Transterrestrial Musings

Comments

I think the moon has the potential of becoming a tourist destination and NASA can help the process along. Mars won't add anything to commercial space development, it will just be a scientists sandbox until we build fusion drives to get us there in less than a month. I don't see how any government program could maintain funding for a series of manned Mars missions based solely on the science-only approach to space.

Posted by B.Brewer at November 18, 2004 11:03 AM

This is an ideal topic thread to discuss "why" we have any space program at all. Why not just cancel NASA outright?

And to address my pet peeve that George Bush fashioned a space vision behind closed doors and announced it as "America's plan" before Congress fully funded it anyway.

> Big grin

Posted by Bill White at November 18, 2004 11:06 AM

Gee, Rand, you actually had to state what you posted? Are you sure you were talking to genuine homo sapiens and not just an unwitting participant in some high-school student's PHP script's attempt to pass the Turing Test?

Posted by Carl Pham at November 18, 2004 11:27 AM

And to address my pet peeve that George Bush fashioned a space vision behind closed doors and announced it as "America's plan" before Congress fully funded it anyway.

You mean the way John F. Kennedy did?

Bill, does George Bush ever do anything right? Or are the things he does wrong just wrong because it's him doing them?

Posted by Rand Simberg at November 18, 2004 11:30 AM

Why not just cancel NASA outright?

We have a space program because there is more to life than just living. It's there to make us all gasp with astonishment from time to time, to make us speechless with admiration for the talent, energy and courage of our pioneers.

It's there to remind us that, as a nation, we are capable of great and glorious things, and that we yield to none when it comes to our belief that American ways of thought will dominate the future of the planet for the next thousand years, that even if America is gone in 3100 AD they will talk about us with the same awe and respect we use when we talk about the ancient Greeks and Romans.

Why do these things matter? Because social myths matter, because self-respect and self-esteem matters, because how you act as a person depends, to some extent, on how you feel about your identity as an American citizen. If you feel you're part of a great nation, optimistic, outward-looking, bold, confident -- then you stand a little taller and work a little better yourself. In short, you act like a winner with big plans for your winnings.

If, on the other hand, you feel you're part of a scaredy-cat worry-wart nation that wants nothing more than to feel everybody's pain, including that of hypochondriacs and crazed murderers, then you stoop a little more, look over your shoulder more, and buy extra chains for your door. In short, you act like a loser hoping to minimize his losses.

That's why, personally, I don't give a damn if there is no scientific, technological or economic argument whatsoever in favor of sending men out into the cosmos to look around.

Although I'm actually willing to believe that the economic benefit to the United States of, for example, the Mars rovers was way more than they cost. What benefit? The benefit that the pride and glow of accomplishment brought to 300 million Americans, and the effect it had on 5.5 billion non-Americans. It made some damn clever physicist in China sit up straight in her chair and say: that's it, I'm emigrating -- that's a country with possibilities. It let a businessman fund a tech venture at a slightly lower interest rate, because both he and the bank felt more confident about America's tech future. It made a high-school student buckle down to study for his next algebra exam, because by God working for JPL looked like something fun to do for a living.

In millions of daily economic decisions, millions of American economic decision-makers felt a little more optimistic and bold -- and almost nothing is more relevant to our overall economic success than our collective confidence and enthusiasm.

Posted by Carl Pham at November 18, 2004 11:45 AM

George Bush fashioned a space vision behind closed doors and announced it as "America's plan" before Congress fully funded it anyway.

That's his job. He's our President, remember? We elected him to lead, to come up with new ideas, to stake out a position for the country. If we only needed a robot to poll Congress and/or the public and summarize the results in one convenient place, we could just program a Linux box to do it and post the results on a blog. Lots cheaper. No danger of actual human inspiration or thought muddying the waters.

We had our chance to reject the President's leadership on November 2. You know the results.

Fortunately, that also means you've now got four more years to try to convince a majority he's out of his mind and we should try some other style of leadership. But I suggest you do not begin by decrying the very notion of leadership itself.

Posted by Carl Pham at November 18, 2004 11:53 AM

Hee! Hee! I knew that would kick over the hornet's nest.

Two issues:

(1) Today's NASA is too timid, too risk adverse to ever actually go anywhere anyway; and

(2) If the CEV contract is given to the usual big aerospace contractors, the program will be too expensive to be sustainable.

