We have to jump to Mars from the Moon - Up for discussion, looking for feedback

PLIND · 2004-04-21 06:30:37

Hello Folks,
I have been snooping around various martian topics. I'd like to bounce off an few ideas and see what all of the chemists out there have to say (sorry, no chemist here).
OK, so for a number of reasons I believe we have to spend at least a decade (unfortunately) in the initial stages on the moon. Here's what I would propose.
The moon has to be central (even though I am as impatient to see us head for Mars as anybody) to the first stage
of getting to Mars. With all the discussions surrounding cost, possible overruns etc.
I would suggest that the vast majority of materials have to come from the Moon. Perhaps the very spacecrafts that are going to head out to Mars begin their journey circling the moon, gathering material for fuel, water, possibly other material (manufactured by the lunar pioneers) for radiation protection, whatever? Wickman Spacecraft, for example, have articles that I recently read regarding Lunar fuel (aluminum/LOX) and a Martian rocket based on CO2 and magnesium. These fuels (LOX is the challenge) could be obtained in vast quantities from the moon and mars respectively ([http://www.space-rockets.com/moon1.html]www.space-rockets.com/moon1.html).
After enough material etc is in place on the orbiting spacecraft then the astronauts (based on the moon) start living on the spacecraft (still circling above the moon surface) to confirm that all of the essentials are available for an extended journey. One, maybe two, years later the bugs are ironed out and the craft is ready to leave orbit and head for Mars. At that point there should be ample confidence and experience to expect a successful trip. By this time the astronauts have been living on the craft for more then a year, a six or eight month journey to Mars would not be all that much more demanding then what they've already been through.?? Because the Mars rockets uses CO2 the amount of material that has to be carted to Mars is much less. To further mitigate failure I would also suggest sending off one or two storage type crafts during the moon phase so that they would be onsite (orbiting Mars, perhaps a landing craft is manufacturing the new fuel etc) with ample supplies.

I see the biggest concern of all as the survival of the astronauts from radiation? That's another discussion.

I do not see why a plan like this could not succeed within 20 years. Now, please go easy on me folks, I am not a chemist just a space exploration enthusiast. What's wrong with this plan?

Look forward to your responses, thanks.

PLIND

GCNRevenger · 2004-04-21 07:16:45

Chemistry wise, an Al/O2 or Mg/CO2 solid rocket engines could theoreticly work, but it probably isn't worth the trouble of making solids on Luna or Mars. Refining of Magnesium or Aluminum metal from their oxides is not that easy on Earth, and would be really hard on Mars due to the temperatures, electrical current, and mechanical processing issues.

There is also the problem of additives, that to take Aluminum oxides and convert them to metal you need sodium hydroxide and a mineral Cryolite, which you'd have to lug along. Processing the metal after its been made would also present difficulties to make it a porus, contiguous solid.

Magnesium presents a similar issue, and the reaction with CO2 isn't very fast, so it would make lousy rocket fuel. There is a solution, to add Iodine as a catalyst to speed reaction, but you'd have to bring this from Earth too and it would present storage concerns (its corrosive, may not withstand radiation).

In either event, even if these methods were accomplished, the engines they would produce would be of low efficency and probably prone to failure compared to conventional liquid or nuclear thermal engines. It makes much more sense to dig up Lunar ice to make hydrogen and oxygen, which would have double the efficency in chemical engines, or to convert Martian CO2 to Methane & O2 using hydrogen brought from Earth.

Doing final assembly of a large ship at the Lunar lagrange point does offer velocity change advantages, but any concieveable Mars ship will probably be built on Earth and launched from here, in which case getting the craft to Lagrange presents a serious payload penalty.

PLIND · 2004-04-21 07:30:13

Thanks for your response.

I understand some of the pitfalls, however, does the fact that the astronauts, engineers etc can easily move from the moon base to an orbiting spacecraft offset some of the additonal challenges. Preparation of the Mars crafts, while they're orbiting above the moon, must provide a number of advantages over assembling and testing a craft in LEO?
For example, it would possible to 'fling' material from the moon to the orbiting craft from the moon, no chance of that from Earth. If the rockets are inefficient, a slow moving rocket headed for Mars (for later rendezvous with an arriving manned craft) orbit powered by inexpensive Lunar material may help solve some of the budget problems?

