Lunar ISRU alternatives

10kBq Jaro · Senior Member

Lunar ISRU alternatives

GoogleNaut · Guru

Jaro,

I'd have to agree that the logistics necessary for an electrolysis plant are formidable, and the machinery involved with liquification of the oxygen and hydrogen are also not trivial. The three major components necessary will be power generation/conversion; electrolysis; liquification. This will almost certainly require a nuclear plant to power anyway.

A more modest system could be done with a smaller nuclear power unit for the steam rocket:

Ice mining/water exrtraction; purification (possibly distillation to remove solutes like ammonia and mineral salts.)

I'm not sure what Isp you could get with superheated steam as reaction mass--obviously it's dependent upon temperature and pressure. Anything over 200 seconds should make the whole thing practical. An lunar orbital cryogenics fascility makes more sense, once water is delivered, but this is still not trivial. It requires a fair amount of infrastructure--and such equipment will be a long way from home....

10kBq Jaro · Senior Member

GoogleNaut wrote:

......purification (possibly distillation to remove solutes like ammonia and mineral salts.)

Actually, a bit of dissolved ammonia might be pretty good: a lower freezing point, requiring less heating to maintain the storage tank contents liquid, and a possibly a slight improvement in Isp, due to the lower molecular weight of NH3 (17) as compared to H2O (18).

To achieve good steam rocket performance, I think that the old Pluto ramjet reactor design could be adapted for the lunar lander shuttle application -- the BeO-UO2 fuel was conceived for resistance to oxidation in the earth's atmosphere at very high temperature, so it should do equally well in extremely hot water -- probably comparable to that of a LOX-LH2 chemical rocket, i.e. close to 300 sec Isp.....

10kBq Jaro · Senior Member

Incidentally, here's an old photo (scanned from a photocopy) of the Pluto ramjet reactor being assembled from a myriad of little BeO-UO2 fuel pellets.....

....if anyone knows of some better quality photos posted somewhere on the web, please let us know !

GoogleNaut · Guru

Hmmm. True about the molecular weight and antifreeze issues--I hadn't thought that far ahead. My leaning was essentially in the direction of corrosion reduction. Although if good lunar insitu production of materials were to include production of titanium from lunar illmenite, then perhaps extremely corrosion resistant tanks could be fabricated on the spot. A lunar propellant tank farm makes a lot of sense.

A steam rocket seems workable. Afterall, LOX/LH2 burns to essentially water vapor and hydrogen gas in a rocket engine, so this is essentially just superheated (very superheated) steam. A reactor core running at 2000 K ought to achieve pretty good performance. Although for gasseous corrosion and erosion resistance, one might need to look at coating some of the BeO, UO2 parts with some kind of coating. Unless they could be sintered or partially fused, you might get problems with the flow of steam. Not sure about the dynamics of superheated steam and ammonia, but there could be a lot of thermal dissociation issues--so some pretty chemically active free radicals may be produced.

I think it is definately worth an experiment--you never know until you try.

In the past, studying a little Selenology (lunar geology) from some of the reports of the Apollo landings, if memory serves, I think Apollo XVI and Apollo XVII both detected elevated levels of thorium in the lunar soils. If thorium is present, then it seems to me that there is hope that one day a rather extensive fissile producing industry could grow on the moon. Of course this means a lot of infrastructure--but now is the time to think in that direction.

10kBq Jaro · Senior Member

I guess that settles it -- no lunar shuttle ISRU for quite a while.... Apollo 2 here we come.

http://news.yahoo.com/s/ap/20051104/ap_on_sc/nasa;_ylt=Am89Zi4JKm6FsfukbF0tLhkPLBIF;_ylu=X3oDMTA5aHJvMDdwBHNlYwN5bmNhdA--

NASA Names New Shuttle a Priority

By RANDOLPH E. SCHMID, AP Science Writer

Fri Nov 4, 5:31 PM ET

WASHINGTON - NASA's top priorities are a replacement for the space shuttle and completing the international space station, and some other programs are being cut or deferred to concentrate the agency's resources, NASA Administrator Michael D. Griffin said Thursday.

"NASA cannot afford to do everything on its plate today," he told the House Science Committee. Funding priorities required the agency to cancel several programs that "we either did not need or did not need right now," Griffin said.

For example, it seemed like putting the cart before the horse to continue life science studies about how people respond to being in space before the agency was sure it could put people back in space, he said.

In addition to life sciences, another affected program is nuclear systems technology, Griffin said.

That program is designed to provide power to an outpost planned for the surface of the moon. But that won't be needed until after 2018, so the work is currently being deferred, he said.

