AsterAnts is such a good idea. I've been thinking further about it. One of the advantages of HEO versus asteroids is proximity to Earth and the ability to use teleoperation (extensive commentary on this exists in threads on ssi_list from this summer). The AsterAnts idea can take advantage of the benefits of HEO by bringing small chunks of asteroidal material back to HEO.
The only problem is the detection of such small bodies. Currently, there are only a handful of known NEOs 15 meters in diameter or less. The following NEOs have absolute magnitude ("H") 28 or higher: 1991 VG, 2000 LG6, 1991 TU, 1994 ES1, 1991 BA, 1993 KA2. See http://cfa-www.harvard.edu/iau/lists/Sizes.html for conversion of H to diameter.
Ron Menich
rmenich@...
09/17/01 05:10 PM
Please respond to spacesettlers
Thank you for reminding us about your wonderful AsterAnts idea. I saw something about AsterAnts summarized on space.com or spacedaily.com a while back, but had forgotten about it.
There are --- as of this afternoon (c.f., http://cfa-www.harvard.edu/iau/lists/Unusual.html) --- 1485 known NEOs. I suspect that the popularity of the AsterAnts idea will grow as the numbers of known NEOs grows. Finding an example of such a small 1/2 to 1-meter diameter NEO in a useful orbit would help to popularize the AsterAnts idea.
I'm really enthralled by the idea. "Mining" in the AsterAnts scenario could take place in a totally enclosed environment, say a bag, enveloping the NEO.
Ron Menich
Al Globus
09/17/01 12:36 PM
Please respond to spacesettlers
I would like to re-introduce a completely different approach to asteroid
mining to this group. See
http://www.nas.nasa.gov/~globus/papers/AsterAnts/paper.html. Basic idea:
find very small asteroids (~1 meter diameter) and return the whole thing
to Earth orbit. Use a large fleet of solar sail powered spacecraft to
get large amounts of returned mass. Using a large fleet gives you
economies of manufacturing scale and failure tolerance. Returning whole
asteroids avoids the uncertainties of rock mining.
...
Al Globus
CSC at NASA Ames Research Center
aglobus@... (650) 604-4404
http://www.nas.nasa.gov/~globus/home.html
The dinosaurs weren't spacefaring. We are. I don't think that's an
accident. Maybe we are life's taxi to the stars.
Dear Space Advocates, Capturing anAsterAnts 1 meter in diameter could be interesting scientifically and as a demonstration, but hardly economically significant. Solid material made of atoms (there are other kinds, in neutron stars, for examples) have densities that vary from 1 (meaning 1 kg/liter or 1 metric ton/cubic meter) for water ice to 7.9 for Iron and 22.5 for Iridium. So a 1 meter sphere of Iron would have a mass of about 4 tons. At 30 cents per pound on Earth's surface, you would have a whopping $ 24,000 worth of Iron. At $ 10,000 per pound for launching to low Earth orbit, if the robot sent after this AsterAnt weighs more that a pound, you will lose money. Even gold is only worth about $ 5,000 per pound (depending on the current market, thoughthere are other metals worthmore per gram), so there seems little hope of bringing back small quantities of minerals and making a profit. For large quantities, a 1 kilometer sphere ofiron would have a mass of about 4 billion tons, it would be different, but it is harder to move and land such objects. Maybe I havemissed some thing here? To follow up on my previous challenge to give presentations, and/or to find other ways to support our dreams, I would be glad to send electronic abstracts of presentations I give to anyone wanting to consider working up their own. I would also mail copies of the syllabus for my course, ISC 2074, The Colonization of Space, and one I have not taught in a few years, The Impact of Asteroids. I appreciate the efforts I know some of you are making, for example, to keep this channel of communication open. Sincerely, Jay Huebner at jhuebn@...
At 30 cents per pound on Earth's surface, you would have a whopping $ 24,000 worth of Iron. At $ 10,000 per pound for launching to low Earth orbit, if the robot sent after this AsterAnt weighs more that a pound, you will lose money. The cost of the metal retrieved to HEO should not be compared to the cost of metal here on the surface of the Earth. It should be compared to the Earth cost plus the cost of lifting equivalent material from Earth up to HEO. Even gold is only worth about $ 5,000 per pound (depending on the current market, thoughthere are other metals worthmore per gram), so there seems little hope of bringing back small quantities of minerals and making a profit. For large quantities, a 1 kilometer sphere ofiron would have a mass of about 4 billion tons, it would be different, but it is harder to move and land such objects. It may be an error to try and think of this in terms of returning space materials for use here on the surface of the Earth. Space materials may remain economical for space construction purposes only for a very long time.