Does that sound reasonable?

PLIND

GCNRevenger · 2004-04-21 07:36:10

In the long run, mining Luna for hydrogen and oxygen fuels might be worthwhile, but for the time being Lunar construction doesn't make alot of sense.

One of the advantages that Earth has is an atmosphere that can be used to aerobrake during reentry, saving on fuel, but on the Moon you have to bring fuel to decelerate all the way from orbit... one of the most complicated issues with Apollo was making the Lunar Module super-duper light weight... it was little more than an aluminum foil balloon with a pair of rockets on the bottom, not even bringing shock absorbers.

Earth orbit assembly also avoids the large payload penalty compared to Lunar orbit assembly... the huge Saturn-V rocket could deliver about double the mass of the Command/Service/Lunar module to Earth orbit versus Lunar orbit, which negates most of the advantage of Lunar surface launch.

PLIND · 2004-04-21 07:52:32

OK, I'll concede that, as far as economics goes, we don't gain that much. However, what about the experience of living on the moon surface, obtaining and utilizing surface material in preparation for what will take place on Mars?
The moon would be the Mars test bed. The Lunar pioneers would have to overcome and deal with the majority of challenges that the Martian pioneers will have to deal with. As part of that they need to have goals, tasks, achievements. Perfecting a fuel developed from Lunar material plus,radiation protection etc, plus other essentials might be what is needed?

Plus, what about the fact that material could be 'fired' up to the orbiting craft as opposed to launched from Earth?

PLIND

GCNRevenger · 2004-04-21 07:57:43

Well, plenty would argue that the Moon and Mars are so different, that such testing on the Moon would be useless... Mars has double the gravity, more stable temperatures, more air pressure, different chemistry, etc etc... I think that it might be somewhat useful, but overall that appeal is pretty limited. You can't test Zubrin's Sabatier reactors on the Moon for instance.

Launching stuff from the Moon by way of railgun is a long, long way off... the gun and its power source would have to be pretty huge, and you couldn't launch anything the least bit fragile. Then there is the question, why? Weighing down a Mars ship with Lunar soil as a radiation shield doesn't work as well as a Borated Polyethylene/Water shield, and you want vehicle mass to be as low as possible. Signifigant quantities of fuel won't be available from the Moon any time soon either.

PLIND · 2004-04-21 09:08:48

Thanks, good information.

Now I'm convinced. Back to the drawing board.

PLIND

clark · 2004-04-21 09:14:11

Sorry to take this off topic... but it does pertain a *little* to the subject at hand.

How difficult would it be to build something akin to a space elevator on the moon?

It wouldn't neccessarily need to be as strong as an Earth rated space elevator, so perhaps we could do something like that... but then, the moon dosen't rotate, right? So perhaps it just won't work.

Just a shot in the dark at the moon.

GCNRevenger · 2004-04-21 09:23:06

Welll you can't, because the Moon doesn't have a geostationary orbit. It spins far too slowly.

clark · 2004-04-21 11:54:58

Look, I just can't be bothered with things like orbital mechanics. Okay?!

Oh well.

PLIND can go back to the drawing board, I think I'll just stick to drawing.

Poorly drawn stick figures on the moon? Proof positive it can be done, in my book!

RobertDyck · 2004-04-21 12:40:30

If you read the referenced article you will see that John Wickman actually got a contract from NASA to develop his idea. Click on his link for Lunar Soil Propellant, or [http://www.space-rockets.com/lsp.html]this link. He produced a liquid monopropellant that uses aluminum powder suspended in liquid oxygen. The rocket engine was tested and worked without flashback into the propellant tank. With fuel pre-mixed with oxygen in a single tank, you want to ensure the engine won't flashback. This is a great idea and absolutely necessary for any Lunar operation. It permits In-Situ Propellant Production (ISPP) on the Moon. However, his article does not mention specific impulse (Isp). I suspect it is significantly lower than LH2/LOX, and may be lower than methane/LOX.

Furthermore, the delta-V required for trans-Mars injection is not much more than trans-Lunar injection. As Robert Zubrin stated in his book "The Case for Mars", starting from Earth and entering a parking orbit around the Moon would actually require more fuel than direct through to Mars. This is due to aerocapture at Mars. The Moon doesn't have an atmosphere so aerocapture is not possible. So making fuel on the Moon would actually require more fuel sent from Earth than directly going to Mars.