Result? When NASA finally sends its CEV to the Moon, Sir Richard Branson will already be there lighting up a billboard to guide the landing.

= = =

Can Bush to anything right? Sure.

By declaring that going beyond LEO is a worthwhile thing to do, he helps open the door for non-NASA players, and offers at least some symbolic support.

If Bush were to support BIG prizes, that would be better. Offer to add $250 million to Bigelow's prize fund.

I would praise that big time.

Posted by Bill White at November 18, 2004 12:10 PM

The sky just fell. I think Bill and I agree on something.

Posted by Dave Allen at November 18, 2004 12:50 PM

No argument here, Bill.

Posted by Carl Pham at November 18, 2004 01:06 PM

On the topic of fuel for a Mars trip, does it have to be water? Have any studies been done regarding the feasibility of using iron pellets and a very long rail gun? Iron is, IIRC, quite abundant on the Moon, and water in space is something you don't really want to just spew away.

Posted by Jason Bontrager at November 18, 2004 01:09 PM

When NASA finally sends its CEV to the Moon, Sir Richard Branson will already be there lighting up a billboard to guide the landing.

I think that's very likely to happen. I wonder if Branson would charge 10x higher price for a NASA astronaut to stay at his hotel? ;)

Posted by B.Brewer at November 18, 2004 01:13 PM

Drats! This agreement stuff is boring.

Lets try another. As launch costs fall, the value of lunar fuel (whether shipped to L1 or LEO) will also fall.

True low cost Earth to LEO access might well make it cheaper and easier to ship a bucket of Lake Michigan water to LEO than digging water out of some lunar cold trap or regolith and sending it to LEO or L1.

Mining in situ lunar oxygen is a terrific idea for travel from the Moon to Earth. Skip the lunar orbit rendevouz nonsense. Send a ship to the Moon with methane, LH2 or even kerosene (a joke, that last one) and mine lunar O2 for the return flight. I support that 100%

= = =

But is there anything on the Moon that can be mined, at a profit?

Posted by Bill White at November 18, 2004 01:47 PM

Mmmm, but if the cost to launch out of Earth's gravity well falls, won't the cost to launch out of the Moon's gravity well fall as well? Thus preserving the lunar advantage?

Here's a scenario for lunar enthusiasts. Say it becomes possible to grow very nice carbon nanotube materials from which to build a skyhook on Earth, something that will really bring down the cost of LEO access.

But say the nanotubes are hard to grow sufficiently pure except slowly, under low gravity, and in a cold vacuum. (Purity is a reasonable key criterion because almost all materials derive their ultimate strength from their density of molecular-scale defects. The requirement of high vacuum, low gravity and cold temperature are plausible if you think of some kind of chemical vapor deposition approach.) Say also that a major cost of building the skyhook is transporting the huge tonnage of the cable to geostationary orbit. Remind ourselves that delta-V from lunar surface to geostationary is much less than from Earth's surface, and that carbon is one of the most common elements in crustal rocks, e.g. on the Moon.

Under these conditions it might make very sound economic sense to ship a factory for making nanostuff to the Moon, let it pull raw materials from the regolith, work without the need for a big expensive tank to get very good vacuum and very low temperatures, and ship the nanostuff to geostationary orbit, there to be assembled.

Oh, and if the industry really gets going, and with the skyhook built, you might as well keep going and use the nanostuff to build engineering marvels like indestructable buildings, car engines that don't need cooling, materials that can easily stand up to the thermal stress of hypersonic flight, or a bridge across the Strait of Gibraltar. . .

Posted by Carl Pham at November 18, 2004 02:19 PM

"On the topic of fuel for a Mars trip, does it have to be water?"

No, i believe abundant aluminium on the moon will make for some nice deep space boosters.
The hydrogen, if its there in accessible form at all, will be better used for local water and chemical agent in regolith processing.

Posted by kert at November 18, 2004 02:46 PM

Carl, now I agree with you. Uh oh. . . ;-)

Remind ourselves that delta-V from lunar surface to geostationary is much less than from Earth's surface, and that carbon is one of the most common elements in crustal rocks, e.g. on the Moon.

