January 5, 2011
Regolith, The “Other” Lunar Resource
The Pantheon of Rome, a 2000-year old concrete structure
In civil engineering, one of the most important material resources on Earth is “construction aggregate” – the sand, gravel and cement building materials that make up the infrastructure of modern industrial life. Aggregate is easily one of the biggest, most valuable economic resources of all mined terrestrial materials – more so than gold, diamonds, or platinum. We depend on aggregates for many different types of objects; they are the fundamental building block of roads and structures. The use of aggregates in building goes back to ancient civilizations; concrete was used in buildings of ancient Egypt. The Romans devised a recipe for a concrete so durable that the molded arches, walls and self-supporting dome of the Pantheon (made over 2000 years ago) stand today. Aggregates in terrestrial use typically depend on a lime-based cement that bonds the particulate material together. Both lime (CaO) and abundant water are needed to make concrete on Earth.
On this blog and elsewhere I have detailed the importance and significance of water at the poles of the Moon. Water is indeed the most important early product to produce from lunar materials but there are other resources on the Moon. A permanent presence on the Moon will require infrastructure that must by necessity use as much local material as possible. Aggregate materials probably will become the primary building blocks of industrial society off planet, just as it has on the Earth. The composition and conditions of local materials will require some adjustments as to how we use lunar aggregate. A little thought reveals some interesting parallels and differences with terrestrial use.
On Earth, gravel pits are carefully located to take advantage of the sorting and layering produced by natural fluvial (river water-eroded) activity. We harvest gravels from alluvial plains and old river beds, where running water has concentrated rocks, sand and silt into deposits that can be easily excavated, loaded, and transported to sites of construction. The highly variable currents, as well as the velocities of flow of our terrestrial streams and rivers, sort the aggregate by size, creating layers of gravel-sized up to cobble-sized stones for the fastest flowing waters. Finer grained material is likewise concentrated where water speeds are low and sand and silt settles out from the suspended sediment (the “bed load”).
No natural process on the Moon creates such deposits, but the lunar surface rock has already been disaggregated by impact into a chaotic upper surface layer called regolith. Regolith is basically ground-up bedrock; impacts of all sizes constantly pummel the surface, breaking, fracturing and grinding up the Moon’s bedrock. Impact both breaks up and creates rock. An impact will destroy a rock both by shock (catastrophic rupture) and through cratering (fragmentation and excavation). The effect of such destruction is to make “soil,” fine-grained rocky material made up of the mineral grains of the bedrock. But impact also creates heat and this heat can weld small fragments into glass-rich aggregate rocks (regolith breccias) as well as quickly cooled fragments of melt that contain mineral inclusions (agglutinates, or glass). In broad terms, impacts destroy and disaggregate more than they create and weld together. Thus, on a given surface, regolith thickness increases with time – older surfaces have thicker regoliths.
The ground up regolith is a readily available building material for construction on the lunar surface. It is an aggregate in the same sense as on Earth, but with some significant differences. We could make lime and water from the surface materials of the Moon but it is very time and energy intensive. Thus, we must adapt and modify terrestrial practice to take advantage of the unique nature of lunar materials. The fractal grain size in the regolith means that we can obtain any specific size fraction we want through mechanical sorting (raking and sieving). Instead of water-set lime-based cement, we can use glass to cement particulate material together. Regolith can be sintered into bricks and blocks, as well as roads and landing pads, using thermal energy (passive solar, concentrated by focusing mirrors) or microwaves that can melt grain edges into a hard, durable ceramic.
The use of aggregate materials on the Moon will likely be gradual and incremental. Our initial presence on the Moon will be supported almost entirely by materials and supplies brought from Earth. As we gain facility using lunar resources, we can incorporate more and more local materials into structures. Simple, unmodified bulk soil is an early useful product. It can be used to build berms to protect an outpost from the rocket blast of arriving or departing spacecraft and to cover surface assets for thermal and radiation protection. The next phase will be to pave roads and pads to keep down randomly thrown dust and provide good traction for the multitude of wheeled vehicles supporting the outpost. Fabrication of bricks from regolith will allow us to construct large buildings, initially consisting of open, unpressurized workspaces and garages but ultimately, habitats and laboratories. Making glass by melting regolith can produce building materials of extreme strength and durability; anhydrous glass made from lunar soil is stronger than alloy steel with a fraction of its mass.