Mike Combs
Mike Combs is right for use of materials in space, in that any material from a low cost extraterrestrial source in space could save $ 10,000 per pound (or more) over the cost of lifting it from Earth's surface, providing it can be made into the desired products (form) in space. But the "machine tools" needed to put raw asteroidal material into usable forms will likely have significant mass. So using extraterrestrial materialscould significantly lower the cost of construction and operations in space if the tools are there, which would suggest a large operation, not on a few tons. Lowering the cost of some operation does not make a profit. It can help if there are other "sales", but what are the quantities to be sold? Maybe this was not what Ron Menich(and the others) had in mind. Sincerely, Jay Huebner
Undoubtedly, the startup cost to
* Engineer an AsterAnts retrieval probe, launch it, and monitor it while it does its job
* Send tools etc to HEO to prepare for the arrival of asteroidal materials
* Process the asteroidal materials, and ship the finished products to point of use in GEO, HEO, or LEO
AsterAnts --- or for that matter, any other extraterrestrial resource utilization scheme, be it asteroidal or lunar --- will only begin to make economic sense if the mass of returned materials to HEO becomes high. Otherwise, the startup costs kill the economics. In order for the AsterAnts idea to be viable, hundreds or thousands of identical, mass-produced retrieval probes would have to be built, ensuring a steady stream of incoming mass to the processing facility. And AsterAnts would not be a viable if the retrieval probes lasted for one and only one retrieval mission --- each would have to be able to retrieve many meteroids during its expected lifetime.
Products that could be produced include:
* Propellants for LEO to HEO transport
* Bulk materials for solar power satellites, GEO antenna farms, space hotels, and other space structures
* Life support materials such as water, air, dirt.
There's a 20-to-1 or so advantage in terms of energy for using extraterrestrial materials in space versus using materials lifted from Earth. But whether or not the cost differential of these products on-orbit vis a vis lifting them from Earth can justify the startup costs of the processing operation is the great conundrum of the extraterrestrial resources community. You can't get the 20-to-1 energy advantage unless you build the infrastructure, but it costs a whole lot to build that infrastructure. If the infrastructure for doing so existed already, then there would already be dozens or hundreds of people visiting space hotels.
Ron Menich
"Huebner, Jay"
09/18/01 03:26 PM
Mike Combs is right for use of materials in space, in that any material from a low cost extraterrestrial source in space could save $ 10,000 per pound (or more) over the cost of lifting it from Earth's surface, providing it can be made into the desired products (form) in space. But the "machine tools" needed to put raw asteroidal material into usable forms will likely have significant mass. So using extraterrestrial materials could significantly lower the cost of construction and operations in space if the tools are there, which would suggest a large operation, not on a few tons. Lowering the cost of some operation does not make a profit. It can help if there are other "sales", but what are the quantities to be sold? Maybe this was not what Ron Menich (and the others) had in mind.
Sincerely, Jay Huebner
But the "machine tools" needed to put raw asteroidal material into usable forms will likely have significant mass. So using extraterrestrial materialscould significantly lower the cost of construction and operations in space if the tools are there, which would suggest a large operation, not on a few tons. Yes, it is an inevitability of this logic that use of space resources only makes sense above a certain scale of operations. I heard someone advocate useof lunar materials for construction of GEO communication satellites. As big a booster of use of lunar resources as I am, I still had to express the opinion that at this scale, such use would not be economical. If talking about giant GEO communication platforms a mile or so across with multiple antennas each around a city block in area, on the other hand... In debating this on Usenet, I've had some people say that the excessive costs of getting set up for refining and manufacturing in orbit are so huge that use of space materials is never going to cost less than lifting everything up from Earth. But I think this is going too far in the other direction. At some scale, there's a crossover point where lift cost savings pay for the space infrastructure needed. I expressed the idea thusly: Would use of space resources save you money on the first, prototype SPS? No. On the first half dozen? Perhaps not even then. On enough SPS to make a significant contribution to global energy needs? You bet. Would space resources save you money on building Alpha? Nonsense. On half a dozen space stations? No. On a Stanford Torus? Yes. But strangely enough, there was one guy who insisted it would be cheaper to build a Stanford Torus from Earth-launched materials than to set up the industrial infrastructure needed to build it from space resources.