It's all in the bean counting. Sadly, accountants will remain with us even as we become space-faring. I very much desire that there to be a way to make money on the Moon, but it has to be realistic.

Look guys, going back to the Moon is waaay cool. I have no problem with that whatsoever.

But I do not want NASA to focus on the Moon based on a "spend billions and money will surely be made. . ." attitude. Profitable lunar mining is not a sure thing no matter how much I may wish it were true.

Also the Moon also is NOT a steppingstone to Mars, except in a very tangential sense. There is an old Jewish saying about practice and marriage I won't repeat here.

By the way, civil-sevants doing science on Mars is absolutely NOT my vision either so I hope we can agree on that as well.

I am a Mars-guy because I believe it will be easier to bear and raise children on Mars and because Mars has less strategic value for future Terran conflicts, meaning Mars settlers are less likely to be sucked up into future Terran wars.

The asteroids are even better for folks who want to escape the Terran radar screens but that may be too big a jump all at once.

Believe it or not, I do have strong libertarian impulses. I merely believe there are a couple of billion humans too many to implement effective libertarian policies here on Earth.

Posted by Bill White at November 18, 2004 02:49 PM

I always believed that if we engage in large scale commercialization on the moon that materials mined on the moon would be used on the moon for hotels,reactors,Taco Bells, etc. ....

Moon based industries would use lunar resources, but there could be some exotic properties of materials manufactured on the moon that would have use throughout cis-lunar space such as titanium-strength glass.

Posted by B.Brewer at November 18, 2004 02:54 PM

Carl, Bill -- did the earth just go into retrograde orbit or something?

Posted by McGehee at November 18, 2004 03:27 PM

Think chemistry, my friends. Living at the bottom of an inexhaustible pool of powerful oxidizer is nifty if you're a combustion-powered machine, but a drag if you want to do any other kind of chemistry. Indeed, the whole of what we understand about the possible chemistry of things is constrained by the fact that nearly all of our experiments have been done in a 21% O_2 soup. That's a little like trying to study orchids by growing them in the middle of the Third Battle of Ypres.

Also, materials chemistry is unbelievably important to modern technology. Let's just name three wonderful inventions that await only the correct solution to a problem in materials chemistry: the artificial heart (need a flexible surface that doesn't throw off clots), the interactive book (need to get those flexible LED surfaces working), and routinely safe Earth atmosphere re-entry (need a non-brittle refractory material).

All I'm saying is, don't forget there's more to fancy technology than physics and engineering.

Posted by Carl Pham at November 18, 2004 03:38 PM

It's MoonMars. One word, not two. ;-)

Rick Tumlinson does some marvelous stand-up comedy using this phrase.

Anyway Carl, I agree with you again! The Moon is a terrific place for chemical processing for precisely the reasons you give. Lunar factories have tremendous potential.

Likewise, Mars is a terrific place to build greenhouses and mine water to support exploration of the asteroids and to grow human populations settled on Mars.

Shipping Mars-grown food to Luna takes less delta V than shipping Earth grown food to Luna. Freeze dried tilapia and tofu anyone?

Carbon, Hydrogen, Nitrogen and Oxygen (CHONs) are easily harvested on Mars, no rocks to smelt, just suck in the atmosphere and process or heat water laden regolith.

= = =

Paul Spudis says we need decades of practice on the Moon before we dare travel to Mars.

I say NO! Do we argue or agree.

NASA, of course, will likely prove too timid to do either.

Posted by Bill White at November 18, 2004 04:06 PM

How realistic is mining the moon for fuel? Are typical surface rocks oxygen bearing? How many solar panels to generate a decent amount of fuel in 6 months via a brute force/low equipment method? Getting aluminum from bauxite is very energy intensive - but once done Al + O2 sounds fine to me. Yes?

At least a half-inch of pre-ground material most everywhere... oxygen-bearing? Skipping a grinder/crusher/etc step could skip some of the heaviest equipment for some routes.

Posted by Al at November 18, 2004 04:57 PM

You might want to look here:

It's a bit long, but it covers a lot of your questions. There's also a little salesmanship on my part. I believe the courts refer to it as "puffery".