Eventually, we may be able to export these lunar building materials into space. A major drawback is the gravity well of the Moon – its escape velocity is about 2.38 km/s, smaller than that of the Earth but substantial. To use large quantities of lunar materials for space construction, we need to develop an inexpensive means to get material off its surface. Fortunately, the small size and no atmosphere of the Moon make this possible by literally throwing stuff off the Moon into space. A “mass driver” can launch objects off the lunar surface by accelerating them along a rail track using electromagnetic coils that hurl capsulated material into space at specific velocities and directions. We can collect such thrown material at a convenient location, such as one of the libration points. From there, it is a relatively simple matter to send the material to wherever it is needed in cislunar space.
Water remains the most important first lunar product, but the “other” lunar material regolith is almost as important. Lunar rock and soil will be the paving stones of the Solar System. As once all roads led to Rome, all new roads in cislunar space lead to – and from – the Moon.
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Fascinating article. Was especially intrigued by the last sentence of the sixth paragraph: “Making glass by melting regolith can produce building materials of extreme strength and durability; anhydrous glass made from lunar soil is stronger than alloy steel with a fraction of its mass.” Table 1 on page 491 at the link gives a great breakdown of the material properties.
Comment by Alan Kruppa — January 5, 2011 @ 3:23 pm
Good article, but I think there is a step missing, namely sandbags (regolith bags). If you’ve ever seen boy scouts filling and stacking sandbags on levees, they are simple, fast, and effective structural components. They stack higher with less mass than piled regolith, and can be stacked over inflatable habitats to provide radiation shielding, thermal mass, and micrometeorite protection. Before we sinter or melt regolith, we can sandbag with very little mass transported from earth. It’s something that could be simply modeled on earth, although the plastic bag formulation would have to be tailored for lunar conditions. Building a sandbag covered inflatable dome on earth would be a great class project, and funding requirements would be minimal.
Comment by Charles Grimm — January 5, 2011 @ 5:00 pm
Charles,
Good points. We could easily stack bags of regolith to build simple structures like berms. Thanks for the comment.
Comment by Paul D. Spudis — January 5, 2011 @ 6:04 pm
How about “glassing over” an area with heat to form a load bearing surface, then digging under it and using the material dug out to cover this area to a depth adequate to shield humans from all radiation? A large focusing mirror operating for long periods could slowly move over the area while “moles” dig underneath and dump the material on top. I am curious how much depth would be required to completely shield humans from radiation. I would guess about 20 to 30 feet. What would emerge could possibly be visualized as 30 foot “igloos.”
Regards, Gary Church
Gary Church.
Comment by Gary Church — January 5, 2011 @ 6:45 pm
On second thought, if the moon’s surface is pretty much uniformly a thin layer of dust over rock, then the scheme I previously posted will not work. So just moving the regolith with a dozer down to the rock would be more workable as a first step. Since the radiation is coming straight down, what you want is 20 or 30 foot (guessing) of material over your head and doing this on solid rock is an interesting problem. Perhaps a suitable crater could be “roofed” with a quilt of pillars and plates of sintered material and then the regolith dumped on top to the required thickness. Are there alot of craters that would make this method workable?
Got to keep brainstorming!
Regards, Gary
Comment by GaryChurch — January 5, 2011 @ 7:05 pm
Since lunar dust could have long term deleterious effects on the respiratory health of permanent residents on the lunar surface, I think it should be a priority for any lunar base to be built on top of extensive areas that have been properly paved and sintered– including landing sites. This should be something that could be easily done by teleoperated robots from Earth long before humans return permanently to the lunar surface.
I’ve always liked the idea of using regolith to shield large inflatable structures. However, at the lunar poles, it might be easier to simply pump water(five meters of water in with) into an exterior shell of such inflatable structures: sort of a titanic dome shaped water bed covering a titanic dome shaped air bed. You could probably construct simple and elegant geodesic domes within the interior of such pressurized habitats for added structural support.
Comment by Marcel F. Williams — January 5, 2011 @ 10:14 pm
For covering smaller hard shelled habitats, I don’t see any reason why you can’t simply surround them with an easy to assemble regolith fence made of metal or cermics perhaps 5 meters in width from the habitat structure and simply fill it with lunar regolith. A second slightly smaller fence about 5 meters high could be assembled on top of the filled lower fence and filled with lunar regolith. That should protect human residents from even the most energetic cosmic rays– with no retinal flashes while they relax or sleep inside.
