Author Topic: Carbon Monoxide for fuel on Mars  (Read 66756 times)

Offline Dalhousie

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Re: Carbon Monoxide for fuel on Mars
« Reply #80 on: 05/06/2016 07:03 am »
Thanks!
Apologies in advance for any lack of civility - it's unintended

Offline Rei

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Re: Carbon Monoxide for fuel on Mars
« Reply #81 on: 05/06/2016 10:25 am »
For simplicity a base will want to use the same fuel for its rockets and for generation of electricity. Various types of engines can work at these combustion temperatures but their heat exchangers and pipes will also need to take the pressure. Such equipment will need building and testing.

Fuel... for the generation of electricity?
 : ???

Solar panels only work during the day. The batteries needed to keep a base going during the night are enormous - possible on Mars but not at the Moon's equator. Carbon monoxide and liquid oxygen can be kept in tanks. ...  A CO/LOX system may have to use a Stirling engine converter to generate the electricity.

"At night" is a good clarification to your earlier statement  ;)  Still, I seriously doubt they're going to use combustion for the creation of energy at night.  Even assuming that power is non-nuclear.  Fuel cells are a possibility, but concerning combustion, I can't begin to imagine that they'd choose a system that throws out 2/3rds of the energy and involves extensive use of moving parts in a hostile environment as their energy storage means of choice.  Fuel cells for space applications are both a much higher TRL and significantly more efficient.

Assuming, again, that batteries aren't used, and that the power isn't nuclear.

What exactly was your link supposed to be about?
« Last Edit: 05/06/2016 10:26 am by Rei »

Offline Vultur

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Re: Carbon Monoxide for fuel on Mars
« Reply #82 on: 05/06/2016 09:58 pm »
Does the process that will be used to make oxygen in the MOXIE experiment planned for the Mars 2020 rover produce CO as a byproduct?

EDIT: remove incorrect quote
« Last Edit: 05/08/2016 06:10 pm by Vultur »

Offline john smith 19

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Re: Carbon Monoxide for fuel on Mars
« Reply #83 on: 05/06/2016 10:37 pm »
Fuel cells are a possibility, but concerning combustion, I can't begin to imagine that they'd choose a system that throws out 2/3rds of the energy and involves extensive use of moving parts in a hostile environment as their energy storage means of choice. 
As always "it depends." Conversion of reactants to electricity, yes. But a settlement is a different issue. It's like IVF, where heat is a valuable 2nd product of the process. Mars is cold at night. Low convection thermal design will certainly help but Mars atmosphere is still substantially above a vacuum.
Quote
Fuel cells for space applications are both a much higher TRL and significantly more efficient.

Assuming, again, that batteries aren't used, and that the power isn't nuclear.
Only for the O2/H2 combination. AFAIK the materials are only really developed for conversion the other way 2 CO2 --> O2 + 2CO
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Robotbeat

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Re: Carbon Monoxide for fuel on Mars
« Reply #84 on: 05/07/2016 01:33 am »
If you're making oxygen from the Martian air, you're already making carbon monoxide by default. The question is whether or not you're going to do anything with it.

So does the process that will be used to make oxygen in the MOXIE experiment planned for the Mars 2020 rover produce CO as a byproduct?
Yes, MOXIE produces both oxygen and carbon monoxide. BTW, you butchered your quote tags, I wasn't the one who said the above.
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Offline A_M_Swallow

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Re: Carbon Monoxide for fuel on Mars
« Reply #85 on: 05/08/2016 02:25 pm »
{snip}
Assuming, again, that batteries aren't used, and that the power isn't nuclear.

What exactly was your link supposed to be about?

We will not be using nuclear on man sized rovers. RTG do not produce sufficient power and full sized nuclear reactors are not moved once started.