You might want to also check out some of the reference materials found at the Lunar Bibliography here:

http://www.space-frontier.org/cgi-bin/BBS/MoonBase/read/5098

Wow, July. It's really in need of an update as there've been a lot of additions to the Lunar Library. I'll have to get on that...

Posted by ken murphy at November 18, 2004 05:42 PM

How realistic is mining the moon for fuel?

Depends what you mean by "fuel." Really, we should distinguish between energy and reaction mass (the stuff you throw out the back to get a rocket effect). There are a lot of models for rockets, so you need to specify what you're thinking of. The engineering trade-offs are not my strong point, so I'll address only the thermodynamics and chemistry

Arguably in deep space (I'm told) it's best to get your energy from the Sun or a nuke (or fusion pile if you can find one in the catalog), and pick up your reaction mass anywhere you can. In which case I think pretty much any old Moon rock will do the job.

But historically when we want energy we've looked for it in chemical reactions. Combustion (something + O_2) reactions tend to dominate our thinking, for two reasons: first, we live, as I said, at the bottom of a huge pool of oxygen, so we get that reactant for free. Second, we share the planet with creatures who specialize in the whole-scale reduction (opposite of oxidation) of carbon and hydrogen, namely plants, and so we've made use of their reduced products (wood, coal, oil, gas) to provide the other reactant also for free.

We tend not to use free reactants for rockets, however. The SSME, for example, uses liquid H_2 and O_2. The H_2 must be chemically generated and the O_2 liquified, both at far greater energy cost than the energy used by the Shuttle. That is, thermodynamically we use the H_2 and O_2 not so much as an energy source so much as an efficient energy storage system, a battery, so to speak. The battery is "charged" when some factory liquifies the O_2 and makes the H_2 from water or sulfuric acid. The SSME "discharges" the battery to climb to orbit.

In principle the same idea works in space. You pick up your energy from some efficient source, e.g. the Sun shining on acres of Moonscape, or a few hundred kilos of plutonium. Then you use the energy to manufacture some highly energetic reactants out of whatever materials you have at hand. This chemically "charges the battery." Then your rocket lights up the reaction and away you go.

It is not necessary to use oxygen as one of the reactants. There other high-energy reactions. You have to think of what starting materials are available and what kind of chemistry is convenient -- and, as I've said, with no oxygen to worry about, it may be that what's chemically convenient on the Moon differs from what's chemically convenient down here.

Oxygen or at least an oxygen-containing compound is, however, likely, since O is a very common element in rocks such as those on the Moon, is one of the most reactive of the common elements and, of course, has a thoroughly understood chemistry.

Posted by Carl Pham at November 18, 2004 06:28 PM

The use of the Moon as a way point to Mars is altogether fuelish.

By way of comparison let's take a single kilogram of payload to Mars from low earth orbit(LEO) in two ways:

1) throw directly from LEO to Mars and aerobrake to land, you'll need about 6 kilograms of mass in LEO.

2) take your rocket from LEO to Moon, land it, fuel up again (using ONLY Lunar material), then throw your 1 kilogram payload to Mars -- now you will need almost 20 kilograms of mass in LEO to make the trip.

Going to the Moon is perhaps worthwhile, but it's definitely not the best path to Mars.

Posted by robert terry at November 18, 2004 07:27 PM

I'm wondering, Robert Terry, why one would want to flaunt an inability to comprehend written English on the World Wide Web.

Do you have zero realization that you are simply repeating the idiotic false strawman that it was the purpose of this post to refute?

Posted by Rand Simberg at November 18, 2004 07:30 PM

The use of the Moon as a way point to Mars is altogether fuelish.

Whoa. They're stalking you, Rand.

Posted by Carl Pham at November 18, 2004 07:40 PM

TERRY: "take your rocket from LEO to Moon, land it, fuel up again (using ONLY Lunar material), then throw your 1 kilogram payload to Mars -- now you will need almost 20 kilograms of mass in LEO to make the trip."

DUH how about throwing the fuel off of the Moon (tethers, electromagnetic launchers - whatever) to a point where your Mars ship can catch it - without landing on the Moon?

You Zubrinites are hell bent to come up with a variant of this faux "Cape Canaveral on the moon" argument that Zubrin imagined at every opportunity just to be difficult, now aren't you?

Posted by Keith Cowing at November 18, 2004 08:15 PM

Rand, take a wild guess.