Comment by Marcel F. Williams — January 5, 2011 @ 10:37 pm
Marcel,
I agree with you that water is a superior substance for radiation shielding and ultimately, I believe it is the way to properly shield lunar habitats. However, it will be a scare resource early in lunar occupation, so I suspect that at least initially, we will want to use regolith first. Even after we begin to jacket the habs in water, an outermost layer of regolith would be useful to provide shielding from micrometeoroid hits and thermal insulation.
Comment by Paul D. Spudis — January 6, 2011 @ 7:58 am
[...] This post was mentioned on Twitter by sun raven and Robyn Villavecchia. Robyn Villavecchia said: Interesting new article by Paul Spudis on the importance of Lunar Regolith http://bit.ly/eqdEoQ [...]
Pingback by Tweets that mention Regolith, The “Other” Lunar Resource | The Once and Future Moon -- Topsy.com — January 6, 2011 @ 9:49 am
I have to wonder if the value of regolith on the Earth applies that well to the Moon. On the Earth regolith is useful as a building material where we stack and pour it to create structures that keep out the wind and the weather. That’s not as necessary on the Moon. The structural needs on the Moon are about keeping air in (which regolith bricks and cement doesn’t do) and ideally thermal control (which vacuum layers do a lot better than regolith layers).
As a shielding medium, though not as efficient as water, it is useful. Both for particles and rocket exhaust. I’ll buy that.
I recall early enthusiasm about the strength of anhydrous glass, but if that’s true, it makes one wonder why we don’t have buildings on the Earth reinforced with the stuff.
I’m just saying that terrestrial lessons don’t obviously apply that well with regard to regolith on the Moon.
Comment by Herman — January 6, 2011 @ 10:30 am
I recall early enthusiasm about the strength of anhydrous glass, but if that’s true, it makes one wonder why we don’t have buildings on the Earth reinforced with the stuff.
Because it’s harder and more expensive to make this on the Earth than it is to make steel and aluminum. The reverse is true on the Moon.
As for your other points, we need structures on the Moon for a variety of purposes besides human shelter — instrument emplacements, service structures, paving, landing pads and undoubtedly other needs yet unidentified.
Comment by Paul D. Spudis — January 6, 2011 @ 10:55 am
I am hoping lunar regolith products can help with delta V. Could lunar ceramics be used for ablation shields/thermal protection?
A propellent tanker’s delta V distance from EML1 to LEO is about 3.8 km/sec. Of that 3.8, 3.1 is a circularization burn at perigee, only .7 km/sec is needed to drop from EML1 to a low perigee.
If all or part of LEO circularization could be accomplished with perigee drag passes, that might increase the mass fraction that is propellent delivered to LEO.
Comment by Hop David — January 6, 2011 @ 12:04 pm
Could lunar ceramics be used for ablation shields/thermal protection?
Absolutely. Several early studies of lunar oxygen production used ceramic heat shields made from lunar regolith to deliver product to LEO via aerobraking.
Comment by Paul D. Spudis — January 6, 2011 @ 12:24 pm
“-the space program no longer gets 7% of the federal budget.”
Why not? DOD is getting all the money.
What about using the moon as an “interceptor” base against impact threats? Would launching an interceptor from the moon be that much easier than earth? Yes, if nuclear weapons and propulsion were being used. These payloads would be much safer to launch from the moon. Would the moon also be a good observatory base for detecting impacting threats? This would be a good way to reduce the international nuclear weapons inventory and also make it an international project.
Your plan might move full speed ahead with some DOD funding Dr. Spudis.
Comment by GaryChurch — January 6, 2011 @ 1:30 pm
I like the idea of textile walls about 3 meters thick suffed with regolith for surface structures, But going under ground, I see no reason to compromise on the building materials used on the moon. ISRU means processing the regolith to remove the oxygen and helium and then treating the slag to go after the iron, silicates for glass, titanium, calcium and even the platinum and chromium. It is in a nice fine powder and can be fed into a processing unit with a turnign screw at a nice steady rate. The melting points differ so they can be separated at the point of production.
We want 2 x 4 sized girders of iron and steel, and have to ge setting up to carve tunnels through rock.