<SNIP>

GoogleNaut · Guru

It's sad to see ongoing budget strangulation with NASA--it has never been funded at the level of Project Apollo during the latter half of the 1960's. If NASA recieved the same level of commitment percentage wise of the total federal budget as it did in 1969, then NASA's budget would be nearly $40 billion per year (adjusted dollars.) You just can't be a world leader in space science and engineering on a shoestring budget. They do wonderful things with what they've got, but they could accomplish so much more with a full appropriation, and a Congressional commitment to continue funding.

Besides, the technologies developed in the course of the space program have always ended up being in the highest generated values of the economy. Computers, microelectronics, alloys, materials science, life sciences and the like--to name just a few. In my humble opinion, we need to invest a lot more in value-added technologies that can actually grow the economy--basic space technologies traditionally have been value added technolgies to the economy--but I digress...

NASA should not have to defer research--instead it should be accelerated. Otherwise Apollo 2 will be just as much of a dead end as Apollo 1. And we really can't afford anymore 50 year recesses!

Development of a heavy lift launcher from the robust components dervied from the Space Shuttle. Development of nuclear power systems for deep space propulsion and power is necessary for safe habitation of the moon through the night cycle which has never been done before, and for supporting human exploration and colonization efforts on Mars. Development and refinement of life sciences in preperation for life support system supporting long duration space missions. Development of compact medical diagnostics in support of crewed missions to Mars. And the development of in situ resource utilization--"Living off the Land"--is an absolutely essential technology suite necessary for long term colonization efforts. We must think in terms of decades, centuries and millenia, but NASA is forced to think in terms of budgets for the next year. It is time for long term budgetary commitments to be made and honored.

O.K., I'm done pounding the pulpit!

-- Edited by GoogleNaut at 17:40, 2005-11-05

10kBq Jaro · Senior Member

In connection with finding alternative funding sources, in order to address the problem of NASA's funding woes, I thought the following Space Review article was quite interesting :

http://www.thespacereview.com/article/479/1

Priming the pump for lunar PGM mining

by Bill White

Monday, October 24, 2005

Dennis Wingo’s bookMoonrush should be mandatory reading for space enthusiasts. Although his hypothesis concerning the presence of lunar platinum group metals (PGMs) remains unproven, his hypothesis is also eminently testable—all we need do is go look, something NASA presumably intends to do, eventually at least.

<SNIP>

If recoverable PGMs are located on the Moon, a robust terrestrial market currently exists to support the commercial exploitation of that resource.

<SNIP>

The significance of startup costs for business ventures in space is not new.

<SNIP>

Today..... most of these businesses still do not exist, even in nascent form, in large part because the startup costs for building the necessary space infrastructure are simply prohibitive.

<SNIP>

In Moonrush, Wingo asserts that lunar PGM mining could be self-supporting (i.e. profitable) but only after the up front costs are paid from another source.

<SNIP>

....in an era of growing budget deficits, perhaps we need more creative sources to help finance the infrastructure needed to begin finding and extracting lunar platinum.

<SNIP>

....it may be possible to enhance temporarily the market value of initial shipments of lunar metals by fusing intangible value to an otherwise tangible asset.

<SNIP>

Wouldn’t the first kilogram of lunar platinum ever mined by our species belong in the Smithsonian? Collectors and speculators will surely wish to share in the history and cachet associated with the first lunar materials returned to Earth for commercial purposes.

One mechanism to transform these intangibles into a commodity would be to create numismatic value. For example even a relatively common 1799 Silver Dollar is worth more than 100 times the bullion value of 27 grams (slightly less than one ounce) of silver. The 1964 JFK half dollar is another example. Close to four million proof coins were minted and current prices for these coins fall between two and two and a half times the current bullion price for silver. The very first coins minted from lunar metals should be worth far, far more that the raw commodity price for platinum. Today, China mints panda platinum coins that are worth between 150% and 200% of bullion value.

Suppose an organizing entity (private mint, US government, or foreign government) issued a coin pegged at a face value of perhaps $1,000 with the coin to be minted exclusively from lunar metals, including a fraction of an ounce of authentic lunar platinum. A second series of coins could be issued having a face value of $100 but be minted entirely from lunar nickel and iron, which leverages the unavoidable fact that asteroid ore found on the Moon and returned to Earth will necessarily include large amounts of nickel and iron as well as PGMs. These coins could be shrink wrapped with an embedded microdot to assure authenticity, preventing counterfeits or forgeries. This chip can also assign a serial number to each coin to help create or enhance artificial scarcity and perceived value.