How long must we practice on the Moon before being ready for Mars? Since we agree using the Moon as a fuel depot is foolish.

;-)

Posted by Bill White at November 18, 2004 08:19 PM

How long must we practice on the Moon before being ready for Mars?

Mmmm, two questions here. . .

1) Isn't the reason to practise on the Moon because it will prove out much of what is still unknown about how to correctly go to Mars? That is, I would have thought a major argument for practising on the Moon is exactly that we don't know enough to answer your question.

2) Is it necessary that the two be in strict sequence? Can't they overlap?

Posted by Carl Pham at November 18, 2004 08:32 PM

Since we agree using the Moon as a fuel depot is foolish.

Gee, did I miss the post or comment in which I agreed with such a moronic and unsupported assertion?

Posted by Rand Simberg at November 18, 2004 08:33 PM

Thanks ken, Carl.

The 'sun as the energy source' part I was assuming already. And the part of the 'moon first' approach that may make sense to me is if there's an honest effort to not just refuel one Mars mission, but make a moon-dust+sunlight=fueling station. Landing optional.

I haven't made it through the twenty page thread ken, but the first couple didn't seem to address: Is moon dust a decent percentage of aluminum oxides? I
m a chemical engineer, but not sufficiently versed in lunar geology to determine for myself what _I_'d do given the task 'make fuel on the moon, go.' Starting from there I'd be looking at a whole ship filled with solar panels + the smallest aluminum ore to aluminum + oxygen chemical reactor setup I could arrange. Other oxygen based ores -> other reactors. But the _dust_ seems at first glance to be by far the best source of materials. (And anything reversing the thermite reaction would store... lots of energy.)

If there's a fuel processing plant established on the moon, and it _does_ take 20x the amount of fuel... then we just better have 20x the number of missions. Running out of just the darn dust should take quite a while. And adding a crusher/grinder wouldn't be a major issue... if we'd already exhausted the dust :)

Posted by Al at November 18, 2004 08:36 PM

Carl Pham, you have given me an intelligent and plausible answer without personal insult.

Thank you.

Okay, I agree. We need to get back to the Moon to learn what we don't know. Fair enough.

Okay then, lets get this show on the road.

Posted by Bill White at November 18, 2004 08:39 PM

PS: Carl Pham I also like your overlap idea.

I have been a Zubrin guy but I am thinking maybe about switching to Tumlinson, you know, "MoonMars" is one word, not two words.

Posted by Bill White at November 18, 2004 08:45 PM

Starting from there I'd be looking at a whole ship filled with solar panels. .

Why drag along all that hardware and do electrochemistry? Let's just do the chemistry directly, either with greenhouse heating or photochemically. The Moon is drenched in the entire Solar spectrum at power densities as high or higher (especially at UV and higher frequencies) than the Earth. Plus the conditions for doing photochemistry are ideal -- no clouds, no atmosphere, 720 hours straight of blazing rock-stable high-UV sunlight each day.

So you need windows. Now, it's going to take creativity to get good reaction rates without solvent, so maybe think about very large volume, low pressure reaction conditions and do it in a giant 15-story 10-acre plastic bubble, because you don't need any support structure -- in a vacuum and under 1/6 gee the thing just inflates itself. And screw the 10x safety factor, no one cares about Bhopal on the Moon.

The little I know says the Moon's chemical composition is essentially the same as the Earth's crust, possibly enriched a little in some of the heavier iron series 'cause of all the lava flow in the maria. Maybe organic-origin stuff like CaCO_3 is going to be depleted.

Posted by Carl Pham at November 18, 2004 10:15 PM

I started on the solar panels because the terrestrial method of making Aluminum doesn't involve baking, it involve boatloads of DC current. Making power some other way would be fine too.

Google turned up this:
http://www.sciforums.com/archive/index.php/t-1198

Which has soil composition estimates. The areas high in alumina would be my personal choice - but I think his chemistry has issues. (Al2O3 is quite stable near 2000 K, 'burning off the oxygen' is not happening)

The key terrestrial technique is explained here:
http://www.rocksandminerals.com/aluminum/process.htm

Not a simple process - but it wasn't designed with a massive 'free' temperature shift in mind either. A 350 C swing in temperature completely flips the normal concerns of making a chemical plant - getting rid of waste heat and not spending too much on actively heating. How the power is generated seems the least of the worries.