I don’t actually like the idea of exporting hydrogen from ice on the moon. It is rare there. We need to recover it remove the salts and put it into biospheric recycling systems, not consume it. You can have all the LOX you want out of the regolith, which is heavily iron oxides and we will want the iron anyway. Hydrogen is light and can be lifted off of the Earth to be combined with lunar LOX in LEO if you want to refuel there or just have a substantial source of water in space.
Comment by John Wilkes — January 6, 2011 @ 3:49 pm
Why not? DOD is getting all the money.
Hardly. Most federal spending is on the various entitlement programs; discretionary spending (of which the DoD budget is but a fraction) is less than 1/3 of total federal expenditures. The rest goes to interest on the national debt and various entitlement payments to people.
Moreover, the DoD has a constitutionally defined mission; the space program doesn’t. I believe the program contributes significantly to national needs, but the DoD has its own concerns. Ultimately, it will include the Moon and cislunar space, but that day is in the future. In the meantime, NASA can contribute by pushing the envelope by creating a permanent cislunar presence and infrastructure.
Comment by Paul D. Spudis — January 6, 2011 @ 6:06 pm
I don’t actually like the idea of exporting hydrogen from ice on the moon. It is rare there.
There is plenty of hydrogen for a lot of different uses; it is not as rare as we used to think. The Moon contains enough water to bootstrap a significant space faring capability. Once we have that, we can transition to other space sources for light elements.
Comment by Paul D. Spudis — January 6, 2011 @ 6:08 pm
@ John Wilkes
“I don’t actually like the idea of exporting hydrogen from ice on the moon. It is rare there.”
There’s some reason to believe ice is abundant at the poles.
http://www.nasa.gov/mission_pages/Mini-RF/multimedia/feature_ice_like_deposits.html
Comment by Hop David — January 6, 2011 @ 6:43 pm
Once we have a reliable transportation infrastructure between the Earth and the Moon, I believe that transporting back-up military satellites to the lunar surface for immediate launch from the Moon in case our Earth orbiting satellites should suddenly become disabled during some sort of laser or EMP attack should be considered as a serious option by the pentagon. Such back-up satellites could be further secured in lunar facilities covered with regolith.
Comment by Marcel Williams — January 7, 2011 @ 3:37 am
@Spudis:
Question, how many sq ft of habitable construction does your plan call for?
Comment by Presley Cannady — January 8, 2011 @ 9:21 am
“ultimately, I believe it (water) is the way to properly shield lunar habitats.”
Why use water when the mass of lunar material is available? Water is the most practical shield in a spaceship but using it to soak up rads overhead on the moon does not make much sense to me. Living under a water tank is fine until the water- for whatever reason- is suddenly not in the tank anymore.
Comment by GaryChurch — January 8, 2011 @ 10:38 am
I would like to see Mark Prado of PERMANENT get some financial backing and make it all happen. Make this a private endeavor.
Either way, another great article Dr. Spudis.
Comment by Rhyshaelkan — January 8, 2011 @ 10:57 am
Why use water when the mass of lunar material is available?
When regolith is used as shielding, the interaction of high energy galactic cosmic rays (GCR) can induce secondary reactions in the regolith cover, producing a cascade of secondary radiation. Water is a better shielding material because it avoids this problem.
Comment by Paul D. Spudis — January 8, 2011 @ 3:09 pm
how many sq ft of habitable construction does your plan call for?
If by my “plan” you mean the Spudis and Lavoie architecture, the answer is none — we only describe the initial emplacement phase of a lunar outpost. Large scale construction would follow the period upon which we concentrate in our paper.
Comment by Paul D. Spudis — January 8, 2011 @ 3:11 pm
“-producing a cascade of secondary radiation. Water is a better shielding material because it avoids this problem.”
Secondary radiation is a problem only when the shield is not thick enough to soak up all or most of the secondary particles. There is secondary radiation from water also- it does not avoid the problem. It is better than denser material because the oxygen and hydrogen fragment into lighter particles and blocks better due to hydrogen content, and produces less secondary than heavier atoms/molecules but it still showers significantly to a depth of just under 5 meters according to Dr. Eugene Parker’s article in scientific american magazine. Even 5 meters of water does not completely stop heavy nuclei secondary radiation- it mitigates to lighter fragments and gives protection equivalent to the earth’s air column at 18,000 feet above sea level. This is why, in my humble opinion, a tunneling machine might be a better investment in regards to lunar base construction. I have never seen any figures quoted but I would guess 25 feet or more of regolith or moon rock would be required to give the equivalent protection of 5 meters of water. It might be more efficient to dig tunnels, perhaps going horizontal from a crater floor, than piling up regolith overhead. But with the lighter gravity I could be wrong.