Mike Combs
> So using extraterrestrial
> materials could significantly lower the cost of construction and
> operations in space if the tools are there, which would suggest a large
> operation, not on a few tons.
that you put say, 1 tonne in and get 2 tonnes back. Rework the
2 tonnes back into new AsterAnts at an orbital factory and do it
again and again.
The materials you have available increase exponentially. The tools
you make on orbit. Any decent workshop is capable of making their
own tools if they REALLY have to.
> Lowering the cost of some operation does
> not make a profit. It can help if there are other "sales", but what are
> the quantities to be sold?
You sell a percentage of the mass you collect and you reinvest the
rest into making more AsterAnts? If you collect some precious
metals you can reenter it and sell it.
>
> But the "machine tools" needed to put raw asteroidal material into
> usable forms will likely have significant mass. So using
> extraterrestrial materials could significantly lower the cost of
> construction and operations in space if the tools are there, which
> would suggest a large operation, not on a few tons.
>
> Yes, it is an inevitability of this logic that use of space resources
> only makes sense above a certain scale of operations.
Many asteroids contain metals that can be separated by heating
alone. If you can capture an asteroid using small reusable
radio controlled ion drive probes it is a lot cheaper to get mass
that way than launching from earth.
I mean the ISS cost how many billion? How many DS1 class spacecraft
would you need to get a hundred tonnes? Not many; and most of
the cost of DS1 was the design.
I don't see that. This can make sense in the very small scale too.
Many asteroids contain metals that can be separated by heating
alone. I would dearly love for this to be right, as I'm pulling for use of space resources as soon as possible. But I remember discussing this topic with one fellow on Usenet who said that a mistake many space resource advocates make is the assumption that getting pure metals out of space ores is as simple as shining some concentrated sunlight on them. Ipromised him I would try to never make that mistake. It's certainly true that the ore reduction methods proposed in the original Summer Studies were quite complex, and involved a fair amount of chemical reagents. I happen to agree that those reagents can be reused, but I think ore reduction will always remain a complicated, multi-step operation, requiring significant infrastructure of considerable mass. If you can capture an asteroid using small reusable
radio controlled ion drive probes it is a lot cheaper to get mass
that way than launching from earth. Absolutely. And if using the mass for radiation shielding, say, that would just about be your only expense. But tomake any product more complicated than that will require industrial infrastructure in space, and the expense of its emplacement must be factored into your costs. Now don't get me wrong, I'mstrongly convinced that above a certain scale this is definitely the most economical way to go. But I think one can imagine a sufficiently small scale where the costs of boosting the necessary infrastructure still outweigh the liftcost savings of space resource use. And I should clarify something. I earlier said that the first prototype SPS, or perhaps even the first half dozen, wouldn't justify use of space resources. I'm still of theopinion thateven the first SPS should bebuilt from spacematerials. Reason being that I don't think we should even consider buildingone or a half dozen SPS and then stopping. We shouldn't consider anything less than solving our global energy and greenhouse problems with SPS. And High Frontier is the most economical way to do that. But if it came down to aEarth-launched prototype SPS, or no SPS at all becausespace resource use is "too risky", I'd vote for the SPS, and hope that once in an era of at least one functional SPS, we could get to High Frontier soon afterward. I mean the ISS cost how many billion? How many DS1 class spacecraft
would you need to get a hundred tonnes? Not many; and most of
the cost of DS1 was the design. Yes,but could we build something comparable to ISS with the small amounts of machine tools being discussed here? Personally, I'll be turning hand-springs on the day we make radiation shields from raw space materials.
Mike Combs
Dear Folks,
It is silly to say that a good machine shop can make their own tools,
unless by tools you mean only those small pieces of metal that are used for
cutting surfaces on, for example, a lathe. If you mean lathes, chucks, etc.
this idea is wrong. Even drill bits. Why do shops order such items even
when they have slack time? How would one make such machines in outer
space?
Capturing small asteroids will never be cheep. Maybe if they are small,
only small space craft will be needed, but those craft will need a lot of
capabilities, engines (ion, sails, or other wise), to navigate (know where
they are) to communicate and respond, to attach them selves and to do these
things over the many years which will be required to get to a small asteroid
and more years to bring something back. It takes only a 2 or 3 days to go
to the Moon, but perhaps 8 months to Mars, and this is a discussion of going
a comparable or greater distance.