Posted by Al at November 18, 2004 10:54 PM

I find that the space program is an excellent litmus test of intelligence. Most people that know the history behind it understand how important it has been for our technological development. People that argue for the cessation of manned space exploration should, for example, be forced to give up their microwaves. And their cell phones. And their computers.

Posted by Greg M. at November 18, 2004 11:01 PM

Al, thanks to your prodding I've thought about the chemistry a little more than the original 60 seconds, and I was hasty. Without some interesting innovation it's not enough to get high energy reactions. If we're after rocket fuel (meaning energy + reaction mass all in one) we also need gaseous products to absorb the heat of reaction and expand, turning our heat energy into mechanical work (i.e., exploding and shoving our rocket forward).

Which means we have to have light elements. Unfortunately, light stuff is exactly what we expect the Moon to be short on, given the low gees and high temps. From orbit you can only look at the surface and there's obviously only hope in the permanent shadows near the poles, but FWIW Clementine suggests this hope is not groundless. Maybe the Moon is being pounded by microcomets, for all we know.

Posted by Carl Pham at November 19, 2004 01:02 AM

Of course, you can always use ion drive robot tugs to grab some regolith from a low delta-v accessible carbonaceous chondrite asteriod - lower velocity change than the moon, lower thrust requirements, and a wider selection of material ...

Not that the moon wouldn't be useful, but don't assume you'll need to go there for resource needs.

Posted by VR at November 19, 2004 02:17 AM

"I merely believe there are a couple of billion humans too many to implement effective libertarian policies here on Earth." -- Bill White.

Mars colonization as a path to libertarian paradise? Uh, as much as I favor libertarian ideas and space exploration/colonization, I have to disagree mightily.

Any real colony is most likely to exist at the edge of survival for a long time and resemble at best a benevolent dictatorship rather than a libertarian paradise. Just look at the early English attempts to colonize the New World for examples. Maybe eventually an off planet colony will develop to the point where life is easy enough to sustain liberty, but by then that colony is likely to be pretty crowded too.

If you want an uncrowded place to colonize to create your libertarian garden of eden, I think Antarctica is much more promising than Mars.

Posted by Brad at November 19, 2004 03:31 AM

Guys, there is a vast literature on lunar materials processing, and it doesn't involve terrestrial-type processes (primarily because of the lack of water, though that's become less of an issue in recent years with the potential Aitken Basin discoveries). Aluminum and oxygen and silicon (and titanium and other metals) can be extracted from the silicates of which much of the regolith is comprised, but it's done via processes like HF acid leaching and magma electrolysis.

But I wasn't even thinking about that. I was just talking about melting ice and cracking it to make cryogenic propellants (a process which is relatiively simply, though power intensive).

Brad, the problem with Antarctica is that it's already spoken for, as is every place on earth. The appeal of space to libertarians is its current lack of governance.

Posted by Rand Simberg at November 19, 2004 04:47 AM

I think NASA already proved the limitations of "aerobreaking" as a reentry mode on the last flight of Columbia.

Seriously, what the Moon is best for, vis-a-vis preparation for Mars expeditions, is as a place to prove out durable engineering approaches to the design of reasonably compact closed-cycle life support systems. As we are unlikely to hit that one out of the park on the first try, it's good to have the option of quickly and safely retreating to Earth if temporarily necessary during the "oopsy" phase of that learning curve.

Posted by Dick Eagleson at November 19, 2004 05:25 AM

While Rand is correct and the issues concerning the economics of lunar fuel is not fully settled, just remember that the benchmark price for H20 in LEO is $1000 per pound, or less.

If a lunar factory can mine water and ship it to LEO for less than $1000 per pound, well I say "Great!" and "Go for It!"

L1 is a bit more complicated.

In any event, using lunar fuel will not significantly lower the cost of going beyond the Earth/Moon system therefore practice at living in space becomes the real reason for Moon-first, correct?