The MMSEV is a prototype manned rover. The quote shows it being powered by a fuel cell.
2H2 + O2 = 2H2O

Repeat
Quote
This applies double to rovers. In 2012 NASA tested running the MMSEV manned rover from a hydrogen fuel cell. A CO/LOX system may have to use a Stirling engine converter to generate the electricity.
http://www.lpi.usra.edu/meetings/lpsc2013/eposter/3097.pdf

Offline Vultur

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Re: Carbon Monoxide for fuel on Mars
« Reply #86 on: 05/08/2016 06:14 pm »
Yes, MOXIE produces both oxygen and carbon monoxide.

OK, cool! So that's an opportunity to test out the production pretty soon (2021 or so...)

When I first heard about this combination, I thought it was kind of silly/unnecessary since methane/LOX has way better Isp. But it could easily be a good choice early on, since the basic chemistry will already be tested out on Mars and it doesn't require either bringing hydrogen from Earth or getting it from Martian ice.

(I have a feeling SpaceX will still go the methalox route so they can use Raptor, though.)

Quote
BTW, you butchered your quote tags, I wasn't the one who said the above.

Oh, sorry  :-[ Fixed.

Offline Proponent

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Re: Carbon Monoxide for fuel on Mars
« Reply #87 on: 05/09/2016 03:56 am »
For example the high ISP SSME ran at a mass ratio of 6:1, but full combustion to H2O is 8:1.  Lowers combustion chamber temps with a still very respectable ISP..

Not merely "still very respectable," but actually better.  The SSME ran leaner than most lox-hydrogen stages (O/F typically being 5-ish), and therefore suffered both lower Isp and higher chamber temperature:  the trade between Isp and bulk propellant density shifts toward density for ground-lit stages.

Offline Tetrakis

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Re: Carbon Monoxide for fuel on Mars
« Reply #88 on: 05/09/2016 04:38 am »
There is a higher performance fuel you can make out of the Martian atmosphere.

It's called Cyanogen.

It is however very toxic to handle.  :(

Now this idea I rather like. What would be the performance of that, exactly?

I realize that cyanogen is toxic, but so is carbon monoxide. More importantly it is comparatively hard to synthesize, but still this is an intriguing idea since a closed cycle can be envisioned where no external hydrogen need be supplied for its preparation from the Martian atmosphere (although some would be needed in the system itself for the preparation of ammonia and hydrogen cyanide as intermediates, thermodynamic driving force comes from oxidation of these compounds by oxygen to make water, which can be split again to make oxygen and regenerate hydrogen for ammonia synthesis)

Also, for those interested in something a bit... spicier, theres always dicyanoacetylene.
« Last Edit: 05/09/2016 04:42 am by Tetrakis »

Offline Rei

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Re: Carbon Monoxide for fuel on Mars
« Reply #89 on: 05/09/2016 10:06 am »
Quote
Now this idea I rather like. What would be the performance of that, exactly?

See earlier in this thread where I ran it through CEA2.

And yes, there are definite advantages for Mars in a hydrogen-free cycle.  Even bigger for Venus.  Although high performance is even more critical there due to the Earthlike gravity, so hydrogen still may be the best option (even though it's harder to get).  Cyanogen is also nice and dense and doesn't require the sort of sub-LOX temperatures of carbon monoxide.  But it burns very, very hot.

Hmm. I wonder if CO and(CN)2 form a eutectic... that could be the best of both worlds.

Quote
Also, for those interested in something a bit... spicier, theres always dicyanoacetylene.

I could be mistaken, but I don't think people are generally fond of their propellants being explosive  ;)  Hehe


Offline acsawdey

Re: Carbon Monoxide for fuel on Mars
« Reply #90 on: 05/09/2016 06:29 pm »
I could be mistaken, but I don't think people are generally fond of their propellants being explosive  ;)  Hehe

That's what I always say about GPIM and its hydroxylammonium nitrate monopropellant --- the concept seems frightening, just put your fuel and oxidizer in an aqueous solution together, nothing could ever go wrong with that, right?

Offline Rei

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Re: Carbon Monoxide for fuel on Mars
« Reply #91 on: 05/10/2016 01:03 pm »
We will not be using nuclear on man sized rovers.

So now we're talking about rovers?