There is a company which is working in the real world to do some of these
tasks who's web site provides useful information, http://www.spacedev.com/.
One can buy stock and apply for employment, etc. there.
Sincerely, Jay Huebner
> Dear Folks,
> It is silly to say that a good machine shop can make their own tools,
> unless by tools you mean only those small pieces of metal that are used for
> cutting surfaces on, for example, a lathe. If you mean lathes, chucks, etc.
> this idea is wrong. Even drill bits. Why do shops order such items even
> when they have slack time? How would one make such machines in outer
> space?
there are economies of scale- you need quite a lot of energy to
melt metal and its cheaper in bulk. It's typical to only melt metal
once a week or so if you have the facilities and many shops don't
have the facilities. Solar ovens remove this scaling issue don't they?
Drill bits I'm not totally sure about, but I think they cast them,
and then sharpen using millstones. Clearly you need a less
malleable and more brittle metal for drill bits; the metallurgy is
important- carbon levels.
> Capturing small asteroids will never be cheep. Maybe if they are small,
> only small space craft will be needed, but those craft will need a lot of
> capabilities, engines (ion, sails, or other wise), to navigate (know where
> they are) to communicate and respond, to attach them selves and to do these
> things over the many years which will be required to get to a small asteroid
> and more years to bring something back.
Think about DS1, or NEAR. This isn't rocket science. Well, ok it IS
rocket science; but you're trying to make it sound super complex
when really it isn't. And they're really just remote controlled
bots they don't have to be AIs.
> It takes only a 2 or 3 days to go
> to the Moon, but perhaps 8 months to Mars, and this is a discussion of going
> a comparable or greater distance.
Yeah, but leaving the moon requires much more propellent. ION
drives only need tens of kilos of propellent, whereas the moon
needs more like equal propellent to the mass you are launching. And
the Russian Hall effect thruster ION drives can run on mostly
oxygen which is easy to separate from ore. I mean sure, if you've
got a mass driver on the moon, you're laughing, but that's a LOT of
work.
In response to "A lot of things are cast. Casting isn't particularly
difficult," etc. I say that, I have done casting and it is difficult and
requires significant gravity. There is a whimsical piece on bubbles in
carbonated beverages in space, called Suds in Space. You don't get a head!
See http://science.nasa.gov/headlines/y2001/ast21sep_1.htm?list73135 . The
same would happen in casting metal in micro-g. It would be full of bubbles,
if you could get the melt into the mold or not. But what about making a
lathe? Where do you get, for example, the copper wire for the motor? And
you are planning to make "bots?" These kind of arguments are usually made
by physicists and other scientists who do only theory and probably could not
make a respectable pencil sharpener, let alone an electric motor. I stand
by my statements; ideas explained at this level of detail are
indistinguishable from fantasy, and are probably not much more useful
(fantasy does have some use).
If you borrow money for a space enterprise (or compare alternative uses
for capital) you will have to calculate the interest in units of time, such
as, lets say 10 % per year. For a one week trip to the Moon and back (or
Earth-Moon L-5), that would be about 1/50th of a year per trip, or 0.2 %
worth of interest. One could make 50 trips per year. If you want to go to
the asteroid belt, that is more like 5 years for the first round trip. In
five years the Moon enterprise could have made ~250 trips, or with bots,
which would be easier to make on the Moon, grown by 250 generations. One
could do castings on the Moon. Which would you be more likely to invest in?
I know where I would put my money.
Sincerely, Jay Huebner
> In response to "A lot of things are cast. Casting isn't particularly
> difficult," etc. I say that, I have done casting and it is difficult
towards building a rocket. What did you find most difficult about it?
> and
> requires significant gravity.
'Centrifuge'
> There is a whimsical piece on bubbles in
> carbonated beverages in space, called Suds in Space. You don't get a head!
'Centrifuge'
> See http://science.nasa.gov/headlines/y2001/ast21sep_1.htm?list73135 . The
> same would happen in casting metal in micro-g. It would be full of bubbles,
> if you could get the melt into the mold or not.
'Centrifuge'
> But what about making a lathe?
'Centrifuge'. Oh wait that's the wrong answer!
Yes. I like the idea of making a lathe. Any idea how we could do it?
> Where do you get, for example, the copper wire for the motor?