Posted by Bill White at November 19, 2004 09:35 AM

Thinking further on the chemistry. I'm wondering, is the Earth as oxidized as it is because of our unusual biogeneric atmosphere, or just because there's a lot of oxygen in the Solar System and it's in the top layer if you're not a gas giant? I'm guessing the color of Mars says the latter. If that's so, then an alarming thought, vis-a-vis the Moon, is that a lot of our metallurgy seems to depend on reducing agents derived from organic sources. That is, we depend on the massive solar-powered reduction going on in plants. There's none of that up in the sky. So where do we get our reductants? Aside from comets, that is. The world is waiting for an artificial chloroplast, clearly. . .

Posted by Carl Pham at November 19, 2004 11:54 AM

Not a geologist, but there is a lot of oxygen around. Mars, possibly because of lower mass, had less differentiation and has a higher concentration of iron oxides in the crust (not that the earth's crust is exactly low on the stuff). There was also a substantial loss of hydrogen, and additional surface oxidation. Mars had plenty of water and heat at one time so had many of the same geological processes as earth.

The moon is different. The leading theory is that a roughly Mars sized planetismal struck the early Earth, and the moon formed from the ejecta. It is heavy on materials similar to earth crustal rock, and incredibly deficient in volatiles. It *MAY* have some water in a few craters, but that hasn't been established yet. It is also extremely low on carbon, nitrogen, and a number of other important elements.

Low delta-v asteroids would be much better sources for many materials, and actually could be easier to reach and process than the moon, and certainly mars. Not that I am against either of those as goals, but it would be dangerous to focus on just one thing.

Posted by VR at November 19, 2004 01:08 PM

Agreeing with VR.

I don't see a big hope for reducing agents. But you can edge around using reducing agents with electrolysis type techniques.

Posted by Al at November 19, 2004 02:55 PM

. . .you can edge around using reducing agents with electrolysis.

Well, sure, given that the electron is the primeval reductant! Heck, that's photosynthesis.

But I wonder whether we can rule out mineral reductants on the Moon? FWIW, it must have been formed when the Earth still had a reducing atmosphere and maybe most of the oxygen blew away as CO_2 before it could thoroughly oxidize the surface. Maybe there are veins of metal lightly oxidized or even native metals in the maria? Not likely, I agree, but possible?

Low delta-v asteroids would be much better sources. .

This I don't understand. If they are low dV relative to the Earth aren't they in orbits similar to the Earth's, hence pretty thoroughly baked out of light elements? I thought the sources of reducing CHON snow were all from deep space and came winging into the inner system at substantial velocities, making it costly to rendezvous with them. What am I missing?

Posted by Carl Pham at November 19, 2004 04:19 PM

This I don't understand. If they are low dV relative to the Earth aren't they in orbits similar to the Earth's, hence pretty thoroughly baked out of light elements?

In some cases the orbits may be out as far as Mars. The issue isn't distance or time (we wouldn't bother sending people) just low dV, and that may be by direct trajectory, but also by gravity assist, and aerobraking could also shave some off.

But it isn't THAT hot around these parts. The moon is especially low on some light elements because of its origin.

I thought the sources of reducing CHON snow were all from deep space and came winging into the inner system at substantial velocities, making it costly to rendezvous with them. What am I missing?

You're thinking comets. Carbonaceous asteroids make up the majority of the main belt. They are very rich in carbon, and have good amounts of hydrogen, nitrogen, etc. in compound and some in ice, BUT are not ice balls. Though not as rich as comets in volatiles, they are far better than the moon - unless special or protected sites are found with rich hidden sources.

Most the the NEAs (Near Earth Asteroids) are perturbed out of the main belt, although some are dead comet cores. This isn't a stable situation over geological time - they'll either run into a planet or be thrown into substantially different orbits. So, the NEAs we see may have been there for many millions of years, but probably not billions.

Posted by VR at November 19, 2004 05:36 PM

OK, thanks.

So you're talking a years-long robot mining mission, I take it? Counting all the self-directable and highly reliable hardware expense, not to mention the inflexibility of long years of planning and waiting, I would have to wonder if it would be at all competitive with just hoisting the stuff up the gravity well. The latter is expensive in fuel, yes, but more flexible in scheduling and requiring cheaper, less autonomous, less reliable hardware. No?

Is it possible these puppies as meteorites have left reduced carbon deposits on the Moon? That would do fine as a reducing agent.