Can we be clear about what is actually being discussed here before discussing it?  First it was "a base will use chemicals to power itself".  Then it was "a base will use chemicals for nightime power storage".  Now it's " a rover will be driven by chemicals".  It's hard to make statements when the topic keeps shifting.

Quote
The MMSEV is a prototype manned rover. The quote shows it being powered by a fuel cell.

And I wrote "Fuel cells are a possibility".  Whether they're "ideal" depends on the application, of course.  IMHO while H2+O2 is more widespread, H2+Cl2  is better suited for closed-cycle fuel-cell applications.  Efficiency and power are both better than H2+O2 and Cl2 can be liquefied with just pressure or moderately low temperatures, no sub-100K temperatures needed.  It also works well (unlike H2/O2 PEMFCs) for both electrolysis and galvanic operation in a single unit. 

We're still not very good at the anode side working with H2/O2, it involves significant overpotential (loss).
« Last Edit: 05/10/2016 01:14 pm by Rei »

Offline A_M_Swallow

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Re: Carbon Monoxide for fuel on Mars
« Reply #92 on: 05/10/2016 06:10 pm »

So now we're talking about rovers?

Can we be clear about what is actually being discussed here before discussing it?  First it was "a base will use chemicals to power itself".  Then it was "a base will use chemicals for nightime power storage".  Now it's " a rover will be driven by chemicals".  It's hard to make statements when the topic keeps shifting.
{snip}

In a well designed power system landers, habitats and rovers all work together.

Offline Proponent

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Re: Carbon Monoxide for fuel on Mars
« Reply #93 on: 05/12/2016 08:54 am »
I've just run lox-carbon monoxide* and, as suggested by john smith 19, lox-cyanogen through Whitehead's SSTO model, with the modifications described earlier.  The results are as tabulated below for a delta-V of 4 km/s, representative of a one-way trip from the surface of Mars to low Mars orbit.  The attached plot portrays the results (except for the hydrogen case) in the density-specific impulse plane, each curve representing the full range from maximum specific impulse to maximum impulse density.  The grey contours represent constant values of mAvail, as labeled.  The oxidizer is oxygen in all cases.  I've added a column MechEff,
which is the mechanical energy efficiency: the kinetic energy of the vehicle at burn-out divided by the mechanical energy of the jet (i.e., 0.5(propellant mass)(effective exhaust velocity)2).


           Fuel   O.F  RelMix Isp Dens Ctemp DenExp MechEff mProp   mEng  mTank  mFluid mAvail
         syntin 2.621   0.435 347 1043  3989  0.408   0.617  2.24 0.0106 0.0214 0.01118  0.957
        boctane 2.707   0.438 347 1036  3954  0.409   0.617  2.24 0.0107 0.0216 0.01120  0.956
          JP-10 2.718   0.418 340 1077  3911  0.401   0.621  2.32 0.0108 0.0215 0.01160  0.956
           JP-5 2.869   0.414 342 1032  3871  0.406   0.620  2.29 0.0111 0.0222 0.01147  0.955
           RP-1 2.891   0.425 342 1030  3864  0.406   0.620  2.30 0.0111 0.0223 0.01149  0.955
         octane 3.023   0.448 344  987  3841  0.412   0.618  2.27 0.0114 0.0230 0.01134  0.954
         hexane 3.065   0.447 345  966  3835  0.414   0.618  2.26 0.0116 0.0234 0.01131  0.954
       ethylene 2.817   0.410 354  902  3981  0.426   0.613  2.17 0.0118 0.0241 0.01085  0.953
      propylene 2.872   0.422 349  931  3931  0.420   0.616  2.22 0.0118 0.0239 0.01110  0.953
        pentane 3.097   0.436 345  949  3830  0.416   0.618  2.26 0.0118 0.0238 0.01128  0.953
         butane 3.142   0.443 346  938  3822  0.418   0.617  2.25 0.0119 0.0240 0.01125  0.953
        propane 3.207   0.440 347  928  3808  0.419   0.617  2.24 0.0120 0.0241 0.01120  0.953
         ethane 3.331   0.451 349  910  3785  0.422   0.616  2.22 0.0121 0.0244 0.01111  0.952
       cyanogen 0.918   0.377 331 1033  4506  0.400   0.625  2.43 0.0119 0.0235 0.01215  0.952
        methane 3.711   0.438 351  838  3711  0.431   0.615  2.20 0.0129 0.0262 0.01098  0.950
  cyanogen-lean 2.178  16.028 295 1073  3900  5.199   0.640  2.99 0.0150 0.0279 0.01496  0.942
       hydrogen 7.932   0.338 415  424  3738  0.518   0.578  1.67 0.0181 0.0395 0.00837  0.934
  cyanogen-rich 0.156 -23.192 271  972  3900 -4.628   0.646  3.51 0.0204 0.0361 0.01754  0.926
carbon monoxide 0.594   0.248 266  895  3543  0.367   0.647  3.63 0.0231 0.0405 0.01814  0.918