Actually calcium can be made to work for that, provided you plate
it (otherwise it has a nasty habit of evaporating in a vacuum.)
Calcium isn't used much on the earth due to its other really nasty
habit of burning spontaneously on contact with air. ;-)
> And you are planning to make "bots?"
Yes.
> These kind of arguments are usually made
> by physicists and other scientists who do only theory and probably could not
> make a respectable pencil sharpener,
Yes, I have a degree in physics. No I have no idea how to make a
respectable pencil sharpener, although I have a pen knife so I
don't have to.
> let alone an electric motor.
Built one of those though. Wasn't very powerful, but then I wasn't
trying too hard.
> I stand
> by my statements; ideas explained at this level of detail are
> indistinguishable from fantasy, and are probably not much more useful
> (fantasy does have some use).
I think the idea would be you would make some of the easier bits
in space, and get the rest sent up in kit form. That way you
leverage your launched mass and use that to return more stuff.
You might cast/build the heavier parts of the ion drives for
example, tanks and fuel from asteroid material. All of the
electronics would be sent from earth. Using space resources may
give you a 10:1 cost advantage.
> If you borrow money for a space enterprise (or compare alternative uses
> for capital) you will have to calculate the interest in units of time, such
> as, lets say 10 % per year. For a one week trip to the Moon and back (or
> Earth-Moon L-5), that would be about 1/50th of a year per trip, or 0.2 %
> worth of interest. One could make 50 trips per year. If you want to go to
> the asteroid belt, that is more like 5 years for the first round trip. In
> five years the Moon enterprise could have made ~250 trips, or with bots,
> which would be easier to make on the Moon, grown by 250 generations. One
> could do castings on the Moon. Which would you be more likely to invest in?
> I know where I would put my money.
Yes, your thoughts here are good. Still, what you should do depends
on where you are at the time. If you are already in space for some
other reason, say tourism, the economics shift. The other problem
is that lunar expeditions are very expensive, so you have to borrow
a LOT of money.
AsterAnts are very cheap and have side advantages such as exploring.
And the moon seems more hostile overall- wild temperature swings,
no obvious power source for 1/2 the month, quite significant
gravity and the sharp, glassy dust problems Apollo found. Also the
moon is quite low on volatiles.
>
> A lot of things are cast. Casting isn't particularly difficult, but
and consistently to the material produced.
The crucible design and construction is critical.
Special materials must be used to assure that
the melt does not mix with the crucible and that purities are not
introduced,
and that the rate of cooling is uniform and just right.
The design of the crucible is different for each alloy that is cast.
>
> Drill bits I'm not totally sure about, but I think they cast them,
> and then sharpen using millstones. Clearly you need a less
> malleable and more brittle metal for drill bits; the metallurgy is
> important- carbon levels.
>
Every type of part you need has to have a different crucible.
Nuts, bolts, girders, beams, washers, rivets, fittings, casings,
pipes, hammers, wrenches, pliers, vices, grips, screws, nails,
sleeve bearings, ball bearings, hinges, rails, frames, doors,
panels, etc etc etc
Each of the types of parts come in a huge range opf size and shapes.
Each inidivudal part requires a special casting crucible and finishing
equipment.
An enormous investment any way you look at it.
Sign up in September to win one of 30 Hawaiian Vacations for 2!
>
>>A lot of things are cast. Casting isn't particularly difficult, but
>>
> Casting is a very skilled proecedure if you want any degree of quality
> and consistently to the material produced.
>
> The crucible design and construction is critical.
> Special materials must be used to assure that
> the melt does not mix with the crucible and that purities are not
> introduced,
> and that the rate of cooling is uniform and just right.
> The design of the crucible is different for each alloy that is cast.
its something that people certainly know how to do already.
>>Drill bits I'm not totally sure about, but I think they cast them,
>>and then sharpen using millstones. Clearly you need a less
>>malleable and more brittle metal for drill bits; the metallurgy is
>>important- carbon levels.
Actually drill bits are forged.
> Every type of part you need has to have a different crucible.
> Nuts, bolts, girders, beams, washers, rivets, fittings, casings,
> pipes, hammers, wrenches, pliers, vices, grips, screws, nails,
> sleeve bearings, ball bearings, hinges, rails, frames, doors,
> panels, etc etc etc
>
> Each of the types of parts come in a huge range opf size and shapes.
>
> Each inidivudal part requires a special casting crucible and finishing
> equipment.