Posted by Carl Pham at November 19, 2004 06:08 PM

Reply to Simberg:

Of course the fuel station idea is nuts, I only sought to quantify just HOW NUTS it is. Further, I dispute your contention that it's just a straw man insofar as there's been many a proponent of this new Lunacy I've seen argue that such a path is indeed viable.

Reply to Cowing:

"DUH how about throwing the fuel off of the Moon (tethers, electromagnetic launchers - whatever) to a point where your Mars ship can catch it - without landing on the Moon?"

Since each kilo of mining equipment and human support equipment landed on the Moon reflects about 9 kilos pushed to LEO, your prospecting system must find and recover at least NINE TIMES its own mass in viable fuel before there is any net gain to this notion. Perhaps this is yet another DUH for ya, if so, prove it!

Ah, oops, now perhaps you just don't know how much good stuff there really is up there do ya? So now absent proven reserves and a track record for how much added Lunar payload mass will accrue for repairs to the mining system and support payload for the miners, it's not at all clear that such an enterprise is a net gain in viable fuel mass at LEO for linkage into other missions. Of course it sure sounds like fun, but since when was that an engineering argument?

Perhaps if there was a really big Mars/Asteroid program ongoing, then folding in this new technology to meet an existing market would be rather sensible, some sort of risk/reward measure could be established. Let's just get started on Mars and the Asteroids as soon as possible and add all this Lunar tech when the need arises.

Posted by robert terry at November 19, 2004 09:19 PM

Dear Terry: spoken like a true Zubrinite. When in doubt, just wave your arms. As for the mining gear - you only have to land it ONCE .....

Posted by Keith Cowing at November 20, 2004 09:47 AM

A single Alcoa Aluminum refinery has an average output of 400,000 metric tons per year of Aluminum.

http://www.alcoa.com/australia/en/images/alcoa_australia/PUREaerialLarge.jpg

If I'm reading Alcoa's site right, this particular plant would produce 4.1 million metric tons of alumina per year. Note the size of the 'Bauxite Stockpiles' relative to the rest of the plant, and that steps 2 & 3 are probably going to get skipped. Half of the other steps are emission control or heat exchange oriented.

Getting to a 9:1 weight ratio of equipment:output seems the least of the worries - this plant's output comes to 123 billion tons thus far, and I don't expect the plant to outweigh a single year's output. Finding moondust can't be a serious problem. Finding a _better_ ore than straight moondust might, but that would reduce the amount of refining that is necessary -> using moondust as a 'worst case' ore for simplicity.

Posted by Al at November 20, 2004 04:46 PM

Carl: We have already been able to land on an asteroid with a spacecraft not designed for it. And we plan on doing sample return soon. We can do that now. Compare that to either a more complex robotic moon base or human base, AND the much greater transport issues.

The nice thing about the asteroid concept is that it can start very small, and the resources are so much richer in volatiles. You can just bring unprocessed material back to earth orbit.

About the moon: there is some hope that in a few dark craters there is icy rock - that would be incredibly dry by earth standards. This hasn't been confirmed, and it wouldn't be easy to process.

The moon could be a good source for aluminum and oxygen, and certainly we want a base there, but asteroids would be a very good source for a number of other elements.

Posted by VR at November 23, 2004 02:54 PM

The nice thing about the asteroid concept is that it can start very small, and the resources are so much richer in volatiles. You can just bring unprocessed material back to earth orbit.

Well. . .in the first place, I'm worried about that delta V. Every time I read about even dinky 200 kg spacecraft making rendezvous out there it takes years and often enough a few gravity assists. It almost seems to me that in space what's close in velocity is more important than what's close in distance, and these rocks, correct me if I'm wrong, don't seem close in velocity. So I envision years of travel time and complex planning, and I wonder if that more than compensates for the extra fuel you need to get off the Moon, or sift water ice out of a load of rubble and dust.

Secondly, I'm not sure I understand why you'd want to bring the stuff back to Earth orbit. I though the idea was you wanted it on the Moon, or in space. Why ship minerals to the Earth? Isn't that like coals to Newcastle? If it's fuels, well maybe, but I still have to wonder if the years required to shoot it back from Mars orbit is better than the extra fuel you need to boost it from Vandenberg.

Posted by Carl Pham at November 26, 2004 01:38 AM

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