In order to capture and commoditize the future numismatic value of the very first coins ever minted from lunar resources, subscriptions for these $1,000 platinum coins would be sold in advance at a price of five to ten times face value. Subscriptions for the $100 coins would also be sold in advance with an asking price between $500 and $1,000. Sell one million platinum coins at $5,000 each and ten million nickel-iron coins at $500 each and this raises $10 billion dollars from the general public to help bootstrap lunar platinum mining.

<SNIP>

However, as Michael Mealling has astutely noted in the context of a space-related charitable giving, there is a chicken and egg problem here.

<SNIP>

I guess the first part of the "chicken and egg problem" is the need for a high resolution global survey of the lunar surface to find concentrations of PGMs -- using neutron bombardment of the surface for spectroscopic analysis of the gamma rays emitted on absorption ("gamma spec").

There's probably reason for some optimism, since even here on earth, asteroid impacts like the Cretaceous-Tertiary dinosaur killer left a thin global geologic layer of PGM-enriched material. Presumably a lunar version could be much more localised due to lower impact velocity, and higher-concentration debris might remain exposed for easy spotting using the neutron-gamma spec method......

GoogleNaut · Guru

Interesting idea about selling lunar 'commemorative' coins--I'm not sure how much money this could raise. Certainly some, but I am a bit skeptical it could raise billions of dollars. Commemoratives typically don't sell that well (although, I admit I'd certainly want to buy one!)

Doing a little research on the subject I have found that asteroids, especially those of the LL class metal-rich iron-silicates, and solid nickel-irons typically contain 100 ppm (parts per million) of precious metals (gold, platinum, iridium, osmium, etc,) with some having abudances two and three times higher than this.

If we restrict ourselves to a typical 1 km diameter "spherical equivalent" nickel-iron asteroid with 100 ppm precious metal content, then assuming the average density of a nearly solid mass of nickel iron was about 6.9 t/m^3, then a typical such asteroid will mass:

M=(4/3)*pi*r^3*rho where pi=3.1415, r=500m, rho=6900 kg/m^3,

or about 3.613*10^12 kg or about 3.6 billion metric tons, of which (and here's the kicker!) 360,000 metric tons are precious metals!

How much precious metals is this? Well it's more than ten times the total quantity of gold and PGM's mined on Earth during humanity's entire history!

361,000 metric tons of precious metals is the equivalent of 11.6 billion troy ounces, or roughly enough to strike two, one troy-ounce coins for every man, woman and child on the planet! (I'll not be picky, I'll take two gold ones, although a gold and a platinum one would be very nice!) Another realization--this is only one, relatively small asteroid. There are literally thousands more, many of which contain even more than 100 ppm precious metals!

Even if this one asteroid were to be mined to depletion and all the extracted precious metals were brought to Earth over twenty years, this still amounts to nearly 18,500 metric tons per year. I suppose future space workers could even be paid in gold and platinum coins, minted in asteroid derived metals. These could be called something like "Astors" or "Sols" or something like that. I suspect that sending that much precious metals back to earth would seriously depress the precious metals market, but hey, think of all the wonderful uses that could be achieved with cheap gold and platinum. Fuel cell vehicles using platinum catalysts will be much more practical, and who could possibly live without a naturally non-stick skillet cast from pure gold (like Julia Childs!) That alone is worth mining asteroids!

Seriously, though, the idea of importing PGM's is practical if insitu resource utilization were achieved to its most logical conclusion: establishing enough seed infrastructure to propel the first missions to begin the major process of resource exploitation. Large nuclear powered craft, with masses in the thousands of tons, propelled by liquid oxygen (derived intitially from lunar regolith) heated and ionized in tuned VASIMIR engines, could make the round trips back and forth from Near Earth Orbit asteroids.
If sufficient carbonaceous materials can also be found on the same body, then perhaps more efficient hydrogen propellants can be used for a return trip.

The problem is one of seed mass: how much is needed will be dependent upon how clever we can be. I'm betting we can be very clever, but the required initial mass for a earth orbit transfer station, ship bourne processors, metal extraction and refining, and of course local fabrication--parts of the ship would actually be built on the spot. And this will require a large crew, substantial multi-axis CNC (computer numerical control) machine tools to fabricate anything not brought along, and a real pioneer spirit of improvisation and 'can-do-it'-ness.

A very good paper written by Shane D. Ross of CalTech is entitled "Near-Earth Asteroid Mining" available at: http://www.cds.caltech.edu/~shane/papers/ross-asteroid-mining-2001.pdf

It has some very good ideas of what materials are available on asteroids, and how hard it is to extract them.

-- Edited by GoogleNaut at 04:08, 2005-11-09