Not really, well for bolts and screws yes. Girders are extruded, so
you need a range of dies, most of the rest can use an older
technology. Doors and frames are usually made from plates and such
like.
For a lot of these parts it used to be called a 'Blacksmith' didn't
it? And yes, it's a highly skilled profession.
> An enormous investment any way you look at it.
I wouldn't call a few crucibles an enormous investment.
>
> > An enormous investment any way you look at it.
>
> I wouldn't call a few crucibles an enormous investment.
>
It is a LOT of crucibles, not a few.
Take a look at the prices of crucibles, they are made of high grade
special alloys and
cast/machined to special profiles. One of them is expensive.
A lot of them is "an enormous investment".
In addition to crucibles, there are needs for precision dies,
workhardening equipment (forges, hammers, rollers)
and all the other things.
Not to mention the annealing equipment, and surface coating treatments,
e.g. case hardening. Electroplating, annealing, painting, etc etc.
There will be huge diversity of finished parts needed.
A typical spacecraft can contains hundreds of thousands of different
parts.
Each needs its own specialized manufacturing equipment.
We haven't even begun to discuss the equipemnt need for manufacturing
silicon wafers and semiconductors chips.
I repeat,
space manufacturing will require an enormous investment,
any way you look at it.
==
The vast majority of components,
espcially small lighhweight precision parts,
will "always" be most cheaply imported from Earth.
For example, it will be at least a century before manufacturing
chipsets in space will be viable. No problem, they
are quite small and ligthweight, we can import them from Earth fairly
cheaply.
The good candidates for space manufacturing are large simple heavy
items.
Things like pressure vessels and radiators.
The first complex things will will need in large quantities will be PV
cells, and
mechanical parts for Solar Dynamic generators. We need to give some
thought as
to how we would manufacture those items in space.
But for everything which on Earth today you can buy in a retail hardware
store,
for space we should most cheaply buy them in the same retail hardware
store and
shoot them into orbit.
I do not see that changing in the next century.
Cheers,
CR.
Sign up in September to win one of 30 Hawaiian Vacations for 2!
> In addition to crucibles, there are needs for precision dies,
> workhardening equipment (forges, hammers, rollers)
> and all the other things.
>
> Not to mention the annealing equipment, and surface coating treatments,
> e.g. case hardening. Electroplating, annealing, painting, etc etc.
>
> There will be huge diversity of finished parts needed.
> A typical spacecraft can contains hundreds of thousands of different
> parts.
>
> Each needs its own specialized manufacturing equipment.
components needed. The number of different parts used to
build something on Earth reflects the fact that manufacturing
here is considerably simpler than it would be off planet. For
initial construction of off planet infrastructure the most
important thing would have to be ease of manufacture, which will
translate into using suboptimal structures in many cases. Only
the stuff that's going to be moved around needs to be light, and
even then it may make sense to take a hit in the weight in order
to simplify manufacturing, making up the difference in additional
fuel.
New cost models will be needed for certain. It might well turn out that
the best course is to churn out large amounts of carbon fiber and
epoxy and use cfiber composites extensively, even where they wouldn't
be used on earth. A modest factory turning out carbon composite erector
set like components could cover a lot of the infrastructure needs.
There would still have to be specialized fabs making custom components,
but a relatively small number of standardized parts could cover the
majority of needs, providing some efficiency was sacrificed.
> We haven't even begun to discuss the equipemnt need for manufacturing
> silicon wafers and semiconductors chips.
Chips are an ideal candidate for launch from earth. Light, expensive,
hard to make.
> I repeat,
> space manufacturing will require an enormous investment,
> any way you look at it.
True. But it can be done smartly, reducing costs by orders of magnitude.
......Andrew
Andrew Case
acase@...
Institute for Plasma Research
University of Maryland, College Park |
I think that we are co-mingling two subjects in this thread.
How to move raw material from a useless place to a useful place. What to do with raw material at the useful place.
It maybe that nothing is done with the raw material. It is used simply as mass say on a teather. Or if there is sufficent manufacturing capability it can be fashioned into increaseingly complex components.
I tend to think that we should waste some time and money captureing lunar & asteroid material at an L point and then experimenting on manufacturing techniques. What we have now is multiple chicken and egg problems inside multiple shells. We need to discuss topics with some assumptions as givens otherwise the conversation slides through a rehash of all the dependancy problems.