There are things you can do on the Moon, and Lunar ISPP would make those things much more affordable. For one, you can test Mars equipment on the Moon where return to Earth would only take 3 days and is possible any time; you don't have to wait for the planets to line up. However, don't expect a mission to Mars to stop at the Moon along the way.

Getting back to chemistry, the last month I have been investigating a way to get aluminum from anorthite. On Earth we get aluminum from bauxite, but that is produced by the ecology of a tropical rainforest; you won't find any bauxite on the Moon or Mars. A rock of pure anorthite was included in the samples Apollo brought back from the Moon. Some of the soil on Mars is also anorthite, which is a constituent of feldspar. Most of Martian feldspar is albite, which is more difficult to smelt, but anorthite is a start. The process starts with hydrochloric acid dissolving it into aqueous calcium, aluminum, and silica. The next step I'm still working on; there are two options. One is to add sodium hydroxide, which is the first step in processing bauxite, then follow the rest of the traditional method to smelt aluminum. The other is to "some how" get calcium and silica out of solution, then use multi-cell electrolysis to convert aluminum chloride into aluminum and chlorine gas. This second method has the advantage that you don't need cryolite, but I haven't figured out how to get calcium and silica out of solution.

This works with anorthite because the 1:1 ratio of aluminum to silica leaves silicon-oxygen tetrahedra isolated. Albite has a 1:3 ratio of aluminum to silica, so the silica tends to form a thin film of glass on the mineral grains, which stops acid. That means hydrochloric acid will etch albite, but stops once it has dissolved a layer as thin as a soap bubble.

Notice the first step of extracting aluminum from anorthite involves hydrochloric acid. Mars has hydrogen and chlorine in its soil (water and salt), but the Moon doesn't. Supplies for Lunar aluminum extraction would have to be brought from Earth.

Bill White · 2004-04-21 12:47:38

Notice the first step of extracting aluminum from anorthite involves hydrochloric acid. Mars has hydrogen and chlorine in its soil (water and salt), but the Moon doesn't. Supplies for Lunar aluminum extraction would have to be brought from Earth.

Therefore, Mars can export hydrochloric acid to Luna and charge (at a minimum) the per pound transportation costs for Earth to Luna delivery, correct?

If a Mars settlement could manufacture any primitive lift whatsoever, virtually all of the revenue from selling hydrochloric acid on Luna could be contributed to the costs of building this Mars settlement.

One of the points from Zubrin's Case for Mars that most impressed me was the observation that a Mars settlement makes lunar resource utilization easier.

Bill White · 2004-04-21 13:04:07

For extraction of aluminium and magnesium in an inexpensive fashion, perhaps [http://www.ejbiotechnology.info/content … e3/full/6/]this technology can be considered. Props are due to BGD for bringing this to my attention. (See New Discoveries thread for a Christian Science Monitor link.)

Yet since magnesium dissolves in CO2, supercritical CO2 should be useful for mining and extracting relatively pure magnesium, correct?

Chemists! Calling our chemists!

Shovel Mars regolith into a reaction chamber. Flood with supercritical C02. Extract the scCO2 with the dissolved magensium and transfer to a new reaction chamber. Reduce the pressure so the CO2 returns to a gaseous state.

Won't pure magnesium then fall to the floor of the reaction chamber? What am I missing, being the history major that I am? :;):

Here is a link concerning [http://reaflow.iwr.uni-heidelberg.de/~i … 00/228.pdf]magnesium combustion in CO2.

= = =

Years ago I answered a web forum poll about what skills would be most useful on the first Mars mission. CHEMIST was at the top of my list for reasons such as the above.

That and the electric tornados that are now predicted for Mars.

Euler · 2004-04-21 13:46:10

How difficult would it be to build something akin to a space elevator on the moon?

Welll you can't, because the Moon doesn't have a geostationary orbit. It spins far too slowly.

Actually the Earth is at the geostationary orbit of the moon. The easiest way to build an elevator on the moon is to build it straight towards Earth. A few years ago I did some calculations on the feasibility of such an elevator, and I think the results were that the lunar elevator would be longer than an Earth elevator, but the required strength would be lower.