In addition, if the reason for the base is water, why “lock up” a significant amount as shielding- requiring constant replenishment and monitoring?
Regards,
Gary Church
Comment by GaryChurch — January 8, 2011 @ 5:01 pm
On the Moon, I think that water shielding only makes sense for large inflatable habitats, biodomes 50 meters plus in diameter. But I would agree with Dr. Spudis that an additional layer of regolith above the water layer would probably be wise to deal with micrometeorites and with the extreme fluctuations in temperature on the lunar surface.
Comment by Marcel Williams — January 9, 2011 @ 3:21 am
if the reason for the base is water, why “lock up” a significant amount as shielding- requiring constant replenishment and monitoring?
Because it’s readily available, we’re making it anyway, and on a per unit mass basis, a superior shielding material.
Comment by Paul D. Spudis — January 9, 2011 @ 6:31 am
“As for your other points, we need structures on the Moon for a variety of purposes besides human shelter — instrument emplacements, service structures, paving, landing pads and undoubtedly other needs yet unidentified.”
Points noted. Glad you agree that regolith for habs is not that helpful. But instrument emplacements? Scientific instruments you mean? Service structures? I’m having trouble picturing how regolith moving or packaging will be helpful for these things. One would likely need to do grading and leveling, but that’s not really “using” the regolith as a construction aggregate.
Paving to reduce dust is a good idea, but it’s pretty energy intensive. Unless you have a nuke, it’s going to be a slow process, and the crust you make will be pretty thin. I’ve always wondered if just paving with rolls of mylar wouldn’t work better, at least in the near term. Very strong, very lightweight. Could probably walk and drive on it without damage if you lay it down on graded, compressed regolith and have properly designed vehicles.
For landing pads, yes, building regolith bunkers for blast shielding would be a smart thing to do.
Good article, that gets one thinking!
Comment by Herman — January 9, 2011 @ 10:24 am
@Presley,
To follow Paul with a little more info, we initially land a 12mT (metric Ton) habitat which acts as a temporary living quarters much like a trailer is at a construction site. We would think that the next phases of such a plan would include the intent to build gradually larger structures either out of regolith or assisted regolith or by using the regolith as feedstock for building materials. Naturally, not all material will come from the Moon, as the pressure vessel integrity will need some sort of flexible seal, and we will need airlocks, avionics, cabling, environmental control, etc. Frankly, we don’t know how far we can lean forward yet, but someone should obviously pave the way with informed ideas for those that come afterwards. Recognize that this realm of thinking is new to space, even though a parallel existed in the settlers and explorers of yesterday. All space missions thus far have brought everything with them; we endeavor to return to the days of living off the land, although the question is, how hard (or how easy) is this going to be in the space environment….
Comment by Tony Lavoie — January 9, 2011 @ 4:27 pm
Doing some research for PERMANENT I ran across this paper.
Another paper talks about a self-contained ‘bot for making PV cells from regolith.
http://www.niac.usra.edu/files/studies/final_report/433Ignatiev.pdf
With the power we could get from >70% peaks of light. We could power some refining kettles to use regolith for multitudinous items laid out in this paper.
http://gltrs.grc.nasa.gov/reports/2005/TM-2005-214014.pdf
The paper starts with using regolith to manufacture PV cells. Then it continues with the by-products that would come from the refining process.
With the raw materials and a few tools, such as a milling maching, or a milling lathe combination, etc we could boostrap industry on Luna. To the point that we no longer launch satellites and exploration probes from Earth. OTV(spaceships) could also be fabricated on Luna and assembled at L1.
The sky is the limit. Only takes a few well placed billion dollars or so to make it happen. You gotta cut out the bureaucracy though
One or five men calling the shots, and that is it. Otherwise things get too bogged down personal agendas. Just one or two personal agendas 
someone nice, far thinking, and wants to change things for for humankind, like me BWAHAHAHA.
Comment by Rhyshaelkan — January 10, 2011 @ 9:32 am
Getting back to using regolith for ablation and thermal protection. So as to save delta V via aerobraking for lunar propellent tankers.
I”ve seen two extreme examples of aerobraking:
The shuttle sheds 8 km/sec in an hour’s time.