I like the concept of asteroid capture and started a project on it at www.InnerTransit.org earlier this year.
Mitchell James
www.InnerTransit.org (Homebase for web based collaborative engineering)
www.InnerTransit.net (email for distributed organizations)
> I think that we are co-mingling two subjects in this thread.
>
> * How to move raw material from a useless place to a useful place.
> * What to do with raw material at the useful place.
> I tend to think that we should waste some time and money captureing
> lunar & asteroid material at an L point and then experimenting on
> manufacturing techniques. What we have now is multiple chicken and egg
> problems inside multiple shells. We need to discuss topics with some
> assumptions as givens otherwise the conversation slides through a rehash
> of all the dependancy problems.
I tend to agree. But if we actually want to do this I think we need
finance. To do that we need to either show somebody that it is so
cool that they would give us a couple hundred million [that would
have to be VERY cool!; actually to some extent NASA works that
way]. Or, we'd have to show how to make money.
Maybe we could argue it's a precious resource like gold, and hence
its a tangible asset you can buy and sell; only trouble is that its
value goes down over time as launch costs reduce.
So I think the question what do we use it for is really quite
important. What do others think?
> Undoubtedly, the startup cost to
> * Engineer an AsterAnts retrieval probe, launch it, and monitor it
while
> it does its job
> * Send tools etc to HEO to prepare for the arrival of asteroidal
materials
> * Process the asteroidal materials, and ship the finished products
to
> point of use in GEO, HEO, or LEO
>
> would be quite large. This very large cost would undoubtedly
swamp the
> benefit if we are only talking about the retrieval of one or a
handful of
> 1-meter asteroids.
you've returned the material and processed it, the startup costs are
gone. You don't have to rebuild the infrastructure for each asteroid.
If the probe is engineered well, it can turn around and get another
asteroid. Same with the processing station. If thought out well, the
processing station will have the ability to replicate itself and the
probe.
Recurring costs
#1. Ground crew (communications, control, tracking, sales and office
workers)
#2. Resupply launch (food, water, air, [cound be reduced by a more
closed loop life support system] and replacement equipment)
#3. Crew rotation (launch, return, training)
#4. Insurance
king_rodent (putting the eek in geek)
> A lot of things are cast. Casting isn't particularly difficult, but
> there are economies of scale- you need quite a lot of energy to
> melt metal and its cheaper in bulk. It's typical to only melt metal
> once a week or so if you have the facilities and many shops don't
> have the facilities. Solar ovens remove this scaling issue don't
they?
> Drill bits I'm not totally sure about, but I think they cast them,
> and then sharpen using millstones. Clearly you need a less
> malleable and more brittle metal for drill bits; the metallurgy is
> important- carbon levels.
Yes, carbon levels are important as well as how you quench the
original cast, but I don't want to go off on a metallurgy discussion.
Drill bits, lathe tools and milling tools are relatively light
compaired to the machinery necessary to make them. They can be sent
up on resupply missions. At a later time, when the station operations
are expanded, they could be made on orbit (is "on orbit" or "in
orbit" the correct phrase?).
>
> > It takes only a 2 or 3 days to go
> > to the Moon, but perhaps 8 months to Mars, and this is a
discussion of going
> > a comparable or greater distance.
Time is only a significant factor when you send people.
> Yeah, but leaving the moon requires much more propellent. ION
> drives only need tens of kilos of propellent, whereas the moon
> needs more like equal propellent to the mass you are launching. And
> the Russian Hall effect thruster ION drives can run on mostly
> oxygen which is easy to separate from ore.
>
Also, you require more propellant to LAND. An asteroid of the size
and mass we are discussing has no apreciatable gravity well. You
don't land on it, you dock with it.
Don't forget that if you're mining the moon, you have to send a lot
more equipment for the propellant manufacturing. You also have to
send people to maintain it, and supplies to maintain the people, and
all the propellant to land all of it AND launch it all from earth.
You're now talking about an order of magnitude larger operation.
king_rodent (putting the eek in geek)
>
> > > It takes only a 2 or 3 days to go
> > > to the Moon, but perhaps 8 months to Mars, and this is a
> discussion of going
> > > a comparable or greater distance.
>
> Time is only a significant factor when you send people.
>
We have discussed this before but you apparently were not paying
attention.
You also apparently have no real world experience in managing large
projects.
Time is money. Money is everything.
The bigger the project, the higher the cost of debt service, and the
more the time pressure.
