't actually demonstrated the ability to fly yet.

That comes off a bit more hostile than I really intend -- I am genuinely curious about the delivered performance of your vehicle configuration.

John Carmack


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Post Re: Moon Lander   Posted on: Wed Feb 21, 2007 6:55 pm
rpspeck wrote:
The Micro-Space effort actually is intended to be a prototype Lunar Lander.
I stand corrected!


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Post    Posted on: Thu Feb 22, 2007 6:01 pm
I have been reading "The Case for Mars" by Robert Zubrin recently, and he talks a lot about ISRU. One of his biggest themes is that CO2 is very plentiful on Mars, so it is eminently reasonable to utilize methane or other hydrocarbons as fuel. He had quite a write-up on a system he built to produce oxygen, water, and methane with a simple process. I remember he also noted that his system also produced some higher hydrocarbons, but in small quantities. He noted that one could leverage a volume of hydrogen brought from home into many times that volume of fuel.

(edit: http://fsi.ucf.edu/special/SolarSystem/ ... /TC010.pdf has a writeup on that system)

The system in the New Scientist article only converts 1% of the CO2 into fuel; but CO2 is not lacking on Mars! The bigger problems I see here are that the limiting factors are power and heat, both of which would have to come from the solar source.

Noting that the efficiency of solar cells is at most 40.7% with multiple-junction research lab cells (and most other silicon-based PV cells max out at 20-25%), that the intensity of sunlight on Mars is much less than on Earth, and that the size/weight ratio of these things isn't good, it seems clear to me that it will indeed be quite a few years before a system based on this process would be feasible for Mars. Perhaps by the time it is, NASA will actually be ready to head to Mars.

Here's hoping that Armadillo, Masten, Micro-Space, and all the other commercial ventures don't wait that long!! :D


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Post    Posted on: Thu Feb 22, 2007 7:20 pm
I read that too, many years ago. I guess they didn't know there was water on Mars back then, or possibly they just assumed it would be hard to extract even if it were there. Although we don't have absolute proof yet, it does seem to me that there is ample evidence of large ice deposits very near the surface that could be tapped by landing in the right location, so I think any plan to bring hydrogen from Earth is out of date. Actually, aren't there hydrated minerals all over the place? It would clearly be harder than just melting ice, but in principle we could get water directly from those rocks.


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