Mars Global Surveyor as well as Mars Reconnaissance Orbiter used many perigee drag passes to shed delta V gradually over months of time.
The first extreme suffers high temperatures. The second extreme suffers long trip times. Either extreme increases boil off of cryogenic propellent.
Yet the possibility of aerobraking off 3.1 km/sec would almost double the amount of propellent a tanker could deliver to LEO on a given trip.
For exporting propellent, I’ve thought of exporting lunar hydrogen as well as oxygen to EML1 and EML2. No aerobraking is used to reach these locations. And they’re much more benign thermal environments for cryogenic propellent depots.
But when it comes to export to LEO, export just lunar oxygen. Oxygen is much less vulnerable to boil off caused by LEO’s warmer environment. Also less vulnerable to the increased time and/or temperature due to aerobraking.
For hydrogen and as well hydrocarbon fuels, oxidizer is the lion’s share of propellent mass.
If the moon could provide 8/9 of the propellent mass to LEO propellent depots, that would still be a major game changer
Comment by Hop David — January 10, 2011 @ 11:49 am
At 21 Tesla, the strongest superconducting magnets are 420,000 times the strength of the Earth’s magnetic field. How much could a magnetic shield reduce radiation doses?
Hop, The PICA-X did quite well keeping the Dragon interior nice. Why should we expect much boiloff during aerocapture?
Why not just transport lunar ice in the form of water? Why not keep the lunar ice at LEO in water for until you need to start breaking it to LOX/H2 in preparation for use? Shaded, the water should be able to be kept well below the boiling point.
Comment by JohnHunt — January 11, 2011 @ 9:25 pm
Does anyone know? What % of rads on the Moon is due to the sun versus cosmic rays. How long can an astronaut live on the Moon (half shielded by the Moon itself) before he/she reaches the max exposure allowed astronauts?
Although setting up shielding shouldn’t be that difficult, it might be that a combination of measures could allow an astronaut to stay on the Moon for months before needing to return.
– setting up a hab in a crater,
– sleeping in a trough in the bottom of the hab,
– working & traveling in a portable magnetic field,
– limiting science excursions,
– taking certain meds,
Also, it seems to me that statistically, older astronauts can afford to bear more radiation because they have fewer years left to develop cancer.
Comment by JohnHunt — January 11, 2011 @ 9:49 pm
Beginning in the late 1980s, the American Society of Civil Engineers (ASCE) has held a series of space exploration conferences every other year. There are several good technical papers describing things like anhydrous lunar concrete, sulfur-based lunar concrete, microwave sintering of lunar regolith, sandbagging, etc. Of course, the problem is there is not much of a program at NASA to fund research to turn these concepts into production capabilities. The Exploration Technology Development and Demonstration (ETDD) program at NASA places these types of technologies at a very low priority. Robotic missions to demonstrate these types of technologies would be good candidates for public-private partnerships, much like NASA is doing with the commercial cargo and crew delivery to low earth orbit with the Commercial Orbital Transportation Services (COTS) program. What NASA needs is a Lunar COTS program to work with the traditional construction companies.
Comment by JohnG — January 12, 2011 @ 3:36 pm
JohnG,
I heartily agree. In the early stages of VSE planning, Bechtel (one of the largest construction/engineering companies in the world) was working with us and NASA to develop strategies for surface operations and facilities. I think that one of the reasons that lunar surface resource utilization and construction from local materials gets little traction at NASA is because they typically rely and have traditionally relied on aerospace contractors, who deliver a piece of precision hardware (made from Earth materials) for some (astronomical) price. The idea of using what we find in space to create something — especially something as low-tech as a sintered-glass lunar regolith brick — is completely alien to their mindset and operational paradigm. It seems like voodoo rather than engineering.
Comment by Paul D. Spudis — January 12, 2011 @ 5:54 pm
John Hunt: “Hop, The PICA-X did quite well keeping the Dragon interior nice. Why should we expect much boiloff during aerocapture?”
Perhaps Dragon can keep humans comfortable. But room temperature is a lot warmer than what liquid hydrogen depots need.
John Hunt: “Why not just transport lunar ice in the form of water? Why not keep the lunar ice at LEO in water for until you need to start breaking it to LOX/H2 in preparation for use?”
Cracking water into hydrogen and oxygen takes a lot of kilowatt hours. See
http://forum.nasaspaceflight.com/index.php?topic=20490.0
Given reasonably sized orbital solar arrays, propellent production would be extremely sloooow. And slow production worsens hydrogen boil off losses.