This is illustrated by unmanned communications satellites today.
They use high thrust rockets
to get themselves on station as quickly as possible even though low
thrust ion drives would be more efficient.
They need to get the revenue stream started as quickly as possible, and
the cost saving of ion drives are outweighed many times over by the high
cost of debt service.
Time is money. Money is everything.
Sign up in September to win one of 30 Hawaiian Vacations for 2!
>
> > But what about making a lathe?
>
> 'Centrifuge'. Oh wait that's the wrong answer!
>
> Yes. I like the idea of making a lathe. Any idea how we could do it?
and to build that you need a lathe, and to build that you need a
foundry. This book shows how to build the foundry, and the books that
follow show how to build the lathe, milling machine, etc. I was about
to pursue builing a forge and bootstrapping up to a milling machine
but my current unemployment has prevented me from even purchasing the
books.
Charcoal Foundry (Build Your Own Metal Working Shop from Scrap Book 1)
by David J. Gingery
Paperback Vol 1 (June 1983)
David J Gingery; ISBN: 1878087002
http://www.amazon.com/exec/obidos/ASIN/1878087002/qid01299811/sr=1-
2/ref=sr_1_2_2/002-9746955-7116034
> > Where do you get, for example, the copper wire for the motor?
>
> Actually calcium can be made to work for that, provided you plate
> it (otherwise it has a nasty habit of evaporating in a vacuum.)
> Calcium isn't used much on the earth due to its other really nasty
> habit of burning spontaneously on contact with air. ;-)
There is a good chance that copper will be found in the asteroid.
Aluminum is another great conductor.
>
> > let alone an electric motor.
>
> Built one of those though. Wasn't very powerful, but then I wasn't
> trying too hard.
When bootstrapping, quality is not as big an issue, cost is. If you
can make an electric motor of comparable useability (emphasis on
useability, not quality) in orbit for significanly less than the cost
of launching a new one from Earth, you do it.
king_rodent (putting the eek in geek)
Please do not compare Lunar utilization scenarios with asteroidal utilization scenarios involving Main Belt asteroids. There are already 1491 known near-Earth asteroids --- a number growing by several hundred yearly --- and astronomers believe that there are 200,000 of them in excess of 100m in diameter. There may be 2 billion or more of the size applicable to AsterAnts. These NEOs can be reached more easily and in less time than Main Belt asteroids.
Ron Menich
"Huebner, Jay"
09/22/01 12:07 PM
In response to "A lot of things are cast. Casting isn't particularly
difficult," etc. I say that, I have done casting and it is difficult and
requires significant gravity. There is a whimsical piece on bubbles in
carbonated beverages in space, called Suds in Space. You don't get a head!
See http://science.nasa.gov/headlines/y2001/ast21sep_1.htm?list73135 . The
same would happen in casting metal in micro-g. It would be full of bubbles,
if you could get the melt into the mold or not. But what about making a
lathe? Where do you get, for example, the copper wire for the motor? And
you are planning to make "bots?" These kind of arguments are usually made
by physicists and other scientists who do only theory and probably could not
make a respectable pencil sharpener, let alone an electric motor. I stand
by my statements; ideas explained at this level of detail are
indistinguishable from fantasy, and are probably not much more useful
(fantasy does have some use).
If you borrow money for a space enterprise (or compare alternative uses
for capital) you will have to calculate the interest in units of time, such
as, lets say 10 % per year. For a one week trip to the Moon and back (or
Earth-Moon L-5), that would be about 1/50th of a year per trip, or 0.2 %
worth of interest. One could make 50 trips per year. If you want to go to
the asteroid belt, that is more like 5 years for the first round trip. In
five years the Moon enterprise could have made ~250 trips, or with bots,
which would be easier to make on the Moon, grown by 250 generations. One
could do castings on the Moon. Which would you be more likely to invest in?
I know where I would put my money.
Sincerely, Jay Huebner
In response to, "Think about DS1, or NEAR. ... you're trying to make it
sound super complex when really it isn't." Maybe so, but DS1 and NEAR did
not soft land, did not arrange to return anything even themselves, took
years to get to where they were going, and were on the verge of failing at
their final targets. And what was their cost? This makes my case rather
nicely, I think. Maybe not forever, but for the next decade at least. It
could well be cheaper to launch such and more ambitious missions in the
future from the Moon. Sincerely, Jay Huebner