Rxke · 2004-04-21 14:11:12

too lazy to look it up (it is on my computer, but where oh where...), but it would be harder to build a cable on the moon than on Earth (rotation blablablah...)

On the other hand, It would be *easier* to do on Mars, compared to earth, so 'liftpeople' see Mars as the logical next step...

You can probably pull the numbers from the liftwatch.org site, i guess...

Euler · 2004-04-21 14:49:28

The Moon-L1 distance is about 61,500 km, or a little less than twice the Earth-GEO distance. However, since the moon has 1/6 Earth's gravity, the required strength would be less (as I said). Mars would be easier than Earth or the Moon.

GCNRevenger · 2004-04-21 16:19:48

L1 isn't the most stable of locations though... it tends to move around a little bit, and would probably be bad news for the cable, carbon nanotubes are kinda brittle off of their long axis.

Mixing powderd aluminum or magnesium with LOX? ARGH! And you thought solid rocket boosters were hazardous!

There isn't that much Magnesium metal in the Martian soil if memory serves, you've have to convert it to the metal first somehow (smelting). Another problem with using supercrit CO2 to solvent separate Magnesium would be it would probably disolve other things you don't want, adding impurities.

Removing calcium and silicon ions from solution wouldn't be easy for Lunar Al/LOX fuel either... the only ways that come to mind would be a selective membrane seperation (very slow) or perhaps chelating, which would take alot of material from Earth to try and remove. Wouldn't work very well on Silicon either I don't think, and may kill the yeild of the Magnesium.

RobertDyck · 2004-04-22 01:04:09

Hmmm, hydrochloric acid is a strong acid, although the paper I have on dissolving anorthite describes it using pH 2.4 to 3.2.

Sodium hydroxide (also known as caustic soda) is an alkali. Blowing CO2 through solution will create carbonic acid (H+ and CO3-). An acid will neutralize an alkali. That neutralization causes aluminum hydroxide to precipitate out leaving silica in solution, and iron oxide from bauxite doesn't dissolve in caustic soda. So the precipitate is aluminum hydroxide with some caustic soda, which can be washed away with water. Aluminum hydroxide is baked to form alumina.

Hydrochloric acid is H+ and Cl- ions in water. Sodium hydroxide is Na+ and OH- ions in water. NaCl is salt, H+ and OH- are water, so that means hydrochloric acid and sodium hydroxide are as opposite as it's possible to get. Adding caustic soda to hydrochloric acid would neutralize the pH. But blowing CO2 through caustic soda reduces the alkali strength of caustic soda, so would reducing the strength of hydrochloric acid cause aluminum hydroxide to precipitate out of solution while silica remains dissolved? Chlorine is a stronger negative ion than hydroxyl so aluminum would precipitate as a hydroxide, not chloride. We would want a neutralizing agent that precipitates out as gas rather than solid, just as carbonic acid breaks down into CO2 gas. We don't want to contaminate the aluminum compound with another solid. Would adding ammonia do the trick? When NH3 dissolves in water it becomes ammonium hydroxide (NH4+ and OH-). Calcium is a stronger postive ion than aluminum so aluminum should precipitate out first, but will calcium remain completely in solution while only aluminum hydroxide precipitates?

Oh, Mars has 2.7% atmospheric nitrogen so we could make ammonia. The Moon doesn't have any detected source of nitrogen.

Mundaka · 2004-04-22 03:46:40

idiom · 2004-04-22 04:15:33

I find its all a little bit gooey actually.

The fuel taken to decelerate all the way to the surface of the moon is < or > the fuel needed to accelerate extra provisions plus extra manouvering requirements plus plus plus.

The person who sets the conditions sets the outcome.

Zubrin argues:
surface of the earth to the surface of Mars is < Surface-Earth to surface-luna

Artemis Argues that:

Earth-orbit to moon-orbit to earth-orbit < Earth-orbit to Mars-orbit

It is comparing Apples to lemons. Who wants to orbit the moon?

We designed our Lunar Transfer Vehicle to fly from Earth orbit to lunar orbit and back again.

We're not landing; this mission is just to get a close-up look at the red planet with real human eyeballs.