As before, mixture ratios are adjusted maximize the available mass fraction, mAvail.  You'll note, though, that there are three entries for cyanogen.  One corresponds to maximal mAvail.  As cleonard pointed out above, however,  cyanogen burns hotter 'n Georgia asphalt.  So, the other two points correspond to the rich and lean lox-cyanogen mixtures which burn at a more moderate 3900 K (these fall outside the usual density range and are represented by small red circles in the plot).  A lean cyanogen mixture burning at 3900 K actually performs quite well:  though it falls near the bottom of the table (which is sorted by mAvail), its mAvail isn't really much lower than those of the best fuels.  For that matter, rich-burning cyanogen at 3900 K and CO aren't awful either.


* The CEA thermodynamic database which RPA uses does not contain an entry for liquid CO.  Entering a substance requires calculating its enthalpy with respect to the chemical elements from which it is formed at STP (25 oC and 1 bar).  To do this, I started with the the CEA heat of formation for CO(g) at STP (-110.535 kJ/mol) then used NIST data to find the difference in enthalpies between CO(g) at STP and CO(l) at its boiling point of 81.6 K.  The result is -122.972 kJ/mol.

Just to check that my calculation was reasonable I applied the same technique to methane, a liquid-state enthalpy for which is contained in CEA.  The result was -89.200 kJ/mol, which differs by just 0.033 kJ/mol from the value -89.233 kJ/mol that is given.  A change of 0.04 kJ/mol in the enthalpy of CO(l) changes its specific impulse by only about 0.02 s.

EDIT:  Removed erroneous second apostrophe from colloquialism "hotter 'n Georgia asphalt."  Corrected table and plot to reflect a take-off thrust-to-weight ratio of 1.3 on Mars rather than Earth.  Added MechEff column and corresponding explanation.  Deleted oxidizer and engine T/W columns.
« Last Edit: 05/16/2016 03:42 pm by Proponent »

Offline Proponent

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Re: Carbon Monoxide for fuel on Mars
« Reply #94 on: 05/12/2016 09:21 am »
Now let's look at a round trip from Mars to LMO and back.  Rei pointed out that the 8-km/s delta-V I previously assumed for this was probably rather harsh.  Let's suppose you can do it for 6 km/s, getting about 2 km/s of braking from the martian atmosphere.