Comment by Hop David — January 12, 2011 @ 8:13 pm
“The idea of using what we find in space to create something — especially something as low-tech as a sintered-glass lunar regolith brick — is completely alien to their mindset and operational paradigm. It seems like voodoo rather than engineering.”
How about a Bernal Sphere? A several kilometer sphere partially filled with water and spun to create artificial gravity on the inner surface at the equator. Lay that on them Doc and they will really look at you funny. But it is completely doable.
Comment by Greyroger — January 13, 2011 @ 3:18 pm
Can’t use just sandbags, turns out there are up to 30 moonquakes a day up there, they just didn’t notice till now.
Gonna have to use these. with the barbed wire construction techinique, may be enough.
http://calearth.org/shop/index.php?l=page_view&p=Unfilled-Superadobe-bag-rolls
A couple layers of Mylar will knock down the Bramstralung radiation enough to let the regolith work as better shielding, if you use it as the sandbag material, you get double bonus. Mix in water to cement it as you go during daylight and 3x bonus. Then glass over the whole shielding structure.
Am fan of building temp structure as inflatable, in a crater, with these sandbags, then starting to tunnel in from there. Can just take a Bigelow for the first one if you take a ladder with you. Gonna be tough to make a bulldozer tho.
Glass will be nice to keep that dust down!!
We need the 1/6 grav to keep our Asteroid miners in good health, and gonna be to expensive in Dv to take ‘em all the way down to earth. We are working on the details at the NEAmines group on yahoo groups, at least the mining portion. Got some of the Mars guys over there too.
You build the mass launcher along the equator, along with the solar panel belt. If you have a superconducting cable running along with it, it works as battery storage also, and picks up inductor energy between the front and backside voltage discrepancies too. bonus !
Look further into AlOxy rockets.
You can actually take a 3-D (LVDP) printer up there, and print directly with the regolith fines. Can print out everything you need except wire, nav computer, and attitude rocket nozzles on-site. AlOxy has enough ISP to lift regolith to orbit for 3-D printing at L4 or LEO, and still make a round trip back, if you make a lunar orbit depot, and reload up there.
(there is enough isp to take a load up, and then soft land back on Luna. will take 3 trips to stock a duplicate version with enough propellent to make a round trip with a full load, without even aerobraking)
You actually print out the rocket bodies with hollows in them (think voids shaped like scuba tanks) coat the insides with glass, and pack ‘em with regolith. there is enough atomic oxy in the regolith to actually burn if it is premixed. No hydrogen needed.Be nice to have adjustable bell, but not required.
Then just strap on your att jets, plug ‘em into an iPhone Nav system,(there is an app for that), and away you go.
In the same deal you get lunar to LEO tug/shuttle if you add optical star nav sys.
Comment by Morgan Knapp — February 23, 2011 @ 6:57 pm
[...] 6. The Moon offers other material and energy resources needed to create new space faring capability, including regolith aggregate, glass and ceramics, metals and solar cell fabrication. We can make composite and ceramic materials from lunar soil by sintering the regolith into parts and structures. Metals can be extracted from lunar rocks and used for construction on the Moon and in space. Engineers have created a roving vehicle that uses lunar soil to make in-place solar cells for the generation of electricity. This ability allows us to create vast photovoltaic arrays for the generation of gigawatts of electrical power. These resources, in addition to the water used for propellant production, are all present and available on the Moon. [...]
Pingback by A Rationale for Cislunar Space | The Once and Future Moon — April 11, 2011 @ 4:11 am
A 15 metre thick layer of ice would give to a dome that’s heavy enough to lid an atmosphere with a pressure of over 20kPa.
Comment by Andrew W — May 2, 2011 @ 3:16 am
[...] massive, which currently have those killer transportation costs when delivered from Earth. Bulk regolith has many different uses, such as shielding (e.g., rocket exhaust blast berms) as well as raw material for simple surface [...]
Pingback by Replicators Have Arrived | The Once and Future Moon — October 24, 2011 @ 1:30 pm
[...] is a good source of material and energy useful in creating a wide variety of objects. I mentioned simple ceramics and aggregates, but additionally, a variety of metals (including iron, aluminum and titanium) are available on the [...]
Pingback by Replicators on the Moon « Xenophilia (True Strange Stuff) — October 25, 2011 @ 4:03 pm