The odd thing, the really bizzare, screwy thing, the really really really dumb thing is this:

Even when comparing orbit to orbit transfers Artemis admits that the delta V to mars is less!!! Theyjust argue that their toy "ltv" would be really really dumb to go in.

If we assume that our crewmembers ... don't mind being cooped up in a vehicle suited for a three-day trip to the moon ... then it really does take less fuel to get to Mars!

I just don't get the lure of the moon.

Personally I would volunteer for a direct one-way trip to mars.

GCNRevenger · 2004-04-22 07:51:23

A few problems with such a method of making aluminum metal...

It isn't very efficent to electrolyze Aluminum Hydroxide in the first place, the Chloride is much more practical. Reclaiming Chloride from NaCl would be hugely expensive energy wise... The thing to do would be to disolve the Aluminum ore in NaOH with heat and then mix it with Calcium Chloride to render Calcium Hydroxide which is only somewhat soluble and Aluminum Chloride which you can electrolyze. Seperation through filtration would be difficult but maybe not impossible.

Mix the resulting Chlorine gas with water to make HCl and then use that to reclaim the CaCl2.

The thing i'm not sure about is how efficent the CaCl2 + Al(OH)3 reaction would be... borrowing a trick from Magnesium refining.

Using carbonic acid to neutralize isn't that practical because you need water to produce the acid which cannot be reclaimed directly through the cycle, CO2 + H2O makes CO3 (-2) anions which will bind to the Calcium which is pretty insoluble, you don't get that back without disolving it in another acid (HCl).

NH3 isn't practical because it may go and form a complex with the Aluminum, which would make it difficult to work with with.

Edit: Though the dissolusion of the aluminum in Hydroxide would may also be an unrecoverable water binding reaction, unless you want to try making your own HCl through gas reaction... In any event, if you have this much water, you might as well turn it into hydrogen and oxygen fuel directly.

RobertDyck · 2004-04-22 08:19:29

Interesting GCNRevenger, I'll have to think about all that for a while. But I do want to point out that the usual method for extracting aluminum from bauxite produces aluminum hydroxide as an intermediate step.

It dissolves silica and alumina in sodium hydroxide (caustic soda), but not iron oxide. Iron oxide remains with the mud, and the liquid is drawn off. Then CO2 is "blown through", which dissolves to create carbonic acid and neutralize the alkali. That causes aluminum hydroxide to precipitate out. The aluminum hydroxide is collected and "washed" with water to collect sodium hydroxide to be recycled. The pure aluminum hydroxide is then "calcinated", which means it is heated so that water boils and oxygen from air combines with hydrogen from aluminum hydroxide to form water vapour, leaving pure aluminum oxide (alumina).

RobertDyck · 2004-04-22 08:25:52

The Artemis web site has a lot of useful information in its Data Book. However, their primary claim that it is easier to get to the Moon than Mars is based on the short trip: you can use a capsule with 3 days life support rather than a habitat with 6 months of life suport and a propper bathroom with a toilet. All that takes fuel to get it off Earth. Good point, however it still means it takes less fuel to go to Mars directly than using the Moon as a stopping point to get to Mars.

nirgal2002 · 2004-04-30 12:30:31

While the idea is nice in theory and seems to be doable on the surface, there are some major problems with this approach. I'll outline two below.

1. Cost
Using the moon as a launch point to Mars is inordantley expensive. The amazing costs involved in just launching the needed materials to get started on the moon with this type of infrastructure is amazing. What would be required are facilities for processing the insitu materials, facilities for storage, equipment for processing and utilization of materials, regular launches for consumables (food, air, water, etc.), large workforce (depending on if you wanted to produce items quickly or not), facilities for the workforce to live and work, vehicles to be used to collect materials, mining equipment, storm shelter for all personnel, etc. This adds up very fast. If we did it, it would force world governments to add space as an important domestic issue, but the startup costs would be enormous.

2. Time
This would be the equivalent of transplanting an aerospace plant from Earth to the Moon. Not by just moving it as one piece, but one small piece at a time. Once moved, it then has to be put together, but all resources (fuels, food, etc) would have to be brought up as well. No country has the political foresight to do this type of undertaking over the amount of time it will take.

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