           Fuel   O.F  RelMix Isp Dens Ctemp DenExp MechEff mProp   mEng  mTank mFluid mAvail
         syntin 2.608   0.347 347 1043  3988  0.323   0.644  4.82 0.0191 0.0462 0.0241  0.911
        boctane 2.692   0.347 347 1035  3953  0.323   0.644  4.83 0.0193 0.0467 0.0241  0.910
          JP-10 2.710   0.331 340 1077  3910  0.316   0.642  5.05 0.0197 0.0469 0.0253  0.908
           JP-5 2.856   0.327 342 1032  3871  0.321   0.642  4.98 0.0201 0.0482 0.0249  0.907
           RP-1 2.876   0.337 342 1029  3863  0.321   0.642  4.99 0.0202 0.0484 0.0249  0.906
         octane 3.002   0.358 345  986  3840  0.326   0.643  4.91 0.0207 0.0497 0.0245  0.905
       ethylene 2.783   0.338 354  901  3979  0.338   0.645  4.64 0.0210 0.0515 0.0232  0.904
         hexane 3.042   0.362 345  965  3834  0.328   0.643  4.89 0.0210 0.0506 0.0244  0.904
      propylene 2.843   0.341 349  930  3930  0.333   0.644  4.78 0.0212 0.0514 0.0239  0.904
        pentane 3.070   0.346 346  948  3829  0.329   0.643  4.87 0.0213 0.0514 0.0244  0.903
         butane 3.115   0.356 346  937  3821  0.331   0.643  4.86 0.0215 0.0518 0.0243  0.902
        propane 3.177   0.351 347  927  3807  0.332   0.644  4.83 0.0215 0.0521 0.0241  0.902
         ethane 3.298   0.364 349  909  3784  0.335   0.644  4.78 0.0217 0.0525 0.0239  0.902
       cyanogen 0.914   0.299 331 1033  4508  0.314   0.639  5.35 0.0221 0.0518 0.0268  0.899
        methane 3.668   0.356 351  836  3710  0.342   0.644  4.71 0.0231 0.0563 0.0235  0.897
       hydrogen 7.763   0.322 417  419  3738  0.426   0.645  3.34 0.0295 0.0796 0.0167  0.874
  cyanogen-lean 2.178  16.028 295 1073  3900  5.199   0.618  6.97 0.0300 0.0650 0.0349  0.870
  cyanogen-rich 0.156 -23.192 271  972  3900 -4.628   0.595  8.57 0.0432 0.0882 0.0429  0.826
carbon monoxide 0.578   0.166 266  893  3545  0.281   0.590  8.94 0.0497 0.1001 0.0447  0.805


By rank order, the results are pretty much the same as in the 4-km/s case.  However, carbon monoxide and fuel-rich low-temperature cyanogen now produce much lower available mass fractions than do other fuels.  Lean cyanogen might be the way to go as for as ISRU propellants are concerned.  Running lean (i.e., oxygen rich) might limit the lifetime of the propulsion system, though.

Lowering the combustion temperature by diluting cyanogen with CO might be a possibility, though CO's poor performance suggests to me that unless the density of the mixture is high (maybe if that eutectic that Rei mused about exists, or if the solubility of solid cyanogen [which freezes at 245 K, far above CO's boiling point] in CO is high), CO-cyanogen mixtures will perform poorly.

I don't think the toxicities of carbon monoxide and cyanogen are much of an issue.  Nobody's going outside without the equivalent of a hazmat suit (i.e., a spacesuit) anyway.

EDIT:  Corrected T/W calculation to Mars and other miscellaneous changes as in previous post.
« Last Edit: 05/16/2016 03:48 pm by Proponent »

Offline Rei

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Re: Carbon Monoxide for fuel on Mars
« Reply #95 on: 05/12/2016 12:26 pm »
Great work  :)  Just as a note: I know for a fact that CO/CH4 eutectics do exist. 

https://books.google.is/books?id=VC2mKJlHbokC&pg=PA344&lpg=PA344&dq=%22methane%22+%22carbon+monoxide%22+%22eutectic%22&source=bl&ots=Qfr8KT4KA7&sig=pBlLyoayaalBiZ-hUSByR1bjj3g&hl=is&sa=X&redir_esc=y#v=onepage&q=%22methane%22%20%22carbon%20monoxide%22%20%22eutectic%22&f=false

However, I don't know their densities.  As a general rule, the density of a eutectic is higher than the proportional mixture of the two densities.  They also tend to have a wider liquid-state temperature range.

(I would expect CO to be cosoluble with a wide range of hydrocarbons - supercritical CO2 is often used as a hydrocarbon solvent)

I know nothing about cyanogen eutectics.  Given that it's a pseudohalogen, however, I'd expect it to behave similar to halogens.
« Last Edit: 05/12/2016 12:40 pm by Rei »

Offline Robotbeat

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Re: Carbon Monoxide for fuel on Mars
« Reply #96 on: 05/12/2016 02:27 pm »
I was thinking CO-O2 would be an ideal propellant for a SSTO Mars RLV just shuttling cargo up to LMO and back. Not actually for leaving Mars.

Use the right tool for the right job. The low Isp of the CO/O2 propellant combo is actually optimal from an energy standpoint (presuming you get really good mass fraction), which is relevant if you have to produce all that propellant from local power sources.

...but it likely would be a poor fuel for further destinations. Use a CO/O2 shuttle to transport water, hydrolox, or CH4/O2 propellant to orbit. That higher Isp for hydrogen and methane makes more sense the higher up the delta-v tree you get, plus it's not bad from a resource-acquisition standpoint since you'll need a lot less of it than you would for getting all that to LMO.

A CO/O2 SSTO RLV, with 2.5-2.6km/s exhaust velocity, perhaps with initial launch assisted by a rail (to like 0.3-1km/s), would be an incredibly efficient and inexpensive way to get payload to low Mars orbit and back.


...launching water is a good idea since solar power is more plentiful in orbit than on the Martian surface anyway and it is much denser than hydrolox plus much easier to store. Split the water in orbit like we do on ISS.
« Last Edit: 05/12/2016 02:28 pm by Robotbeat »
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Offline Robotbeat

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Re: Carbon Monoxide for fuel on Mars
« Reply #97 on: 05/12/2016 02:30 pm »
Proponent:
Try running the numbers for 4-4.2km/s delta-v. Include the energy needed to electrolyze the propellant (if you want, assume 50% electrolysis efficiency across the board as a simplifying assumption, so multiply the fuel specific energy by 2).
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Offline Proponent

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Re: Carbon Monoxide for fuel on Mars
« Reply #98 on: 05/16/2016 03:56 pm »
In my two preceding posts, I had mistakenly assumed Earth gravity in imposing a take-off thrust-to-weight ratio of 1.3.  I've now corrected the error.  The result is to improve performance, since engines can now be quite a bit lighter.  Although in the 4-km/s case the available mass fraction improves by only about 0.01 for the best-performing fuels, CO improves by about 0.04.

Try running the numbers for 4-4.2km/s delta-v. Include the energy needed to electrolyze the propellant (if you want, assume 50% electrolysis efficiency across the board as a simplifying assumption, so multiply the fuel specific energy by 2).

I'm afraid I don't understand.  Could you please spell out what you have in mind in a little more detail.

PS  I added back in to the tables above a column for mechanical efficiency.  It's the kinetic energy of the vehicle at burn-out, in the launch-site frame, divided by the kinetic energy of the jet, in the vehicle's frame.  You'll note that though CO is the lowest-performing fuel, it does have high (in fact, the highest) mechanical efficiency for 4 km/s, as you've been saying.
« Last Edit: 05/18/2016 03:02 pm by Proponent »

Offline Robotbeat

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Re: Carbon Monoxide for fuel on Mars
« Reply #99 on: 08/18/2016 09:53 pm »
I mean:

Given really good tank and engine mass fraction (adjusted based on the density of the fuel, of course, but I'm assuming a really good effort is made to reduce tankage mass by using state of the art materials):

How much energy does it take to electrolyze the propellant needed to launch 1 ton of cargo into low Mars orbit?

Compare CO/O2 with CH4/O2.

Energy needed to electrolyze CO:
10.1MJ/kg, so double that to 20.2MJ/kg to account for 50% efficiency.

Energy needed to electrolyze CH4:
Hydrogen has 142MJ/kg, and it takes 0.5kg of hydrogen to produce 1kg of CH4 via Sabatier reaction, so 71MJ/kg, double that back to 142MJ/kg to account for 50% efficiency of electrolysis.

So, how much CO (in kg) does it take to put 1000 kg of payload through 4km/s? How much CH4 does it take to put 1000kg of payload through 4km/s?

Multiply that mass of fuel by 20.2MJ/kg and 142MJ/kg, respectively. Which number is the least?
« Last Edit: 08/18/2016 10:03 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

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